The lithosphere is associated with resources not only of traditional types of mineral fuel, but also of such an alternative type of energy as the heat of the earth's interior.
Sources geothermal energy can be of two types. The first type is underground pools of natural heat carriers - hot water (hydrothermal springs), steam (steam thermal springs) or steam-water mixture. In essence, these are directly ready-to-use underground "boilers" from where water or steam can be extracted using ordinary boreholes. The second type is the warmth of hot rocks. By pumping water into such horizons, one can also obtain steam or superheated water for further use for energy purposes.
Depending on the temperature of the water, steam or steam-water mixture, geothermal sources are divided into low- and medium-temperature (with temperatures up to 130–150 °C) and high-temperature (over 150 °C). The nature of its use largely depends on the temperature of the source.
It can be argued that geothermal energy has four advantageous features.
First, its resources are practically inexhaustible. This conclusion can be reached despite the very large discrepancies in the available estimates. So, according to German experts, these resources reach 140 trillion toe, and at the session of the World Energy Conference in 1989 they were defined as "only" 880 billion toe. Even if we keep in mind that the resources suitable for economic use do not exceed 1% of the total, they are a considerable amount. Most of these resources are related to low-temperature sources.
Secondly, the use of geothermal energy does not require significant costs, since in this case we are talking about already “ready-to-use” sources of energy created by nature itself.
Thirdly, geothermal energy is environmentally completely harmless and does not pollute the environment.
Fourth, localization geothermal resources determines the possibility of using them for the production of heat and electricity in remote, uninhabited areas.
Rice. 12. Earth's geothermal belts
Geothermal energy resources are quite widespread in the earth's crust. Their concentration is mainly associated with belts of active seismic and volcanic activity, which occupy 1/10 of the Earth's area. (Fig. 12). Within these belts, some of the most promising "geothermal" areas can be distinguished. Their examples are California in the USA, New Zealand, Japan, Central American countries.
In Russia, the main reserves of geothermal energy are associated with areas of Cenozoic folding, as well as Quaternary and modern volcanism. These areas include, first of all, the Kamchatka Peninsula, Sakhalin Island, the Kuril Islands, the Stavropol Territory, and Dagestan.
16. World Land Fund
English economist of the 17th century. William Petty said "Work is the father of wealth, and land is its mother." Indeed, the earth is universal natural resource, without which practically no branch of human economic activity can exist - neither industry, nor transport, and even more so agriculture and animal husbandry. Compared with other types of natural resources, land resources have some features. First, they are practically impossible to move from place to place. Secondly, they are exhaustible and, moreover, are usually limited to the boundaries of a certain territory (district, country, etc.). Thirdly, despite the wide multi-purpose nature of use, at any given moment in time, one or another piece of land can be occupied either for development, or for arable land, pasture, recreation, etc.
The uppermost layer of the earth is of particular value to people - the soil, which has fertility, the ability to produce biomass; moreover, this fertility can be not only natural, but also artificial, that is, supported by people. That is why the role of the soil cover of the planet (pedosphere) was so highly appreciated by the luminaries of Russian science V. V. Dokuchaev, V. I. Vernadsky and other scientists who formed the doctrine of soils.
Table 19
SIZE AND STRUCTURE OF THE WORLD LAND FUND
The first and most general idea of land resources is given by the concept of the land fund. The land fund is understood as the totality of all lands within a particular territory (from a small area to the entire land area), subdivided according to the type of economic use. With a broader approach, the entire land fund of the planet is usually estimated at 149 million km2, or 14.9 billion hectares, which corresponds to the entire land area. But in most sources it is estimated at 130–135 million km 2, or 13–13.5 billion hectares, subtracting the area of Antarctica and Greenland from the first indicator. The most reliable estimates of this kind belong to the specialized body of the UN - FAO, according to which Table 19 was compiled.
An analysis of Table 19 makes it possible to get acquainted not only with the size, but also with the structure of the world land fund. In doing so, some important conclusions can be drawn.
First, the conclusion that agricultural land occupy only 37% of the world land fund. Including the most valuable lands under arable land and perennial crops, which provide the supply of 88% of the food people need, account for only 11%. Of course, pastures also play a significant role (they include natural and improved pastures and meadows, crops used for grazing). However, with an area almost two and a half times the area of arable land, they provide only 10% of the world's agricultural output.
Secondly, the conclusion that forest land occupy almost 32% of the total area of the world land fund. Of course, the importance of these lands - primarily climate-forming, water protection, forestry - is very high. However, in supplying the population with food (as a result of hunting, fishing, grazing, fur farming, picking mushrooms, berries, etc.), their role can be assessed as purely auxiliary.
Thirdly, the conclusion that other lands in the structure of the land fund occupy almost the same share as the forest. The term "other land" used by FAO needs some clarification, as this category includes land of very different productivity and equally different economic uses. It includes lands under residential (urban and rural) development, under industrial and infrastructure (roads, canals, airports) structures, mine workings (quarries, mines, overburden dumps), etc. In the literature, there are various estimates of territories occupied by such technogenic formations, but the figure of 2.5-3% prevails. It already in itself indicates that the vast majority of the so-called other lands fall into some other category. Basically, these are unproductive and unproductive lands - deserted deserts, high mountains, rocky outcrops, areas under glaciers and water bodies, etc.
Rice. 13. Structure of the world land fund by major regions (share in %)
For geographical research, it is of great interest to study the structure of the land fund not only of the whole world, but also of its individual large regions. Shown in Figure 13, it provides rich material for comparison. It is quite natural, for example, that the share of land occupied by residential, industrial, transport development, and cultivated land is the largest in foreign Europe - one of the main regions of world civilization. It is also quite natural that the share of pastures in the structure of the land fund is especially high in Australia, the share of forests in South America, and the share of marginal and unproductive land in Asia.
Of course, even greater differences can be found when comparing the size and structure of the land fund of individual countries. The arable land is of the greatest interest in this respect. The countries with the largest area of arable land are shown in Table 20. It also gives a clear idea of how significantly these countries differ in terms of the share of arable land in the total land fund.
In addition to Ukraine and India, Bangladesh and Denmark are also among the “record holders” in the second of these indicators, where plowing reaches 56–57%.
Table 20
THE TOP TEN COUNTRIES BY AREA
Australia (414 million ha), China (400 million), the USA (240 million), Kazakhstan (187 million), Brazil (185 million), Argentina (142 million ha) stand out in terms of pasture area against the world background. But in the structure of the land fund, the share of pastures is especially high in Kazakhstan (70%), Australia and Argentina (50–55%), and of the countries that did not make it into the top ten, in Mongolia (75%).
In terms of the area of other lands, the uncompetitive first place in the world belongs to Russia (700 million hectares). It is followed by Canada (355 million ha), China (307 million), Algeria (195 million), USA (193 million) and Libya (159 million ha). But in terms of the share of such land in the land fund, Libya (91%) and Algeria (82%) located within the Sahara are ahead of all.
Another very important issue is directly related to the characteristics of the structure and size of the land fund - the availability of land resources. The indicator of such provision is calculated in hectares per capita.
It is easy to calculate that in 2007, with a total world population of more than 6.6 billion people and a global land stock (rounded) of 13 billion hectares, this figure is 2.0 hectares. But with such an average between individual large regions, there should be differences. Statistics show that in terms of per capita provision of land resources, the vast but relatively sparsely populated Australia (30 hectares per person) stands out sharply. It is followed by the CIS (8.0 ha per person), South America (5.3), North America (4.5), Africa (1.25), foreign Europe (0.9) and overseas Asia(0.8 ha per 1 person). Of the individual countries, in addition to Australia, the highest level of land availability is, for example, Russia (11.4 hectares per 1 person), Brazil (5.2), the Democratic Republic of the Congo (4.8), the USA (3.4), Argentina (3.1), Iran (2.3 ha per person).
However, for all the importance of the indicator of specific land availability, the indicator of availability of arable land is even more important. For the whole world, it now averages 0.20 hectares per person. Australia and Oceania (1.8 hectares per 1 person) stand out from individual regions and according to this indicator, followed by the CIS (0.8), North America (0.6), South America (0.35), foreign Europe (0 .25), Africa (0.22) and foreign Asia (0.13 ha per 1 person). As for individual countries, the differences between them (on individual examples) are shown in Table 21.
Table 21
PROVISION OF ARABLE LAND IN SOME COUNTRIES
Separately, we present some data on the land fund of Russia. In general, it is 1,709 million hectares, of which about 1,100 million hectares are in the permafrost zone. In the late 1990s in the structure of this fund, agricultural land accounted for 13% (including arable land - 7.5%), forest land - 61%, land for residential, industrial and transport development - 2.2%.
For many centuries, if not millennia, mankind has been striving to increase the area of cultivated - primarily arable - land, reducing forests for this, plowing meadows and pastures, irrigating dry steppes and deserts, etc. In other words, an offensive is being carried out on the so-called other lands. There have been significant achievements along this path. So, only in 1900-1990. The total area of agricultural land in the world has doubled. However, the population is growing faster, and this in itself predetermines a trend towards a reduction in the specific provision of arable land: if in 1950 the world indicator was 0.48 hectares per 1 person, in 1990 - 0.28, then in 2005 g. - about 0.20 ha per 1 person.
But this is only one reason for the decline in per capita income. The other is the growing degradation of land and soil cover.
geothermal resources
The surface of the planet is usually divided into three geothermal regions: hyperthermal, semithermal and normal. The hyperthermal region, with a temperature gradient of more than 80 o C/km, is most preferable for the construction of geothermal power plants. The semi-thermal region has a temperature gradient of 40 to 80 o C/km. The quality of geothermal energy is usually low, and it is better to use it directly for heating buildings and other structures. A normal thermal region with a temperature gradient of less than 40 o C/km is unpromising when using the Earth's heat. Such areas occupy the most extensive territory, the heat flux is on average 0.06 W / m 2.
All sources of geothermal energy are divided into petrothermal and hydrothermal. Petrothermal springs are located in those parts of the earth's crust where there is no water. At a depth of more than 3 km, the temperature is quite high. By driving water into such a source in one well, steam can be obtained from another. This principle is based on the use of "dry" heat of the Earth.
Hydrothermal sources, in turn, are divided into water, steam and steam. Water sources lie at different depths. One of the main conditions for their existence is the presence of an impenetrable layer of rocks above the water. Being under high pressure, water can be heated to temperatures above 100 o C and exit to the earth's surface in the form of a steam-water mixture.
In steam-water and steam deposits, aquifers are located between two impermeable layers. The lower one transfers heat from the Earth's core, while the upper one does not allow it to escape to the surface of the earth. In such places, water turns into steam, and when high pressure- in superheated water. Extraction of steam to the surface of the earth is possible only with the help of drilling.
Geothermal resources have been explored in many countries of the world: in the USA, Italy, Iceland, New Zealand, Russia, the Philippines, etc. The identified reserves of geothermal waters in Russia can provide approximately 14 million m 3 of hot water per day, which is equivalent to 30 million tce. At the same time, the reserves of geothermal water brought to the earth's surface are used by 5%. In our country, deposits of geothermal waters are exploited in Sakhalin, Kamchatka and the Kuril Islands, in the Krasnodar and Stavropol Territories, Dagestan, Ingushetia. The Kuril-Kamchatka zone of young volcanism is distinguished by the maximum proximity of geothermal systems to the earth's surface. The largest and most promising in Kamchatka is the Mutnovskoye field, located 130 km from the city of Petropavlovsk-Kamchatsky. Drilling operations have been carried out here since 1978. To date, about 90 wells have been drilled with a depth of 250 to 2500m. The total reserves are estimated at 245 MW.
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on the topic: "Geothermal resources"
1. Concept and classification of geothermal resources
2. Stages and stages of geological study of the subsoil
3. Principles and methods for studying and evaluating geothermal resources
4. Geothermal station in Belarus
Conclusion
Bibliography
subsoil geothermy resource station
1. Concept and classgeothermal resource identification
Geothermal energy - the production of electricity, as well as thermal energy due to the energy contained in the bowels of the earth.
The advantage of geothermal energy is its almost complete safety for the environment. The amount of CO2 emitted during the production of 1 kW of electricity from high-temperature geo thermal springs, ranges from 13 to 380 g (for example, for coal it is 1042 g per 1 kW / h).
Sources of geothermal energy according to the classification of the International Energy Agency are divided into 5 types:
Deposits of geothermal dry steam - relatively easy to develop, but quite rare; nevertheless, half of all geothermal power plants operating in the world use heat from these sources;
Wet steam sources (mixtures of hot water and steam) are more common, but when they are developed, it is necessary to solve the issues of preventing corrosion of GeoTPP equipment and environmental pollution (removal of condensate due to high degree its salinity);
Geothermal water deposits (containing hot water or steam and water) are the so-called geothermal reservoirs, which are formed as a result of filling underground cavities with precipitation water heated by nearby magma;
Dry hot rocks heated by magma (at a depth of 2 km or more) - their energy reserves are the largest;
Magma, which is molten rocks heated to 1300 ° C.
The experience gained by various countries relates mainly to the use of natural steam and thermal waters, which are still the most realistic base for geothermal energy. However, its large-scale development in the future is possible only with the development of petrogeothermal resources, i.e. thermal energy of hot rocks, the temperature of which at a depth of 3-5 km usually exceeds 100 °C.
When compared with traditional energy sources, the following advantages of geothermal resources are obvious: inexhaustibility, ubiquity of distribution, proximity to the consumer, locality of providing the consumer with heat and electricity, belonging to local resources, full automation, safety and practical desertion of geothermal energy production, economic competitiveness, the possibility of building low-power installations, environmental cleanliness.
However, the specificity of geothermal resources also includes a number of disadvantages: low temperature potential of the coolant, non-transportability, storage difficulties, dispersed sources, and limited industrial experience.
Currently, it is customary to distinguish 2 main classes of geothermal resources - hydro and petrogeothermal. The former represent that part of geothermal energy resources that is confined to natural collectors and is represented by natural heat carriers: groundwater, steam or steam-water mixtures. They are industrially operated by circulation systems (France, USA, Germany, Denmark, Ukraine, Poland, Switzerland, Russia, etc.). Petrogeothermal - that part of the thermal energy of the subsoil, which is directly connected with the skeleton of water-bearing rocks or with practically impermeable rocks. The technology for extracting petrogeothermal resources (drilling depth up to 10 km) is at an experimental level. Created only a few experienced circulation systems with artificial collectors in the USA, England, Japan, Russia (Tyrnyauz), Germany, France.
The operational reserves (resources) of hydrogeothermal energy are generally understood as the amounts of heat and water that can be obtained from the assessed aquifer (complex) by technically, economically and environmentally rational water intake facilities under a given mode of their operation and the appropriate quality of the heat carrier (temperature, chemical and gas composition) during the entire estimated service life. The operating heat reserves are expressed either in units of power or in tons of fuel (conditional) per year, the operational reserves of thermal waters have the dimension of a volume flow rate for water (l / s, m3 / day) or a weight flow rate for steam and steam-water mixtures (kg / s, t/day).
The most complete classification of resources and reserves of geothermal energy was developed by E. I. Boguslavsky.
For the lower temperature limit of thermal waters, it is advisable to take 20º C, taking into account the possible use of heat pumps and the presence in many industries National economy needs for subthermal coolants with temperatures of 20-40º C.
Low-potential waters (with a temperature of 20-100º C), in which it is advisable to distinguish a subclass of waters with temperatures of 20-40º C. These waters can be consumed for heat engineering needs mainly with the use of heat pumps. They can also be effectively used for thawing frozen rocks and washing placers, intensifying fishing, heating open ground, injection into oil-bearing formations, technological processes requiring low-grade coolants. The main purpose - heat supply, industrial, agricultural and household facilities.
Medium-potential (100-150º C) waters can be effectively used both for heat supply of industrial, agricultural and household facilities, and for generating electricity using intermediate working fluids.
High-potential (more than 150º C) water can be effectively used to generate electricity in a direct cycle. In the composition of such waters, it is advisable to distinguish superheated waters (150-250º C), highly superheated waters (250-350º C) and extremely superheated waters (more than 350º C).
The quality of thermal waters intended for therapeutic use (in terms of temperature, salinity, ionic and gas composition, gas saturation, content of pharmacologically active trace elements in the waters, radioactivity, pH) should be assessed in accordance with special requirements for the study and classification of mineral medicinal waters.
2. Stages and stages of the study of geothermal resources of the subsoil
The sources of geothermal subsoil resources are:
Underground geothermal waters;
Warm mountain range bowels
Geothermal subsoil resources can be used for:
Receiving electricity;
Hot water supply;
Heat supply of residential and industrial premises;
Therapeutic, recreational and other purposes, due to the value, usefulness and other characteristics of geothermal resources of the subsoil.
1) Regional geological study of the subsoil is carried out in the following stages:
Small-scale geological surveys;
Medium-scale geological surveys;
Large-scale geological surveys.
2) The search for geothermal subsoil resources and the evaluation of the deposit are carried out in order to identify and preliminary evaluate the deposit suitable for development. The search for geothermal resources of the subsoil and the evaluation of the deposit are carried out in the following stages: - prospecting; - assessment of the deposit.
3) Exploration of geothermal resources of the subsoil and preparation of the deposit for development are carried out in order to obtain information about the phenomena and processes occurring in the subsoil, the geological structure of the deposit, the technological and other features of the deposit, the quality and quantity of the geothermal resources of the subsoil located in it, the conditions for the development of the deposit , allowing to carry out a geological and economic assessment of this field. Exploration of geothermal subsoil resources and preparation of a deposit for development are carried out in the following stages:
Preliminary exploration of geothermal resources of the subsoil, carried out in order to obtain reliable data for a preliminary assessment of the quality and quantity of the identified reserves of geothermal resources of the subsoil, to obtain an economically justified industrial assessment of the field, to justify the feasibility of financing further exploration work;
Detailed exploration of geothermal resources of the subsoil, carried out in order to prepare a deposit for development. Based on the results of a detailed exploration of geothermal resources of the subsoil, permanent exploration conditions of geothermal resources of the subsoil are developed, according to which the reserves of geothermal resources of the subsoil are calculated;
Additional exploration of geothermal subsoil resources, carried out at a field that has been explored in detail, but not transferred to development, in case of insufficient knowledge of this field, as well as at a field under development, if additional study is required in connection with a revision of production volumes and technology, primary processing(cleaning, enrichment) use of geothermal subsoil resources;
Operational exploration of geothermal resources of the subsoil, carried out in the process of developing a deposit in order to clarify the quantity and quality of reserves of geothermal resources of the subsoil, to obtain other geological information necessary for the preparation of annual plans for the development of mining operations.
3. Principles and methods of studyand assessment of geothermal resources
Important in the cycle of tasks of widely involving hydrogeothermal resources in the fuel and energy balance of the country is to increase the efficiency of prospecting and exploration, which, in turn, is possible provided that the principles and methodological foundations of their planning and implementation are constantly improved. The methodology for planning prospecting and exploration for thermal waters, as well as for other types of minerals, should be based on the fundamental principle of environmental and economic feasibility. Its effective implementation is possible if the leading general principles of field study are observed: completeness of the study, consistent approximation, equal reliability, minimization of socially necessary labor, material and time costs.
One of the most important is the requirement of staged prospecting and exploration, which allows, with a minimum of socially necessary costs, to produce a phased geological and economic assessment of deposits and sites.
The ultimate task of the entire research cycle is the discovery, geological, economic and environmental assessment of natural coolant deposits, i.e. determination of the value of their operational reserves and heat and power potential, as well as assessment of the conditions and aggregated technical and economic indicators for the development of productive aquifers, complexes or fractured zones.
When studying geothermal resources, a fairly wide range of methods is used, which is determined in each specific case by the complexity and characteristics of the object under study and the degree of its study in the previous period.
In general, the main types of field work are: geological and hydrological surveys, special surveys (geothermal, gas-hydrochemical, etc.), reconnaissance survey of the exploration site, drilling and thermohydrodynamic studies of wells, geophysical and hydrological surveys, stationary observations of natural and disturbed regimes of thermal and cold water, inspection of previously drilled deep wells and existing water intake facilities, sampling of water and core material, special types of research (geophysical, hydrogeochemical, geothermal, isotope, nuclear physics, etc.).
Geological and hydrogeological survey, depending on the size and complexity of the studied objects, is carried out on a scale of 1:50,000 - 1:10,000 (in some cases 1:5000), mainly when searching for deposits of a fissure-vein type. The purpose of the survey is to study the geological structure, geothermal and hydrogeological conditions of the deposit and adjacent areas, and to delineate the most productive areas. Particular attention should be paid to the study of the conditions for the discharge of thermal and cold waters, steam-gas jets, heated areas and zones of altered rocks, as well as the identification of zones of tectonic faults.
Special surveys are carried out, as a rule, in combination with geological and hydrogeological surveys, or as an independent type of work at the exploration stage (usually, when geological and hydrogeological surveys have been carried out earlier). The tasks of these surveys are mapping of individual (or complex) parameters that are direct or indirect search indicators (criteria): temperature, components of the chemical and isotopic composition of gases, groundwater and surface water. these studies are carried out by conducting thermometric (hole or in shallow wells), aerospace (IR survey) and gas-hydrochemical surveys (testing of all steam, gas and water manifestations, sampling of subsoil gas, etc.).
A reconnaissance survey of exploration sites is carried out mainly at the beginning of exploration work (build-up, forest cover, passability, availability of communications, energy supply, etc.).
Drilling operations include drilling of exploratory, exploration, exploration and production, observation and (if necessary) injection wells. The main type of research in order to obtain the information necessary to assess the operating reserves of the coolant is special experimental filtration work. The methodology for carrying out these works is determined by their intended purpose, the staging of research, the complexity of the hydrogeological and hydrogeothermal conditions. According to the method of their implementation, experimental filtration works are divided into releases carried out by using the elastic energy of the reservoir (fractured zone), thermal lift (steam lift), gas lift, pumping, performed using special water-lifting equipment, and injection.
Depending on the intended purpose, releases (pumping out) are divided into trial, experimental and experimental-operational.
Trial releases (pumping out) are carried out at the stage of prospecting; in individual cases- at the stages of preliminary and detailed exploration. At the exploration stage, the task of test releases (pumping) is to obtain preliminary information about the filtration and capacitive properties of rocks, their water abundance, quality and temperature of thermal waters, steam-water mixtures and steam.
Pilot releases (pumping) are carried out at the stages of preliminary and detailed exploration and are divided into single, cluster and group. Their tasks are: determination of the calculated hydrogeological parameters of productive horizons and filtration features of fractured zones, identification of patterns of their change in plan and section; establishing the relationship between well flow rate and water level decrease; determination of the values of cut levels in the assessment of reserves by the hydraulic method, etc.
Pilot-operational releases (pumping) are carried out at fissure-vein type deposits in order to obtain initial information for assessing the operational reserves of thermal waters by the hydraulic method. The main task is to identify the dependence of the level decrease over time at a given design flow rate. They are carried out until stable patterns of change in the levels and (or) quality of water in observation wells over time are obtained, which make it possible to predict their drawdown at the end of the estimated life of the deposit (site).
Before carrying out trial, experimental and pilot production (pumping), it is necessary to measure the position of groundwater levels in a natural setting (or reservoir and excess pressures), the water temperature at the wellhead and in reservoir conditions, and take water samples for general analysis.
Hydrological studies are carried out during the search and exploration of deposits of thermal waters of the fissure-vein type, which are, to one degree or another, in connection with surface waters. In the process of research, data should be obtained on the runoff regime, level, temperature and chemical regime of rivers, cold springs in the area of the deposit and in adjacent areas upstream and downstream of the water artery.
Stationary observations of the natural regime of thermal waters are carried out both at wells and at thermal water sources. They include observations of the regime of flow rates of sources, steam-gas jets, chemical (including gas) composition and temperature. Tasks:
Clarification of the conditions for the relationship of underground thermal and surface cold waters;
Determination of seasonal and long-term changes in the spring runoff of thermal waters;
Study of the nature of changes in mineralization, chemical and gas composition, temperature of thermal waters in annual and long-term sections;
Determination of the parameters of the relationship of thermal waters of individual fissure zones.
Observations of the disturbed regime of thermal waters in the areas of existing water intake facilities should include observations of water levels in production and specially equipped observation wells, the chemical and gas composition of thermal waters, the temperature of the water in the outflow and along the wellbore, and the flow rate of water intake wells.
Special research methods (hydrogeochemical, geothermal, isotope, nuclear physics) are designed to determine the conditions for the formation of operational reserves of thermal waters, identify and localize areas of recharge and discharge, study the conditions of interaction between aquifers through separating low-permeable layers and interaction between fracture zones, as well as to study the processes of the movement of injected water into the reservoirs, its cooling, etc. This also includes geobotanical studies that are carried out at the exploration stage in the deposits of the fissure-vein type. They consist in the study of plant communities, which are used to identify and delineate areas of heating and hidden thermal manifestations.
Geophysical methods. When studying deposits of thermal waters, almost all types of geophysical methods are used: borehole, ground, airbrush, etc. With their help, the geological structure of the study area (especially deep), hydrogeological stratification and correlation of sections are carried out, hydrogeodynamic, hydrogeochemical and hydrogeothermal characteristics of the studied strata are studied.
Ground, aquatic (marine) and aerographic methods provide an almost continuous study of the territory. They include electrical, seismic, gravity-magnetic exploration, radio and thermometry, most often performed on the ground, but can be performed at the bottom of reservoirs or from the water surface: these same methods, with the exception of seismic exploration, are implemented using aircraft. As well as geophysical surveys of wells (GIS), ground and aerographic works are carried out by setting up special field observations, or on the basis of re-interpretation of available multi-purpose materials.
Landscape-indicating methods in relation to the object of research are divided into ground and remote ones.
Ground-based methods are used in geothermal research to a very limited extent, only for geological referencing and interpretation of anomalies detected by remote methods. At the same time, the tasks of the general geological and hydrogeological plan and a special geothermal direction are solved.
When searching for thermal waters and other types of geological work, remote (aerospace) methods are widely used. With their help, they take pictures of the earth's surface, registering light, infrared and decimeter electromagnetic fields, i.e. having a length of 0.3 microns to 1.0 m. modern remote methods are essentially a set of methods for electrical exploration, thermometry, landscape studies, using both the above methods and visual observations.
In the remote study of the Earth's surface, both air vehicles (airplanes, helicopters) and space vehicles (manned spaceships, artificial satellites Earth, orbital scientific stations). The height of aerial observations varies from a few tens of meters to several kilometers, and space ones - from 300 to 3000 km.
Especially important in forecasting, prospecting and exploration of thermal waters are aerospace photography (AFS and FSC) and infrared photography.
Aerospace photography is currently the main type of remote observation. When shooting with spacecraft covers a huge area, measured in hundreds of thousands of square kilometers, while from aircraft - only tens of square kilometers. In general, APS and CPS allow solving a series of geological and hydrogeological problems, however, this information is not always sufficient for hydrogeothermal studies.
Infrared photography is based on the ability of natural bodies to emit infrared rays. Their intensity is determined by the temperature and emissivity of these bodies. IR imaging is the most important remote sensing method in geothermal studies, especially in the study of hydrothermal volcanism, which is manifested in the near-surface part of the section. In conditions of haze and fog, IR imaging has a significant advantage over APS and FSC and allows you to get a good quality image. With the help of IR survey, it is possible to solve a series of hydrogeological problems: to assess soil moisture, to determine the level of groundwater, to identify groundwater discharge zones within water areas, to trace tectonic disturbances that are flooded, to outline talik zones, to detect heated areas of the earth's surface, to identify thermal water outlets.
4 . Ggeothermal station in Belarus
Two territories were discovered in the republic in the Gomel and Brest regions with reserves of geothermal waters with a density of more than 2 tons of conventional units. t./m² and a temperature of 50°C at a depth of 1.4-1.8 km and 90-100°C at a depth of 3.8-4.2 km. But temperature conditions The bowels of the territory of the republic have not been studied enough. Great depth occurrence of thermal waters, their relatively low temperature, high salinity and low flow rate of wells (100-1150 cubic meters / day) do not currently allow considering the thermal waters of the republic as a noteworthy source of energy.
In February 2010, the Brest enterprise launched the first geothermal station in Belarus.
The work of the country's first geothermal station was launched. The pilot project was carried out by the Berestye greenhouse complex. In fact, this is a new word in the use of alternative energy sources.
On the territory of the plant, a well was drilled to a depth of 1520 meters, where the water temperature exceeds 40 degrees. True, the volume of the source turned out to be small. In the process further work it was found that at a depth of 1000-1100 meters there are very thick layers of sufficiently warm, about 30 degrees, water suitable for industrial use. It is unsalted and high quality. The next step was the purchase of heat pumps and other special equipment.
A geothermal station is an electronic-mechanical system that allows, relatively speaking, from 1000 liters of water at a temperature of 30 degrees to get, for example, 300 liters of water at a temperature of 65 degrees and 700 liters at a temperature of 4 degrees. Hot water goes for heating greenhouses. And cold, according to the project, will be cleaned and supplied to the drinking network of the city within the limits of one and a half thousand tons per day. It will be bottled and sold.
The system so far provides 1.5 hectares of greenhouses and is tied to general cycle with boilers. Natural heat is distributed to part of the area occupied by flowers, lettuce line, cucumbers and tomatoes. It is made so that if the air temperature drops sharply, the central boiler room will immediately turn on. According to calculations, 1 million cubic meters of gas will be replaced per year, and this will save more than 200 thousand dollars. For example, more than one and a half hundred two-story cottages can be heated with the saved fuel. The power of the station is one gigacalorie per hour. The station produces more heat than is calculated according to the project.
The entire control system operates in automatic mode, and all desired parameters displayed on the monitor in the central boiler room.
The main difficulty was and still remains that there are practically no specialists in the design and adjustment of such systems.
The well was drilled by Belgeology in order to search for oil, gas and other minerals. The work was financed by the Ministry of Natural Resources and Environmental Protection of the Republic of Belarus. Two powerful heat pumps cost about 100 thousand euros. The regional executive committee helped, they used their own funds. By and large, the project was inexpensive. In addition, it should pay off in 5 years.
If water is pumped out from the depth, then there is by no means a vacuum created. Layers of sand, saturated with water, are constantly renewed. And heating is due to the temperature of the earth.
Conclusion
Geothermal resources - the amount of heat contained in the lithosphere or its sections, to a depth technically achievable by means of drilling for the forecast period.
The main stages in the study of geothermal resources of the subsoil are:
Regional geological study of the subsoil;
Search for geothermal subsoil resources and evaluation of the deposit;
Exploration of geothermal subsoil resources (including trial operation of hydrocarbon fields or individual boreholes), preparation of a field for development.
The main types of field work are: geological and hydrological surveys, special surveys (geothermal, gas-hydrochemical, etc.), reconnaissance survey of the exploration area, drilling and thermohydrodynamic studies of wells, geophysical and hydrological work, stationary observations of natural and disturbed regimes of thermal and cold waters, inspection of previously drilled deep wells and existing water intake facilities, sampling of water and core material, special types of research (geophysical, hydrogeochemical, geothermal, isotope, nuclear physics, etc.).
The temperature conditions of the bowels of the territory of the Republic of Belarus have not been studied enough. The great depth of occurrence of thermal waters, their relatively low temperature, high salinity and low flow rate of wells (100-1150 cubic meters / day) do not currently allow considering the thermal waters of the republic as a noteworthy source of energy.
Bibliography
1. A.A. Shpak, I.M. Melkanovitsky, A.I. Sereznikov "Methods of studying and evaluating geothermal resources". M.: Nedra, 1992. - 316 p.
3. www.baltfriends.ru
4. www.news.tut.by
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Geothermal source (Greek GBYab - earth and IESM - heat, heat) - access to the surface of groundwater heated above 20 ° C. There is also a definition according to which a source is called hot if it has a temperature above the average annual temperature of the area.
Most hot springs are fed by water that is heated by igneous intrusions in areas of active volcanism. However, not all thermal springs are tied to such areas, the water can also be heated in such a way that seeping down The groundwater reach a depth of about a kilometer or more, where the rock has more high temperature due to the geothermal gradient of the earth's crust, which is about 30 °C per km for the first 10 km.
Thermal mineral springs are divided into warm (20-37 °C), hot (37-50 °C) and very hot (50-100 °C).
Man simply cannot exhaust this - strictly speaking, non-renewable - internal resource of the planet. Where the earth's crust is thin and magma flows to the surface, this heat can be used to turn water into steam, which turns a turbine and generates electricity.
According to the method of application of geothermal energy, the following three categories are distinguished:
Direct use, in which hot water and steam directed directly to the Earth's surface are used in heating systems, horticulture and industrial processes;
Electricity generation, in which geothermal heat is used to drive turbines with geothermal steam or hot water; or
Heat pumps that work by moving heat and are used to control the temperature of buildings.
Direct use methods such as bathing and cooking do not require advanced technology and have been around for thousands of years. Current direct uses include heating buildings (and districts, as well as entire villages and cities), greenhouse horticulture, crop drying, aquaculture, and industrial processes such as pasteurization.
Thermal waters, as I said, are used for heat supply and as an alternative source of electricity. Reykjavik (the capital of Iceland) is completely heated by the heat of thermal waters. In Italy, Iceland, Mexico, Russia, the USA and Japan, a number of superheated power plants operate. thermal waters with temperatures over 100 °C.
The heat of underground water sources is an environmentally friendly and renewable energy source. The technology for extracting and converting geothermal energy into electrical energy is also safe from an environmental point of view. The use of geothermal energy does not lead to the emission of harmful substances, soot and smoke into the atmosphere. Currently, the heat of the subsoil is used in 78 countries of the world. Of these, 24 countries have learned how to generate electricity through the use of underground steam. There are now about 5,000 geothermal installations in Estonia. In Switzerland, the number of stations has exceeded 40,000. In Sweden, there are more than 300,000. There are about 200,000 heat pump units in the United States, and 600 such units have been installed in Poland.
Theoretically, the Earth's geothermal resources are sufficient to meet human needs for electricity, but only a very small part of them can be used in reality, because the exploration and drilling of deep-seated resources is very expensive. However, ongoing technological progress is expanding the range of resources.
The first geothermal generator was launched in Italy in 1904 in the Larderello region, in Tuscany. Prince Piero Ginori lit five light bulbs in front of the cameras, and already in 1911 the Tuscans launched the first full-fledged geothermal station. Today, the station provides a million homes in Tuscany - a quarter of the electricity in the region. Geothermal stations are actively used in New Zealand and Iceland - lands with high volcanic activity. So in Iceland there are more than 7 thousand geothermal sources: the largest number per unit area in the world. Thanks to greenhouses powered by thermal springs, in a country where there are no fruit trees everywhere, and only potatoes and cabbage grow on the ground, a lot of not only their own vegetables, but also flowers, 85% of Icelanders live in houses heated by the waters of thermal springs. Hot water is also supplied to numerous greenhouses and swimming pools.
But what about the rest of the world? The main hopes are associated with deep drilling - from 3 to 10 km - to get to the so-called heated hard rock. Only on the territory of the United States it contains enough energy to provide all mankind with energy for 30 thousand years. deep drilling has become standard technology. Water is poured into the well, where it boils, the steam comes out and turns the generator turbines. The only problem is that water escapes into underground cracks and needs to be constantly updated. FROM negative consequences applications of this technology collided in 1996 in Basel, Switzerland: shortly after water was pumped into the well, a small earthquake occurred. The water was removed, but the tremors continued for some time. We concluded: in seismically hazardous areas, this method of obtaining energy can go sideways. Can geothermal resources be depleted? This is of course out of the question. But local cooling of sources is quite possible, so in the same Tuscany, energy production reached its maximum capacity in 1958, since then things have been declining. The capacities of GeoTPPs in the world at the end of the 1990s were almost halved due to the rise in the cost of operation.
Today, the world leaders in the geothermal power industry are the USA, the Philippines, Mexico, Indonesia, Italy, Japan, New Zealand and Iceland. Especially a prime example The use of geothermal energy serves as the last state. The island of Iceland appeared on the surface of the ocean as a result of volcanic eruptions 17 million years ago, and now its inhabitants enjoy their privileged position - approximately 90% of Icelandic homes are heated by underground energy. As for power generation, there are five Geothermal power plants with a total capacity of 420 MW, using hot steam from a depth of 600 to 1000 meters. Thus, with the help of geothermal sources, 26.5% of all electricity in Iceland is produced.
geothermal mineral electricity
Top 15 countries using geothermal energy (data for 2007)
Geothermal energy is one of the types of renewable energy sources (RES). The history of the use of geothermal energy for balneotherapy begins with ancient rome, for the generation of electrical energy - from the end of the 19th century (the city of Lorderollo, Italy). According to the World Geothermal Congress, by 2010, geothermal power plants with a total installed capacity of 10.7 GW, geothermal heat supply systems with a total thermal capacity of more than 50.6 GW were operated in the world.
This type of renewable energy is practically inexhaustible, a fraction of a percent of the heat of the earth's interior is enough to provide all energy needs humanity on long time. The source of geothermal energy is the magmatic heat of the Earth. Geothermal deposits are localized with zones of geological movement of the layers of the earth's crust and associated volcanic processes. In these areas of the earth's surface, magmatic flows rise close to the surface and heat the overlying sedimentary water-saturated rocks.
For the emergence of a geothermal deposit, three main conditions are necessary: the supply of deep heat, the presence of water-saturated rocks and aquicludes above them. Atmospheric precipitation in mountainous areas, where rocks are bare, penetrate into them and move towards their slope with a decrease to a depth where they are heated by magmatic heat. The geothermal coolant from the well is fed to a geothermal power plant (GeoPP) and then ends up in another well.
In international practice, surface geothermy (up to 400 m) and deep geothermy are distinguished. In surface geothermy, the heat of groundwater and rocks is used with the device of borehole umbrellas and tubular fields buried below the freezing depth. The article deals with the issues of geothermy with wells with a depth of 1500 to 4000 m with the extraction of geothermal coolant in a liquid or vapor state.
According to the classification of the International Energy Agency (IEA), five types of geothermal deposits are distinguished: dry steam, wet steam, geothermal water, dry hot rocks, and magma. The resources of geothermal fields in Russia provide good prospects development of electricity and heat supply. According to d.t.s. Professor P.P. Bezrukikh, their gross potential is 22.9 trillion toe, technical potential - 11.87 trillion toe, economic potential - 114.9 million toe.
A total of 3,000 geothermal wells 2.5-3.5 km deep have been drilled in Russia. On fig. 1 shows the values of the capacities of geothermal heat supply systems of Russian regions in 2003; in fig. 2 - values of the capacities of individual technologies for the use of geothermal waters. According to d.t.s. professor O.A. Povarov, the total capacity of existing geothermal heat supply systems is up to 430 MW, promising up to 21 GW.
In some regions, their use can provide up to 10% of the total energy consumption. Currently, thermal water intakes are operated mainly in three regions: Dagestan, Krasnodar Territory, Kamchatka Peninsula. In 1984, about 250 geothermal wells up to 3 km deep were on the balance sheet of Podzemburgaz OJSC (Moscow).
Of all types of geothermal resources according to the IEC classification, Russia has deposits of wet steam (Kamchatka, Kuril Islands), geothermal water (Kamchatka, Kuril Islands, North Caucasus), dry hot rocks. From explored deposits - most of contains geothermal water with a surface temperature of 70-110 °C.
During the existence of the USSR, geothermal waters were used in the Krasnodar and Stavropol Territories, Kabardino-Balkaria, North Ossetia, Chechen-Ingushetia, Dagestan, Kamchatka Region, Crimea, Georgia, Azerbaijan and Kazakhstan. In 1988, 60.8 million m3 of geothermal water was produced (in Krasnodar, Stavropol Territories, Kabardino-Balkaria, Kamchatka Oblast).
In the USSR, there was a system of exploration, development and exploitation of geothermal resources. The VSEGINGEO Institute developed an atlas of geothermal resources of the USSR with 47 deposits with geothermal water reserves of 240-1000 m3/day. and steam hydrotherms with reserves of more than 105-103 m3/day. On its basis, NPO Soyuzburgeothermia (Makhachkala) developed a scheme for promising geothermal heat supply for the country.
In the USSR, research work on this problem was carried out by the institutes of the Academy of Sciences, the ministries of geology and the gas industry. The functions of the leading research organizations were assigned: on the problems of geothermal power plants - to the Energy Institute. G.M. Krzhizhanovsky (Moscow), on the problems of geothermal heat supply - at the Central Scientific - Research institute engineering equipment(Moscow), but the problems of operation - to the Academy public utilities(Moscow).
The development of fields, their development and operation, the solution of all problems (cleaning, re-injection) was carried out by subdivisions of the Ministry of the gas industry. It included five regional operational departments, the Soyuzgeoterm research and production association (Makhachkala).
The operation of systems of geothermal heating and hot water supply of buildings was entrusted to the Gosstroy of the USSR. In the USSR, the first normative document on geothermal VSN 36-77 "Instructions for the integrated use of geothermal waters for heat supply to buildings and structures" was developed in 1977. In 1987, at the Institute "TsNIIEP Engineering Equipment" under the guidance of Ph.D. IN AND. Krasikov, the design standards "Geothermal heat supply of residential and public buildings and structures”, VSN 56-87.
Currently, geothermal resources are practically used in three regions of the country: Kamchatka and the Kuril Islands, Krasnodar Territory and Dagestan. The total capacity of the GeoPP in Kamchatka and the Kuriles is 84.6 MW, including the largest in Russia Mutnovskaya GeoPP with a capacity of 50 MW. Geothermal deposits with water coolant are much more widespread.
In the Krasnodar Territory and Adygea, 18 deposits of geothermal waters have been explored, including 13 in operation, and five are idle without consumers. A total of 86 geothermal wells have been drilled in this region, of which 40 are in operation. According to 1986 data in Fig. Figure 3 shows the structure of geothermal water production at the deposits of the Krasnodar Territory with a total volume of 8.5 million m3; 4 - the structure of their consumption for heating greenhouses with a total volume of 4.6 million m3, in fig. 5 - structure of consumption for heating and hot water supply of facilities with a total volume of 3.9 million m3.
On fig. Figure 6 shows a graph of geothermal water production in the Krasnodar Territory with a decrease of almost three times compared to the Soviet period. Potential thermal power and thermal energy generation of geothermal deposits in the Krasnodar Territory and Adygea are shown in Fig. 1. 7. The first phase of the 5 MW Geothermal Heat Supply Demonstration Project has been implemented in this region.
123 wells have been drilled in Dagestan, of which 58 wells have been operated at eight water intakes. The maximum amount of geothermal water was produced in 1988 - 9.4 million m3. The region currently produces 4.1 million m3 of geothermal water annually. The largest field in Dagestan is Kizlyarskoye, where 1.4 million m3 of geothermal water is produced annually from nine wells.
At this field, two wells are successfully re-injected in the amount of 0.8 million m3 per year of spent geothermal coolant, which is 57% of the total volume of water produced. Heating systems are double-circuit. In the first circuit, the heating medium is the water of the so-called "Chokrak" horizon with a temperature of 115 °C, in the second - the water of the Apsheron horizon with a temperature of 48 °C.
With a population of 45 thousand people in the city of Kizlyar, 70% of the inhabitants are provided with geothermal heating and hot water. There is a project to increase the capacity of this geothermal system based on the provision of 100% of the city's needs with the reinjection of all waste heat carrier. Implementation cost this project about $ 1 million. The payback period is seven years.
In Makhachkala, six geothermal wells with a total flow rate of 13.6 thousand m3 / day are used to supply hot water to multi-storey residential buildings. at a temperature of 95-100 °C. The geothermal thermal water intake of the city has a capacity of about one million m3/year with a storage tank with a capacity of 4000 m3. In Russia, with large reserves of geothermal resources, their practical use is limited.
There is no state policy in geothermal energy. Regulations obsolete, new technologies are of limited use.
