Well pattern arrangement structure for high and steep coal seam development and drainage and mining regulation and control method

Abstract

The well pattern arrangement structure comprises an integrated wellbay and a horizontal well group, the horizontal well group comprises a plurality of well mouths which are intensively arranged in the same area in a high and steep coal seam area, and the horizontal well group comprises at least three horizontal wells which are arranged at intervals in the inclination direction of the coal seam; the horizontal sections of the horizontal wells are arranged along the trend of the coal seam, hydraulic fractures generated by the horizontal wells are developed in the coal seam along the inclination direction of the coal seam, and each horizontal well is matched with one well mouth. The horizontal wells are distributed at intervals according to the inclination direction of the coal seam, and the hydraulic fractures generated by the horizontal wells are developed along the inclination direction of the coal seam; by means of the drainage and mining regulation and control method, the replacement frequency of a drainage and mining pipe column can be reduced, the drainage and mining cost can be reduced, the stability of a production system can be guaranteed, and the comprehensive development effect can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coalbed methane development, and in particular to a well network arrangement structure and a drainage and production control method for high-steep coal seam development. Background Art

[0003] The high and steep characteristics of coal seams have brought certain difficulties to the development of coalbed methane. Due to the poor permeability of high and steep coal seams, it is necessary to increase the conductivity of coal seams through reservoir transformation during development. Due to the high and steep structural characteristics of coal seams, artificial fractures in coal seams after transformation tend to extend to the high parts of the structure. On the other hand, during the production of coalbed methane, due to the difference in gas and water density, gas and water differentiation will occur during the flow of gas and water in coal seams, because the gas density is small and it is easier to flow to the high parts of the structure, while the water density is larger and it is easier to flow to the low parts of the structure. Gas and water differentiation will cause gas accumulation in the high parts of the structure, increase pressure, and affect the further desorption of coalbed methane in the high parts of the structure. The low parts of the structure are affected by water accumulation, and gas flow is difficult.

[0004] Research has found that coalbed methane production can generally be divided into six stages: drainage, gas / water production, first stable production, first production decline, second stable production and second decline. Due to the complex production law of coalbed methane, the gas and water volume in different stages varies greatly. The production process often requires the replacement of drainage pipes, which not only reduces the production rate and increases the operating costs, but also leads to poor drainage effects due to the discontinuous drainage system, affecting the overall production. For high-steep coalbed methane, directional wells built along the coal seam dip are generally used for development. The corresponding burial depths of the reservoir sections vary greatly, and it is easy for sections at different locations in the same well to be in different production stages, which further increases the difficulty of drainage and production and reduces production efficiency.

[0005] Therefore, there is an urgent need for a well network layout structure and drainage and production control method for high-steep coal seam development to solve the above technical problems. Summary of the invention

[0006] The present invention aims to solve the above-mentioned technical problem, that is, to solve the problem that the drainage pipe column often needs to be replaced during the existing high-steep coal seam production process, which not only reduces the production time rate and increases the operating costs, but also leads to poor drainage effect due to the discontinuous drainage system, affecting the overall output; and for high-steep coalbed methane, directional wells built along the dip of the coal seam are generally used for development. The corresponding burial depths of the reservoir sections vary greatly, and it is easy for sections at different positions in the same well to be in different production stages, further increasing the difficulty of drainage and low production efficiency.

[0007] To this end, in a first aspect, the present invention provides a well network arrangement structure for the development of high-steep coal seams, comprising an integrated well platform and a horizontal well group, wherein the integrated well platform comprises a plurality of wellheads concentrated in the same area of ​​the high-steep coal seam area, the horizontal well group comprises at least three horizontal wells arranged at intervals along the inclination direction of the coal seam, the horizontal sections of the horizontal wells are arranged along the direction of the coal seam, and the hydraulic fractures generated by the horizontal wells develop in the coal seam along the inclination direction of the coal seam, and each of the horizontal wells is matched with a wellhead.

[0008] In the specific implementation of the well network arrangement structure for the development of the above-mentioned high-steep coal seam, the high-steep coal seam area is divided into an upper area, a middle area and a lower area along the inclination direction of the coal seam according to the gas and water distribution law of the high-steep coal seam, and the upper area, the middle area and the lower area each contain at least one horizontal well in the horizontal well group.

[0009] In a specific embodiment of the well pattern arrangement structure for high-steep coal seam development described above, the horizontal wells in the lower area are installed with a first drainage pipe string during production.

[0010] In a specific embodiment of the well pattern arrangement structure for high-steep coal seam development, the horizontal wells in the upper area are installed with a first gas production string during production, and the first gas production string is a self-flowing gas production string.

[0011] In the specific implementation of the well network layout structure for the development of high-steep coal seams, the horizontal wells in the middle area are installed with corresponding second drainage pipe strings or second gas production pipe strings according to the gas production and liquid production during production, and the drainage volume of the second drainage pipe string is less than that of the first drainage pipe string.

[0012] In a specific implementation of the well pattern arrangement structure for high-steep coal seam development, there are two horizontal well groups, and the horizontal sections of the horizontal wells in the two horizontal well groups are in opposite directions.

[0013] In a second aspect, the present invention further provides a method for controlling production by using the well pattern arrangement structure for high-steep coal seam development described in the first aspect, comprising the following steps:

[0014] During production, the wellhead pressure, liquid production and gas production of each horizontal well are obtained in real time;

[0015] According to the wellhead pressures, liquid production and gas production corresponding to the horizontal wells in the upper area, the lower area and the middle area, the first drainage pipe string corresponding to the horizontal wells in the upper area, the first gas production pipe string corresponding to the horizontal wells in the lower area and the second drainage pipe string or the second gas production pipe string corresponding to the horizontal wells in the middle area are controlled to enter the drainage operation, and the horizontal wells in the lower area enter the drainage operation before the upper area, and the horizontal wells in the upper area enter the drainage operation before the middle area.

[0016] In a specific implementation of the above-mentioned drainage and production control method using the well pattern arrangement structure for high-steep coal seam development, the drainage and production control method further includes:

[0017] If the liquid production of the horizontal wells in the middle area is greater than the first liquid production threshold, a second drainage string is installed in the horizontal wells in the middle area; or

[0018] If the gas production of the horizontal wells in the middle area is greater than the first gas production threshold, a second gas production string is installed in the horizontal wells in the middle area.

[0019] In the specific implementation of the above-mentioned drainage and production control method for production using the well pattern arrangement structure for high-steep coal seam development, the step of "selectively controlling the first drainage pipe string corresponding to the horizontal well in the upper area, the first gas production pipe string corresponding to the horizontal well in the lower area, and the second drainage pipe string or the second gas production pipe string corresponding to the horizontal well in the middle area to enter the drainage operation according to the wellhead pressure, liquid production and gas production corresponding to the horizontal wells in the upper area, the lower area and the middle area" specifically includes:

[0020] Determine whether the wellhead pressure value corresponding to the horizontal well in the lower area currently obtained is less than the wellhead pressure value obtained last time and whether the liquid production value is less than the liquid production value obtained last time;

[0021] If the current wellhead pressure value is less than the wellhead pressure value obtained last time and the liquid production value is less than the liquid production value obtained last time, then obtain the wellhead pressure difference between the current wellhead pressure value and the last wellhead pressure value and obtain the liquid production difference between the current liquid production value and the last liquid production value;

[0022] If the wellhead pressure difference is less than the preset pressure difference, and the liquid production difference is less than the preset liquid production difference, the first drainage pipe string corresponding to the horizontal well in the lower area is controlled to enter the drainage operation;

[0023] When all the first drainage pipe strings in the lower area are started, determining the magnitude of the wellhead pressure value corresponding to the horizontal well in the upper area and the first pressure threshold value, and the magnitude of the gas production and the second gas production threshold value;

[0024] If the wellhead pressure value corresponding to the horizontal well in the upper area is greater than the first pressure threshold and the gas production is greater than the second gas production threshold, the self-flowing gas production pipe string corresponding to the horizontal well in the upper area is controlled to enter the drainage operation;

[0025] When the first gas production string in the upper area is started, determining the magnitude of the wellhead pressure value corresponding to the horizontal well in the middle area and the second pressure threshold, and the magnitude of the gas production and the third gas production threshold;

[0026] If the wellhead pressure value corresponding to the horizontal well in the middle area is greater than the second pressure threshold and the gas production is greater than the third gas production threshold, the second gas production string or the second drainage string corresponding to the horizontal well in the middle area is controlled to enter the drainage operation.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention arranges the positions of horizontal wells at intervals according to the inclination direction of the coal seam, and makes the hydraulic fractures generated by the horizontal wells develop along the inclination direction of the coal seam, that is, it utilizes the law that the fracturing fractures of the high-steep coal seam will be affected by the formation stress and expand in the vertical wellbore direction in the coal seam. At this time, the coal seam transformation volume is the largest, and the gas production process of the high-steep coal seam is affected by gravity. The gas migration upwards and the water migration downwards cause the gas production law of the high-steep coal seam, so as to achieve the maximum degree of coal seam transformation and improve the production capacity of the high-steep coal seam methane.

[0029] 2. The drainage and production control method designed in the present invention can reduce the replacement frequency of the drainage pipe column and reduce the drainage cost of high-steep coal seams. Moreover, combined with the layout of horizontal wells, it can maximize the release of high-steep coalbed methane production capacity, extend the stable production period, increase production capacity, ensure the stability of the production system, and enhance the comprehensive development effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which:

[0031] Figure 1 This is a schematic diagram of the well pattern arrangement structure for high-steep coal seam development provided by the present invention;

[0032] Figure 2 yes Figure 1 A top view of

[0033] Figure 3 This is a flow chart of the main steps of the drainage and production control method for production using the well pattern arrangement structure for high-steep coal seam development provided by the present invention;

[0034] Figure 4 It is a detailed step flow chart of step S2.

[0035] List of reference numerals:

[0036] 1. Integrated well platform; 2. Horizontal well. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the system or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc., are used to define components, only for the convenience of distinguishing the above components, and unless otherwise stated, the above terms have no special meanings and cannot be understood as indicating or implying relative importance.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "setting", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] The present invention relates to the technical field of coalbed methane development, and in particular to a well pattern arrangement structure and drainage control method for high-steep coal seam development. The purpose is to solve the problem that the drainage pipe column often needs to be replaced during the existing high-steep coal seam production process, which not only reduces the production time rate and increases the operating cost, but also leads to poor drainage effect due to the discontinuous drainage system, affecting the overall output; and for high-steep coalbed methane, directional wells built along the coal seam inclination are generally used for development. The corresponding buried depths of the reservoir sections are quite different, and it is easy for sections at different positions in the same well to be in different production stages, which further increases the difficulty of drainage and production and the problem of low production efficiency. To this end, the well network arrangement structure for high-steep coal seam development provided by the present invention comprises an integrated well platform and a horizontal well group, the integrated well platform comprises a plurality of wellheads concentrated in the same area of ​​the high-steep coal seam area, the horizontal well group comprises at least three horizontal wells arranged at intervals along the inclination direction of the coal seam, the horizontal sections of the horizontal wells are arranged along the direction of the coal seam, and the hydraulic fractures generated by the horizontal wells develop in the coal seam along the inclination direction of the coal seam, and each horizontal well matches a wellhead. The drainage and production control method for production using the well network arrangement structure for high-steep coal seam development provided by the present invention comprises the following steps: during production, the wellhead pressure, liquid production and gas production of each horizontal well are obtained in real time; according to the wellhead pressure, liquid production and gas production corresponding to the horizontal wells in the upper area, the lower area and the middle area, the first drainage pipe string corresponding to the horizontal wells in the upper area, the first gas production pipe string corresponding to the horizontal wells in the lower area, and the second drainage pipe string or the second gas production pipe string corresponding to the horizontal wells in the middle area are controlled to enter the drainage and production operation, and the horizontal wells in the lower area enter the drainage and production operation before the upper area, and the horizontal wells in the upper area enter the drainage and production operation before the middle area. The use of drainage and production control methods can reduce the frequency of replacement of drainage pipes and reduce the drainage costs of high-steep coal seams. Moreover, combined with the layout of horizontal wells, it can maximize the release of high-steep coalbed methane production capacity, increase production capacity, ensure the stability of the production system, and improve the overall development effect.

[0041] The well pattern arrangement structure and drainage and production control method for high-steep coal seam development provided by the embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0042] See also Figure 1-2 The present invention provides a well pattern arrangement structure for developing high-steep coal seams, including an integrated well platform and a horizontal well group. The integrated well platform includes a plurality of wellheads centrally arranged in the same area of ​​the high-steep coal seam area. The horizontal well group includes at least three horizontal wells arranged at intervals along the inclination direction of the coal seam. The horizontal sections of the horizontal wells are arranged along the direction of the coal seam. Figure 1 As shown in Figure 2, the hydraulic fractures generated by the horizontal well develop in the coal seam along the inclination direction of the coal seam, as shown in Figure 2. Figure 1 The line segment perpendicular to the horizontal wells in the figure, each horizontal well matches a wellhead.

[0043] Specifically, there are two groups of horizontal wells, and the horizontal sections of the horizontal wells in the two groups of horizontal wells are in opposite directions. Figure 1-2 As shown. In addition, the horizontal section lengths of the horizontal wells in the two horizontal well groups can be the same or different. Multiple wellheads are concentrated in the same area, which reduces the distance between the wellheads, making it easier for workers to check and repair all wellheads within a close range, making the operation more convenient. The area where the integrated wellheads are concentrated can be flexibly selected according to the actual situation on site. For example, Figure 1 As shown, it is distributed in the middle part of the high and steep coal seam area.

[0044] More specifically, according to the distribution law of gas and water in the high-steep coal seam, the high-steep coal seam is divided into the upper area, the middle area and the lower area along the inclination direction of the coal seam, and the upper area, the middle area and the lower area all contain at least one horizontal well in the horizontal well group. In this way, it is ensured that horizontal wells are set in the upper, middle and lower three areas. Regarding the spacing between horizontal wells, this application does not make specific restrictions, but predicts the gas production, liquid production and bottom hole pressure of wells in different positions based on the numerical simulation software of the coalbed methane layer, and uses these data as a reference for the design of the horizontal well spacing. The upper area, the middle area and the lower area all contain at least one horizontal well in each horizontal well group.

[0045] In the above embodiments, the present application distributes the locations of horizontal wells at intervals according to the inclination direction of the coal seam, arranges the horizontal sections along the direction of the coal seam, and develops the hydraulic fractures generated by the horizontal wells along the inclination direction of the coal seam, that is, utilizes the expansion law of fracturing cracks in high-steep coal seams and the gas production law of high-steep coalbed methane production process affected by gravity, so as to achieve the maximum degree of coal seam transformation and improve the production capacity of high-steep coalbed methane.

[0046] In one embodiment, the horizontal wells in the lower area are installed with a first drainage pipe column with a large displacement function during production. The first drainage pipe column is a large displacement drainage pipe column with a large drainage capacity and is mainly responsible for drainage. Affected by the downward supply of free water contained in the upper coal seam under the action of gravity, the gas field is flooded or has high water content during the entire process of development. A large displacement drainage pipe column is used to achieve full reservoir drainage and pressure reduction of high-steep coal seams, and alleviate the impact of large water volume in the middle and upper horizontal wells on gas production. The drainage volume of the drainage pipe column is determined according to parameters such as the type of drainage pump, the size of the pipe column, and the depth of the drainage pump, which is a known prior art to those skilled in the art. The selection of the type of drainage pipe column is determined according to the predicted liquid production and bottom hole pressure. The higher the liquid production and bottom hole pressure, the greater the drainage volume of the selected drainage pipe column.

[0047] In one embodiment, the horizontal well in the upper area is installed with a first gas production string during production, and the first gas production string is a self-flowing gas production string. During the coalbed methane production process, due to the difference in gas and water density, gas and water differentiation will occur during the flow of gas and water in the coal seam. Since the gas density is small, it is easier to flow to the high part of the structure, so there is more gas accumulation in the upper area, and a self-flowing gas production string is used for gas production.

[0048] In one embodiment, during production, the horizontal wells in the middle area are equipped with a corresponding second drainage pipe string or a second gas production pipe string according to the gas production and liquid production. The drainage of the second drainage pipe string is less than that of the first drainage pipe string. The middle position of the high-steep coal seam is affected by the gas-water differentiation of the upper coal seam. In the early stage, drainage is used for gas production, and in the later stage, it is mainly responsible for gas production. Depending on the water volume in the early stage and the gas volume in the later stage, the production pipe string is replaced according to the dynamic production demand. If the gas production is large, it is replaced with the second gas production pipe string, and if the water volume is large, it is replaced with the second drainage pipe string.

[0049] For another embodiment, see Figure 3 The present invention also provides a method for controlling production by using the well pattern arrangement structure for high-steep coal seam development described in the above embodiment, comprising the following steps:

[0050] S1, during production, real-time acquisition of the wellhead pressure, liquid production and gas production of each horizontal well;

[0051] S2, according to the wellhead pressure, liquid production and gas production corresponding to the horizontal wells in the upper area, the lower area and the middle area, control the first drainage pipe string corresponding to the horizontal wells in the upper area, the first gas production pipe string corresponding to the horizontal wells in the lower area, and the second drainage pipe string or the second gas production pipe string corresponding to the horizontal wells in the middle area to enter the drainage operation, and the horizontal wells in the lower area enter the drainage operation before the upper area, and the horizontal wells in the upper area enter the drainage operation before the middle area.

[0052] It should be noted that since there may be more than one horizontal well in the upper, middle and lower areas, the decision on whether to start the production operation will be based on the wellhead pressure, liquid production and gas production of each horizontal well in each area. That is, the production operation between each horizontal well is judged separately, and the horizontal well in the same area that meets the production conditions first will start the production operation first.

[0053] In the present application, the drainage and production control method also includes: if the liquid production of the horizontal wells in the middle area is greater than the first liquid production threshold, a second drainage pipe column is installed in the horizontal wells in the middle area.

[0054] The production and drainage control method also includes: if the gas production of the horizontal wells in the middle area is greater than a first gas production threshold, installing a second gas production string in the horizontal wells in the middle area.

[0055] In one embodiment, see Figure 4 Step S2 of "selectively controlling the first drainage pipe string corresponding to the horizontal wells in the upper area, the first gas production pipe string corresponding to the horizontal wells in the lower area, and the second drainage pipe string or the second gas production pipe string corresponding to the horizontal wells in the middle area to enter the drainage operation according to the wellhead pressure, liquid production and gas production corresponding to the horizontal wells in the upper area, the lower area and the middle area" specifically includes:

[0056] S21, determining whether the wellhead pressure value corresponding to the horizontal well in the lower area currently obtained is less than the wellhead pressure value obtained last time and whether the liquid production value is less than the liquid production value obtained last time;

[0057] S22, if the current wellhead pressure value is less than the wellhead pressure value obtained last time and the liquid production value is less than the liquid production value obtained last time, then obtain the wellhead pressure difference between the current wellhead pressure value and the last wellhead pressure value and obtain the liquid production difference between the current liquid production value and the last liquid production value;

[0058] S23, if the wellhead pressure difference is less than the preset pressure difference, and the liquid production difference is less than the preset liquid production difference, then control the first drainage pipe string corresponding to the horizontal well in the lower area to enter the drainage operation;

[0059] S24, when all the first drainage pipe strings in the lower area are started, determining the magnitude of the wellhead pressure value corresponding to the horizontal well in the upper area and the magnitude of the first pressure threshold and the magnitude of the gas production and the second gas production threshold;

[0060] S25, if the wellhead pressure value corresponding to the horizontal well in the upper region is greater than the first pressure threshold and the gas production is greater than the second gas production threshold, control the self-flowing gas production pipe string corresponding to the horizontal well in the upper region to enter the drainage operation;

[0061] S26, when all the first gas production strings in the upper area are started, determining the magnitude of the wellhead pressure value corresponding to the horizontal well in the middle area and the magnitude of the second pressure threshold, and the magnitude of the gas production and the third gas production threshold;

[0062] S27, if the wellhead pressure value corresponding to the horizontal well in the middle area is greater than the second pressure threshold and the gas production is greater than the third gas production threshold, the second gas production string or the second drainage string corresponding to the horizontal well in the middle area is controlled to enter the drainage operation.

[0063] Before executing step S24, it is necessary to determine whether all horizontal wells in the lower area have entered the drainage operation. If all horizontal wells have entered the drainage operation, the determination operation of step S24 is performed again. Before executing step S26, it is necessary to determine whether all horizontal wells in the upper area have entered the drainage operation. If all horizontal wells have entered the drainage operation, the determination operation of step S26 is performed again.

[0064] In the above embodiment, the production of horizontal wells in the lower area is put into operation the earliest in the same well area, the production of horizontal wells in the upper area is put into operation second to that in the lower area in the same well area, and the production of horizontal wells in the middle area is put into operation the latest in the same well area. Through this production control, the workload of replacing production tubings in the high-steep coal seam area can be reduced by about 2 / 3, thereby achieving the functions of reducing the replacement frequency of production tubings and reducing the production cost of high-steep coal seams. Moreover, combined with the arrangement of horizontal wells, the release of high-steep coalbed methane production capacity can be maximized, the stable production period can be extended, the production capacity can be increased, the stability of the production system can be guaranteed, and the comprehensive development effect can be improved.

[0065] It should be noted that this application does not make any specific restrictions on the specific numerical values ​​of the first gas production threshold, the second gas production threshold, the third gas production threshold, the first pressure threshold, the second pressure threshold, the preset pressure difference, and the preset liquid production difference, and they are flexibly set according to actual conditions.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A well pattern arrangement structure for high and steep coal seam development, characterized in that: It includes an integrated well platform and a horizontal well group. The integrated well platform includes a plurality of wellheads concentrated in the same area of ​​a high-steep coal seam area. The horizontal well group includes at least three horizontal wells arranged at intervals along the inclination direction of the coal seam. The horizontal sections of the horizontal wells are arranged along the direction of the coal seam, and the hydraulic fractures generated by the horizontal wells develop in the coal seam along the inclination direction of the coal seam. Each of the horizontal wells is matched with a wellhead.

2. The well pattern arrangement structure for high-steep coal seam development according to claim 1 is characterized in that: According to the gas and water distribution law of the high-steep coal seam, the high-steep coal seam area is divided into an upper area, a middle area and a lower area along the inclination direction of the coal seam, and each of the upper area, the middle area and the lower area contains at least one horizontal well in the horizontal well group.

3. The well pattern arrangement structure for high-steep coal seam development according to claim 2 is characterized in that: The horizontal wells in the lower zone are installed with a first drainage string during production.

4. The well pattern arrangement structure for high-steep coal seam development according to claim 2 is characterized in that: The horizontal well in the upper area is installed with a first gas production string during production, and the first gas production string is a self-flowing gas production string.

5. The well pattern arrangement structure for high-steep coal seam development according to claim 3 is characterized in that: During production, the horizontal wells in the middle area are installed with a corresponding second drainage pipe string or a second gas production pipe string according to the gas production and liquid production, and the drainage volume of the second drainage pipe string is less than the drainage volume of the first drainage pipe string.

6. The well pattern arrangement structure for high-steep coal seam development according to claim 2 is characterized in that: There are two horizontal well groups, and the horizontal sections of the horizontal wells in the two horizontal well groups are in opposite directions.

7. A method for controlling production by using the well pattern arrangement structure for high-steep coal seam development as claimed in any one of claims 5 to 6, characterized in that: The following steps are involved: During production, the wellhead pressure, liquid production and gas production of each horizontal well are obtained in real time; According to the wellhead pressures, liquid production and gas production corresponding to the horizontal wells in the upper area, the lower area and the middle area, the first drainage pipe string corresponding to the horizontal wells in the upper area, the first gas production pipe string corresponding to the horizontal wells in the lower area and the second drainage pipe string or the second gas production pipe string corresponding to the horizontal wells in the middle area are controlled to enter the drainage operation, and the horizontal wells in the lower area enter the drainage operation before the upper area, and the horizontal wells in the upper area enter the drainage operation before the middle area.

8. The method for controlling production by using the well pattern arrangement structure for high-steep coal seam development according to claim 7, characterized in that: The drainage and production control method also includes: If the liquid production of the horizontal wells in the middle area is greater than the first liquid production threshold, a second drainage string is installed in the horizontal wells in the middle area; or If the gas production of the horizontal wells in the middle area is greater than the first gas production threshold, a second gas production string is installed in the horizontal wells in the middle area.

9. The method for controlling production by using the well pattern arrangement structure for high-steep coal seam development according to claim 8, characterized in that: The step of "selectively controlling the first drainage pipe string corresponding to the horizontal wells in the upper area, the first gas production pipe string corresponding to the horizontal wells in the lower area, and the second drainage pipe string or the second gas production pipe string corresponding to the horizontal wells in the middle area to enter the drainage operation according to the wellhead pressure, liquid production and gas production corresponding to the horizontal wells in the upper area, the lower area and the middle area" specifically includes: Determine whether the wellhead pressure value corresponding to the horizontal well in the lower area currently obtained is less than the wellhead pressure value obtained last time and whether the liquid production value is less than the liquid production value obtained last time; If the current wellhead pressure value is less than the wellhead pressure value obtained last time and the liquid production value is less than the liquid production value obtained last time, then obtain the wellhead pressure difference between the current wellhead pressure value and the last wellhead pressure value and obtain the liquid production difference between the current liquid production value and the last liquid production value; If the wellhead pressure difference is less than the preset pressure difference, and the liquid production difference is less than the preset liquid production difference, the first drainage pipe string corresponding to the horizontal well in the lower area is controlled to enter the drainage operation; When all the first drainage pipe strings in the lower area are started, determining the magnitude of the wellhead pressure value corresponding to the horizontal well in the upper area and the first pressure threshold value, and the magnitude of the gas production and the second gas production threshold value; If the wellhead pressure value corresponding to the horizontal well in the upper area is greater than the first pressure threshold and the gas production is greater than the second gas production threshold, the self-flowing gas production pipe string corresponding to the horizontal well in the upper area is controlled to enter the drainage operation; When the first gas production string in the upper area is started, determining the magnitude of the wellhead pressure value corresponding to the horizontal well in the middle area and the second pressure threshold, and the magnitude of the gas production and the third gas production threshold; If the wellhead pressure value corresponding to the horizontal well in the middle area is greater than the second pressure threshold and the gas production is greater than the third gas production threshold, the second gas production string or the second drainage string corresponding to the horizontal well in the middle area is controlled to enter the drainage operation.

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