Hydrofracture optimization design method for controlling fracture height of deep coal bed gas reservoir and related device

Abstract

The invention belongs to the field of petroleum and natural gas engineering, and discloses a hydrofracture optimization design method for controlling the fracture height of a deep coal bed gas reservoir and a related device. Establishing a three-dimensional fracture crossing numerical simulation model by using the modeling parameters; calculating the critical mechanical parameters and the critical bedding number of the roof rock and the floor rock of the target coal seam section by using the three-dimensional fracture crossing numerical simulation model; according to the calculated critical mechanical parameters of the top plate rock and the bottom plate rock, the actual mechanical parameters of the critical bedding number and the bedding number, whether the target coal seam section needs to be subjected to crack height control or not is judged; and when the target coal seam section needs to be subjected to fracture height control, performing fracture form simulation by utilizing the three-dimensional fracture crossing numerical simulation model to obtain a fracture construction parameter when the fracture height meets the requirement, and taking the fracture construction parameter as a final fracture construction parameter. The method can effectively control the crack height of the target coal seam section, and the single well production effect after fracturing is improved.

Description

Technical Field

[0001] The invention belongs to the field of petroleum and natural gas engineering, and in particular relates to a hydraulic fracturing optimization design method for controlling the crack height of deep coalbed methane reservoirs and related devices. Background Art

[0002] Deep coalbed methane reservoirs are usually buried more than 2,000 meters deep and are an important part of unconventional oil and gas resources. The geological resources of deep coalbed methane with a burial depth greater than 2,000 meters reach 40.71 trillion m 3 With the significant reduction in effective shallow coalbed methane development areas, deep coalbed methane reservoirs will be the main battlefield for the development of large gas fields in the future. Vigorously developing deep coalbed methane reservoirs can not only effectively solve the current energy shortage problem, but also is crucial to energy security and the realization of dual carbon goals.

[0003] The thickness of deep coalbed methane reservoirs usually does not exceed 6m. The reservoir thickness is small and cleats are widely developed, which are typical characteristics of deep coalbed methane reservoirs. The development of deep coalbed methane reservoirs must rely on large-scale extreme volume fracturing technology to form an effective support fracture network in the reservoir and ultimately achieve economic and profitable mining. However, during the fracturing process, the typical characteristics of deep coalbed methane reservoirs make it difficult to control the fracture extension trajectory, and the fracture height is difficult to control within the target coal seam section, which seriously affects the fracturing development effect and restricts the vigorous development of deep coalbed methane reservoirs. How to regulate the fracturing parameters and effectively control the fracture height has become a technical bottleneck problem that restricts the economic and profitable development of deep coalbed methane reservoirs. Summary of the invention

[0004] In order to solve the technical bottleneck problem that it is difficult to control the crack height in the extreme volume fracturing of deep coalbed methane reservoirs, the purpose of the present invention is to propose a hydraulic fracturing optimization design method and related devices for controlling the crack height of deep coalbed methane reservoirs. Based on the present invention, a real simulation of the fracturing process of deep coalbed methane reservoirs can be achieved, with the goal of optimizing the pumping program and determining critical reservoir parameters, ultimately achieving effective control of the crack height of the target coal seam section and improving the production effect of a single well after fracturing.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows: A hydraulic fracturing optimization design method for controlling the fracture height of deep coalbed methane reservoirs includes the following processes: Obtaining modeling parameters required for modeling; Using the modeling parameters, a three-dimensional fracture penetration numerical simulation model is established based on the fracturing module of the petrel software platform; Calculate the critical mechanical parameters and critical bedding quantity of the roof rock above the target coal seam section and the critical mechanical parameters and critical bedding quantity of the floor rock below the target coal seam section using the three-dimensional fracture penetration numerical simulation model; According to the calculated critical mechanical parameters and critical bedding quantity of the roof rock, the calculated critical mechanical parameters and critical bedding quantity of the floor rock, the actual mechanical parameters and bedding quantity of the roof rock, and the actual mechanical parameters and bedding quantity of the floor rock, it is determined whether the target coal seam section needs to be controlled in terms of fracture height; When the target coal seam section needs to control the fracture height, the three-dimensional fracture penetration numerical simulation model is used to simulate the fracturing morphology to obtain the fracturing construction parameters when the fracture height meets the requirements, and the fracturing construction parameters at this time are used as the final fracturing construction parameters.

[0006] Preferably, the modeling parameters required for modeling include: The number and distribution angle of cleats in the target coal seam section; The lithology and amount of bedding of the roof rock above and the floor rock below the target coal seam interval; Mechanical property parameters, ground stress characteristic parameters, basic physical property parameters, vertical fracture toughness index and horizontal fracture toughness index of roof rock, target coal seam section and floor rock.

[0007] Preferably: the number and distribution angle of the cleats in the target coal seam section are determined by combining logging interpretation data with drilling coring, including: the number of cleats is counted according to the number of cleats per unit area on the core end face, and the distribution angle of the cleats is counted according to the angle between the cleats and the maximum horizontal principal stress of the formation; For the top plate rock and bottom plate rock, when the lithology is mudstone or shale, the actual number of beddings needs to be counted; when the lithology is sandstone, the number of beddings is zero; Mechanical property parameters include Young's modulus, Poisson's ratio, tensile strength, compressive strength and friction coefficient; The vertical fracture toughness index and horizontal fracture toughness index are calculated through mechanical property parameters; The characteristic parameters of geostress include maximum horizontal principal stress, minimum horizontal principal stress and vertical principal stress; Basic physical property parameters include porosity and permeability.

[0008] Preferably, it is characterized in that: vertical fracture toughness index KICvertical=0.005+0.155×K1-0.00312×K2+0.0148×E, unit is MPa.m 0.5 ; Horizontal fracture toughness index KIC horizontal = 0.6 × KIC vertical; Among them, K1 is the tensile strength, K2 is the compressive strength, and E is the Young's modulus.

[0009] Preferably, the three-dimensional fracture penetration numerical simulation model is used to calculate the critical mechanical parameters and critical bedding quantity of the roof rock above the target coal seam section, as well as the critical mechanical parameters and critical bedding quantity of the floor rock below the target coal seam section, including: When the lithology of the roof rock is sandstone or limestone, the first layer penetration simulation control parameter is set, and then the fracture penetration shear slip control module in the fracturing module is enabled to simulate the fracture extension. During the simulation, it is determined whether the fracture will penetrate the roof rock, and then the first layer penetration simulation control parameter is continuously adjusted until the fracture height does not penetrate the roof rock. At this time, the critical mechanical parameters of the roof rock are determined; When the lithology of the bottom plate rock is sandstone or limestone, the first layer penetration simulation control parameter is set, and then the crack penetration shear slip control module is enabled to simulate the crack extension. During the simulation, it is determined whether the crack will penetrate the bottom plate rock, and then the first layer penetration simulation control parameter is continuously adjusted until the crack height does not penetrate the bottom plate rock. At this time, the critical mechanical parameters of the bottom plate rock are determined; Among them, the first penetration simulation control parameters include the minimum horizontal principal stress, friction coefficient and tensile strength of the rock, and the critical mechanical parameters include the critical minimum horizontal principal stress, critical rock friction coefficient and critical rock tensile strength; When the lithology of the roof rock is shale, the second penetration simulation control parameter is set, and then the fracture penetration offset control module in the fracturing module is enabled to simulate the fracture extension. During the simulation, it is determined whether the fracture will penetrate the roof rock, and then the second penetration simulation control parameter is continuously adjusted until the fracture height does not penetrate the roof rock. At this time, the critical number of layers of the roof rock is determined; When the lithology of the bottom plate rock is shale, the second penetration simulation control parameter is set, and then the fracture penetration offset control module in the fracturing module is enabled to simulate the fracture extension. During the simulation, it is determined whether the fracture will penetrate the bottom plate rock, and then the second penetration simulation control parameter is continuously adjusted until the fracture height does not penetrate the bottom plate rock. At this time, the critical number of layers of the bottom plate rock is determined; When the lithology of the roof rock is mudstone, set the second layer penetration simulation control parameter, and then enable the fracture penetration offset control module in the fracturing module to simulate the fracture extension. During the simulation, determine whether the fracture will penetrate the roof rock, and then continuously adjust the second layer penetration simulation control parameter until the fracture height does not penetrate the roof rock. At this time, the critical number of layers of the roof rock is determined; When the lithology of the bottom plate rock is mudstone, set the second layer penetration simulation control parameter, and then enable the fracture penetration offset control module in the fracturing module to simulate the fracture extension. During the simulation, determine whether the fracture will penetrate the bottom plate rock, and then continuously adjust the second layer penetration simulation control parameter until the fracture height does not penetrate the bottom plate rock. At this time, the critical number of layers of the bottom plate rock is determined; The second layer penetration simulation control parameters include an offset and a layer quantity.

[0010] Preferably, judging whether the target coal seam section needs to be controlled in terms of the calculated critical mechanical parameters and critical bedding quantity of the roof rock, the calculated critical mechanical parameters and critical bedding quantity of the floor rock, the actual mechanical parameters and bedding quantity of the roof rock, and the actual mechanical parameters and bedding quantity of the floor rock comprises: When the lithology of the roof rock is shale or mudstone, if the actual number of beddings in the roof rock is greater than the calculated critical number of beddings of the roof rock, it indicates that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is no need to control the crack height at this time; if the actual number of beddings in the roof rock is not greater than the calculated critical number of beddings, it indicates that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is a need to control the crack height at this time; When the lithology of the floor rock is shale or mudstone, if the actual number of beddings in the floor rock is greater than the calculated critical number of beddings of the floor rock, it indicates that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is no need to control the crack height at this time; if the actual number of beddings in the floor rock is not greater than the calculated critical number of beddings, it indicates that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is a need to control the crack height at this time; When the lithology of the roof rock is sandstone or limestone, if the actual minimum horizontal principal stress of the roof rock is greater than the calculated critical minimum horizontal principal stress of the roof rock, or the actual tensile strength of the roof rock is greater than the calculated critical rock tensile strength of the roof rock, it means that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is no need to control the crack height at this time; if the actual rock friction coefficient of the roof rock is less than the calculated critical rock friction coefficient of the roof rock, it means that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is no need to control the crack height at this time; When the lithology of the bottom plate rock is sandstone or limestone, if the actual minimum horizontal principal stress of the bottom plate rock is greater than the calculated critical minimum horizontal principal stress of the bottom plate rock, or the actual tensile strength of the bottom plate rock is greater than the calculated critical rock tensile strength of the bottom plate rock, it means that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is no need to control the crack height at this time; if the actual rock friction coefficient of the bottom plate rock is less than the calculated critical rock friction coefficient of the bottom plate rock, it means that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is no need to control the crack height at this time; When the lithology of the roof rock is sandstone or limestone, if the actual minimum horizontal principal stress of the roof rock is greater than the calculated critical minimum horizontal principal stress of the roof rock, or the actual tensile strength of the roof rock is greater than the calculated tensile strength of the roof rock, it indicates that the crack height will penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that the crack height needs to be controlled at this time; if the actual rock friction coefficient of the roof rock is greater than the calculated critical rock friction coefficient of the roof rock, it indicates that the crack height will penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that the crack height needs to be controlled at this time; When the lithology of the bottom plate rock is sandstone or limestone, if the actual minimum horizontal principal stress of the bottom plate rock is greater than the calculated critical minimum horizontal principal stress of the bottom plate rock, or the actual tensile strength of the bottom plate rock is greater than the calculated tensile strength of the bottom plate rock, it indicates that the crack height will penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that the crack height needs to be controlled at this time; if the actual rock friction coefficient of the bottom plate rock is greater than the calculated critical rock friction coefficient of the bottom plate rock, it indicates that the crack height will penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that the crack height needs to be controlled at this time.

[0011] Preferably, when the target coal seam section needs to control the fracture height, a three-dimensional fracture penetration numerical simulation model is used to simulate the fracturing morphology, and the fracturing construction parameters when the fracture height meets the requirements are obtained, and the fracturing construction parameters at this time are used as the final fracturing construction parameters, including: When the target coal seam section needs to control the fracture height, the three-dimensional fracture penetration numerical simulation model is used to simulate the fracturing morphology, and the fracturing construction parameters are continuously adjusted until the fracture height shown by the fracturing results meets the requirements. The fracturing construction parameters at this time are used as the final fracturing construction parameters. Among them, fracturing construction parameters include fracturing fluid displacement, fracturing fluid viscosity, sand ratio and total fluid volume; When the crack height is less than 1 / 4 of the thickness of the roof rock or floor rock layer, it indicates that the crack height meets the requirements.

[0012] The present invention also provides a hydraulic fracturing optimization design system for controlling the height of deep coalbed methane reservoir fractures, which is used to implement the hydraulic fracturing optimization design method for controlling the height of deep coalbed methane reservoir fractures of the present invention. The system includes: Data acquisition module: used to obtain the modeling parameters required for modeling; Modeling module: used to establish a three-dimensional fracture penetration numerical simulation model based on the fracturing module of the petrel software platform by using the modeling parameters; A calculation module: used to calculate the critical mechanical parameters and critical bedding quantity of the roof rock above the target coal seam section, and the critical mechanical parameters and critical bedding quantity of the floor rock below the target coal seam section using the three-dimensional fracture penetration numerical simulation model; Judgment module: used to judge whether the target coal seam section needs to control the fracture height according to the calculated critical mechanical parameters and critical bedding quantity of the roof rock, the calculated critical mechanical parameters and critical bedding quantity of the floor rock, the actual mechanical parameters and bedding quantity of the roof rock, and the actual mechanical parameters and bedding quantity of the floor rock; Optimization module: When the target coal seam section needs to control the fracture height, the three-dimensional fracture penetration numerical simulation model is used to simulate the fracturing morphology, and the fracturing construction parameters are obtained when the fracture height meets the requirements. The fracturing construction parameters at this time are used as the final fracturing construction parameters.

[0013] The present invention also provides an electronic device, comprising: one or more processors; a storage device having one or more programs stored thereon; When the one or more programs are executed by the one or more processors, the one or more processors implement the hydraulic fracturing optimization design method for controlling the fracture height of deep coalbed methane reservoirs as described above in the present invention.

[0014] The present invention also provides a storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the hydraulic fracturing optimization design method for controlling the fracture height of deep coalbed methane reservoirs as described above.

[0015] This hair has the following beneficial effects: The principle of the hydraulic fracturing optimization design method for controlling the height of cracks in deep coalbed methane reservoirs of the present invention is: for deep coalbed methane reservoirs, due to the uncertain properties of the top and bottom plate rocks (i.e., the top plate rocks and the bottom plate rocks), when the cracks expand along the longitudinal direction, the shear slip between the layers may affect the crack height, and the offset caused by the cracks contacting the bedding may also affect the crack height. The present invention combines the above two sets of crack height expansion criteria, first judges the lithology, and then selects the crack penetration control criteria on this basis to judge whether the reservoir will penetrate the layer under specific formation attribute parameters, and then optimizes the design of the fracturing process parameters in a targeted manner, so as to finally achieve the control of the crack height in the target coal seam section. The present invention can truly restore the expansion morphology of the cracks in the crack height direction during the extreme volume fracturing of the deep coalbed methane reservoir; it can also analyze whether the cracks will penetrate the layer under different top and bottom plate rock properties; it can also optimize the pumping program, effectively control the height of the cracks in the target coal seam section, and improve the single well fracturing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0017] Figure 1 A three-dimensional fracture penetration numerical simulation model diagram is established using the fracturing module of the petrel software platform in an embodiment of the present invention; FIG. 2( a ) is a longitudinal cross-sectional morphology diagram of a crack before optimization in an embodiment of the present invention; FIG. 2( b ) is a longitudinal cross-sectional morphology diagram of a crack after optimization in an embodiment of the present invention.

[0018] In the figure, 1-target coal seam section, 2-roof rock, 3-bottom rock. DETAILED DESCRIPTION

[0019] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0020] The hydraulic fracturing optimization design method for controlling the fracture height of deep coalbed methane reservoirs of the present invention comprises the following steps: Step (1) determines the number and distribution angle of cleats in the target coal seam section by combining logging interpretation data with drilling coring, and determines the lithology and number of beddings of the top rock in the upper part of the deep coal seam gas reservoir coal seam section (i.e., the target coal seam section) and the bottom rock in the lower part of the deep coal seam gas reservoir coal seam section. e-trueSpecifically, the number of cleats in the coal seam section of the deep coalbed methane reservoir is counted according to the number of cleats per unit area on the core end face, and the distribution angle of the cleats is counted according to the angle between the cleats and the maximum horizontal principal stress of the formation. Determine the lithology of the top plate rock at the top and the bottom plate rock at the bottom of the target coal seam section. If the lithology is determined to be mudstone or shale, it is necessary to count the actual number of beddings in the top plate rock and the bottom plate rock. e-true ; If the rock type is sandstone, there is no need to consider the influence of stratification, and there is no need to count the actual number of stratifications in the top rock and bottom rock.

[0021] Step (2) uses drilling coring combined with indoor true triaxial compression tests and steady-state displacement tests to measure the mechanical property parameters, ground stress property parameters and basic physical property parameters of the roof rock, target coal seam section and floor rock; the mechanical property parameters include Young's modulus E, Poisson's ratio ν, tensile strength K1, compressive strength K2 and friction coefficient μ of the rock; the ground stress property parameters include the maximum horizontal principal stress SH, the minimum horizontal principal stress Sh and the vertical principal stress SV; the basic physical property parameters include the porosity of the rock φ and permeability k.

[0022] Step (3), combining the parameters collected in step (1) and step (2), using the fracturing module of the petrel software platform to establish a three-dimensional fracture penetration numerical simulation model; specifically, before establishing the three-dimensional fracture penetration numerical simulation model, firstly, according to the rock mechanics parameters, the vertical fracture toughness and horizontal fracture toughness KIC parameters (i.e., fracture toughness index) of the three layers of the top rock, the target coal seam section, and the bottom rock required for establishing the model are calculated. The calculation formulas of the vertical fracture toughness KIC parameter and the horizontal fracture toughness KIC parameter are as follows: KIC vertical = 0.005 + 0.155 * K1 - 0.00312 * K2 + 0.0148 * E, unit MPa.m 0.5 KIC horizontal = 0.6*KIC vertical Step (4), set the cross-layer simulation control parameters of the top plate rock and the bottom plate rock through the fracture cross-layer offset control module (OFFSET) and the fracture cross-layer shear slip control module (Shear Slip) in the petrel software platform fracturing module, and continuously adjust the control parameters to perform cross-layer fracturing simulation until the critical mechanical parameters and critical bedding quantity B of the top and bottom plate rocks (i.e., the top plate rock and the bottom plate rock) are determined. e-critical To date; specifically: When the lithology of the roof rock (or bottom rock) is sandstone or limestone, set the layer penetration simulation control parameters, which include the minimum horizontal principal stress of the rock, the friction coefficient of the rock, and the tensile strength of the rock. Then enable the fracture penetration shear slip control module (Shear Slip) to simulate the fracture extension, and judge whether the fracture will penetrate the roof rock (or bottom rock). Then, continuously adjust the layer penetration simulation control parameters until the fracture height does not penetrate the roof rock (or bottom rock). At this time, the critical mechanical parameters are determined when the lithology of the roof rock (or bottom rock) is sandstone or limestone. The critical mechanical parameters include the critical minimum horizontal principal stress Sh- critical , critical rock friction coefficient μ- critical and critical rock tensile strength K1- critical ; When the lithology of the roof rock (or bottom rock) is shale, set the layer penetration simulation control parameters, which include the offset and the number of strata. The offset is set to a fixed value of 5.5 cm. Then enable the fracture penetration offset control module (OFFSET) to simulate the fracture extension. Determine whether the fracture will penetrate the roof rock (or bottom rock). Then, continuously adjust the layer penetration simulation control parameters until the fracture height does not penetrate the roof rock (or bottom rock). At this time, the critical number of strata B when the lithology of the roof rock (or bottom rock) is shale is determined. e-critical ; When the lithology of the roof rock (or bottom rock) is mudstone, set the layer penetration simulation control parameters, which include the offset and the number of strata. The offset is set to a fixed value of 2.5 cm. Then enable the fracture penetration offset control module (OFFSET) to simulate the fracture extension. Determine whether the fracture will penetrate the roof rock (or bottom rock). Then, continuously adjust the layer penetration simulation control parameters until the fracture height does not penetrate the roof rock (or bottom rock). At this time, the critical number of strata B is determined when the lithology of the roof rock (or bottom rock) is shale. e-critical ; Step (5), comparing the critical mechanical parameters and critical bedding number of the top and bottom plate rocks (i.e., the top plate rocks and the bottom plate rocks) determined in step (4) with the mechanical parameters and bedding number of the top and bottom plate rocks (i.e., the top plate rocks and the bottom plate rocks) actually corresponding to the target coal seam section, to determine whether it is necessary to control the fracture height; specifically, when the lithology of the top plate rock (or the bottom plate rock) of the actual target coal seam section is shale or mudstone, if the actual bedding number of the top plate rock (or the bottom plate rock) exceeds the critical bedding number of the top plate rock (or the bottom plate rock) determined in step (4), it means that the fracture height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and therefore, no fracturing optimization design is required; if the actual bedding number of the top plate rock (or the bottom plate rock) does not exceed the critical bedding number of the top plate rock (or the bottom plate rock) determined in step (4), it means that the fracture height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and therefore, it is necessary to perform fracturing optimization design.

[0023] When the lithology of the roof rock (or floor rock) of the actual target coal seam section is sandstone or limestone, if the actual minimum horizontal principal stress of the roof rock (or floor rock) exceeds the critical minimum horizontal principal stress Sh- of the roof rock (or floor rock) determined in step (4), critical , or, if the actual rock tensile strength of the roof rock (or bottom rock) exceeds the critical rock tensile strength K1- critical ; It means that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam segment, so there is no need to perform fracturing optimization design. If the actual rock friction coefficient of the top rock (or bottom rock) is less than the critical rock friction coefficient μ- critical This indicates that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, so there is no need for fracturing optimization design.

[0024] When the lithology of the roof rock (or floor rock) of the actual target coal seam section is sandstone or limestone, if the actual minimum horizontal principal stress of the roof rock (or floor rock) does not exceed the critical minimum horizontal principal stress Sh- of the roof rock (or floor rock) determined in step (4), critical , or, if the actual rock tensile strength of the roof rock (or floor rock) does not exceed the critical rock tensile strength K1- critical ; It indicates that the crack height will penetrate the layer during hydraulic fracturing of the target coal seam segment, so it is necessary to optimize the fracturing design. If the actual rock friction coefficient of the top rock (or bottom rock) is greater than the critical rock friction coefficient μ- critical , indicating that during hydraulic fracturing of the target coal seam section, the fracture height will also penetrate the layer, so it is necessary to carry out fracturing optimization design; Step (6), for the target coal seam section that needs to control the fracture height, a three-dimensional fracture penetration numerical simulation model is used to simulate the fracturing morphology, and the four fracturing construction parameters, namely, the fracturing fluid displacement, fracturing fluid viscosity, sand ratio and total fluid volume, are continuously adjusted until the fracturing results show that the fracture height meets the requirements; specifically, the fracturing construction parameters are continuously adjusted to calculate the height H of the simulated hydraulic fracture passing through the roof rock (or bottom rock). When the fracture height H is less than 1 / 4 of the thickness of the roof rock (or bottom rock) layer, it can be regarded that the fracture height is effectively controlled, and the fracturing construction parameters at this time are the final fracturing construction parameters obtained by the optimized design.

[0025] The fracturing construction parameters optimized in step (6) of the present invention are used to design a pumping schedule, and then the on-site fracturing construction is carried out.

[0026] Example The deep coalbed methane resources in a certain area of ​​a certain oil field are rich in reserves, the reservoir depth exceeds 2000m, and the main development layer is the No. 8 coal series. However, the on-site fracturing results show that the fracture height is often unable to be effectively controlled, and the effect of single well fracturing is poor. Therefore, the above technical solution of the present invention is used to optimize the pumping program of the 10-32-56 well in a certain place. The specific steps are as follows: Step (1), through the well logging interpretation data combined with the drilling coring, it is determined that the top rock of the target coal seam section of the 10-32-56 well in a certain place is limestone and the bottom rock is mudstone, and the actual number of beddings in the bottom mudstone is 10.

[0027] Step (2) uses drilling coring combined with indoor true triaxial compression tests and steady-state displacement tests to measure the mechanical property parameters, ground stress property parameters and basic physical property parameters of the roof rock, target coal seam section and floor rock. The specific parameters are shown in Table 1: Table 1

[0028] Step (3) uses the fracturing module of the petrel software platform to establish a three-dimensional fracture penetration numerical simulation model as follows: Figure 1 As shown; Step (4), for the 10-32-56 well in a certain place, since the roof rock is limestone, the fracture penetration shear slip control module (Shear Slip) is enabled to simulate the fracture extension to determine whether the fracture will penetrate the roof rock. Then, the penetration simulation control parameters are continuously adjusted until the fracture height does not penetrate the roof rock. Finally, the critical mechanical parameters of the roof rock are determined. Among the critical mechanical parameters, the critical minimum horizontal principal stress Sh- critical =46MPa, critical rock friction coefficient μ- critical =0.63, critical rock tensile strength K1-critical =25.3MPa.

[0029] Since the bottom rock of Well 10-32-56 is mudstone, the fracture penetration offset control module (OFFSET) is used to simulate the fracture extension to determine whether the fracture will penetrate the bottom rock. Then, the penetration simulation control parameters are adjusted continuously until the fracture height does not penetrate the bottom rock. Finally, the critical number of layers B in the bottom rock is determined. e-critical =30 items.

[0030] Step (5), comparing the critical parameters determined in step (4) with the actual values, the results show that since the actual number of stratification of the bottom plate rock is less than the critical number of stratification, the bottom plate rock will undergo delamination, and the minimum horizontal principal stress and tensile strength of the top plate rock are also less than the critical parameters, so the top plate rock will also undergo delamination. Therefore, it is necessary to optimize the design of the fracturing pumping program.

[0031] Step (6), for the target coal seam section of Well 10-32-56, a three-dimensional fracture penetration numerical simulation model was used to simulate the fracturing morphology, and then the four fracturing construction parameters, namely, the fracturing fluid displacement, fracturing fluid viscosity, sand ratio and total fluid volume, were continuously adjusted until the fracturing results showed that the height H of the fracture penetrating the top rock (or bottom rock) was less than 1 / 4 of the thickness of the top rock (or bottom rock) layer. The final optimized pumping parameters were: fracturing fluid displacement 16m 3 / min, fracturing fluid viscosity 15mPa·s -45mPa·s, sand ratio 0.7, total fluid volume 1943m 3 ,The comparison of the fracture morphology before and after optimization is shown in FIG2(a) and FIG2(b). As can be seen from FIG2(b), after optimization by the present invention, the fracture height direction is basically controlled within the coal seam section.

[0032] The pumping schedule was designed using the optimized fracturing parameters in step (6) above, and then the on-site fracturing was carried out. The final post-fracturing production results were compared with those of adjacent wells that were not optimized, as shown in Table 2: Table 2

[0033] It can be seen from Table 2 that the cumulative gas production of a single well (i.e., well 10-32-56) has been greatly increased compared with the unoptimized adjacent well (i.e., well 147).

[0034] The present invention also provides a system for optimizing the hydraulic fracturing design method for controlling the height of deep coalbed methane reservoir fractures, the system comprising: Data acquisition module: used to obtain the modeling parameters required for modeling; Modeling module: used to establish a three-dimensional fracture penetration numerical simulation model based on the fracturing module of the petrel software platform by using the modeling parameters; A calculation module: used to calculate the critical mechanical parameters and critical bedding quantity of the roof rock above the target coal seam section, and the critical mechanical parameters and critical bedding quantity of the floor rock below the target coal seam section using the three-dimensional fracture penetration numerical simulation model; Judgment module: used to judge whether the target coal seam section needs to control the fracture height according to the calculated critical mechanical parameters and critical bedding quantity of the roof rock, the calculated critical mechanical parameters and critical bedding quantity of the floor rock, the actual mechanical parameters and bedding quantity of the roof rock, and the actual mechanical parameters and bedding quantity of the floor rock; Optimization module: When the target coal seam section needs to control the fracture height, the three-dimensional fracture penetration numerical simulation model is used to simulate the fracturing morphology, and the fracturing construction parameters are obtained when the fracture height meets the requirements. The fracturing construction parameters at this time are used as the final fracturing construction parameters.

[0035] The embodiments of the present invention also provide corresponding electronic devices and computer-readable storage media for implementing the solutions provided by the embodiments of the present invention.

[0036] Among them, the device includes a memory and a processor, the memory is used to store instructions or codes, and the processor is used to execute the instructions or codes so that the device executes the hydraulic fracturing optimization design method for controlling the height of deep coalbed methane reservoir fractures as described in any embodiment of the present application.

[0037] The storage medium stores a computer program, wherein the computer program, when executed by the processor, implements the hydraulic fracturing optimization design method for controlling the height of deep coalbed methane reservoir fractures as described in any embodiment of the present application.

[0038] The present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, readable storage media, optical storage, etc.) containing computer-usable program codes.

[0039] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0040] 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 above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A hydraulic fracturing optimization design method for controlling the height of deep coalbed methane reservoir fractures, characterized in that: The process includes the following: Obtaining modeling parameters required for modeling; Using the modeling parameters, a three-dimensional fracture penetration numerical simulation model is established based on the fracturing module of the petrel software platform; Calculate the critical mechanical parameters and critical bedding quantity of the roof rock above the target coal seam section and the critical mechanical parameters and critical bedding quantity of the floor rock below the target coal seam section using the three-dimensional fracture penetration numerical simulation model; According to the calculated critical mechanical parameters and critical bedding quantity of the roof rock, the calculated critical mechanical parameters and critical bedding quantity of the floor rock, the actual mechanical parameters and bedding quantity of the roof rock, and the actual mechanical parameters and bedding quantity of the floor rock, it is determined whether the target coal seam section needs to be controlled in terms of fracture height; When the target coal seam section needs to control the fracture height, the three-dimensional fracture penetration numerical simulation model is used to simulate the fracturing morphology to obtain the fracturing construction parameters when the fracture height meets the requirements, and the fracturing construction parameters at this time are used as the final fracturing construction parameters.

2. A hydraulic fracturing optimization design method for controlling the height of deep coalbed methane reservoir fractures according to claim 1, characterized in that: The modeling parameters required for modeling include: The number and distribution angle of cleats in the target coal seam section; The lithology and amount of bedding of the roof rock above and the floor rock below the target coal seam interval; Mechanical property parameters, ground stress characteristic parameters, basic physical property parameters, vertical fracture toughness index and horizontal fracture toughness index of roof rock, target coal seam section and floor rock.

3. A hydraulic fracturing optimization design method for controlling the height of deep coalbed methane reservoir fractures according to claim 2, characterized in that: The number and distribution angle of the cleats in the target coal seam section are determined by combining the logging interpretation data with the drilling coring, including: the number of cleats is counted according to the number of cleats per unit area on the core end face, and the distribution angle of the cleats is counted according to the angle between the cleats and the maximum horizontal principal stress of the formation; For the top plate rock and bottom plate rock, when the lithology is mudstone or shale, the actual number of beddings needs to be counted; when the lithology is sandstone, the number of beddings is zero; Mechanical property parameters include Young's modulus, Poisson's ratio, tensile strength, compressive strength and friction coefficient; The vertical fracture toughness index and horizontal fracture toughness index are calculated through mechanical property parameters; The characteristic parameters of geostress include maximum horizontal principal stress, minimum horizontal principal stress and vertical principal stress; Basic physical property parameters include porosity and permeability.

4. A hydraulic fracturing optimization design method for controlling the height of deep coalbed methane reservoir fractures according to claim 2 or 3, characterized in that: Vertical fracture toughness index KICvertical = 0.005 + 0.155 × K1-0.00312 × K2 + 0.0148 × E, unit is MPa.m 0.5 ; Horizontal fracture toughness index KIC horizontal = 0.6 × KIC vertical; Among them, K1 is the tensile strength, K2 is the compressive strength, and E is the Young's modulus.

5. The method for optimizing the hydraulic fracturing design for controlling the fracture height of deep coalbed methane reservoirs according to claim 2, characterized in that: The three-dimensional fracture penetration numerical simulation model is used to calculate the critical mechanical parameters and critical bedding quantity of the roof rock above the target coal seam section, as well as the critical mechanical parameters and critical bedding quantity of the floor rock below the target coal seam section, including: When the lithology of the roof rock is sandstone or limestone, the first layer penetration simulation control parameter is set, and then the fracture penetration shear slip control module in the fracturing module is enabled to simulate the fracture extension. During the simulation, it is determined whether the fracture will penetrate the roof rock, and then the first layer penetration simulation control parameter is continuously adjusted until the fracture height does not penetrate the roof rock. At this time, the critical mechanical parameters of the roof rock are determined; When the lithology of the bottom plate rock is sandstone or limestone, the first layer penetration simulation control parameter is set, and then the crack penetration shear slip control module is enabled to simulate the crack extension. During the simulation, it is determined whether the crack will penetrate the bottom plate rock, and then the first layer penetration simulation control parameter is continuously adjusted until the crack height does not penetrate the bottom plate rock. At this time, the critical mechanical parameters of the bottom plate rock are determined; Among them, the first penetration simulation control parameters include the minimum horizontal principal stress, friction coefficient and tensile strength of the rock, and the critical mechanical parameters include the critical minimum horizontal principal stress, critical rock friction coefficient and critical rock tensile strength; When the lithology of the roof rock is shale, the second penetration simulation control parameter is set, and then the fracture penetration offset control module in the fracturing module is enabled to simulate the fracture extension. During the simulation, it is determined whether the fracture will penetrate the roof rock, and then the second penetration simulation control parameter is continuously adjusted until the fracture height does not penetrate the roof rock. At this time, the critical number of layers of the roof rock is determined; When the lithology of the bottom plate rock is shale, the second penetration simulation control parameter is set, and then the fracture penetration offset control module in the fracturing module is enabled to simulate the fracture extension. During the simulation, it is determined whether the fracture will penetrate the bottom plate rock, and then the second penetration simulation control parameter is continuously adjusted until the fracture height does not penetrate the bottom plate rock. At this time, the critical number of layers of the bottom plate rock is determined; When the lithology of the roof rock is mudstone, set the second layer penetration simulation control parameter, and then enable the fracture penetration offset control module in the fracturing module to simulate the fracture extension. During the simulation, determine whether the fracture will penetrate the roof rock, and then continuously adjust the second layer penetration simulation control parameter until the fracture height does not penetrate the roof rock. At this time, the critical number of layers of the roof rock is determined; When the lithology of the bottom plate rock is mudstone, set the second layer penetration simulation control parameter, and then enable the fracture penetration offset control module in the fracturing module to simulate the fracture extension. During the simulation, determine whether the fracture will penetrate the bottom plate rock, and then continuously adjust the second layer penetration simulation control parameter until the fracture height does not penetrate the bottom plate rock. At this time, the critical number of layers of the bottom plate rock is determined; The second layer penetration simulation control parameters include an offset and a layer quantity.

6. The method for optimizing the hydraulic fracturing design for controlling the fracture height of deep coalbed methane reservoirs according to claim 1, characterized in that: According to the calculated critical mechanical parameters and critical bedding quantity of the roof rock, the calculated critical mechanical parameters and critical bedding quantity of the floor rock, the actual mechanical parameters and bedding quantity of the roof rock, and the actual mechanical parameters and bedding quantity of the floor rock, it is judged whether the target coal seam section needs to be controlled in terms of fracture height, including: When the lithology of the roof rock is shale or mudstone, if the actual number of beddings in the roof rock is greater than the calculated critical number of beddings of the roof rock, it indicates that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is no need to control the crack height at this time; if the actual number of beddings in the roof rock is not greater than the calculated critical number of beddings, it indicates that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is a need to control the crack height at this time; When the lithology of the floor rock is shale or mudstone, if the actual number of beddings in the floor rock is greater than the calculated critical number of beddings of the floor rock, it indicates that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is no need to control the crack height at this time; if the actual number of beddings in the floor rock is not greater than the calculated critical number of beddings, it indicates that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is a need to control the crack height at this time; When the lithology of the roof rock is sandstone or limestone, if the actual minimum horizontal principal stress of the roof rock is greater than the calculated critical minimum horizontal principal stress of the roof rock, or the actual tensile strength of the roof rock is greater than the calculated critical rock tensile strength of the roof rock, it means that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is no need to control the crack height at this time; if the actual rock friction coefficient of the roof rock is less than the calculated critical rock friction coefficient of the roof rock, it means that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is no need to control the crack height at this time; When the lithology of the bottom plate rock is sandstone or limestone, if the actual minimum horizontal principal stress of the bottom plate rock is greater than the calculated critical minimum horizontal principal stress of the bottom plate rock, or the actual tensile strength of the bottom plate rock is greater than the calculated critical rock tensile strength of the bottom plate rock, it means that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is no need to control the crack height at this time; if the actual rock friction coefficient of the bottom plate rock is less than the calculated critical rock friction coefficient of the bottom plate rock, it means that the crack height will not penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that there is no need to control the crack height at this time; When the lithology of the roof rock is sandstone or limestone, if the actual minimum horizontal principal stress of the roof rock is greater than the calculated critical minimum horizontal principal stress of the roof rock, or the actual tensile strength of the roof rock is greater than the calculated tensile strength of the roof rock, it indicates that the crack height will penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that the crack height needs to be controlled at this time; if the actual rock friction coefficient of the roof rock is greater than the calculated critical rock friction coefficient of the roof rock, it indicates that the crack height will penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that the crack height needs to be controlled at this time; When the lithology of the bottom plate rock is sandstone or limestone, if the actual minimum horizontal principal stress of the bottom plate rock is greater than the calculated critical minimum horizontal principal stress of the bottom plate rock, or the actual tensile strength of the bottom plate rock is greater than the calculated tensile strength of the bottom plate rock, it indicates that the crack height will penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that the crack height needs to be controlled at this time; if the actual rock friction coefficient of the bottom plate rock is greater than the calculated critical rock friction coefficient of the bottom plate rock, it indicates that the crack height will penetrate the layer during hydraulic fracturing of the target coal seam section, and it is judged that the crack height needs to be controlled at this time.

7. A hydraulic fracturing optimization design method for controlling the height of deep coalbed methane reservoir fractures according to claim 1, characterized in that: When the target coal seam section needs to control the fracture height, the three-dimensional fracture penetration numerical simulation model is used to simulate the fracturing morphology, and the fracturing construction parameters when the fracture height meets the requirements are obtained. The fracturing construction parameters at this time are used as the final fracturing construction parameters, including: When the target coal seam section needs to control the fracture height, the three-dimensional fracture penetration numerical simulation model is used to simulate the fracturing morphology, and the fracturing construction parameters are continuously adjusted until the fracture height shown by the fracturing results meets the requirements. The fracturing construction parameters at this time are used as the final fracturing construction parameters. Among them, fracturing construction parameters include fracturing fluid displacement, fracturing fluid viscosity, sand ratio and total fluid volume; When the crack height is less than 1 / 4 of the thickness of the roof rock or floor rock layer, it indicates that the crack height meets the requirements.

8. A hydraulic fracturing optimization design system for controlling the height of deep coalbed methane reservoir fractures, characterized in that: include: Data acquisition module: used to obtain the modeling parameters required for modeling; Modeling module: used to establish a three-dimensional fracture penetration numerical simulation model based on the fracturing module of the petrel software platform by using the modeling parameters; A calculation module: used to calculate the critical mechanical parameters and critical bedding quantity of the roof rock above the target coal seam section, and the critical mechanical parameters and critical bedding quantity of the floor rock below the target coal seam section using the three-dimensional fracture penetration numerical simulation model; Judgment module: used to judge whether the target coal seam section needs to control the fracture height according to the calculated critical mechanical parameters and critical bedding quantity of the roof rock, the calculated critical mechanical parameters and critical bedding quantity of the floor rock, the actual mechanical parameters and bedding quantity of the roof rock, and the actual mechanical parameters and bedding quantity of the floor rock; Optimization module: When the target coal seam section needs to control the fracture height, the three-dimensional fracture penetration numerical simulation model is used to simulate the fracturing morphology, and the fracturing construction parameters are obtained when the fracture height meets the requirements. The fracturing construction parameters at this time are used as the final fracturing construction parameters.

9. An electronic device, characterized in that: include: one or more processors; a storage device having one or more programs stored thereon; When the one or more programs are executed by the one or more processors, the one or more processors implement the hydraulic fracturing optimization design method for controlling the height of deep coalbed methane reservoir fractures as described in any one of claims 1 to 7.

10. A storage medium, characterized in that: A computer program is stored thereon, wherein when the computer program is executed by a processor, the hydraulic fracturing optimization design method for controlling the height of deep coalbed methane reservoir fractures as described in any one of claims 1 to 7 is implemented.

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