Oriented perforation point location optimization method for broken and soft coal bed gas roof horizontal well

Abstract

The invention relates to a broken and soft coal bed gas roof horizontal well directional perforation point location optimization method, and belongs to the field of coal bed gas exploitation. The method comprises the steps that coal bed gas roof rock mechanical property data and coal rock property data of a known area are obtained; constructing a three-dimensional geomechanical model of the target area according to the well test data of the top plate, the bottom plate and the coal seam of the target area, the three-dimensional seismic structure data, the rock mechanical property data of the coal bed gas top plate and the coal rock property data; obtaining drilling test data, determining a candidate perforation interval according to the drilling test data, and determining a plurality of candidate perforation point locations in the candidate perforation interval; and screening the plurality of candidate perforation point locations to obtain an optimized perforation point location. According to the method, the perforation point positions are optimally selected, so that the problem that a casing coupling is shot through in the perforation construction process is effectively avoided, the perforation accident rate is reduced, and the single well productivity is effectively improved.

Description

Technical Field

[0001] This application relates to the field of coalbed methane extraction, specifically to a method for optimizing the location of directional perforation points in horizontal wells in soft coalbed methane roofs. Background Technology

[0002] Coalbed methane, as an important unconventional natural gas resource, relies on establishing an effective communication channel between the wellbore and the coal seam for its efficient development. Perforation technology, as a core component of well completion engineering, plays a crucial role in this process. Its core objective is to precisely penetrate perforations into the casing (or open hole) and cement sheath, creating a flow path for fluids (gas and water) to flow from the coal seam matrix and fracture system into the wellbore.

[0003] Compared to conventional sandstone or carbonate reservoirs, coal seams possess significant unique characteristics, posing unique requirements and challenges to perforation technology: Coal and rock are relatively loose, brittle, and have low mechanical strength, making them prone to breakage. Conventional high-density, deep-penetration perforation patterns can lead to the generation of large amounts of coal dust in the near-wellbore zone, clogging the throat and wellbore, severely impairing production capacity. The coal seam also has a highly developed network of natural fractures (surface and end fractures), which serve as primary seepage channels. Perforation design needs to fully consider how to effectively connect or extend these natural fracture systems, rather than simply pursuing "drilling holes" in dense rock. Coal and rock are highly sensitive to stress changes; improper perforation techniques (such as excessive negative or positive pressure differentials) can cause coal structure instability, collapse, or exacerbate stress sensitivity effects, leading to a sharp decrease in permeability and reduced production.

[0004] With the development of coalbed methane (CBM) development technology, most CBM development blocks now rely on long-distance horizontal wells combined with large-scale hydraulic fracturing for efficient development. The vast majority of CBM wells require hydraulic fracturing to achieve economical production capacity. Traditional CBM horizontal well perforations often directly contact the coal seam, but the low mechanical strength and high heterogeneity of the coal seam easily lead to uncontrolled fracture height, sand blockage, and low communication efficiency. Existing CBM roof horizontal wells use conventional perforation technology to connect the wellbore and the coal seam. However, due to the precision of drilling trajectory control, the large undulations of the coal seam roof in long-distance horizontal wells, and the strong heterogeneity of roof thickness, the selection of conventional perforation points often does not match the actual formation structure. The lack of a systematic selection standard for perforation points results in ineffective communication between the roof and the coal seam, leading to large fluctuations in subsequent fracturing effects. Summary of the Invention

[0005] To overcome at least one deficiency in the prior art, this application provides a method for optimizing the directional perforation points of horizontal wells in soft coalbed methane roofs.

[0006] Firstly, a method for optimizing the location of directional perforation points in horizontal wells with roofs in soft coal seams is provided, including: Obtain data on the rock mechanical properties of the coalbed methane roof and the coal and petrology properties of the known area; Based on well test data of the roof and floor of the target area and coal seams, 3D seismic tectonic data, data on the rock mechanical properties of the coalbed methane roof, and data on coal and rock properties, a 3D geomechanical model of the target area is constructed. Acquire drilling test data, including horizontal well directional drilling trajectory data, coalbed methane content data, drilling time data, casing running data, and cementing data for the target area; determine candidate perforation intervals based on the drilling test data, and identify multiple candidate perforation points within the candidate perforation intervals; The vertical distance between each candidate perforation point and the top boundary of the coal seam is calculated based on the three-dimensional geomechanical model of the target area; the candidate perforation points are then screened according to the vertical distance to obtain multiple perforation points after one screening. Determine the distance between each perforation point after the first screening and the fault, and then screen each perforation point after the first screening based on the distance to obtain multiple perforation points after the second screening. For each perforation point after secondary screening, a crack extension simulation is performed to obtain the crack extension distance; based on the crack extension distance, each perforation point after secondary screening is further screened to obtain multiple perforation points after tertiary screening. The minimum principal stress gradient difference is determined for each perforation point after three screenings. Based on the minimum principal stress gradient difference, each perforation point after three screenings is screened to obtain multiple optimized perforation points.

[0007] In one embodiment, the vertical distance between each candidate perforation point and the top boundary of the coal seam is calculated based on a three-dimensional geomechanical model of the target area using the following formula:

[0008]

[0009]

[0010] in, The vertical distance is... For safety reasons, The Young's modulus of the top plate. The minimum principal stress of the top plate is... The minimum principal stress of the coal seam, This is the tensile strength weighting coefficient. The tensile strength of the top plate, This is a reference value for tensile strength. This is the interface bonding weight coefficient. The coal-rock interface coefficient, This is a reference value for the bonding coefficient. Based on the offset, For the maximum destructive load, The diameter of the rock core. This refers to the thickness of the top plate.

[0011] In one embodiment, candidate perforation points are filtered based on vertical distance to obtain multiple perforation points after one-time filtering, including: If the vertical distance is greater than the top plate thickness corresponding to the candidate perforation point, the candidate perforation point is retained; otherwise, the candidate perforation point is removed.

[0012] In one embodiment, the perforation points after primary screening are filtered according to distance to obtain multiple perforation points after secondary screening, including: If the distance is greater than the first set value, retain the perforation points after one screening; otherwise, remove the perforation points after one screening.

[0013] In one embodiment, the perforation points after secondary screening are screened according to the crack extension distance to obtain multiple perforation points after tertiary screening, including: If the fracture extension distance is greater than or equal to 85% of the coal seam thickness, the perforation points after secondary screening are retained; otherwise, the perforation points after secondary screening are removed.

[0014] In one embodiment, the perforation points after each of the three screenings are screened based on the minimum principal stress gradient difference to obtain multiple optimized perforation points, including: If the minimum principal stress gradient difference is greater than the second set value, the perforation points after three screenings are retained; otherwise, the perforation points after three screenings are removed.

[0015] Secondly, a device for optimizing the directional perforation point of a horizontal well in a soft coal seam gas roof is provided, comprising: The data acquisition module is used to acquire data on the mechanical properties of the coalbed methane roof rock and coal and rock properties in known areas; The model building module is used to construct a three-dimensional geomechanical model of the target area based on well test data of the roof and floor and coal seams of the target area, three-dimensional seismic tectonic data, rock mechanical property data of the coalbed methane roof, and coal and rock property data. The candidate perforation point determination module is used to acquire drilling test data, including horizontal well directional drilling trajectory data, coalbed methane content data, drilling time data, casing running data, and cementing data for the target area; based on the drilling test data, it determines the candidate perforation interval, and within the candidate perforation interval, it determines multiple candidate perforation points; The first screening module is used to calculate the vertical distance between each candidate perforation point and the top boundary of the coal seam based on the three-dimensional geomechanical model of the target area; and to screen each candidate perforation point according to the vertical distance to obtain multiple perforation points after one screening. The second screening module is used to determine the distance between each perforation point after primary screening and the fault, and to screen each perforation point after primary screening based on the distance to obtain multiple perforation points after secondary screening. The third screening module is used to simulate the crack extension of each perforation point after secondary screening to obtain the crack extension distance; and to screen each perforation point after secondary screening based on the crack extension distance to obtain multiple perforation points after tertiary screening. The fourth screening module is used to determine the minimum principal stress gradient difference of each perforation point after three screenings. Based on the minimum principal stress gradient difference, the perforation points after three screenings are screened to obtain multiple optimized perforation points.

[0016] Thirdly, a computer-readable storage medium is provided, which stores a computer program that, when executed by a processor, implements the aforementioned method for optimizing the directional perforation points of horizontal wells in soft coalbed methane roofs.

[0017] Fourthly, a computer program product is provided, including a computer program / instruction, which, when executed by a processor, implements the aforementioned method for optimizing the directional perforation point of a horizontal well in a soft coalbed methane roof.

[0018] Compared with the prior art, this application has the following beneficial effects: 1. This application, through mechanical analysis of the coal seam roof and coal seam rock, can effectively connect the roof strata and the coal seam channel, and through fracture extension simulation analysis, the fracture connection efficiency is improved by more than 40%.

[0019] 2. This application effectively prevents the high rate of sand blockage accidents during segmented fracturing operations caused by obstructed passage between the wellbore and the coal seam.

[0020] 3. This application effectively avoids the problem of perforation through casing coupling during perforation construction by optimizing the selection of perforation points, thereby reducing the occurrence of perforation accidents and effectively improving single-well productivity. Attached Figure Description

[0021] This application can be better understood by referring to the description given below in conjunction with the accompanying drawings, which, together with the detailed description below, are incorporated in and form part of this specification. In the drawings: Figure 1 A flowchart illustrating the optimization method for directional perforation points in horizontal wells with soft coal seam gas roof is shown. Figure 2 A schematic diagram of the extension of the perforation crack in the top plate is shown. Detailed Implementation

[0022] Exemplary embodiments of the present application will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of the actual embodiments are described in the specification. However, it should be understood that many embodiment-specific decisions can be made in the development of any such actual embodiment to achieve the developer’s specific objectives, and these decisions may vary as the embodiments differ.

[0023] It should also be noted that, in order to avoid obscuring this application with unnecessary details, only the device structure closely related to the solution according to this application is shown in the accompanying drawings, while other details that are not closely related to this application are omitted.

[0024] It should be understood that this application is not limited to the described embodiments by virtue of the following description with reference to the accompanying drawings. In this document, embodiments may be combined with each other, features may be substituted or borrowed between different embodiments, and one or more features may be omitted in one embodiment, where feasible.

[0025] This application provides a method for optimizing the directional perforation points in horizontal wells with roofs in soft coalbed methane formations. Figure 1 A flowchart illustrating the method for optimizing the directional perforation points in horizontal wells with roofs in soft coal seams is shown. (See attached diagram.) Figure 1 The method mainly includes the following steps: Step S1: Obtain the rock mechanical properties data of the coalbed methane roof and the coal and rock properties data of the known area.

[0026] Here, the data on the rock mechanics properties of the coalbed methane roof and the coal and rock properties include key parameters such as: coal seam and roof lithology, compressive strength (natural state), tensile strength (natural state), elastic modulus, Poisson's ratio, and maximum geostress field.

[0027] Step S2: Based on the well test data of the roof and floor of the target area and coal seam, three-dimensional seismic tectonic data, data on the rock mechanical properties of the coalbed methane roof, and data on coal and rock properties, construct a three-dimensional geomechanical model of the target area.

[0028] Based on the known rock mechanical properties data and coal and rock properties data of the coalbed methane roof obtained in step 1, the rock mechanical properties data and coal and rock properties data of the coalbed methane roof of the target area can be determined.

[0029] Before constructing a three-dimensional geomechanical model of the target area, it is necessary to determine the model's boundary conditions and geometric dimensions. Here, the model boundary condition is the maximum geostress field (maximum principal stress). minimum principal stress Vertical stress The stresses are applied to the model in the X, Y, and Z directions, respectively. The geometric dimensions are determined as follows: the X direction is the direction of maximum principal stress, the Y direction is the direction of minimum principal stress, and the Z direction is the direction perpendicular to the ground stress. The dimensions of the model in the X direction are 500m, the dimensions of the model in the Y direction are 500m, and the dimensions of the model in the Z direction are 3-5 times the total thickness of the roof and coal seam.

[0030] Step S3: Obtain drilling test data, including horizontal well directional drilling trajectory data, coalbed methane content data, drilling time data, casing running data, and cementing data for the target area; determine candidate perforation intervals based on the drilling test data, and determine multiple candidate perforation points within the candidate perforation intervals.

[0031] The purpose of obtaining drilling test data here is to determine the candidate perforation interval.

[0032] Specifically, the directional drilling trajectory data of horizontal wells is the basis for determining the vertical distance between the wellbore trajectory and the coal seam, and the distance is generally controlled at around 5m; Based on coalbed methane content data, perforation sections with high coalbed methane content are selected for perforation, as these locations have good permeability, which is beneficial for increasing gas production in the later stages. Drilling data indicates whether the rock strata are easily fractured, providing a reference for subsequent perforation fracturing. The casing running data and cementing data are used to avoid perforation points located at casing coupling locations or areas with poor cementation. To avoid adverse factors affecting perforation, it is generally required to avoid locations 3m to the left and right of the casing coupling location. By using the above data for preliminary screening, candidate perforation intervals are determined, reducing the workload of subsequent calculations of the vertical distance ΔH.

[0033] Step S4: Calculate the vertical distance between each candidate perforation point and the top boundary of the coal seam based on the three-dimensional geomechanical model of the target area. The top boundary of the coal seam refers to the top interface of the coal seam. Based on the vertical distance, each candidate perforation point is screened to obtain multiple perforation points after one screening.

[0034] Specifically, the following formula is used:

[0035]

[0036]

[0037] in, The vertical distance is... For safety reasons, The Young's modulus of the top plate. The minimum principal stress of the top plate is... The minimum principal stress of the coal seam, For example, it can be a tensile strength weighting coefficient. , The tensile strength of the top plate, The reference value for tensile strength can be, for example, 15 MPa, based on the median average of rock mechanics tests from multiple wells in the target area, which is relatively representative. This is the interface bonding weight coefficient, for example, it can be 0.6. The coal-rock interface coefficient, This is a reference value for the bonding coefficient, for example, it can be 0.7, based on experience. The crack can stably extend across the interface; Based on the offset, For the maximum destructive load, The diameter of the rock core. This refers to the thickness of the top plate.

[0038] The calculation formula essentially describes the stress barrier effect of crack propagation, where This represents the minimum principal stress difference (critical control term) between the roof and the coal seam. A larger stress difference makes it easier for cracks to propagate downwards from the high-stress roof to the low-stress coal seam; therefore, ΔH and Young's modulus can be appropriately increased. The higher the value, the more brittle the roof rock becomes, resulting in wider but limited-height cracks, which reduces ΔH.

[0039] Specifically, if the vertical distance is greater than the top plate thickness corresponding to the candidate perforation point, the candidate perforation point is retained; otherwise, the candidate perforation point is removed.

[0040] Step S5: Determine the distance between each perforation point after primary screening and the fault. Based on the distance, screen each perforation point after primary screening to obtain multiple perforation points after secondary screening.

[0041] Specifically, if the distance is greater than a first set value (here, the first set value can be 180m), then the perforation points after one screening are retained; otherwise, the perforation points after one screening are removed. Here, the distance between the perforation point and the fault is a known value.

[0042] Here, the distance is greater than the first set value, the purpose of which is to ensure that the perforation point avoids the fault / aquifer location, thus isolating the aquifer and fault hazards.

[0043] Step S6: Simulate the crack extension of each perforation point after secondary screening to obtain the crack extension distance; screen each perforation point after secondary screening according to the crack extension distance to obtain multiple perforation points after tertiary screening.

[0044] Specifically, the COMSOL software was used to simulate fracture propagation and determine the model boundary conditions. The control condition was a radius of 250-300m around the wellbore. For each perforation point after secondary screening, the displacement and total injected fluid volume values ​​in the fracturing construction parameters were input to simulate the fracture initiation pressure, fracture propagation distance, and diffusion radius corresponding to different perforation points. Figure 2 A schematic diagram of the extension of the perforation crack in the top plate is shown.

[0045] If the fracture extension distance is greater than or equal to 85% of the coal seam thickness, the perforation points after secondary screening are retained; otherwise, the perforation points after secondary screening are removed.

[0046] Step S7: Determine the minimum principal stress gradient difference for each perforation point after three screenings, and screen each perforation point after three screenings according to the minimum principal stress gradient difference to obtain multiple optimized perforation points.

[0047] Specifically, if the minimum principal stress gradient difference is greater than a second set value (here, the second set value can be 3 MPa / 100 m), then the perforation points after three screenings are retained; otherwise, the perforation points after three screenings are removed. Here, the minimum principal stress gradient difference of the perforation points is obtained experimentally and is a known value.

[0048] In this embodiment, by optimizing the selection of perforation points, the problem of perforation through casing couplings during perforation construction is effectively avoided, the perforation accident rate is reduced, and the single-well productivity is effectively improved.

[0049] In a specific embodiment, taking a horizontal coal seam well in a certain mining area as an example, the collected data is shown in Table 1.

[0050] Table 1

[0051] Well logging data: Gamma values ​​distinguish roof sandstone (API < 60) from coal seams, and the interface cementation coefficient is calculated.

[0052] In-situ stress test data were obtained through well testing experiments. =43.2MPa, =38.1MPa =18MPa A three-dimensional geomechanical model of the target area was constructed.

[0053] The perforation points are screened using the method described in the foregoing embodiments.

[0054] For point A, calculate ΔH: =1.037 =3.52 Point A meets the condition of being ≥180m away from the fault, so a crack extension simulation experiment is conducted. Using COMSOL software, the input parameters are a displacement of 12m / min and a sand ratio of 10. The simulation experiment is performed, and the crack extension distance is output. For example, if the crack extension distance at point A is 6.2m, which is greater than the condition of 6m * 0.85 = 5.4m coal thickness, then point A is the preferred point, and the coordinates of point A are output.

[0055] Based on the same inventive concept as the method for optimizing the directional perforation point of a horizontal well in a soft coalbed methane roof, this embodiment also provides a corresponding device for optimizing the directional perforation point of a horizontal well in a soft coalbed methane roof, including: The data acquisition module is used to acquire data on the mechanical properties of the coalbed methane roof rock and coal and rock properties in known areas; The model building module is used to construct a three-dimensional geomechanical model of the target area based on well test data of the roof and floor and coal seams of the target area, three-dimensional seismic tectonic data, rock mechanical property data of the coalbed methane roof, and coal and rock property data. The candidate perforation point determination module is used to acquire drilling test data, including horizontal well directional drilling trajectory data, coalbed methane content data, drilling time data, casing running data, and cementing data for the target area; based on the drilling test data, it determines the candidate perforation interval, and within the candidate perforation interval, it determines multiple candidate perforation points; The first screening module is used to calculate the vertical distance between each candidate perforation point and the top boundary of the coal seam based on the three-dimensional geomechanical model of the target area; and to screen each candidate perforation point according to the vertical distance to obtain multiple perforation points after one screening. The second screening module is used to determine the distance between each perforation point after primary screening and the fault, and to screen each perforation point after primary screening based on the distance to obtain multiple perforation points after secondary screening. The third screening module is used to simulate the crack extension of each perforation point after secondary screening to obtain the crack extension distance; and to screen each perforation point after secondary screening based on the crack extension distance to obtain multiple perforation points after tertiary screening. The fourth screening module is used to determine the minimum principal stress gradient difference of each perforation point after three screenings. Based on the minimum principal stress gradient difference, the perforation points after three screenings are screened to obtain multiple optimized perforation points.

[0056] The device for optimizing the directional perforation point of a horizontal well with a broken soft coalbed methane roof in this embodiment has the same inventive concept as the method for optimizing the directional perforation point of a horizontal well with a broken soft coalbed methane roof described above. Therefore, the specific implementation of this device can be found in the embodiment section of the method for optimizing the directional perforation point of a horizontal well with a broken soft coalbed methane roof described above, and its technical effects correspond to the technical effects of the above method, so it will not be repeated here.

[0057] This application provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the above-described method for optimizing the directional perforation point of a horizontal well in a soft coalbed methane roof.

[0058] This application provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the above-mentioned method for optimizing the directional perforation point of a horizontal well in a soft coalbed methane roof.

[0059] The above descriptions are merely various embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for optimizing the location of directional perforation points in horizontal wells with roofs in soft coal seams, characterized in that, include: Obtain data on the rock mechanical properties of the coalbed methane roof and the coal and petrology properties of the known area; Based on well test data of the roof and floor of the target area and coal seams, 3D seismic tectonic data, data on the rock mechanical properties of the coalbed methane roof, and data on coal and rock properties, a 3D geomechanical model of the target area is constructed. Acquire drilling test data, which includes horizontal well directional drilling trajectory data, coalbed methane content data, drilling time data, casing running data, and cementing data for the target area; determine candidate perforation intervals based on the drilling test data, and determine multiple candidate perforation points within the candidate perforation intervals; The vertical distance between each candidate perforation point and the top boundary of the coal seam is calculated based on the three-dimensional geomechanical model of the target area; the candidate perforation points are then screened according to the vertical distance to obtain multiple perforation points after one screening. Determine the distance between each perforation point after primary screening and the fault, and screen each perforation point after primary screening according to the distance to obtain multiple perforation points after secondary screening; For each perforation point after secondary screening, crack propagation simulation was performed to obtain the crack propagation distance; Based on the crack extension distance, each of the secondary screening perforation points is screened to obtain multiple tertiary screening perforation points. The minimum principal stress gradient difference of each perforation point after three screenings is determined, and the perforation points after three screenings are screened according to the minimum principal stress gradient difference to obtain multiple optimized perforation points.

2. The method as described in claim 1, characterized in that, in, The vertical distance between each candidate perforation point and the top boundary of the coal seam is calculated based on the three-dimensional geomechanical model of the target area using the following formula: in, The vertical distance is... For safety reasons, The Young's modulus of the top plate. The minimum principal stress of the top plate is... The minimum principal stress of the coal seam, This is the tensile strength weighting coefficient. The tensile strength of the top plate, This is a reference value for tensile strength. This is the interface bonding weight coefficient. The coal-rock interface coefficient, This is a reference value for the bonding coefficient. Based on the offset, For the maximum destructive load, The diameter of the rock core. This refers to the thickness of the top plate.

3. The method as described in claim 1, characterized in that, in, Based on the vertical distance, each candidate perforation point is filtered to obtain multiple perforation points after one-time filtering, including: If the vertical distance is greater than the top plate thickness corresponding to the candidate perforation point, the candidate perforation point is retained; otherwise, the candidate perforation point is removed.

4. The method as described in claim 1, characterized in that, Based on the distance, each of the first-selection perforation points is further filtered to obtain multiple second-selection perforation points, including: If the distance is greater than the first set value, the perforation points after the first screening are retained; otherwise, the perforation points after the first screening are removed.

5. The method as described in claim 1, characterized in that, in, Based on the crack extension distance, the perforation points after secondary screening are further screened to obtain multiple perforation points after tertiary screening, including: If the fracture extension distance is greater than or equal to 85% of the coal seam thickness, the perforation points after secondary screening are retained; otherwise, the perforation points after secondary screening are removed.

6. The method as described in claim 1, characterized in that, in, Based on the minimum principal stress gradient difference, the perforation points after each of the three screenings are further screened to obtain multiple optimized perforation points, including: If the minimum principal stress gradient difference is greater than the second set value, the perforation points after the three screenings are retained; otherwise, the perforation points after the three screenings are removed.

7. A device for optimizing the location of directional perforation in horizontal wells with roofs in soft coal seams, characterized in that, include: The data acquisition module is used to acquire data on the mechanical properties of the coalbed methane roof rock and coal and rock properties in known areas; The model building module is used to construct a three-dimensional geomechanical model of the target area based on well test data of the roof and floor and coal seams of the target area, three-dimensional seismic tectonic data, rock mechanical property data of the coalbed methane roof, and coal and rock property data. The candidate perforation point determination module is used to acquire drilling test data, which includes horizontal well directional drilling trajectory data, coalbed methane content data, drilling time data, casing running data, and cementing data for the target area; and to determine candidate perforation intervals based on the drilling test data, and to determine multiple candidate perforation points within the candidate perforation intervals. The first screening module is used to calculate the vertical distance between each candidate perforation point and the top boundary of the coal seam based on the three-dimensional geomechanical model of the target area; and to screen each candidate perforation point according to the vertical distance to obtain multiple perforation points after one screening. The second screening module is used to determine the distance between each perforation point after primary screening and the fault, and to screen each perforation point after primary screening according to the distance to obtain multiple perforation points after secondary screening. The third screening module is used to simulate crack extension for each perforation point after secondary screening and obtain the crack extension distance. Based on the crack extension distance, each of the secondary screening perforation points is screened to obtain multiple tertiary screening perforation points. The fourth screening module is used to determine the minimum principal stress gradient difference of each perforation point after three screenings, and to screen each perforation point after three screenings according to the minimum principal stress gradient difference to obtain multiple optimized perforation points.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the method for optimizing the directional perforation points of horizontal wells in soft coalbed methane as described in any one of claims 1-6.

9. A computer program product, characterized in that, The method includes a computer program / instruction, which, when executed by a processor, implements the method for optimizing the directional perforation point of a horizontal well in a soft coalbed methane roof as described in any one of claims 1-6.

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