KR20100101059A - System and method of creating egs group utilizing fault zone - Google Patents

Abstract

PURPOSE: A system and a method for forming an Enhanced Geothermal System group using a fault zone are provided to remarkably reduce required costs by cost-efficiently forming an EGS group. CONSTITUTION: A method for forming an Enhanced Geothermal System group using a fault zone is as follows. An open hole section of a production well is arranged in a fault core of an inactive fault zone. Open hole sections of an injection well are arranged in a fault damage zone or a host rock of the fault zone to complete boring. Natural fracture zones formed in the fault zone are expanded by performing hydraulic-fracturing. An artificial fracture zone is created in the host rock when necessary.

Description

System and method of creating EGS Group utilizing fault zone}

The present invention relates to an ESG group composition system and method using a fault zone, and more particularly, to complete the open hole section of the production well in the fault core of the inactive fault zone, the open hole sections of the injection wells Certain Enhanced Geothermal Systems (EGSs) that complete in the mother rock are attached one after another along the periphery of the mononuclear nucleus, such that portions of the outer boundaries of the EGSs contact each other and share some injection wells. By creating the EEG Group, it is possible to use the smaller crushing units to create new crushing zones with little or no natural crushing zones, while using the smaller crushing units and at the same time with much higher success rates. Making it possible to significantly lower costs, and significantly reducing the number of injection wells per production well. Made possible to reduce the non-paid, yijieseu (EGS) relates to a system and method that significantly improves the composition of the relevant economy.

Binary Geothermal Power Generation, which uses geothermal water produced by forming EGS as a heat source, increases greenhouse gas reduction pressure in addition to rising oil and gas prices and supply instability, as explained in Document 1. It is emerging as a promising solution to the increasingly difficult energy situation.

Geothermal energy exists underground at any point in Korea's territory, and its size is almost infinite. However, the depth of geothermal energy at the same temperature is deeper than that of geothermal power generation projects around the world.

In many areas of Korea, it is possible to produce geothermal energy at a temperature that can achieve binary geothermal power generation if EGS is formed from 3km to 4km underground. Therefore, by securing and developing core technologies such as low-cost and high-efficiency deep drilling technologies, it is possible to carry out geothermal power by drilling deeper and producing geothermal energy in parallel with rising energy prices.

Deep geothermal energy existing in our territory has been left undeveloped because it was recognized as not worth developing with conventional geothermal power generation methods, but recently, the geothermal energy production and binary geothermal energy which are beneficial in patent documents 1 to 8 Means and methods have been disclosed to enable development.

Korea's energy self-sufficiency rate is as low as 3%, and it is a very fragile structure that requires 97% of the energy required to be imported. Oil and gas prices are rising, and to make matters worse, according to the UN Convention on Climate Change, the world's top ten greenhouses. Due to the increasing pressure on greenhouse gas reduction due to being a gas emitter, the energy situation is confined in an increasingly difficult direction. Therefore, in addition to the systems and methods disclosed in Patent Documents 1 to 8, EGS (EGS) composition, geothermal The creation of means and methods to further improve the efficiency and economics of energy production and geothermal power generation is required.

KR Patent Application No. 10-2008-0044966, "Method of binary geothermal power generation using deep seawater", application date: 2008.05.15. KR Patent Application No. 10-2008-0105167, "System and method of binary geothermal power generation utilizing river zone", application date: October 27, 2008. KR Patent Application No. 10-2008-0131009, "System and method of producing geothermal energy utilizing off-peak power", application date: December 22, 2008. KR Patent Application No. 10-2009-0003582, "System and method of creating EGS utilizing off-peak power", filed Jan. 16, 2009. KR Patent application No. 10-2009-0078070, "System and method of constructing drilling derrick utilizing tower crane mast", filed: 2009.08.24. KR Patent Application No. 10-2010-0046729, "System and method of creating EGS having zonal injection wells", dated May 19, 2010. KR Patent Application No. 10-2010-0046735, "System and method of creating EGS Group", filed May 19, 2010. KR Patent Application No. 10-2010-0065274, "System and method of operating EGS power plant utilizing compressed air", application date: 07.07.2010.

In the project of geothermal power generation using Geothermal Fluid (EGS) produced by creating Enhanced Geothermal Systems (EGS) as a heat source, the primary and most important task for securing and improving economic feasibility is (EGS) is made at the lowest possible cost.

Even though there are almost infinite deep geothermal resources in the territory of Korea, the primary and biggest reason that has been left undeveloped is because the cost of creating EGS (EGS) using conventional technology was very high.

In Korea, most of the igneous rocks or metamorphic rocks are formed with EGS, and there are no natural crushing zones or no crushed igneous rocks or metamorphic rocks. In order to create a large scale, it is necessary to mobilize the latest hydraulic fracturing equipment such as high pressure pumps on a large scale above the level performed in the tight gas field. However, since the equipment is not present in the country and must be obtained from overseas, it may cost U $ millions per well depending on the size of the hydraulic fracturing.

Even with the high cost of mobilizing the latest hydraulic fracturing equipment on a large scale as described above, the results of the worldwide EGSs described in Chapter 4 of Document 1 (MIT report) of Patent Document 1 Likewise, the success rate of forming a desired EGS by performing hydraulic fracturing on a rock layer having no or little natural shredding zone is not yet high with existing hydraulic fracturing techniques.

Moreover, since there have never been any EGS in our land, it is expected that it will be more difficult to develop and pioneer EGS, especially in the early stages.

Therefore, for the early stages of creating the first EGS in our homeland and developing and pioneering subsequent EEGs, we have solved the above-mentioned challenges at a lower cost and with a higher success rate. The creation of systems and methods to create and pioneer EGSs is required.

SUMMARY OF THE INVENTION The present invention has been made in accordance with the above needs, and an object of the present invention is to provide a system and method capable of forming desired EGSs at a lower cost and with a higher success rate in our land.

In order to achieve the above object, the present inventors have been conducting an in-depth investigation and research on the characteristics, development conditions, and technologies of geothermal energy resources existing in various forms in our land for a long time. The open hole section of the production well is completed in the fault core of the inactive fault zone formed to the deep part, and the open hole sections of the injection wells are fault damaged zone or host rock. Specific EEGs, in accordance with the direction and shape of the expansion and formation of crushing zones in the core rock layer, so that some of the edges of the EEGs are in contact with each other and share some injection wells. In order to create the desired crushing zones, they are formed one after another along the periphery of the mononuclear nucleus to form an EGS Group (Enhanced Geothermal Systems Group). Written, it has led to the present invention with the ability to accomplish the above object conclusion.

On the Korean Peninsula, many crustal deformations occurred from the Protozoan to the New Seondae, and the fault movements were repeated, resulting in the formation of a number of fault zones. The fault zones are formed with a large amount of fracture zones due to fault movement, and the fracture zones extend to a depth of several kilometers underground and the width of the fault zones can also reach several kilometers. The fault zones are known to be mostly inactive.

Many of the world's geothermal power plants produce geothermal water (including steam) through fault zones and accompanying fracture zones. A typical example is the Geysers geothermal complex, the world's largest geothermal complex, located in northern California, USA.

In the EEG composition, the results vary greatly depending on the presence or absence of natural crushing zones. As described in '4.10 Generalizations from EGS Field Testing' in Patent Document 1 (MIT report) of Patent Document 1, many of the crushers formed by hydraulic fracturing have been analyzed. Reopened or expanded ones are not only advantageous in terms of success rate, cost, etc., but also cost-effectively and using existing hydraulic fracturing techniques. It was analyzed that it is a method that can generate desired EGS with high success rate.

In other words, even in closed shredding zones, the presence of natural shredding bands will allow for the creation of desired EGSs, both cost-effectively and with high success rates. Existing hydraulic fracturing techniques are still inadequate to create the desired EGS in a cost-effective and high success rate in igneous or metamorphic rocks with little or no natural crushing zone.

In addition to the difficulties mentioned above, in order to create EGS in igneous rocks or metamorphic rocks with no natural crushing zone or no natural crushing zone, there has been no EGS in Korea. It will be very expensive to obtain the latest hydraulic fracturing equipment such as high pressure pumps from overseas in a large scale. Therefore, it will be the first EGS in Korea and subsequent EGS. • In the early stages of pioneering, attempts to create EGS for rock formations with little or no natural crushing bands seem unlikely to produce successful results.

The present inventors have concluded that the above-mentioned problems can be solved by forming an EGS Group composed of specific EGSs in fault zones formed in the Korean territory. Reached.

Fault Zones are generally divided into Fault Damage Zones, where fractures are concentrated on both sides of the Fault Core, which receives the most deformations and concentrates displacements. Mixed zones are also developed at the boundaries of This fault zone is distinguished from the host rock or wall rock, which is an unaffected rock distributed at both ends.

Strong faults occur in fault cores where most displacement is absorbed during fault motion. Secondary fault (secondary fault), insulation (Fracture), vein (Vein) is formed in the fault damage. Some of these fault zones extend to the depths of several kilometers underground, while others are several kilometers wide.

The present invention arranges an open hole section of a production well in a fault core of an inactive fault zone formed at a depth of 3 km or more from the ground, and fault fault zone or host rock of the fault zone. Open hole sections of injection wells are drilled and completed, and hydraulic fracturing is performed to basically open the natural fracture zones formed by fault movement in the fault zone, and to reopen and expand the closed ones if necessary. (EGS) is created as a system and method for creating small scale artificial crushers at Host Rock.

As mentioned above, the composition of EGS is much smaller in size and capacity (injection pressure, injection flow rate, etc.) than in the case of forming EEG in igneous rock or metamorphic rock layers with little or no natural crushing zone. Requires shredding equipment. This can significantly lower the cost.

In addition to the above cost reduction effect, since it is basically to expand the formed natural crushing zone, the success rate that can create the desired EEG (Sigma) is also much higher than when creating a new crushing zone. This will significantly improve the economics associated with the creation of EGS.

Accordingly, the present invention for achieving the above object, a plurality of specific EGS (EGS), a part of the outer boundary of the EEG (EGS) in contact with each other (EGS) share some injection tablets (共有) A system and method for successively forming an Enhanced Geothermal Systems Group (EGS Group), comprising: an Inactive Fault Zone formed from a surface to a depth of at least 3 km underground; The production section of the deep rock formation completes the geothermal water to produce the geothermal water as an open hole section of the production wells, the open hole section is completed as close as possible to the center of the fault core of the fault zone Production Well; All of the injection section corresponding to the entire section or only a part of the injection section as open hole sections of the injection wells, the open hole sections are 200m or more horizontally away from the open hole section of the production well, Injection wells that are spaced 150 m or more horizontally from the centerline in the (Strike) direction and are disposed and completed at optimal locations 50 m or more horizontally from the open hole sections of all other injection wells; EGS (EGS) consisting of one production well and one or more injection wells; EGS (EGS) 1 is configured to have the same characteristics as the EGS (EGS); Arrange the open hole sections of the production wells of the following EGS 2 at an optimal position horizontally at least 300 m horizontally along the periphery of the fault nucleus from the open hole sections of the production wells of the EGS 1 The EGS 1 and the EEG 2 below to share one or more injection wells so that a desired crushing zone is generated based on the expansion and generation direction and shape of the crushing zone in the core rock layer. Aegis (EGS) 2 configured to have a characteristic similar to the eges (EGS) in contact with a part of an outer boundary of EEGs (EGS) 1; An open hole section of the production well of the following EGS 3 is disposed at an optimal position horizontally 300 m or more horizontally along the periphery of the fault nucleus from the open hole section of the production well of the EGS 1 or the EEG 2 And constructing the required number of injection wells so that the EGS 1 or EEG 2 and the following EEG 3 share one or more injection wells, thereby expanding and creating a fracture zone in the deep rock layer. EGS 3 which is constructed to have a characteristic similar to the EGS in contact with a part of an outer boundary of EGS 1 or EGS 2 so that a desired crushing zone is generated based on the direction and shape. ; And conditions underground and above ground of a geothermal production complex centering the fault zone, such as EGS 4, EGS 5, EGS 6, EGS 7, etc., according to the system and method described above. According to the present invention, an optimum number of EGSs determined in accordance with the monolayer nucleus are formed in succession, in order to form an EGS group.

In the system and method for forming a group of EEG using the fault zone of the present invention, an optimal number of specific EGSs in the inactive fault zone, such that a part of the outer boundary of the EEGs in contact with each other and share some injection wells, Established EGS Group by continually attaching faults along fault of nucleus of fault zone, using much smaller size and capacity of hydraulic shredding equipment than when creating new crushing zone with no or few natural crushing rocks. At the same time, it is possible to build up the desired EGSs with a much higher success rate, which significantly lowers the cost, and also significantly reduces the number of injection wells per production well, compared to single EEGs each. This reduces the burden of drilling costs and significantly improves the economics associated with EGS. It provides.

Accordingly, the present invention, through the above effects, by expanding the geothermal power generation by creating more excellent EGS (EGS) in our land, by increasing the amount of power produced by pure domestic energy alone, the energy self-sufficiency rate of Korea To increase energy consumption and reduce greenhouse gas emissions.

1 is a plan explanatory view showing a preferred example of the present invention.

The EGS group composition system and method using the fault zone of the present invention is an open hole of a production well as close as possible to the center of the fault core of the fault fault using an inert fault zone formed from the ground to 3 km or more underground. ) Section, and the open hole sections of the injection wells are completed in the fault damage zone or host rock of the fault zone, and then subjected to hydraulic frcturing. Natural fracture zones formed by fault movement in fault zones create EGS (EGS) as a system and method for closing, reopening, expanding, and, if necessary, creating new, small artificial fracture zones in the mother rock.

The composition as described above requires much smaller scale and capacity (injection pressure, injection flow rate) hydraulic fracturing equipment, compared to the case where new crushing zones are created in the rock layer with no or little natural crushing bed. It can be greatly lowered, and by expanding the crushing base that is basically formed, the success rate for creating the desired EGS will be much higher. As a result, the economics related to EGS composition can be significantly improved.

The reason for arranging the open hole sections of the production well and the injection well as described above is that as the distance from the fault core decreases, the density of the crushing zone decreases, so that the permeability decreases. By placing it in a single layer damage bed or host rock with a lower permeability, the injected water slowly passes through the crushing zone to sufficiently absorb the geothermal heat of the deep cancer layer.In contrast, the closer to the monolayer nucleus, the stronger the fracture action. As the density of the crushing zone rises and the permeability increases, the open hole section of the production well is placed as close as possible to the center of the monolayer nucleus with the highest permeability, thereby increasing the geothermal water productivity (flow rate) and injecting water injected into the injection well. Flows into the open hole section of the higher production well, A single layer core and a single layer sonsangdae adjacent to the above is to use a reservoir (Reservoir).

In the present invention, each EGS is composed of one production well and one or more injection wells, and the production wells represent the entire section for producing geothermal water in the core rock layer. Completion into an open hole section, the injection wells complete all of the injection section corresponding to the open hole section of the production well or only a part of the injection section into the open hole section, and perform hydraulic breakdown to open the production well. By connecting the interval between the open hole intervals of the injection wells and the crushing zone, the injection water injected into the injection wells is passed through the crushing zone to absorb the geothermal heat of the deep cancer layer is heated to flow into the production wells.

The open hole sections of the injection wells are 200 m or more horizontally away from the open hole sections of the production well, and 150 m or more horizontally away from the center line (direct direction) of the monolayer nucleus, and from the open hole sections of all other injection wells. Place it in an optimal position at least 50m horizontally.

The reason for arranging the open hole sections of the injection wells at a position 200 m or more horizontally from the position of the open hole section of the production well is that the injection water reaches the production well while absorbing geothermal heat while passing through the crushing zone of that distance. To do that. Based on geothermal production characteristics, particularly geothermal heat absorption characteristics, since the 200m is the lower limit, a distance of 500m or more may be necessary depending on the temperature of the rock layer and the characteristics of the crushing zone. The optimum distance can be calculated by observing the performance of at least one injection well and production well in the geothermal production complex for a long time.

In addition, the reason for arranging the open hole sections of the injection wells at positions 150 m or more horizontally away from the center line in the strike direction of the fault core, as described above, the further away from the fault core, Since the density of the crushing zone is lowered, the open hole sections of the injection well are disposed in the low density density damage bed or the mother rock, so that the injected water slowly passes through the crushing zone to sufficiently absorb the geothermal heat of the deep rock layer, and the 150m is The lower limit calculated in relation to the lower limit line (200 m) of the horizontal distance between the open hole section of the production well and the open hole sections of the injection well. Therefore, a distance of 400 m or more may be required depending on the temperature of the rock layer and the characteristics of the crushing zone. The optimum distance can be calculated by observing the performance of at least one injection well and production well in the geothermal production complex for a long time.

Further, the reason why the open hole sections of the injection wells are spaced 50 m or more horizontally from the open hole sections of all other injection wells is to be based on the thermal conductivity of the rock layer in order to produce geothermal water at a required temperature for 20 years. This is because a rock layer of at least 50 m is required between the open hole sections of the injection wells. Since 50m is a lower limit, it is preferable to arrange | position further away as conditions permit.

Even when the open hole sections of the injection wells are several hundred meters vertically, when the injection wells are operated for more than 10 years, the injection may occur in a section in which casing or cementing is weakened and blocked. Considering this situation, the open hole sections of all the injection wells should be spaced more than 50m horizontally.

In the present invention, the open hole sections of the production wells of the AEGs that are in contact, for example, the open hole section of the production wells of the EEG (EGS) 2 and the open hole section of the production wells of the EEG 3 in Figure 1, the corresponding fault zone Along the striking of the fault nucleus of the core is placed more than 300m horizontally. The 300m is a lower limit calculated in relation to the lower limit 200m of the horizontal distance between the open hole section of the production well and the open hole sections of the injection well. Therefore, a distance of 700 m or more may be necessary depending on the temperature of the rock layer and the characteristics of the crushing zone. The optimal distance can be calculated by observing the performance of at least two EGSs in the geothermal complex for a considerable time.

The present invention, according to the system and method described above, illustrates an optimal number of EGSs having the above-described characteristics determined according to various conditions of the underground and ground of the geothermal production complex centering the inactive fault zone. As in the example shown in Fig. 1, part of the outer boundary of the EGS is in contact with each other, so that the EGS share some injection wells, and the direction and shape of the expansion and formation of the fracture zone in the corresponding deep rock layer. Based on the fault of the fault zone band, the sequential bands are formed one after another so as to produce a desired crush zone, thereby forming an EGS group.

In selecting an inactive fault zone formed at a depth of 3 km or more from the ground to form the EGS Group as described above, the wider the fault damage zone of the fault zone is, the higher the density of the fracture zone is. It is advantageous for forming an excellent EGS Group. It also examines whether high-quality geothermal energy is present, whether it is easy to transport heavy equipment such as drilling equipment, whether it is easy to connect with the distribution system, and whether it is easy to secure the injection water required for the formation of cold sources and EGS.

Most of the fault zones in our country are found to be inactive. However, if a fault zone is selected that may be active, the response of the fault zone was closely observed and analyzed through microseismic monitoring, with one EGS being formed in a 3km underground. When the question is resolved, an EGS Group is formed in the depth.

As a result of closely examining and analyzing the faults of the fault zone through the micro-earthquake observation while continuing geothermal production for many years in the EGS Group, the question is solved and the fault zone is extended to the required depth. If it is found to be present, the EGS Group is formed in the rock layer deeper than a certain depth (for example, 3.5 km depth) according to the above system and method.

In accordance with the system and method described above, the EGS Group is gradually expanded to deeper rock layers (eg, 4 km, 4.5 km, 5 km).

EEG (EGS) composition and geothermal production process can be accompanied by a small earthquake, the deeper the depth tends to increase the size of the small earthquake. Therefore, to ensure safety, it is desirable to form an EGS Group by gradually expanding from about 3 km underground to a deeper rock layer according to the system and method described above, even if it turns out to be an inert fault. .

Using the AEG group composition system and method using the fault zone of the present invention as described above, according to the following procedure, to form an AEG Group (EGS Group) in the geothermal production complex centering the inactive fault zone.

(1) EGS 1 is formed to have the above characteristics. Microseismic monitoring, logging, placing the open hole section of the first injection well at the optimal location of the fault damage zone or host rock, drilling and closing, and performing hydraulic fracturing. (Well Logging) to identify the expansion zone and the direction and shape of the fracture zone.

The crushing zone generated by the hydraulic fracturing has a unique three-dimensional orientation and shape according to the stress distribution characteristics of the core rock layer. That is, it has a characteristic of being created and expanded in three directions in a specific direction and in a specific form. Hydraulic fracturing in fault zones primarily opens up natural crushers that are formed, reopens and expands closed ones, and creates some new crushers secondly. Figure out.

In a complex with little crushing table-related data, it is necessary to complete the open hole section of the first injection well with all the injection sections corresponding to the whole section to produce geothermal water, and to grasp the direction and form of expansion and generation of the crushing zone by hydraulic fracturing. desirable.

The fault core of the fault zone is such that the open hole section of the injection well and the open hole section of the production well are connected to the desired fracture zone based on the expansion direction and the shape and the direction and shape of the fracture zone identified as described above. Arrange, drill and complete the open hole section of the production well as close as possible to the center of the plant.

The additional injection wells necessary to produce the desired crushing zone are placed, drilled and completed to form EGS 1 to have the above characteristics.

The reason for drilling the injection well first is that the production well drilling ratio is generally much higher than the injection well drilling ratio, so that the expansion and formation direction and shape of the crushing band in the injection well are determined and produced based on the production well. Definition For more accurate placement of open hole sections. However, if necessary, the well can be drilled first and the direction and shape of the crusher expansion and generation can be determined.

Hydraulic fracturing results obtained from successive EGSs are analyzed to understand in more detail the direction and shape of expansion and generation of the fracture zone.

(2) EEG 2 is formed to have the above characteristics. The fault layer, which is 300 m or more horizontally, downwardly or vice versa along the strike of the fault core from the open hole section of the production well of the EGS 1, as shown in FIG. Place the open hole section of the production well of EGS 2 in the optimal position as close as possible to the center of the nucleus, and make up the required number of injection wells, one EEG 1 and one EEG 2 Expansion and formation direction of the fracture zone in the core rock layer so as to share the above injection wells, that is, the injection water injected into the shared injection wells flows into the production wells of EGS1 and EGS2. In order to produce a desired crushing zone based on the shape and shape, the EGS 2 is formed in contact with a part of the outer boundary of the EGS 1 to have the above characteristics.

(3) EEG 3 is formed to have the above characteristics. When EGS 3 is formed in contact with EGS 2 as shown in the example shown in FIG. 1, 300 m or more horizontally along the periphery of the monolayer nucleus from the open hole section of the production well of the EGS 2. In the optimal position as close as possible to the center of the fault monolayer nucleus, the open hole section of the production well of EGS 3 is arranged, and composed of the required number of injection wells, EGS 2 and EGS 3 In order to share the one or more injection wells, the above-described features are encountered in contact with a part of the outer boundary of EGS 2 so that a desired crushing band is generated based on the expansion and generation direction and shape of the crushing bed in the deep rock layer. EGS 3 to be prepared.

When the EEG 3 is formed in contact with the EEG 1 in the opposite direction, the monolayer nucleus is horizontally 300 m or more horizontally along the periphery of the monolayer nucleus from the open hole section of the production well of the EGS 1. Place the open hole section of the production well of EGS 3 at the optimum position as close as possible to the center of the product, and make up the required number of injection wells, so that EEG 1 and EEG 3 are at least one. In order to share the injection wells, the desired zone of crushing zones are generated based on the direction and shape of the crushing zones in the corresponding deep rock layers. EGS) 3 is formulated.

(4) EEG 4 is formed to have the above characteristics. When EGS 4 is formed in contact with EGS 3 as shown in the example shown in FIG. 1, 300 m or more horizontally along the periphery of the monolayer nucleus from an open hole section of the production well of EEG 3. The open hole section of the production well of EGS 4 is arranged at the optimum position as close as possible to the center of the fault monolayer nucleus, and composed of the required number of injection wells, EGS 3 and EGS 4 The features described above are in contact with a portion of the outer boundary of EGS 3 such that the desired fracture zone is generated based on the direction and shape of the fracture zone expansion and formation in the core rock layer so that the at least one injection well shares. EGS 4 to be prepared.

In the opposite direction, for example, EGS 1 is formed at the opposite end, and is formed in contact with EGS 1, along the periphery of the monolayer nucleus from the open hole section of the production well of EGS 1. In the optimal position as close as possible to the center of the fault nucleus at least 300 m horizontally, the open hole section of the production well of EGS 4 is arranged, and composed of the required number of injection wells, EGS 1 and EG In contact with a portion of the outer boundary of EGS 1 such that (EGS) 4 shares one or more injection wells so that a desired fracture zone is created based on the direction and shape of the fracture zone expansion and formation in the core rock layer, EGS 4 is formed to have the above characteristics.

(5) According to the system and method described above, the fault zone such as EGS 5, EGS 6, EGS 7, EGS 8, EGS 9, EGS 10, etc. An optimal number of EGSs determined in accordance with various underground and ground conditions of the geothermal complex in the center are formed in order along the periphery of the fault nucleus to form an EGS Group. .

In the present invention, each of the AEGs that constitute the EGS Group is composed of one production well and one or more injection wells having the characteristics described above. Therefore, the number of injection wells of each EGS group constituting the EGS Group and the arrangement of the open hole sections and the distance between the open hole sections of the production wells of the EGS groups are different from each other. Optimized according to the various conditions, each irregularly has a unique number, arrangement and distance.

The EGS Group shown in FIG. 1 was composed of seven EGSs. Here, including the shared injection wells, EGS 1 is two injection wells, EEG 2 to EEG 6 each with 4 injection wells and EGS 7 is 2 It consists of two injection wells.

If the seven AEGs are separated and formed into a single AEG, respectively, a total of 24 injection wells should be drilled. In doing so, the average number of injection wells per production well is 3.4 (= 24/7).

However, since 12 injection wells were drilled in the EGS Group shown in FIG. 1, the average number of injection wells per production well is significantly reduced to 1.7 (= 12/7), which is half of the above 3.4. Accordingly, the drilling cost burden can be reduced accordingly.

According to the composition system and method described above, by forming an EGS Group in a geothermal production complex centered on an inactive fault zone (EGS Group), compared to the case of creating a new crushing zone in a rock layer with little or no natural crushing zone. By using small size and capacity hydraulic fracturing equipment (injection pressure, injection flow rate, etc.), it is possible to create the desired EGS, which can significantly reduce the required cost and also expand the basically formed shredding table. Compared to the generation of crushing zones, the success rate for producing the desired EGS is much higher, and the number of injection wells required per production well is generated in a single EEG. In comparison, it significantly reduces the drilling cost burden and significantly improves the economics associated with EGS. Injured.

Accordingly, the present invention, through the above effects, by expanding the geothermal power generation by creating more excellent EGS (EGS) in our land, by increasing the amount of power produced by pure domestic energy alone, the energy self-sufficiency rate of Korea To increase energy consumption and reduce greenhouse gas emissions.

1: Fault Core of Inactive Fault Zone
2: boundary line between faulty nucleus and faulty injury
3: Fault Damage Zone
4: boundary between fault damage and host rock
5: Location of the open hole section of the production well of EGS 1
6: Position of the open hole section of the production well of EGS 2
7: Position of the open hole section of the production well of EGS 3
8: Position of the open hole section of the production well of EGS 4
9: Position of the open hole section of the production well of EGS 5
10: Location of the open hole section of the production boat of EGS 6
11: Location of the open hole section of the production boat of EGS 7
20: Position of the open hole section of the injection well

Claims (1)

A number of specific enhanced geothermal systems (EGS) are placed in series so that a portion of the edges of the EGSs are in contact with each other so that the EGSs share some injection wells. A system and method for forming an Enhanced Geothermal Systems Group,
An inactive fault zone formed from the surface to a depth of more than 3 km underground;
The production section of the deep rock formation completes the geothermal water to produce the geothermal water as an open hole section of the production wells, the open hole section is completed as close as possible to the center of the fault core of the fault zone Production Well;
All of the injection section corresponding to the entire section or only a part of the injection section as open hole sections of the injection wells, the open hole sections are 200m or more horizontally away from the open hole section of the production wells, and the center line of the fault core Injection wells that are at least 150 m horizontally from and are positioned and completed at optimal locations at least 50 m horizontally from the open hole sections of all other injection wells;
EGS (EGS) consisting of one production well and one or more injection wells;
EGS (EGS) 1 is configured to have the same characteristics as the EGS (EGS);
An open hole section of the production well of the following EGS 2 is disposed at an optimal position horizontally 300 m or more along the strike of the fault core from the open hole section of the production well of the EGS 1 Based on the direction and shape of the expansion and generation of the crushing zone in the core rock layer so that the EGS 1 and the EEG 2 share one or more injection tablets. An EGS 2 constructed to have a characteristic such as the EEG in contact with a part of an outer boundary of an EGS 1 so that a desired crushing zone is generated;
An open hole section of the production well of the following EGS 3 is disposed at an optimal position horizontally 300 m or more horizontally along the periphery of the fault nucleus from the open hole section of the production well of the EGS 1 or the EEG 2 And constructing the required number of injection wells so that the EGS 1 or EEG 2 and the following EEG 3 share one or more injection wells, thereby expanding and creating a fracture zone in the deep rock layer. EGS 3 which is constructed to have a characteristic similar to the EGS in contact with a part of the outer boundary of EGS 1 or EGS 2 so that a desired crushing zone is generated based on the direction and shape. ; And
According to the system and method described above, the ground and ground conditions of the geothermal production complex centering the fault zone such as EGS 4, EGS 5, EGS 6, EGS 7, etc. A method for forming an EEG group using a fault zone, characterized in that to form an EEG Group by sequentially forming the optimum number of EEG (EGS) determined in accordance with the main portion of the fault nucleus in order.

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