Hydrogeology of the USSR, chapter 4
Thermal waters as a complex mineral can be used: 1) for heat supply (heating and hot water supply), and in individual cases and obtaining electricity; 2) for medicinal purposes; 3) as a source of obtaining valuable chemical products; 4) for various technological needs (drying, washing, etc.). Not in all distribution areas, thermal waters can be used in all of the above areas. Most often they are used for medicinal purposes and in these cases should be considered as mineral. It was noted above that the demand for mineral waters is most often relatively small.
In cases where thermal waters are used as chemical raw materials, they are considered as industrial waters. In this section, we will mainly consider the possibility of using thermal waters in the first of the selected areas.
General information, distribution of thermal waters
Thermal waters include underground waters with a temperature of 20 ~ C and above.
This temperature boundary can serve as a dividing line between less mobile (viscous) cold waters and more mobile (less viscous) thermal waters.
For practical purposes, you can take the classification of groundwater on the basis of temperature, given in Table. 33.
Table 33
Classification of groundwater according to temperature
In the following presentation, we will use the given in Table. 33 classification. It should be noted that thermal waters (i.e., waters with a temperature of 20 to 100 ~ C) in the reservoir and at the exit to the earth's surface are in the liquid phase, while superheated waters (i.e., waters heated to temperatures above 100 ~ C) under the thermodynamic conditions of the formation, they are, as a rule, in the liquid phase, and when they are brought to the surface, they give steam-water mixtures and vapors. Isothermal surface at 20 ~ C depending on geothermal conditions upper parts the earth's crust lies at various depths - from 200 - 300 m in the south Soviet Union(for example, within the Scythian plate) up to 1200 - 1500 m in the area of permafrost development (for example, in the north of the Siberian platform).
Let us characterize the main patterns of distribution of thermal waters within the USSR. As a result of the last years organizations of the Ministry of Geology of the USSR and the Academy of Sciences of the USSR for hydrogeothermal research have established that thermal waters are common in geological and structural areas of two types - platform and folded.
Within the platform areas, formation-pore and formation-fissure thermal waters are developed, in folded areas - fissure-vein waters (only in intermountain depressions thermal waters acquire a formation-fracture or formation-pore character).
A brief description of the patterns of distribution of thermal waters is given in an enlarged plan, in relation mainly to the scheme of hydrogeological zoning given in Ch. I real work. The exception is the areas of the Scythian platform area (West Crimean, Azov-Kuban and East Ciscaucasian), which, according to the accepted zoning, are assigned to the Crimean-Caucasian folded area, but when characterizing thermal waters, they are considered as a separate platform area. In addition, when describing the East European platform area, a number of artesian basins adjacent to it are considered, belonging to the Timan-Ural hydrogeological folded area.
Thermal waters occupy the largest area within the West Siberian platform artesian region, where they are developed in three main aquifers of the Mesozoic: Apt-Cenomanian, Neocomian and Yurak; the first two are of practical interest. In the Aptian-Cenomanian complex, which is distributed over almost the entire area of the basin and occurs at a depth of 200 to 1300 m (with a thickness varying from 100 to 800 m, less often more), thermal waters are enclosed, having a temperature in reservoir conditions from 20 to 60 ~ C. When opened by wells, these waters give a self-discharge with a temperature at the mouth of 35 - 45 ~ C, rarely more; the pressure of water over a larger area of the basin exceeds the surface of the earth by 20 - 40 m. The mineralization and composition of the waters change in the direction from south to north (from areas of nutrition to areas of runoff): from nitrogen mainly: bicarbonate sodium with salinity up to 1, g / l in the south (Kol-pashevo, Kupino, Ipatovo, etc.) to methane chloride sodium with mineralization up to 10 - 15 g/l in the north (Tara, Vikulovo, Surgut, etc.). The flow rates of wells during self-flowing reach 5 - 15 l / s, rarely more.
According to the testing of oil exploration wells, wells for fresh, thermal, mineral and iodine waters, the water conductivity of the aquifers of the complex varies from 20 to 200 m2 / day, and its largest value is noted in the strip stretching from Kupino through Tara for Surgut, i.e. in the central part of the basin, where the complex has the greatest capacity.
The Neocomian aquifer complex is developed on almost the same area as the Aptsenomanian; it lies at depths from 300 to 1800 m, less often more, has a thickness of 200 to 1000 m. The complex contains thermal waters that have a temperature of 20 to 95 ~ C in reservoir conditions. land at 20 - 60 m. In a number of wells with prolonged self-flowing, the water temperature reaches 65 - 70 ~, rarely more (Kolpashevo, Omsk, Tobolsk, etc.).
In the Neocomian aquifer, as in the Aptian-Cenomanian, the mineralization of thermal water increases from south to north in the direction of the total flow of groundwater in the deep horizons of the basin: from 1–3 g/l in the south and east (Ipatovo, Kolpashevo, etc.) up to 15 - 25 g/l in the north (Omsk, Tobolsk, Tara, Surgut, etc.). The composition of the waters also changes from nitrogen bicarbonate sodium to methane chloride sodium. Oil and gas deposits and iodine waters are confined to this complex in the central parts of the basin. The reservoir properties of the Neocomian rocks are unstable due to the variability of the lithological composition and the thickness of the water-bearing rocks. Well flow rates during self-discharge vary from 5 to 10 l/s, rarely more. The water conductivity of rocks, according to the test of wells drilled during the exploration of oil fields, thermal, mineral and iodine waters, ranges from 20 to 60 m2 / day, in some cases rising to 80 - 100 m2 / day. Almost in the entire central part of the basin, the water-bearing complex has a water conductivity of 40 - 60 m2 / day, only in the Khanty-Mansiysk region, due to the predominance of clay varieties among the rocks of the complex, this indicator decreases to 10 - 20 m2 / day and more.
The Jura aquifer, lying on a folded basement, has a variable thickness - from 100 to 1000 m and more. The greatest depth of occurrence is noted in the central parts of the basin, where it often exceeds 2500 m. The temperature of the water in reservoir conditions reaches 100 - 150 ~ C in the more submerged northern parts of the basin, but when they are opened by wells, it rarely reaches 65 - 70~C (Omsk).
Almost throughout the development area, the Jurassic complex contains methane chloride sodium thermal waters, the mineralization of which varies from 5–10 g/l at the periphery to 50 g/l, rarely more in the center. The thermal waters of the complex, opened by wells, self-pour out at low flow rates, usually less than 5 l / s. In a number of areas, it is not possible to cause self-discharge due to poor reservoir properties of the rocks of the complex, which cause a weak water inflow to the wells.
On the territory of the Scythian platform area, uneven-aged aquifers with thermal water are developed. In its western Black Sea part, thermal waters are confined to Paleogene sandy-argillaceous deposits, carbonate and terrigenous rocks of the Cretaceous and Jurassic, and the Jurassic aquifer complex is distributed only in the south of Moldova (Predobrudzhinsky trough). Thermal waters occur at a depth of 300 - 500 to 3000 m (slightly deeper in the Predobruzhinsky trough). The Paleogene and Upper Cretaceous complexes contain brackish and salty thermal waters. The pressure of the waters does not always reach the surface of the earth. The water content of the rocks is insignificant and the wells self-pour out with flow rates from 1 - 3 l/s to fractions of a liter per second. The Lower Cretaceous and Jurassic aquifers contain mainly brine chloride sodium thermal waters. The pressure of water in some places does not reach the surface of the earth, and the flow rates of wells rarely exceed 1 l/s. Due to the poor filtration properties of the reservoirs, which affect the flow rates of wells, the temperature of the waters raised to the surface rarely exceeds 30 - 40 ~ C, although in reservoir conditions the temperature reaches 70 - 90 ~ C.
In the flat Crimea, thermal waters are contained in aquifers of the Miocene, Paleogene, Upper and Lower Cretaceous and Jurassic, developed only in the foothills. The Miocene complex contains weakly thermal brackish waters; during testing, well flow rates are usually small. The carbonate and terrigenous sediments of the Paleogene contain mainly saline chloride sodium waters. In the central parts of the Crimea, low-thermal water with debits up to 1 l/s usually self-flows from wells; on Tarkhankut, in the dislocation zone, the flow rate of wells in places rises to 15 l / s, and the water temperature reaches 60 ~ C or more (Glebovskaya area).
The Upper and Lower Cretaceous aquifers, composed of carbonate and terrigenous deposits up to 800 - 1000 m thick, are distributed throughout the entire area of the plain Crimea, being traced to the north of it. These deposits contain thermal waters from brackish in the south (Saki, Evpatoria) to brine in the north (Genichesk). When wells are opened, these waters self-spill, well flow rates during self-spill vary from 1 to 10 l / s, in places increasing to 20 l / s, and the temperature at the mouth varies from 30 - 40 ~ C (Saki, Evpatoria) to 60 - 70 ~ C (Tarkhankut, Genichesk). The water conductivity of mole rocks, determined from the data of sampling wells of the Saki-Evpatoriya water intake and oil exploration wells, reaches 30 m2/day in the Upper Cretaceous complex, and 40 m2/day in the Lower Cretaceous.
In the Jurassic water-bearing complex, weakly thermal (up to 40 ~ C) brackish waters are opened, with self-outflow of which the flow rate of wells varies from 2 to 10 l / s, less often more.
Within the eastern regions of the Scythian artesian region, basically the same aquifers with thermal water are distributed as in its western regions.
Neogene aquifers with thermal water (mainly Akchagyl-Apsheron, Chokrak-Karagan) are developed within the Azov-Kuban and East Ciscaucasian artesian basins. They are composed of sandy-clay and lesser degree carbonate rocks, have a significant thickness (up to 500 - 1000 m each) and contain thermal waters from fresh to salty, in the most submerged parts (3500 - 4000 m) to slightly brine (Karaman). The pressure of the waters exceeds the surface of the earth by 20 - 100 m, rarely more. The wells self-discharge with flow rates from 5 to 20 l/s, and the water temperature at the mouth reaches 50 - 70~C (Makhachkala), in some places it rises to 90 - 100~C (Kizlyar, Khankala). The Chokrak-Karagan aquifers within Dagestan and Checheno-Ingushetia are especially watery. Here, the water conductivity of the Chokrak and Karagan deposits reaches 150 - 200 m2 / day and more (Makhachkala, Izberbash, the Grozny region, etc.).
Paleogene water-bearing complexes (Khadum-Maikop and Paleo-Cene-Eocene) are developed everywhere and contain thermal waters from brackish (in the south) to weakly brine (central regions of Ciscaucasia), mainly methane chloride sodium. When the wells open, the waters self-spout with flow rates from 5 to 15 l / s, the temperature at the spout is up to 90 ~ C (Georgievsk, Black Market, etc.).
The Upper Cretaceous and Lower Cretaceous aquifers, which are opened at a depth of 1000–2000 m or more, contain saline and brine methane chloride sodium thermal waters over a larger development area; wells with self-flowing waters have flow rates in the range of 5 - 15 l / s, and the flow rates decrease in the direction from south to north. In the south, in a strip stretching along the foothills, thermal waters from fresh to brackish and salty are common. The water temperature at the mouth ranges from 50 - 80 ~ C in the southern regions at a depth of 1000 - 2500 m (Cherkessk, Nalchik) to 100 ~ C and somewhat more in the central regions at a depth of 2500 - 3.000 m (Pri- Kumsk, the village of Praskoveyskaya), the water conductivity of the collectors of the Cretaceous complexes rarely exceeds 100 m2 / day, usually much less (20 - 60 m2 / day).
In the terrigenous-carbonate salt-bearing deposits of the Jura there are brine (up to 160 g/l and more) methane chloride sodium thermal waters, which have excess pressures of up to 100-150 m and more in the south; in the northern Caspian, the pressure drops to ground level. The flow rates of wells during self-discharge in the same direction decrease from 15 to 1 l / s, the water temperature during self-discharge usually does not exceed 40 - 60 ~ C.
It should be noted that deposits from the Neogene to the Jurassic are oil and gas bearing in the Ciscaucasian region.
In the Turan platform artesian region, thermal waters are confined mainly to Mesozoic carbonate and terrigenous deposits, in the Upper Jurassic - to salt-bearing rocks.
In the Syrdarya artesian basin, in the northern part of the Chui basin, in the basins of the Kyzylkum uplift zone and the Bukhara-Karshi hydrogeological region, mainly fresh and brackish waters are developed, enclosed in the Albian-Cenomanian aquifer complex, occurring at a depth of 500 to 2000 m From the wells that open up these waters, water flows spontaneously with flow rates from 2 to 15 l / s, rarely more, with a water temperature at the mouth from 40 to 60 ~ C and somewhat higher. Approximately the same hydrogeothermal conditions are observed on the Mangyshlak peninsula, in areas adjacent from the north and south to the Karatau mountains.
In all these areas, the water conductivity of the reservoirs of the Cretaceous aquifer ranges from 20 to 100 m2 / day, in some places it is more, more often it changes within 30 - 60 m2 / day.
Salt and brine thermal waters are developed in the rest of the Turan region in the Cretaceous deposits with low discharges and the temperature at the outflow, rarely exceeding 50 - 60 ~ C.
The Jurassic aquifer contains thermal waters from brine to strong brines (up to 350 g/l and more). High mineralization of waters causes a rapid blockage of wellheads with falling salts from self-flowing waters.
The following general regularity is noted: in the western part of the Turan artesian region (west of the Aral Sea), Mesozoic aquifers contain mainly saline and brine thermal waters, with which gas and oil deposits are in contact; in the eastern part of the region, mainly fresh and brackish thermal waters are distributed, gas and oil deposits are absent.
In the systems of artesian basins of the East European and East Siberian hydrogeological platform regions, thermal waters are classified as brine (up to strong brines) and, as a rule, do not self-flow when opened. When pumping out, well flow rates are very low (up to 1 - 2 l / s) with significant drawdowns.
In the area of the East European platform artesian region, thermal waters are ubiquitous, with the exception of its western part, where, due to the small thickness of the sedimentary cover, thermal waters are not found.
On a large area of the artesian region, the main aquifer with thermal water is the Devonian, composed of terrigenous-carbonate saline strata. It contains waters with mineralization from 100 to 250 g/l and more, temperature at the depth of the reservoir up to 60 ~ C. Low-thermal brines are enclosed in the overlying carboniferous deposits. The Perm water-bearing complex, developed within the Pechora, Caspian, Dnieper-Donetsk depressions, Cis-Ural trough, contains brine thermal waters.
In the north of the Pechora system of basins, in the Baltic-Polish and Caspian artesian basins, thermal saline and brine waters are developed in the Mesozoic deposits (from the Triassic to the Cretaceous). In all these areas, due to poor filtration properties of water-bearing rocks, well flow rates during pumping do not exceed 1 - 2 l / s, usually they are less. As a result of this, the resulting brine water almost never has a temperature of more than 40 ~ C, although in some places it rises from depths (exceeding 2500 m. At greater depths, the water temperature in a number of areas reaches 75 - 85 ~ C (Naryan- Mar, depth 3500 m; Dobrogostov, Dolina, depth 2500 - 3000 m; Novouzenskaya exploration area, depth 2700 - 3000 m, etc.).
In the silt of the East Siberian platform artesian region, the bulk of the thermal waters are associated with salt-bearing Cambrian deposits. The waters are brine (mineralization up to 350 - 450 g / l), as a rule, when opening wells, they do not self-flow, and due to the poor filtration properties of the rocks, the well flow rates during pumping are insignificant (fractions of a liter per second), when lowering reaching tens of meters. At a depth of 2500 - 3000 im, the temperature in reservoir conditions reaches 50 - 75 ~ C. In the Jurassic and Cretaceous deposits of the eastern part of the Yakutsk artesian basin (the Vilyui syneclise and the Verkhoyansk trough adjacent to it), thermal waters penetrated by wells weakly self-flow, while well flow rates are 1 - 2 l/s. The mineralization of waters varies from 20 to 90 g/l. At the depth of the reservoir, the temperature reaches 75 - 85 ~ C (Ust-Vilyui wells, depth 2550 - 2850).
Let us now turn to the characterization of thermal waters distributed in hydrogeological folded regions of different ages. Among them, the Kamchatka and Kurilsk regions of modern volcanism, which are attributed to the area of Cenozoic (Kamchatka) folding, are distinguished by intense thermal activity.
In the Kamchatka hydrogeological region, the largest thermal springs and steam-water jets are concentrated within the East Kamchatka uplift, where all active volcanoes Kamchatka Peninsula. All thermal springs are associated with large fault zones that cut through the strata of volcanic-sedimentary rocks.
The water temperature of the largest springs varies from 60 to 100 ~ C, and their debits from 10 to 30 l / s (Para / Tsunsky, Kireunsky, Apapelsky, Malkinsky, Dvukhyurtochnye, etc.). The mineralization of water sources is often less than 1 g / l, the composition is from hydrocarbonate-sulphate to sodium chloride with a silica content of up to 80 - 100 mg / l. Steam-hydrotherms in natural outlets have a temperature of 100 ~ C and a little more (Pauzhetsky, Zhirovsky, Uzonsky, Semyachinsky, etc.), their composition is sodium chloride, mineralization is 3-5 g / l. When opening with wells, the temperature of steam-water mixtures increases to 150 - 200 ~ C (Pauzhetsky, Bol. Bannye).
On the Kuril Islands, steam hydrotherms are of the greatest practical importance, the outlets of which are associated with large fault zones (Hot Beach, etc.). These steam hydrotherms are similar in temperature, composition and mineralization to Kamchatka.
Large thermal springs are found in the Koryaksko-Kamchatsky uplift, where they are associated with large tectonic disturbances (Olyutorsky, Tymlatsky, Palansky, Pankratovsky, Rusakovsky springs). The temperature of the springs reaches 40 - 95~C, flow rates are 15 - 50 l/s, rarely more. In composition and mineralization, they are close to the sources of the East Kamchatka uplift.
Intermountain artesian basins (West and Central Kamchatka, Anadyr, Penzhinsky, etc.) are almost not studied in hydrogeothermal terms, and it is currently difficult to judge the thermal waters of these basins. According to a rare network of oil exploration wells, low-thermal waters can be found here.
Cenozoic folding refers to the folded structure of the Sakhalin hydrogeological region, where in intermountain artesian basins filled with Paleogene and Neogene terrigenous deposits, thermal waters are common, opened by deep oil exploration wells. The main aquifers with thermal water are Miocene and Pliocene complexes. The thickness of sandstone horizons in these complexes varies from tens of meters to 100 m or more.
In the largest Severo-Sakhalinsk and related Paronaisk artesian basins, hydrocarbonate and sodium chloride thermal waters with mineralization from 1 to 20 g/l, in some places more are developed. In wells with a depth of 2700 - 3300 m, the water temperature in reservoir conditions reaches 100 ~ C or more, and when it self-spills at the wellhead, it is 50 - 70 ~ C, while the flow rates of the wells are 3 - 5 l / s.
The water conductivity of rocks in individual complexes ranges from 20 to 60 m2/day, rarely more.
The Cenozoic (Alpine) hydrogeological folded area includes structures stretching along the southern borders of the country (from the Carpathians to the Pamirs): the Carpathian and Crimean-Caucasian, Kopetdag-Bolshebalkhan and Pamir hydrogeological folded areas.
In the Carpathian region, thermal waters are opened by wells in the Mukachevo and Solotovinsky intermountain basins, filled with Miocene terrigenous salt-bearing deposits. In this regard, saline and brine sodium chloride thermal waters predominate here, the flow rates of which rarely exceed 1 l / s during self-discharge, and the temperature is 35 ~ (Vyshkovo, Zaluzh, etc.). Thermal waters are not found in the meganticlinorium of the Carpathians.
In the Mountainous Crimea, there are also no thermal waters in practically significant amounts. From the Yalta well from a depth of 1300 m, which uncovered the shales of the Tauride Formation, brine chloride sodium water with a temperature of up to 27 ~ C self-outflowed, the well flow rate was 0.2 l / s.
Within the Greater Caucasus, thermal springs come out along tectonic faults and usually have a temperature of 20 to 50 ~ C, their flow rates do not exceed 1 - 2 l / s, and the mineralization of water most often does not exceed 1 g / l. According to the composition, the water of the springs is hydrocarbonate-sulfate sodium and only in some places sodium chloride with a mineralization of up to 5 g / l (Karmadon, Goryachiy Klyuch).
In the Lesser Caucasus, mainly carbonic waters are developed, with a temperature of 20 to 50 ~ C, only the springs of Jermuk and Isti-Su have a temperature of 65 - 70 ~ C. The composition of the water is mainly hydrocarbonate sodium. The flow rates of the sources are small, but when drilling out sections of their outlet, the total well flow rate reaches 15 l / s (Borjomi, Jermuk, Ankavan, etc.).
In the Adjara-Trialeti hydrogeological folded zone and in Talysh, there are nitrogen and nitrogen-methane chloride sodium (Massalinsky, Lankaran, Astara springs) and chloride-hydrocarbonate-sulphate sodium (Tbilisi springs) therms. Mineralization of waters from 1 to 20 g/l. When opened by wells, waters self-pour with flow rates from 5 to 30 l/s and more; the water temperature is 40 - 65 ~ C. The Nakhichevan and Ararat intermontane artesian basins gravitate towards the Lesser Caucasus, filled with Miocene saline, mainly clayey, deposits with thin sandy layers. Oil exploration wells up to 2500 - 3300 m deep reveal salty and brine thermal waters, the flow rates of which during self-flowing, as a rule, do not exceed 1 l / s.
In the intermontane East Black Sea (Rionsky) artesian basin, the main aquifer with thermal water is Neocomian, composed of carbonate rocks occurring at a depth of 1000 to 2500 m or more. Deep wells (2000 - 3200 m) drilled in the northern part. of the Rion basin, fresh sulfate-chloride (and bicarbonate) sodium high-thermal waters are brought to the surface of the earth with a temperature at the spout from 70 to 100 ~ C and flow rates from 10 to 50 l / s (Menji, Zugdidi), rarely up to 80 l / with (Okhurei). In the Megrelian zone of tectonic disturbances, wells 800 - 1000 m deep reveal waters with temperatures up to 80 ~ C, heads up to. 80 - 150 m above the surface of the earth, flow rates at self-spill up to 40 l / s (Tsaishi, Nakalakevi).
In the southwestern part of this basin, the mineralization of waters from the Lower Cretaceous complex increases to 3–20 g/l or more, the composition changes to sodium chloride, well flow rates do not exceed 15 l/s, and the water temperature at the outflow is 80 ~ C ( Cheladidi, Kvaloni). In the eastern part of the basin, the Lower Cretaceous aquifer occurs at a depth of 500 - 1500 m, and brackish waters with a temperature of up to 45 ~ C, flow rates of 3 - 7 l / s (Kvibisi, Kvemo-Simoneti, Argveti and etc.). The water conductivity of the rocks of the Lower Cretaceous aquifer complex ranges from 20 to 300 m2/day, sometimes more.
The rest of the aquifers (Jurassic, Upper Cretaceous, Paleogeon, Neogene) contain mineralized thermal waters (in the saline Jurassic up to brines); the reservoir properties of the rocks are much worse than those of the Lower Cretaceous complex, therefore, the flow rates of wells during self-flow usually do not exceed 3–5 l/s.
In the Kuri intermontane artesian basin, which is also part of the Caucasus region, thermal waters at accessible depths are enclosed in Tertiary terrigenous deposits. Over a larger area of distribution, these deposits contain saline and brine waters, which, when opened, self-flow with a small flow rate. The main aquifer with thermal water in the east of the basin is the Pliocene (productive stratum), with which all the oil and gas fields of Azerbaijan are connected. Only in the southwestern part of the Kura basin (Kirovobad zone) fresh and brackish thermal waters were found in the Apsheron and Akcha-Gul aquifers. The Maikop water-bearing complex contains saline waters with salinity up to 20 g/l. Wells with a depth of 600 to 2500 m discharge self-flowing water with a flow rate of up to 10 l / s, rarely more (Barda, Mir-Bashir, etc.). The water temperature at the wellhead varies from 30 to 65 ~ C. The water conductivity of the rocks varies from 20 - 30 m2 / day (Maikop complex) to 40 - 80 m2 / day (Absheron complex).
In the Western Turkmen intermountain artesian basin, aquifers with thermal water are developed in Apsheron, Akchagyl and red-colored deposits. The main water-bearing complex is confined to the red-colored sandy-argillaceous strata with a thickness of up to 1500 - 2000 m. The main oil fields of the region are confined to it. Thermal waters, which are opened at a depth of 100 to 4000 m, are brine (up to 200 g / l and more), when self-spill, they have a temperature of up to 50 - 80 ~ C and flow rates of up to 20 l / s, less often more.
In the hydrogeological folded zone of Kopet-Dag, adjacent to the West Turkmen basin, thermal waters come to the surface of the earth in the form of springs along the fault that limits the northern face of Kopet-Dag (Archman, Coe, etc.). The waters of the springs are fresh and slightly brackish, chloride-sulfate-hydrocarbonate sodium, temperature up to 35 ~ C; flow rates of sources range from 50 to 150 l/s.
The Pamir region is included in the region of Alpine folding. Here, in deep gorges along large fault zones that cross dislocated ancient igneous and metamorphic rocks, thermal springs come out, most often with fresh water heated to 60 - 72 ~ C. Two groups are distinguished among these sources: nitrogen, which - are found in the central and southeastern parts of the region, and carbonic, located mainly in its southwestern part. Flow rates of sources from 2 to 15 l / s (Dzhilandinsky, Yashkulsky, Issyk-Bulaksky, Garm-Chashminsky, Lyangaroky, etc.).
The composition of water from nitrogen sources is predominantly sulfate-hydrocarbonate sodium, carbonic sources - hydrocarbonate sodium (and sodium-calcium).
In the area of Mesozoic folding, outcrops of thermal springs are noted. In a number of artesian basins, confined to intermountain depressions, thermal waters with insignificant debits are opened by wells. This region is located in the east of our country, stretching from the Arctic Ocean to Sea of Japan and separating from the hydrogeological area of the Cenozoic (Kamchatka) folding by the powerful Chukchi-Katazian volcanogenic belt, which is considered as a superimposed structure that arose in the Late Mesozoic time. The outcrops of thermal springs are also confined to this belt, similar in composition to the sources of the Mesozoic folding area. The most powerful of the therms of this vast area are the springs of the Chukotka Peninsula in the Verkhoyano-Chukotka hydrogeological folded region, having temperatures up to 60 - 80 ~ C and flow rates from 5 to 70 l / s (Chaplinsky, Senyavinsky, Mechigmensky, Kukunsky, etc. .). The composition of the water of all Chukchi springs is sodium chloride, mineralization varies from 1.5 to 40 g/l.
In the Okhotsk sector of the volcanogenic belt, a number of springs with water temperatures from 40 to 90 ~ C are known (Tavatumsky, Motykleisky, Berendzhinsky, Talsky). The waters of the Talsky spring are the most heated (90~C). The total flow rate of two wells drilled within the source reaches 10 l/s. Other sources have costs close to those indicated.
In the Primorsky sector of the volcanogenic belt belonging to the Sikhote-Alin hydrogeological region, there are rare nitrogen hot springs heated to 30 - 55 ~ C (Annensky, Tumninsky, Van Goussky), with flow rates from 1.5 to 7 l / s. Their composition is mainly sodium hydrogen carbonate. The mineralization of water is less than 1 g / l. The intermountain basins (Oloysky, Zyryansky), confined to the Kolyma massif, have not been studied at all in hydrogeothermal terms. The intermontane depressions of the Sikhote-Alin hydrogeological folded region (Suifunekaya, Prikhankayskaya, Middle-Amurskaya) and the artesian basins confined to them are significantly developed. lithified and dislocated Cretaceous rocks overlain from above by a relatively thin cover of loose Cenozoic deposits. The depth to the basement of the depressions rarely reaches 2000 m. According to non-numerous deep wells(up to 1100 - 1250 m) very weak water inflows of fresh and brackish waters are noted. The temperature of water at the bottoms of deep wells did not exceed 35 ~ C.
Thermal waters are widespread in the vast hydrogeological folded region of the Hercynides of the Asian belt, stretching within the Soviet Union from the western spurs of the Tien Shan to Altai and from Transbaikalia to the coast of Okhotsk.
The largest number of thermal springs is noted in the Tien Shan folded region, their outlets are associated with large fault zones. The temperature of the water in these springs varies from 30 to 90 ~ C, the flow rates of springs - from 3 to 50 l / s (Khoja-Obi-Garm, Obi-Garm, Issyk-Ata, Ak-Su, Alma-Arasan, etc.). The mineralization of waters, as a rule, does not exceed 1 g/l, the composition is sulfate-chloride sodium, only in a few sources is sodium chloride composition and mineralization from 3 to 13 g/l (Dzhety-Oguz, Yavroz).
A number of complexly built intermountain basins are confined to the Tien Shan hydrogeological region, the largest of them are the South Tajik, Fergana and Ili. In the first, thermal waters are mainly contained in the Paleogene and Cretaceous salt-bearing terrigenous-carbonate strata. Neogene sediments, composed of red-colored mainly clayey sediments, in the axial parts of the Surkhan-Darya, Kafirnigan, Vakhsh and Kulyab synclines have a thickness of up to 4000 m, contain thin aquifers with salt water. The Jurassic salt-bearing rocks contain brine waters. The main explored complex here is Paleogene, its thickness reaches 400 m. Wells drilled to a depth of 2000 m brought self-flowing waters from Paleogene rocks to the earth's surface with a temperature of 25 - 50 ~ C and a flow rate of 2 - 15 l / s, less often more. In the marginal parts of the structures, the mineralization of thermal waters ranges from 5 to 50 g/l, increasing with the subsidence of rocks up to 200 g/l and more. According to the composition of water, methane-nitrogen and methane chloride sodium. Approximately the same temperature and composition have waters that are discharged by wells from the Cretaceous aquifer with a total thickness of up to 900 m. In the Dushanbe region, the mineralization of water usually does not exceed 10 g / l, and the flow rates of wells in three self-discharging reaches 10 - 15 l / s at a water temperature at the mouth equal to 40 - 60 ~ C; in the south of the basin, the waters are brine.
In the Ferghana basin, in the Neogene, Paleogene, Cretaceous and Jurassic deposits, over a larger area of their distribution, salt and brine thermal waters are enclosed, which are discharged by deep (from 1200 to 3800 m) sacks. The waters are self-flowing, with a temperature at the spout of 40 - 70 ~ C, flow rates of 1 - 5 l / s (in the Neogene horizon up to 15 l / s), only in the marginal parts of the basin in separate structures, in zones of tectonic disturbances flow rates of wells during self-flowing reach up to 30 l / s, brackish waters with a temperature of 35 - 40 ~ C (Jurassic complex, Jalal-Abad).
In the Iliyok artesian basin (Jarkent part), Mesozoic deposits (from the Triassic to the Cretaceous) contain thermal waters, self-flowing at a flow rate of up to 30 - 75 l / s, with a temperature of 50 to 95 ~ C. The depth of the opening of these waters ranges from 1200 to 2700 m. The waters are fresh and slightly brackish, from hydrocarbonate to sodium chloride.
In the Alma-Ata part of the Ili basin, wells up to 3100 m deep penetrate in Neogene and Paleogene deposits weakly water-abundant interlayers with thermal water from fresh to brine (up to 55 g/l in the Alma-Ata well).
In the Issyk-Kul basin, salt and brine thermal waters are associated with Paleogene and Neogene deposits. Testing of deep wells showed different water content of the rocks.
The Balkhash-Alakul and Zaisan intermountain artesian basins have a relatively small (about 1,000 - 1,500 m) depth to the foundation (in Fergana and Tajik - up to 8 - 10 km, in Iliy - 4 - 6 km). In the Neogene and Paleogene deposits that fill these basins, fresh and brackish thermal waters are revealed. In the Balkhash-Alakul basin, the flow rate of self-flowing wells reaches 10 l/s, and the water temperature at the outflow is 30-50~ C. In the Zaisan basin, the water abundance of the rocks is insignificant. Cretaceous and Jurassic deposits, the presence of which can be assumed in these basins, have not been penetrated by wells and the degree of their water content is unknown.
In the hydrogeological folded regions of Transbaikalia and the Amur region there are a number of thermal springs heated to 45 - 70 ~ C (Kyrinsky, Bylyrinsky, Alsky, Tyrminsky, Kuldursky). The flow rates of sources usually do not exceed 5 l/s. The thermal waters brought out by two wells at the Kuldurskoye deposit have a temperature of 72 - 73 ~ C, the total flow is up to 22 l / s. The water of the springs is fresh nitrogen, from hydrocarbonate to hydrocarbonate-chloride-sulphate sodium composition.
In numerous intermountain artesian basins of this Rayon, filled with terrigenous and volcanogenic deposits of the Jurassic, Cretaceous and Cenozoic and having the structure of grabens, hydrogeothermal conditions have been studied very poorly. Judging by the data of testing wells with a depth of up to 2800 m, passed in the largest Zeya-Bureya basin, the flow rate of wells that penetrated Cretaceous rocks turned out to be negligible, equal to tenths and hundredths of a meter per second. The water temperature at a depth of 2500 - 2800 m did not exceed 75 ~ C, the mineralization increased from 1.4 g / l at a depth of 750 m to 2.5 g / l at a depth of 2000 m. The composition of the water is bicarbonate-chloride sodium. The same reservoir properties of rocks can be expected in other intermountain artesian basins similar in type to the Zeya-Bureya artesian basin in terms of the type of their constituent rocks.
The hydrogeological region of the Baikal Rift Zone is one of the largest rift zones in the world. It includes a system of grabens laid down in the Neogene and continued to develop in the Quaternary. A number of artesian basins are confined to them. Grabens are limited by a system of young faults, which are associated with outlets of numerous thermal springs (up to 60 springs). The water temperature of the springs ranges from 20 to -82 ~ C, flow rates - from 1 to 85 l / s, mineralization rarely reaches 1 g / l. The chemical composition of water varies from hydrocarbonate-sulphate to sulfate-chloride sodium. The largest and heated springs are Mogoisky, Allinsky, Bauntovsky, Khakussky, Pitatelevsky, Kotelnikovsky, Umkheysky, Garginsky, Goryachinsky and others.
The Selenginsky, Tunkinsky, Barguzinsky and other intermontane artesian basins, mainly filled with Neogene terrigenous deposits, are associated with fresh and brackish thermal waters. In the Selenginsky basin, from wells from a depth of 1800 - 2900 m, water with flow rates up to 3 l / s and a temperature at the mouth of 50 - 75~C self-flowed. In the Tunkinsky basin in the zone of tectonic disturbance from the well
From a depth of 750 - 900 m, a self-spill of water was obtained in the amount of 2 - 8 l / s with a temperature at the mouth of 38 - 41 ~ C, from a depth of 1500 - 1900 m, the flow rate during self-spill decreased to 0.6 l / s. In the Barguzin basin, from a well from a depth of 900 m, the flow rate during self-outflow of water was small, and the temperature was 22 ~ C.
There are a number of nitrogen and carbon dioxide thermal springs emerging along large tectonic faults in the Sayan about - Altai with about - Ye Nisei with the hydrogeological folded region in the region of the Western and Eastern Sayan, belonging to the region of the Caledonian folding. The water temperature of nitrogen sources is the highest - from 40 to 83 ~ C (Teirys, Abakansky, Ush-Beldyr-sky), flow rates - from 1 to 12 l / s. The last figure refers to the most heated Ush-Beldyr spring, captured by several wells. The water is fresh, sulfate-hydrocarbonate sodium. Carbonic sources (Izig-Sug, Khoito-Gol, etc.) are located near the Quaternary volcano, the water temperature is from 30 to 42 ~ C, the flow rate is up to 17 l / s, the salinity is up to 2, 5 g/l, according to the composition of water they belong to hydrocarbonate sodium.
Only three thermal springs are known in Altai, the largest of them is Belokurikhinsky. Wells with a depth of up to 525 m here bring out thermal waters with a temperature of up to 42 ~ C, with a total well flow rate of up to 12 l / s. The waters are fresh, sulfate-hydrocarbonate sodium.
Intermountain basins of the Sayano-Altai-Yenisei region (Minusinsk, Tuva, Rybinsk, Kuznetsk) are made mainly by Devonian, Carboniferous and Permian deposits (Tuva, in addition, by Silurian rocks), contain mainly brine chloride sodium thermal waters with mineralization up to 250 - 320 g/l; Salt waters are confined to the Carboniferous and Lower Permian deposits of the Kuznetsk Basin. Testing of oil exploration wells with a depth of up to 2900 m showed low reservoir properties of rocks (mainly medium and upper Devonian water-bearing deposits of the Minusinsk basin and carbonic with Permian deposits in the Kuznetsk basin were tested), as a result of which the flow rate of wells during pumping reached only 0.5 - 1 l/s at level drops of several tens of meters. The highest water temperature (80 - 82 ~ C) was noted at a depth of 2800 - 2850 m.
Forecast operational resources of thermal waters
In accordance with the above brief description of the distribution of thermal waters on the territory of the Soviet Union, promising areas are outlined (Fig. 4), where thermal waters can find practical application, and within these areas, the main aquifers with thermal water and the exploitation resources of these waters have been calculated.
When identifying promising areas, the following hydrogeothermal indicators were taken into account: the depth of occurrence of the main aquifers with thermal water, reservoir properties of rocks, temperature, salinity and composition of water. In addition, technical and economic indicators were taken into account, which allow us to evaluate economic efficiency use of thermal waters in the national economy.
It is known that in order to use thermal waters as a source of thermal energy, thermal waters must have significant operational resources (tens and hundreds of liters per second), while the lower the water temperature, the large quantity it is required to cover certain thermal loads. When evaluating the prospects for the use of thermal waters, it should be taken into account that during the construction of geothermal installations, a significant proportion of capital costs falls on drilling operations.
The most promising should be considered those areas where the highest geothermal gradient, which allows you to open waters with a fairly high temperature at relatively shallow depths, thermal waters, when opened by wells, give a self-outflow with sufficiently large flow rates and in terms of composition and mineral lizations are suitable for operation.
Rice. 4. Map of prospects for the use of thermal waters in the USSR. Compiled by B. F. Mavritsky.
Promising areas for the use of thermal waters from fresh to salty with temperatures from 40 to 120 ~ C: 1 - in the Mesozoic deposits of artesian basins; 2 - the same, in the deposits of the Mesozoic and Cenozoic; 3 - the same, in Cenozoic deposits; 4 - areas with a limited prospect of using thermal waters (with low temperatures - 20 - 40 ~ C or with a saline nature of the mineralization of highly heated waters); b - unpromising areas; 6 - areas with the absence of thermal waters in the sedimentary cover of the basins. Promising areas for the use of thermal waters of fissure systems: 7 - modern volcanism (temperature 40 - 200 ~ C); 8 - outside the areas of modern volcanism (temperature 40 - 100 ~ C). Districts: 9 - with limited prospects for use; 10 - unpromising; And - with unclear prospects: a - In reservoir systems, 6 - in fractured systems. Areas with possible water intake capacity (in l/s): 12 - up to 50; 13 - 50 - 100; 14 - 100 - 200; 15 - 200 - 300; 16 - more than 300. Borders: 17 - districts with different prospects; 18 - areas with self-flowing waters; 19 - development of permafrost rocks. solid thin lines- geological and structural boundaries
It should be emphasized that the largest values of the geothermal gradient are characteristic of platform artesian areas and intermountain artesian basins filled with Meso-Cenozoic deposits. Within these structures, the geothermal gradient reaches 3~C per 100 m; and often more. For platform artesian areas and intermontane basins filled with Paleozoic deposits, the value of the geothermal gradient is not higher than 2.5 ~ C per 100 m, often less.
Thus, within the platform artesian areas and intermountain artesian basins, areas where the value of the geothermal gradient is close to 3 ~ C per 100 m or more than 3 ~ C per 100 m should be considered promising. wells self-discharge, while within the ancient platforms, self-discharge is not observed.
When calculating the operating resources, thermal waters with a mineralization not higher than 35 g/l were taken into account.
Only after the accumulation of sufficient experience in the use of mineralized thermal waters will the exploitation of deposits with brine waters begin.
The above considerations concerned mainly the thermal waters of the reservoir type. Of the areas where thermal waters of the fissure-vein type are developed, those that are characterized by intense thermal manifestations associated with tectonic movements of the Alpine stage should be considered promising.
Thus, among the promising areas, according to the conditions of occurrence and circulation of thermal waters, two groups are distinguished:
1) areas located in hydrogeological folded areas that have experienced an intense impact of the latest tectonic movements and related phenomena of volcanism. Here, thermal waters have a local development and belong to the fissure-vein type;
2) areas of epipaleozoic platform artesian areas and intermountain artesian basins, filled with Meso-Cenozoic sediments, with areal distribution of formation-pore and formation-fissure thermal waters.
The promising areas of the first group include the areas of modern volcanism of the Kamchatka and Kuril hydrogeological folded areas, the hydrogeological folded areas of the Tien Shan, Baikal, Pamir, the Chukchi-Katazian volcanic belt, and some others.
Among the promising areas of the second group, the following can be distinguished: in the West Siberian platform artesian region, the areas of development of thermal waters south of 60 ~ s. sh. and especially south of the Trans-Siberian Railway; on the Turan platform artesian region - the Bukhara-Karshi hydrogeological region, the Syrdarya basin, the system of basins of the Kyzylkum uplift zone, individual sections in the Mangyshlak and Ustyurt regions; on the Scythian platform artesian region - areas of the plain part of the Crimea and Ciscaucasia. Among the intermountain basins, one should single out the East Black Sea (Rionsky), separate sections of the Kura, Fergana and Tajik basins, the Dzharkent, Selenga, Tunkinsky basins, the artesian basins of about. Sakhalin and some others.
In platform artesian areas, deposits of thermal waters have such big sizes(thousands and tens of thousands of square kilometers), that within their limits operational areas can be identified, characterized by a certain geological and structural structure, hydrogeological conditions and technical and economic indicators. In some areas, due to their insufficient hydrogeothermal knowledge, it is difficult to establish the exact boundaries of thermal water deposits. This is also associated with a very gradual change in the quality indicators of thermal waters and their depths (for example, in the area of the West Siberian platform artesian region).
In hydrogeological folded areas, deposits of fissure-vein thermal waters have clearly defined boundaries and rarely exceed 1 km2 in size. Only a few deposits in areas of modern volcanism occupy areas of several square kilometers.
The typification of thermal water deposits according to the geological and structural features, taking into account the sources of formation of their exploitation resources, is given in Ch. I. In this typification, deposits of platform-type artesian basins, intermountain depressions and deposits of crystalline massifs of folded areas, areas of modern volcanism, were identified. At the same time, the first two types are reservoir, and the last two are fissure-vein deposits. The revealed general patterns of distribution and conditions of occurrence of thermal waters on the territory of the USSR make it possible to approach the development of a number of more detailed typifications according to the parameters that determine the expediency of developing deposits. Such indicators include depth, occurrence conditions, temperature of thermal waters, possible water intake costs, water salinity, and the position of the static level.
By temperature, all deposits can be subdivided into low-thermal (20 - 50 ~ C), thermal and high-thermal (50 - 100 ~ C) and with superheated waters (more than 100 ~ C).
According to the water intake debits, the deposits can be subdivided into low-debit (less than 50 l/s), medium-debit (50-100 l/s) and high-debit (over 100 l/s). At the same time, for deposits of a fissure-vein type, these costs will correspond to the possible operational reserves of the entire deposit in case of self-outflow of water; at reservoir-type deposits, these values correspond to the flow rates of standard water intakes located on an area of 25 km2, consisting of five wells, with a decrease in the dynamic level to 100 m below the earth's surface and an estimated life of 10 thousand days.
Deposits are distinguished according to the mineralization of water fresh water(up to 1 g/l), brackish (1 - 10 g/l) and salty (10 - 35 g/l). Deposits with brine thermal waters, as noted above, are off-balance.
According to the nature of the self-spouting of the waters of the deposit, there can be self-spouting non-gassing, self-spouting gassing and giving an eruption of a steam-water mixture from the wells.
Finally, according to the depth of occurrence of thermal waters, the deposits can be divided into a number of categories. Within the limits of artesian basins of platform and folded hydrogeological regions, one can distinguish deposits with aquifers occurring relatively shallow (up to 1500 m), deep (from 1500 to 2500 - 3000 m) and at the maximum allowable hydrogeothermal and technical and economic indicators. depths (from 2500 - 3000 to 3500 m). In deposits of fissure-vein type in hydrogeological folded areas, the depth usually varies from 150 to 200 m, less often up to 300 m, in areas of modern volcanism it is up to 500 m, less often more.
It should be emphasized that the most common deposits of both reservoir and fissure-vein types are weakly thermal and thermal. Deposits with superheated waters (water temperature over 100 ~ C) have practical value mainly in areas of modern volcanism (Kamchatka, Kuril Islands) and belong to the fissure-vein type. Deposits with overheated reservoir-type waters are rare, only within the Cis-Caucasus and the Rion depression. At such deposits as Kizlyarskoe, Ochemchirskoe, and Praskoveiskoe (in the latter, the mineralization of the waters far exceeds 35 g/l), wells deeper than 3,000 m produce water and steam-water mixtures with temperatures ranging from 100 to 115~C, rarely up to 120~G.
To determine the practical significance of thermal waters in the national economy, it is important to have an idea of the total operational resources of thermal waters and the heat reserves contained in these waters within the selected promising areas.
Features of the methodology for the regional assessment of the operational resources of thermal waters are considered in Chapter 1. The results of the assessment of the resources of promising areas in the artesian basins of the platform and folded areas are given in Table. 34.
To date, it has not been possible to obtain sufficiently complete and reliable data on the predicted reserves of thermal waters for all of the above areas. This is mainly due to the unequal knowledge and uneven drilling of individual areas. For a number of sites, there was not enough actual data on the reservoir properties of aquifers; for them, the calculated values of water conductivity and piezoconductivity were taken by analogy with neighboring, more studied sites located in similar geological and hydrogeological conditions. With limited information about the hydrodynamic parameters of water-pressure systems, schematized data were used. All this in a certain way affected the completeness and reliability of the calculations.
Table 34
Exploitation resources of thermal waters of reservoir type in certain regions of the USSR
aquifer complex | Prognostic resources, | Thermal water temperature, ~С | Forecast heat reserves, million Gcal/year (at efficiency factor = 0.5) |
|
West Siberian platform art-tesian region | Apt-Albsenomanian | |||
Southern Areas (South of 58~N) | neocomian | |||
Northern region (north of | Apt-Albian-Cenomanian | |||
neocomian | ||||
Turan platform artesid area | ||||
Syrdarya artesian basin | Alb-Cenomanian, Neo-Comian | |||
Bukhara-Khiva region of the Amu-Darya complex artesian basin | Alb-Cenomanian | |||
Artesian basin of the Kyzylkum uplift zone | ||||
South-Mangyshlak and North-Ustyurt complex artesian basins | Alb-Cenomanian | |||
Scythian platform artesian region | ||||
North Crimean artesian basin | ||||
Azov-Kuban artesian basin | Paleogene-Neogene | |||
East Ciscaucasian artesian basin | Paleogene, Neogene, Cretaceous | |||
Intermountain artesian basins | ||||
East Black Sea (Rionsky), Alazani | Neocomian, Paleogene, Neogene | |||
Kurinsky and Kusaro-Divichensky | ||||
South Tajik | Cretaceous, Paleogene, Neogene | |||
Fergana | Neogene (partly Cretaceous) | |||
Dzharkent | Triassic to Cretaceous age | |||
Barguzinsky, Selengensky, Tunkinsky | Neogene | |||
O. Sakhalin | Mainly Neogene | |||
Notes: 1. In addition to the author, G. K. Antonenko and I. S. Otman took part in the calculation of forecast resources. 2. The reserves of thermal waters with a temperature of 40 - 60 ~ C are 195 m3 / s, with a temperature of 60 - 80 ~ C - 34 m3 / s, with a temperature of 80 - 100 ~ C - 5 m3 / s.
As can be seen from Table. 34, the identified operational resources of thermal waters of reservoir-type deposits are about 235 m3/s, with more than 75% falling on the West Siberian artesian region. Natural (elastic) reserves are the main source of formation of operational resources at reservoir-type deposits; in intertoral artesian basins, attracted natural resources have a certain value. Operating resource modules in various promising areas vary from 0.05 to 0.2 l/s per 1 km2.
As noted above, the operational resources of thermal waters in the mountainous folded areas are calculated according to the data of exploration work, and where exploration work has not been carried out, they are determined by the magnitude of the natural discharge of thermal waters, taking into account the coefficient of increase in costs during drilling . This coefficient was taken equal to 2 - 3, i.e., the minimum of those obtained in practice during exploration work!
As shown by the exploration data of numerous deposits of fissure-vein type thermal waters, the natural discharge of these waters, as a rule, is many times (up to 10 - 20 times or more) less than the reserves of thermal waters that are detected by exploration and (Goryachinok, Kuldur, Isti-Su, Pauzhetka, Paratunka and many other deposits). The temperature of the water at depth is higher than at the outlet of the springs.
Table 35
Exploitation resources of thermal waters of fissure-vein type in promising areas
Forecast resources | Water temperature, | Heat reserves, million Gcal/year (with k.p.d. = 0.5) |
||
parohydro- |
||||
Kamchatka hydrogeological folded | ||||
Kuril hydrogeological folded | ||||
Baikal hydrogeological fold | ||||
Folded hydrogeological zone Tien- | ||||
Folded hydrogeological zones Bol- | ||||
shgogo and Lesser Caucasus, Talysh, Pami- | ||||
ra, Sayan, Amur region, Chukotka, district | ||||
volcanogenic belt | ||||
The calculation data for the operational resources of thermal waters in mountain-folded areas (deposits of the fissure-vein type) are summarized in Table. 35 (for Kamchatka, when calculating the resources of steam hydrotherms, materials from the Institute of Volcanology, Siberian Branch of the USSR Academy of Sciences, were used). As follows from this table, the identified predictive operational resources of thermal waters in mountain-folded areas are only 7 m3 / s, and steam hydrotherms - 5 t / s. From a comparison of the data in Table. 34 and 35 it follows that the predicted operational resources of thermal waters of the formation type are many times greater than the resources of thermal waters of the fissure-vein type. This determines the main practical significance of both types of deposits and the methodology for conducting geological exploration for thermal waters.
Tables 36 and 37 show the possible flow rates of group water intakes at deposits of reservoir and fissure-vein types. These data more clearly define the possible scale of the use of thermal waters for various purposes.
Based on the table. Based on the data on possible water intake costs and water temperature, the predicted heat output of water intakes at reservoir-type thermal water deposits was estimated. The results of the determinations are summarized in table. 38.
The heat output of deposits of thermal waters of fissure-vein type with water temperatures up to 100 ~ C can vary from 1 to 70 - 75 Gcal / h. Thus, the heat output of thermal water intakes at deposits of formation and fissure-vein types in promising areas ranges from 1 to 75 Gcal/h. Only at steam hydrotherm deposits in areas of modern volcanism, the heat output of water intakes can be hundreds of gigacalories per hour, and power plants with a capacity of thousands and tens of thousands of kilowatts can operate on the basis of such deposits.
The identified operational resources of thermal waters have different values in terms of their practical development and can be divided into two categories: resources of priority development and resources of a more distant development perspective.
The first category of resources must satisfy a number of indicators, of which the main ones are: 1) a sufficiently high water conductivity of collectors (from 30 - 50 m2 / day and more), providing high water intake costs; 2) the water temperature at the vent is above 40 ~ C;
3) relatively low mineralization of water (no more than Yug/l);
4) absence or insignificant salt deposition in pipelines during operation; 5) low corrosivity of water.
Thermal waters that meet the above indicators, in their practical use, as a rule, will not require the use of water heat exchangers and the solution of special issues of discharge and disposal of waste thermal waters, which will increase the economic efficiency of the operation of such waters.
Of the total predicted reserves of thermal waters, which are about 250 m3/s, the specified requirements are met by reserves determined at 80 m3/s. Of this amount, more than 70 m3/s are thermal waters of the formation type, developed, as a rule, in already inhabited areas or in intensively developed areas.
An approximate distribution of reserves of the first stage of development in separate areas is given in Table. 39.
Of those indicated in the table. 36 reservoir-type thermal water deposits in possible costs water intakes, water temperature at the spout and its mineralization can be recommended for the priority development of the Ciscaucasia, Ochamchira, Megrelskoe (Zugdidskoe) deposits. Of the deposits of the fissure-vein type (Table 37), the largest deposits of steam-hydrotherms of Kamchatka and Kuril Islands(Semyachinsko-Uzonskoye, Mutnovsko-Zhirovskoye, Koshelevskoye, Pauzhetskoye, Kireunokoe, Hot Beach, etc.) - Other deposits of thermal waters of the fissure-vein type, for example, the Baikal rift zone, are of great practical value.
At present, the GKZ of the USSR, in the sum of all categories, has approved the operational reserves of thermal waters and steam hydrotherms for 15 deposits and sites located in Georgia (seven sites), the North Caucasus (four sites), in Kamchatka (four sites), a little more 3 m3/s of thermal water and 0.25 t/s of hydrothermal steam. Thus, the degree of knowledge of the identified predictive resources is only about 1.5%.
The Pauzhetskaya GeoTPP with a capacity of up to 5 MW has been built and is operating on the basis of the explored reserves of larohydrotherms, and the construction of the Yuzhno-Kurilskaya GeoTPP is planned. Thermal waters are used for heating, hot water supply and household needs in a number of cities, rural settlements, resorts. Thermal waters are used to heat Paratunskoe, Khankalskoe, Ternairekoe; Okhureyskoye and other greenhouse-hothouse farms with a total area of over 20 hectares.
For a wider use of thermal waters in the national economy, a broad development of geological exploration is required. Exploration work should be accelerated in Kamchatka, where the development of heat contained in thermal waters and steam-hydrotherms can become the basis of energy and heat supply to this remote area and will make it possible to do without the import of expensive fuel. Exploration work should be intensified in Ciscaucasia, in the Georgian SSR, in the southern regions of Western Siberia and in a number of regions of Uzbekistan and Kazakhstan. In the semi-desert regions of the flat part of Uzbekistan, Mangyshlak and Ustyurt, thermal waters are already and will find even greater practical application in the future. In these areas, which lack drinking and technical water, thermal waters are of drinking quality or close to them, so using them will reduce the water shortage. On the basis of thermal waters, it is possible to organize hot water supply, a network of balneotherapy, build baths, laundries, swimming pools, greenhouse facilities, etc.
The technical and economic calculations performed by the Central Research Institute of Engineering Equipment of the State Civil Engineering of the USSR (Lokshin, 1969) for a number of objects under development (Makhach-Kala, Khankala, Zugdidi, Tsaishi, Cherkessk, Tobolsk, etc.) showed a fairly quick payback of capital costs for the construction of heating facilities, hot water supply based on thermal waters. Depending on the size of the geothermal facility, the annual profit ranges from 100 to 500 thousand rubles, tens of thousands of tons of coal and millions of cubic meters of tap water are saved per year. The payback period for investments usually does not exceed five years. .
Foreign and domestic experience in the use of thermal waters shows that the more diverse and at a more advanced technical level all the useful properties of water are utilized, the higher the economic efficiency of exploitation of these deposits.
Table 36
Hydrogeothermal characteristics of typical reservoir-type thermal water deposits
Field | The main aquifers with thermal water | Approximate depth of wells, m | Water conductivity, m2/day | Excess pressure, m | Temperature, ~С | Mineralization, | Estimated costs of standard water intakes, |
||||
West Siberian artesian platform area | |||||||||||
Kolpashevskoe | Neocomian and Apt-Cenomanian | ||||||||||
Barabinsko-Kupinskoye | |||||||||||
Omsko-Tarskoe | |||||||||||
Tobolsk | neocomian | ||||||||||
Tyumen | |||||||||||
Surgut | Neocomian and Apt-Cenomanian | ||||||||||
Turan artesian platform area Plain part of Uzbekistan | |||||||||||
Tashkent | Alb-Cenomanian | ||||||||||
Bukhara | |||||||||||
K arshin with something | |||||||||||
Mangyshlak and Ustyurt | |||||||||||
Shevchenkovskoe | Alb-Cenomanian | ||||||||||
Tenginsky | |||||||||||
Tigenskoye | |||||||||||
Scythian artesian platform area Plain Crimea | |||||||||||
Saki-Evpatoria | neocomian | ||||||||||
Belogorsk | |||||||||||
Dzhankoy | Date-Eocene | ||||||||||
Ciscaucasia | |||||||||||
Maikop | Cretaceous and Tertiary | ||||||||||
Circassian | Alb-Cenomanian | ||||||||||
Nalchik | |||||||||||
Grozny | Chokrak-Karagansky | ||||||||||
Mozdok | |||||||||||
Prokhladnenskoe | |||||||||||
Makhach-Kalinsky | |||||||||||
Kizlyar | |||||||||||
Artesian basins of intermontane depressions East Black Sea (Rionsky) artesian basin | |||||||||||
Megrelian. | Heocomian | ||||||||||
Ochamchira | |||||||||||
Kurinsky a | Ztesian C | ||||||||||
Kirovobad | Maikop, Akchagyl, Apsheron | ||||||||||
Dzharkent artesian basin | |||||||||||
Panfilovskoe | Cretaceous, partly Jurassic and Triassic | ||||||||||
Artesian basins about. Sakhalin | |||||||||||
North Sakhalin | Neogene | ||||||||||
Paronai | |||||||||||
* The water intake area of 25 km2, consisting of five wells, was taken as standard. The calculation of expenses was carried out according to the formula of a large well based on the conditions: the estimated decrease is equal to the excess; drop pole 100 m below ground level; piezoconductivity coefficient - 105 m2 / day, estimated period of operation - 10 thousand days, radius of a large well - 400 m
Table 37
Characteristics of the main deposits of thermal waters of fissure-vein type
District, deposit | Approximate depth of wells, m | Mineralization, g/l | Temperature, ~С | Explored and probable reserves, l/s (for steam-hydrotherms, kg/s) |
Talysh, Alashinsky | ||||
Tien Shan, Issyk-Ata | ||||
Pamir, Dzhilandinsky | ||||
Sayany, Ush-Beldyrskoe | ||||
Baikal system | ||||
Mogoyskoe | ||||
Pitatelevskoe | ||||
Goryachinskoe | ||||
Allinsk | ||||
Seiyu | ||||
Bureinsky massif, Kuldurskoe | ||||
Chukotka-Okhotsk sector of the volcanogenic | ||||
belts, Chaplinsky | ||||
Tavatum | ||||
Talskoe | ||||
Kamchatka | ||||
palanskoe | ||||
Kireunskoe | ||||
Semyachinsko-Uzonskoye | ||||
Pauzhetsky | ||||
Koshelevskoe | ||||
More-Bath | ||||
Mutnovsko-Zhirovskoe | ||||
Paratunskoye | ||||
Nalychevskoe | ||||
Malkinskoye | ||||
Essovskoe | ||||
Kuriles, Hot Beach |
* Deposits explored.
** Explored deposits.
The extensive development of geological exploration for thermal waters is dictated by the significant demand for heat within the above-mentioned promising areas. These needs, according to the Institute "Teploelektroproekt" and the Research Institute of Vegetable Economy, amount to more than 120 million Gcal / lod for domestic needs and agriculture, and by 1980 will increase to about 150 million Tcal / year. If we assume that only 50% of the thermal potential of thermal waters will be usefully used, then in this case, too, thermal waters can cover a significant part of the specified heat demand.
To use the deep heat of the Earth on an industrial scale, it must be significantly expanded against modern level exploration work at the identified deposits of thermal waters classified as priority development. Simultaneously with the expansion of exploration work, it is necessary to plan the construction of heat supply facilities on the proven reserves of thermal waters.
Table 38
Possible heat output of water intakes at reservoir-type deposits
Note. When calculating the coefficient beneficial use heat is taken equal to 0.5.
Table 39
Distribution by regions of predicted reserves of thermal waters of priority development
Age of water-bearing rocks | Mineralization, g/l | Water temperature, ~С | Inferred reserves |
||
heat, mln Gcal/year (k.p.d.=0.5) |
|||||
Thermal waters of reservoir type | |||||
Western Siberia (Novo-Siberian, Omsk, Pavlodar regions, | |||||
Altai region) | Alb-Cenomanian and Neocomian | ||||
Syrdarya (Kzyl-Orda, Tashkent-skaya, Chimkent ob- | |||||
Alb-Cenomanian | |||||
Bukharo-Khiva | |||||
Kyzyl-Kumsky | |||||
South Mangyshlak and North Ustyurt | Alb-Cenomanian | ||||
Plain Crimea | |||||
Western Ciscaucasia (Krasnodar Territory) | Cretaceous, Paleogene, Neogene | ||||
Central Predkavka-kazye (Stavropol Territory) | |||||
Eastern Ciscaucasia (Stavropol Territory, Dagestan, Kabardino-Balkarian and Chechen-Ingush Autonomous Republics) | Cretaceous, Paleogene, Neogene | ||||
Rionsky (Georgian | |||||
Alazani | |||||
Kurinsky (Kirovobad region) | Neogene, chalk | ||||
Fergana | |||||
Dzharkent (Alma-Ata and Taldy-Kurgan regions, Kazakh SSR) | Triassic to Cretaceous | ||||
Selenginsky (Buryat ASSR) | |||||
Sakhalin | |||||
Thermal waters of fissure-vein type | |||||
Kamchatka | |||||
Kurile Islands | |||||
Pribaikalsky (Buryat ASSR) | |||||
THERMAL WATERS (French Thermal - warm, from Greek therme - heat, heat * a. thermal water; n. Thermalwasser; f. eaux thermales, eaux thermominerales; and. aguas termales) - groundwater with a temperature of 20 ° C or more. The temperature of 20°C is conditionally taken as the boundary between cold (less mobile) and thermal (more mobile) waters, since at this temperature the viscosity of water, which determines its mobility, is 1 centipoise (1.10 -3 Pa.s). The depth of the 20°С isotherm in the earth's crust depends on the climatic zonality: in areas of permafrost development it is 1500-2000 m, in the subtropics up to 100 m, in the tropics the 20°С isotherm comes to the surface. Within each zone, there is an increase in the temperature of thermal waters with depth, which is determined by the geological and structural features of the area and the associated hydrogeothermal conditions. There are four types thermal regime thermal waters: low with geothermal gradient up to 1°С/100 m, heat flux density 30-40 mW/m 2 ; moderate - respectively 1-2 ° C / 100 m, 40-50 mW / m 2; elevated - 2-3 ° C / 100 m, 50-60 mW / m 2; high - more than 3 ° С / 100 m, more than 60 mW / m 2. The low thermal regime is observed mainly on the territory of ancient shields and ancient folded systems, moderate - within the ancient artesian platform areas, elevated - in the artesian areas of the Epipaleozoic plates and associated intermountain depressions and troughs, as well as in the hydrogeological regions of Alpine folding, where systems of discontinuous tectonic faults. The high thermal regime is associated with areas of artesian basins (discharge of thermal waters from the deep parts of the basins) and hydrogeological folded areas that have experienced intense neotectonic impact. Thermal anomalies are most clearly expressed in areas of modern volcanism.
Thermal waters are most waters of the underground hydrosphere. The water temperature at the lower boundary of the earth's crust can reach 500-600°C, and in the zones of magma chambers, where water vapor and its dissociation products predominate, up to 1000-1200°C. In the artesian basins of young slabs at a depth of 2000-3000 m, wells break up water with a temperature of 70-100°C or more. In the areas of ancient shields, the temperature at a depth of 5-6 km does not exceed 60-70°C. In areas of neotectonic disturbances (Alps, Caucasus, Pamir, Himalayas, etc.), deep thermal waters come to the surface in the form of hot springs with temperatures up to 90-100 ° C, and in areas of modern volcanism - in the form of geysers and steam jets. Wells with a depth of 1000-1500 m, passed in the zone of discharge of steam jets, reveal steam-water mixtures and vapors with temperatures up to 200-300 ° C (Pauzhetskoye field in Kamchatka, Large geysers in, Wairakei in New Zealand, Larderello in Italy, etc.).
The chemical, gas composition and mineralization of thermal waters are diverse: from fresh and brackish hydrocarbonate, hydrocarbonate-sulfate, hydrocarbonate-chloride, calcium, sodium, nitrogen, carbon dioxide and hydrogen sulfide to salt and brine chloride sodium, calcium-sodium, nitrogen-methane and methane, in places hydrogen sulfide. Brine thermal waters are genetically related to evaporites. For biochemical processes occurring in the zone of thermal waters, a characteristic temperature threshold of 50 ° C is the beginning of protein coagulation, although the vital activity of some types of bacteria is possible even at high temperatures. The composition of thermal waters is influenced by the processes of regional epigenesis, which develops in the zone of elevated and high temperatures, when recrystallization of rock-forming minerals occurs and active exchange reactions occur between heated aqueous solutions and rock. An increase in temperature with depth leads to the release of physically bound water, an increase in the filtration capacity of rocks. The processes of mineral formation and the formation of deposits are associated with thermal waters (see Hydrothermal deposits).
Thermal waters serve as an object of extraction and processing for the purpose of use in the national economy. The classification of thermal waters by temperature depends on their practical application. In balneology, thermal waters are divided into warm (subthermal) - 20-35 ° C, thermal (hot) - 35-42 ° C and very hot (hyperthermal) - over 42 ° C. In the group of thermal waters for heat and power use, low-potential waters with a temperature of up to 70 ° C, medium-potential - from 70 to 100 ° C and high-potential - over 100 ° C (including slightly overheated - 100-150 ° C, significantly overheated - 150 -250°C and very overheated - 250-375°C). Significantly and highly superheated thermal waters are used mainly for electricity generation. Thermal waters with a temperature of 70-150°C are widely used for heating residential and industrial buildings, swimming pools, heating greenhouses, for technological purposes. On the basis of deposits of thermal waters, many large resorts operate, which have global importance. These include the Caucasian
Mineral waters of the Crimea are very diverse in terms of gas and chemical composition and temperature. They can be used for therapeutic and prophylactic purposes, as well as as raw materials for industry. The following areas of distribution of mineral waters are distinguished:
nitrogen, nitrogen-methane and methane waters of the artesian basins of the Plain Crimea;
nitrogen and methane-nitrogen waters of the Crimean Mountains;
nitrogen and nitrogen-methane waters of the Kerch Peninsula with local manifestations of carbonic waters.
Mineral waters are opened, as a rule, by wells in sediments from the Middle Miocene to Paleozoic age. 5 deposits have been explored, the mineral water reserves for which have been approved by the State Commission (GKZ): Saki weakly alkaline chloride-sodium waters (2 sites), Evpatoria marine type (2 sites), Evpatoria subthermal waters, Feodosiya sulfate-chloride-hydrocarbonate-sodium waters (2 sites ), Chokrakskoye (2 sites) (Fig. 14). Information on the reserves of these deposits and their development is given in Table 8.
Table 8
state balance sheet (according to "Geoinform" as of 01.01.2000)
|
Name of fields |
State of stocks m 3 / day |
Selection for 1999 THOUS.M 3 |
Operating organization |
||||
|
Sakskoye: section Saksky 1 section Saksky 2 Evpatoria (mor) section City section Pionersky |
96,87 54,40 23,28 7,52 |
JSC "Ukrprof-zdravnitsa" JSC "Ukrprof-zdravnitsa" |
|||||
Continuation of table 8.
|
Evpatoria (ter) section Yeshisriyzhda section of the Gorzhuzoy aquifer Chokrakskoe: section Northern section South Feodosiyskoe: Western area section Vostochny |
Nonexpl. Nonexpl. Not exploit. 10.0 |
JSC "Ukrprof-zdravnitsa" JSC "Ukrprof-zdravnitsa" JSC "Ukrprof-zdravnitsa" |
|||||
|
Total in the Autonomous Republic of Crimea |
The explored reserves of mineral waters in these five deposits amount to 20.8 thousand m 3 /day. 7 plots are operated. The selection of mineral waters in 1999 amounted to 264.59 thousand m 3 or an average of 724.9 m 3 /day. In addition, 6 more fields have been explored, the reserves of which have been tested by the STC PGO "Krymgeologiya" and "Dneprogeologiya". Information on these deposits is given in Table 9.
Table 9
Information on mineral water deposits, the reserves of which have been tested by the NTS of industrial enterprises.
|
Place of Birth |
NTS protocol number and date of reserves approval |
Number of stocks m 3 / day |
Usage |
|
|
Diamond Aji-Su Medical-Grushevka Beloglinskoe |
PGO "Crimea-Geology" PGO "Dnepro-geology", No. 1173 dated 3.06.1969 PGO "Crimea- geology", No. 80 dated 12.09.1970. PGO "Dnepro-geology", No. 77 dated 8.10.1970. |
220 forecast |
Boarding house "Diamond" Water spill "Evpatoria" Hospital "Black Waters" Not in operation Not in operation |
Continuation of table 9.
In addition, GGP "Krymgeologia" estimated the predicted resources of mineral waters for 5 aquifers of the Crimea. Information about the forecast resources of mineral waters is given in table 10.
Table 10
Information about the forecast resources of mineral waters.
The data in Table 10 indicate great prospects for discovering new deposits of mineral waters in the Crimea, since the predicted resources (151D thousand m 3 / day) are a reserve for this. In the process of geological exploration, 33 promising areas and manifestations of mineral waters were identified and taken into account (Fig. 14).
Separately, the Novoselovskoye deposit of thermal waters (fig. 14) is taken into account, the reserves of which are estimated at 8412 m 3 /day, including the explored 3912 m 3 /day. They are also mineral waters, since they contain iodine, bromine and boron in quantities sufficient to classify them as groundwater. Thermal waters are partly used for therapeutic showers
and baths. In the short term, they should find wider application as a fuel and energy raw material.
When carrying out prospecting and exploration robots for oil and gas in 50-70, a large factual material on deep aquifers, which indicates the prospects of the Crimean peninsula for the discovery of new deposits of thermal waters. In the 80-90s, in the course of further exploration and thematic work, the main promising aquifers (complexes) were identified, their hydrogeological and hydrogeothermal characteristics were given. The main promising object for thermal waters is the basal unit of the Lower Cretaceous, represented mainly by coastal-marine and subcontinental deposits (sandstones, siltstones, gravellites).
In the Foothills, these rocks come to the surface. In the Plain Crimea, they sink to a depth of 4.0-4.5 km, reaching maximum depths of 5.5-6.0 km in the west of the Tarkhankut Peninsula. The reservoir properties of water-bearing rocks decrease as they sink. Their maximum values were recorded in the Novoselovskaya and Oktyabrskaya areas (Fig. 14), where a deltaic complex with a thickness of up to 370 m was uncovered at depths of 1.0-2.3 km, which makes it possible to receive self-spouting tributaries up to 4925 m / day. (well 35 Oktyabrskaya). In the Plain Crimea, the waters of this horizon are pressure, the pressure on the wellheads is 5-15 atm. The temperature regime is determined mainly by the depth of the rocks. The maximum values of water temperatures were recorded in the west of the Tarkhankut Peninsula -180-190 ° C. On the Central Crimean uplift, the water temperature varies within 50-90 ° C. The waters of the horizon are mineralized, as you move north, the salt content increases from 1.1 (well 38 Oktyabrskaya) to 71.7 g/dm 3 (well 5 Genicheska).
The second promising water-bearing complex is confined to Paleogene deposits, which in the North Sivash area are represented mainly by sandstones and siltstones occurring at a depth of 1400-1800 m. The flow rates of wells during self-flowing reach 2440 m 3 /day. (well 15 Strelkovaya). Formation water temperature 51-78°C, salinity - 25-33 g/dm 3 . Waters contain industrial concentrations of iodine (up to 30 mg/dm3).
Hydrogeological studies were carried out in the Novoselovskaya, Oktyabrskaya and Severo-Sivashskaya areas in order to calculate the reserves of Teshuenergy waters using geocirculation systems (GS). The results of these works make it possible to estimate the potential reserves in the amount of 40 thousand m 3 /day. with thermal energy potential of 1200 Gcal/day. (table 11).
Table 11
Hydrogeological and thermal power characteristics of promising aquifers of thermal waters.
|
Name of areas |
Aquifer data |
Thermal power |
||||
|
Age Depth, m |
well flow rate, |
Water temperature at the mouth, 0 C |
Pot. reserves, m 3 / day |
thermal potential, |
||
|
Bovoselshskaya Oktyabrskaya North-Sivashskaya |
K| ps 900-1400 Cugs 1000-2400 |
47-69 55-85 45-72 |
17210 17860 5680 |
1.35 to 3.60 1.08 to 6.92 1.20 to 3.30 |
||
thermal springs or hot waters of the Earth- this is another amazing gift of nature to man. thermal springs are an indispensable element of the global ecosystem of our planet.
Briefly define what is thermal springs.
thermal springs
Thermal springs are underground water temperatures above 20°C. Note that it is more "scientific" to say geothermal springs, since in this version the prefix "geo" indicates the source of water heating.
Ecological Encyclopedic Dictionary
Hot springs - sources of thermal waters with a temperature of up to 95-98 ° C. Distributed mainly in mountainous areas; are extreme natural conditions for the spread of life on Earth; they are inhabited by a specific group of thermophilic bacteria.
Ecological encyclopedic dictionary. - Chisinau: Main edition of the Moldavian Soviet encyclopedia. I.I. Grandpa. 1989
Technical Translator's Handbook
thermal springs
Sources with a temperature significantly higher than the average annual air temperature near the source.Handbook of the technical translator. - Intent. 2009 - 2013
Classification of thermal springs
Classification thermal springs depending on the temperature of their waters:
- thermal springs With warm waters- springs with a water temperature above 20 ° C;
- Thermal springs with hot water— springs with a water temperature of 37-50°С;
- Thermal springs, which chen hot water- springs with water temperature above 50-100°C.
Classification thermal springs depending on the mineral composition of the waters:
Mineral composition thermal waters different from the composition of minerals. This is due to their deeper penetration, compared with mineral waters, into the thickness of the earth's crust. Based on the medicinal properties, thermal springs are classified as follows:
- thermal springs with hypertonic waters - these waters are rich in salts and have a tonic effect;
- thermal springs with hypotonic waters - stand out due to the low salt content;
- thermal springs with isotonic waters - soothing waters.
What heats the water thermal springs to these temperatures? The answer, for most, will be obvious - this is the geothermal heat of our planet, namely its earthly mantle.
Thermal water heating mechanism
heating mechanism thermal waters occurs according to two algorithms:
- Heating occurs in places of volcanic activity, due to the "contact" of water with igneous rocks formed as a result of the crystallization of volcanic magma;
- Heating occurs due to the circulation of water, which, sinking into the thickness of the earth's crust for more than a kilometer, "absorb the geothermal heat of the earth's mantle", and then, in accordance with the laws of convection, rise upwards.
As the results of studies have shown, when immersed in the depths of the earth's crust, the temperature rises at a speed of 30 deg / km (excluding areas of volcanic activity and the ocean floor).
Types of thermal springs
In the case of water heating according to the first of the above principles, water can escape from the bowels of the Earth under pressure, thereby forming one of the types of fountains:
- Geysers - fountain hot water;
- Fumaroles - a fountain of steam;
- Mud fountain - water with clay and mud.
These fountains attract many tourists and other lovers. natural beauties nature.
Use of thermal waters
long time ago hot water were used by man in two directions - as a source of heat and for medicinal purposes:
- Heating houses - for example, even today, the capital of Iceland, Reykjavik, is heated thanks to the energy of underground hot water;
- In balneology - Roman baths are well known to everyone ...;
- To generate electricity;
- One of the most famous and popular qualities thermal waters are their medicinal properties. Circulating through earth's crust water geothermal sources, dissolve in great amount minerals, thanks to which they have amazing healing healing qualities.
Pro healing properties Thermal waters have been known to man for a long time. There are many world-famous thermal resorts open on the basis of thermal springs. If we talk about Europe, the most popular resorts are in France, Italy, Austria, the Czech Republic and Hungary.
At the same time, one should not forget about one important point. Despite the fact that the waters of thermal springs can be very hot, bacteria dangerous to human health live in some of them. Therefore, it is necessary in without fail each geothermal source check for purity.
And in conclusion, we note that thermal springs, or hot waters of the Earth, are a vital and necessary resource for entire regions of our planet and many types of living beings.
PUBLISHING DATE: Aug 24, 2014 13:05
Eocene exc (Stavropol) iodine J up to 90 mg/l.
K 1J iodine up to 70 mg/l, Sr up to 700 mg/l.
Thermal waters Neogene: self-draining up to 50 l / s. and more, T 70–95 ° С.
Prikumsk K 2- steam-water mixture Т 104.5°С.
K 1- steam-water mixture T 117 ° C.
Widespread term. waters (Chechnya, etc.)
Features of the hydrogeological conditions of the basin, which must be “beaten!
1. The presence in the zone of the advanced folding of the Caucasus and in the marginal zone of the basin of numerous young tectonic disturbances associated with the era of Alpine folding.
2. Established numerous facts of significant discharge of deep (K, J, possibly deeper) fluids over zones of tectonic disturbances: thermal springs, springs with a relatively high mineralization of water and a specific composition of components, including micro., especially widespread CO 2 ( KMV region). High conc. B (up to 600 mg/l) as an indicator of the inflow of deep gas-steam fluids.
3. Widespread development in the Tersko-Sunzha zone and adjacent areas of abnormally high formation pressures in Paleogene and especially in Cretaceous sediments, which are most likely also associated with subvertical filtration of deep fluids. ???
4. The widest (practically to the Caspian coast) distribution in the deposits of the Baku complex of groundwater with low (mainly up to 1 g/l, only in a narrow coastal strip up to 7 g/l) mineralization, while in the overlying complexes of the Khazar and Khvalyn deposits, the mineralization of groundwater is variegated; points up to 20 g/l and more. This indirectly indicates that the Baku horizon, due to the presence of weakly permeable clayey rocks in the upper part of the section and in the overlying Khazar and Khvalynian age, lies in a zone of relatively difficult water exchange of the 1st hydrogeological stage. In this connection, the interaction with ground and upper pressure waters. horizons containing partially mineralized waters of continental salinity is relatively difficult and does not affect the composition of the underground. waters of the Baku complex. Such a "partial" inversion of the hydrogeochemical section is very typical for the artesian basins of the arid zone (Syrdarya, Amudara basins, etc.). The same in Apsh. and Akch. with a miner. up to 5 g/l.
The sub-Maikop floor of the central part of the basin (for all aquifers) is characterized by two regional features:
The presence of pronounced AVPD with pressure subtitle. waters up to 3000-4000 m a.s.l. c. (up to 2000 and more above the surface of the earth according to I. G. Kissin)
The presence of high temperatures, varying from 55° at depths of about 500 m to 170°C or more at ch. 3500 m
Area, Relief: Borders. The Ciscaucasian foothill region is up to 1500 m and more, the Terek-Sunzha uplift is up to 500–750 m, the central part of the basin is up to about 100–250 m. The Caspian Sea is up to –28 m.
Drains: rivers Terek, Kuma and their few tributaries.
Precipitation, temperature
Upper hydrogeological stage: Quaternary, Neogene-Quaternary and Pliocene and Middle Miocene (N 1 2) predominantly sandy-argillaceous deposits up to 3000-3500 m thick in the troughs of the Terek-Sunzhenskaya zone and in the central part of the basin and wedged out to the Karpinsky swell and partly in center uplifts T-C region, where the Maykop clays occur from the surface.
Lower waterfall. 1st floor are the clays of the Maikop suite (P 3 -N 1 1) thick. up to 1500–2000 m and more in the center of the basin. Quarter. deposits, as well as the Apsheron and Akchegyl stages. (Pliocene N 2 1-2). Middle Miocene???.
Quaternary deposits are represented by cover, alluvial, eolian and alluvial-marine and marine deposits in the coastal part and lower Quaternary deposits. transgressions of the Caspian (Khvalyn. and Khazars. stages
Absheron and Akchegyl are also transg. Caspian.
A characteristic structure with the presence of cont., approx. marine and marine sediment facies. Probable sustained aquiclude – clay deposits of the Apsheron (“jumps” with mineralization).
The depth of the groundwater level varies from 50–100 m or more in the foothill zone, to 10–20 m on the Stvropol uplift, to 5–10 m or less in the center of the basin. and up to 1-3 m in the Caspian part. Levels of pressure waters of the 1st floor in the lower areas of the center of the basin and in the near-Caspian region up to the self-spill.
Supply of groundwater and pressure water of the 1st floor at the expense of inf. atm. precipitation and overflow are most intense in the foothill zone, due to absorption from rivers and irrigation. channels and to the center. and prikasp. bottom-up parts. Unloading to the river network and to the center. and esp. in the Caspian part due to evaporation.
Feed quantities…….Unloading……..
Soil mineralization. waters …………. In the Caspian steppes, up to 10 -50 and even up to 100 g/l (salt marshes). It is more correct to say that in the central part of the basin, groundwater has a "variegated" mineralization. In the "near" Caspian region (the so-called black lands), in the areas of distribution of eolian sands, lenses of low-mineralized (up to 1.5 g / l) waters occurring on saline groundwater are widespread
Pressure self-flowing waters in the Quaternary and Pliocene deposits are the basis of the water supply of the territory. Tersko-Kuma basin. The productivity of wells during self-flow, depending on the composition of the rocks, from the fraction of l / s to 30-40 l / s. (Wednesday? 2 l/s).
Upper and middle Miocene (N 1 2-3) last supra-Maikop about 300 m.
In the sub-Maikop (P) y/y stage of the basin, water-bearing complexes are distinguished: Paleocene-Eocene, Upper Cretaceous, Upper Jurassic-Lower Cretaceous, Middle Jurassic and Paleozoic, silty-argillaceous and carbonate rocks. The total thickness in the central part of the basin is up to 1500–2000 m and baud. Main aquicludes: clay top. and avg. Albian (K 1), and clays of the Bathonian Stage (J 2) upper cf. jura. (Oil and gas bearing interval of the basin).
All these deposits occur directly from the surface on the northern slope of the Caucasus. Numerous sources of fresh water with different flow rates are associated with them, including those with carbonate rocks of the upper. Cretaceous and Jurassic with debits up to 1000–2000 l/s and more.
Well flow rates are 0.1–0.5 l/s. From limestone top. chalk. complex on monoclinal uplifts of the Ciscaucasian zone and in Dagestan (southeast) up to 460–800 l/s.
The sub-Maikop floor of the basin (for all complexes) is characterized by two (regional) features:
– the presence of pronounced AVPD, which is associated with high claims. subheading pressures waters up to 3000–4500 m. a. in., (up to 2000 m and more above the surface of the earth) in Ter. Sun. region (according to I.G. Kissin).
– the presence of high temperatures, varying from 55 at depths of about 500 m to more than 170 °C. on ch. 3500 m
Points of view on the formation of AVPD. !!!
Mineral ledge
