Fracturing method and device for building uniform fracture network in coal rock reservoir and storage medium

Abstract

The invention belongs to the technical field of oil-gas field development of petroleum engineering, and relates to a fracturing method and device for building a uniform fracture net in a coal rock reservoir and a storage medium, and the method comprises the following steps: preparing a fracturing fluid according to the permeability of the coal rock reservoir; cleaning a shaft of the coal rock gas well; hydrochloric acid is injected into the well bottom of the coal rock gas well; and fracturing the coal rock reservoir. According to the fracturing method and device for building the uniform fracture net in the coal rock reservoir and the storage medium, the operation process is simple and easy to implement, complex technologies and equipment are not needed, and the fracturing method and device can be widely applied to coal rock reservoir mining; the method can effectively improve the complexity of cleat developed coal rock reservoir far-well fractures, and further improve the recovery efficiency and yield increase benefits.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil engineering and oil and gas field development, and particularly relates to a coal rock reservoir uniform fracture network fracturing method and device and a storage medium. BACKGROUND

[0002] Coalbed methane is an important natural gas resource, mainly exists in coal seams, is adsorbed on the surface of coal matrix particles, and is free in coal pores, and the main component is methane. The global proven coalbed methane geological resource is 260 trillion cubic meters, and China is rich in coalbed methane resources, with a total reserve of 36.8 trillion cubic meters, accounting for 14.2% of the world's total reserves, ranking third in the world. Its development and utilization has important significance for promoting the adjustment of national energy structure, improving energy security, and protecting the environment.

[0003] However, the problems in the development of coalbed methane cannot be ignored. Most coalbed methane blocks have low single-well production, short stable production time, and poor development benefits, which seriously restrict the development and utilization of coalbed methane. In order to effectively solve these problems, coalbed methane development personnel have carried out research on various stimulation technologies such as hydraulic fracturing, acidification, gas injection and heat injection to improve coal seam permeability and promote coalbed methane desorption. Among them, hydraulic fracturing technology is the most widely used as the main technical means. However, the coal rock reservoir cleat is developed, and only hydraulic pressure operation cannot well communicate the original fissure and artificial fracture. In addition, the original fissure filling material is mostly rich in calcite, dolomite, siderite and hematite, etc. Generally, pre-acid can be used to improve the connectivity between coal seam pores and reduce the damage of fracturing fluid to coal seam, but this method will cause excessive filtration of fracturing fluid during fracturing, and the fracture is difficult to extend along the main fracture direction. On the contrary, the fracture is more likely to extend along the coal seam cleat, thereby forming a non-uniform fracture network, which limits the overall reconstruction effect of the coal seam, and the reconstruction effect is more obvious in the near-wellbore zone, but the reconstruction effect is poor in the far-wellbore zone, and it is difficult to maintain stable production.

[0004] Therefore, how to make the fracture still extend along the main fracture direction under the condition of serious coal seam cleat filtration and form a long main fracture uniform fracture network is a major problem that needs to be solved at present. SUMMARY

[0005] Therefore, the present application provides a coal rock reservoir uniform fracture network fracturing method and device and a storage medium.

[0006] Specifically, the present application is realized by the following technical scheme:

[0007] According to a first aspect of the present application, a coal rock reservoir uniform fracture network fracturing method is provided, and the method comprises the following steps:

[0008] According to the coal rock reservoir permeability, a fracturing fluid is prepared;

[0009] cleaning the wellbore of the coalbed gas well;

[0010] injecting hydrochloric acid into the bottom of the coalbed gas well;

[0011] fracturing the coalbed reservoir.

[0012] Optionally, the step of preparing fracturing fluid according to the permeability of the coalbed reservoir comprises:

[0013] when the permeability of the coalbed reservoir is 0.01-0.1 mD, a first fracturing fluid with a viscosity of 33-38 mPa·s is prepared, a second fracturing fluid with a viscosity of 14.5-17 mPa·s is prepared, a third fracturing fluid with a viscosity of 5.5-6 mPa·s is prepared, and 100 mesh and 40-70 mesh quartz sand is prepared.

[0014] Optionally, the step of preparing fracturing fluid according to the permeability of the coalbed reservoir comprises:

[0015] when the permeability of the coalbed reservoir is 0.1-0.5 mD, a fourth fracturing fluid with a viscosity of 70-74.5 mPa·s is prepared, a fifth fracturing fluid with a viscosity of 25.5-27.5 mPa·s is prepared, a sixth fracturing fluid with a viscosity of 9.5-12 mPa·s is prepared, and 100 mesh and 40-70 mesh quartz sand is prepared.

[0016] Optionally, the step of preparing fracturing fluid according to the permeability of the coalbed reservoir comprises:

[0017] when the permeability of the coalbed reservoir is 0.5-5 mD, a seventh fracturing fluid with a viscosity of 75-78 mPa·s is prepared, an eighth fracturing fluid with a viscosity of 27.5-30 mPa·s is prepared, a ninth fracturing fluid with a viscosity of 12-13.5 mPa·s is prepared, and 200 mesh and 40-70 mesh quartz sand is prepared.

[0018] Optionally, the step of cleaning the wellbore of the coalbed gas well comprises:

[0019] cleaning the wellbore of the coalbed gas well by injecting clean water into the coalbed gas well through the casing at a rate of 2 m3 / min;

[0020] injecting clean water into the coalbed gas well to test and stabilize the wellhead and high-pressure pipeline for 10 minutes.

[0021] Optionally, the step of injecting hydrochloric acid into the bottom of the coalbed gas well comprises:

[0022] injecting 10-15 m3 of hydrochloric acid with a concentration of 15% into the bottom of the coalbed gas well at a rate of 2 m2 / min;

[0023] the fracturing operation is started after the hydrochloric acid is injected for 30 minutes.

[0024] Optionally, the fracturing of the coal and rock reservoir includes the following steps:

[0025] Use hydraulic fracturing to fracture coal and rock reservoirs.

[0026] According to a second aspect of the present invention, a fracturing device for creating a uniform fracture network in a coal and rock reservoir is provided, comprising:

[0027] Equipped with a module for preparing fracturing fluid based on the permeability of coal and rock reservoirs;

[0028] Cleaning module, used to clean the wellbore of coal and rock gas wells;

[0029] An injection module is used to inject hydrochloric acid into the bottom of the coal gas well;

[0030] Fracturing module, used for fracturing coal and rock reservoirs.

[0031] According to a third aspect of the present invention, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of any of the preceding methods.

[0032] According to a fourth aspect of the present invention, a storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described above.

[0033] The technical solution provided by this invention brings at least the following beneficial effects:

[0034] The method, apparatus, and storage medium for creating a uniform fracture network in coal and rock reservoirs provided in this application have a simple and easy-to-implement operation process, do not require complex technology and equipment, and can be widely used in coal and rock reservoir mining; it can effectively improve the complexity of far-well fractures in coal and rock reservoirs with well-developed cleavage, and further improve the recovery rate and production benefits. Attached Figure Description

[0035] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0037] Figure 1 A schematic flowchart of a method for creating a uniform fracture network in a coal and rock reservoir, provided in an embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram of a fracturing device for creating a uniform fracture network in a coal and rock reservoir, provided in an embodiment of the present invention.

[0039] Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention;

[0040] Figure 4 A schematic diagram of the structure of a storage medium provided in an embodiment of the present invention;

[0041] Figure 5 The type of fracturing fluid and its corresponding viscosity required during the construction process of a uniform fracture network fracturing method for coal and rock reservoirs provided in this embodiment of the invention;

[0042] Figure 6 The types of proppant and their corresponding diameters required during the construction process of a uniform fracture network fracturing method for coal and rock reservoirs provided in this embodiment of the invention;

[0043] Figure 7 This invention provides a method for creating a uniform fracture network in coal and rock reservoirs, which includes the design of main fracture lengths and corresponding total amounts of pre-fracturing fluid for different types of coal and rock reservoirs.

[0044] Figure 8 In the sand-carrying fluid stage of a uniform fracture network fracturing method for coal and rock reservoirs provided in this embodiment of the invention, 40-70 mesh quartz sand is added to different types of coal and rock reservoirs.

[0045] Figure 9 A flowchart illustrating the specific construction process of a uniform fracture network fracturing method for coal and rock reservoirs, provided in this embodiment of the invention, for coal seam stimulation in the Yi 10-23-56 platform;

[0046] Figure 10 A pumping procedure diagram for a uniform fracture network fracturing method for coal and rock reservoirs provided in this embodiment of the invention, used for coal seam stimulation in the Yi 10-23-56 platform. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Figure 1 The illustration shows a schematic flow diagram of a method for creating a uniform fracture network in a coal and rock reservoir, applicable to an embodiment of the present invention.

[0049] See Figure 1 This invention provides a method for creating a uniform fracture network in coal and rock reservoirs, the method comprising the following steps:

[0050] S1: Prepare fracturing fluid according to the permeability of the coal and rock reservoir;

[0051] For example, the step of preparing fracturing fluid according to the permeability of the coal and rock reservoir includes the following steps:

[0052] When the permeability of the coal and rock reservoir is 0.01-0.1 mD, a first fracturing fluid with a viscosity of 33-38 mPa·s is prepared, a second fracturing fluid with a viscosity of 14.5-17 mPa·s is prepared, a third fracturing fluid with a viscosity of 5.5-6 mPa·s is prepared, and 100-mesh and 40-70-mesh quartz sand are prepared.

[0053] In this embodiment, for coal-rock reservoirs with permeability of 0.01-0.1 mD, a first fracturing fluid (high-viscosity fracturing fluid 1) with a viscosity of 33-38 mPa·s, a second fracturing fluid (medium-viscosity fracturing fluid 1) with a viscosity of 14.5-17 mPa·s, and a third fracturing fluid (low-viscosity fracturing fluid 1) with a viscosity of 5.5-6 mPa·s are prepared, along with 100-mesh and 40-70-mesh quartz sand. The fracturing fluid can be 15% hydrochloric acid.

[0054] For example, the step of preparing fracturing fluid according to the permeability of the coal and rock reservoir includes the following steps:

[0055] When the permeability of the coal and rock reservoir is 0.1-0.5 mD, a fourth fracturing fluid with a viscosity of 70-74.5 mPa·s, a fifth fracturing fluid with a viscosity of 25.5-27.5 mPa·s, and a sixth fracturing fluid with a viscosity of 9.5-12 mPa·s are prepared, along with 100-mesh and 40-70-mesh quartz sand.

[0056] In this embodiment, for coal-rock reservoirs with permeability of 0.1-0.5 mD, a fourth fracturing fluid (high-viscosity fracturing fluid 2) with a viscosity of 70-74.5 mPa·s, a fifth fracturing fluid (medium-viscosity fracturing fluid 2) with a viscosity of 25.5-27.5 mPa·s, and a sixth fracturing fluid (low-viscosity fracturing fluid 2) with a viscosity of 9.5-12 mPa·s are prepared, along with 100-mesh and 40-70-mesh quartz sand. The fracturing fluid can be 15% hydrochloric acid.

[0057] For example, the step of preparing fracturing fluid according to the permeability of the coal and rock reservoir includes the following steps:

[0058] When the permeability of the coal and rock reservoir is 0.5-5 mD, a seventh fracturing fluid with a viscosity of 75-78 mPa·s is prepared, an eighth fracturing fluid with a viscosity of 27.5-30 mPa·s is prepared, a ninth fracturing fluid with a viscosity of 12-13.5 mPa·s is prepared, and 200 mesh and 40-70 mesh quartz sand are prepared.

[0059] In this embodiment, for coal-rock reservoirs with permeability of 0.5-5 mD, a seventh fracturing fluid (high-viscosity fracturing fluid 3) with a viscosity of 75-78 mPa·s, an eighth fracturing fluid (medium-viscosity fracturing fluid 3) with a viscosity of 27.5-30 mPa·s, and a ninth fracturing fluid (low-viscosity fracturing fluid 3) with a viscosity of 12-13.5 mPa·s are prepared, along with 200-mesh and 40-70-mesh quartz sand. The fracturing fluid can be 15% hydrochloric acid.

[0060] S2: Cleaning the wellbore of a coal gas well;

[0061] For example, the cleaning of the wellbore of the coal gas well includes the following steps:

[0062] Clean water is injected into the coal gas well through the casing at a rate of 2 m³ / min to clean the wellbore.

[0063] Inject clean water into the coal gas well to test the pressure at the wellhead and high-pressure pipeline and stabilize the pressure for 10 minutes.

[0064] In this embodiment of the application, clean water is slowly injected into the coal and rock gas well that needs to be fracturing through the casing at a flow rate of 2 m3 / min to clean the wellbore. Then, clean water is injected to test the pressure at the wellhead and high-pressure pipeline, and the pressure is stabilized for 10 minutes. It is considered qualified when the pressure drop is less than 0.7 MPa, at which point the cleaning operation is stopped.

[0065] S3: Inject hydrochloric acid into the bottom of the coal gas well;

[0066] For example, the injection of hydrochloric acid into the bottom of the coal gas well includes the steps of:

[0067] 10-15 m3 of 15% hydrochloric acid was injected into the bottom of the coal gas well at a discharge rate of 2 m2 / min.

[0068] Fracturing operations will begin 30 minutes after hydrochloric acid injection.

[0069] In this embodiment, 10-15 m³ of 15% hydrochloric acid is injected into the bottom of the coal gas well at a flow rate of 2 m² / min to improve the connectivity of coal seam cleavage. The acid's dissolving effect expands the permeability channels of the oil-bearing rock, dissolving blockages in these channels and facilitating subsequent fracturing and sand-carrying fractures. To ensure complete reaction of the injected hydrochloric acid, fracturing operations begin 30 minutes after injection.

[0070] S4: Fracturing coal and rock reservoir.

[0071] For example, the fracturing of the coal and rock reservoir includes the steps of:

[0072] Use hydraulic fracturing to fracture coal and rock reservoirs.

[0073] like Figures 5-8 In this embodiment of the application, the entire fracturing process is divided into three stages, and the specific steps are as follows:

[0074] Phase 1: High-viscosity fracturing fluid main fracture creation phase: High-viscosity fracturing fluid is injected into the bottom of the coal-rock gas well at a flow rate of 16 m³ / min, and the fracturing operation curve is observed on-site. In the initial stage of fracturing, the fracturing operation curve shows that the bottom hole pressure steadily increases. When the bottom hole pressure Pw decreases at a rate of less than or equal to 0.12 MPa / s, it indicates that the rock mass at the target formation has fractured. At this point, the injection of high-viscosity fracturing fluid continues. When the bottom hole pressure decreases again at a rate of 0.015 MPa / s ≤ Pw < 0.12 MPa / s, it indicates that the main fracture propagation has encountered coal seam cleavage. At this point, the injection of high-viscosity fracturing fluid ends, completing the high-viscosity fracturing fluid main fracture creation phase. Subsequently, proppant-carrying fluid can be injected to plug the coal seam cleavage.

[0075] Specifically, high-viscosity fracturing fluid 1 is used for coal and rock reservoirs with permeability of 0.01-0.1 mD; high-viscosity fracturing fluid 2 is used for coal and rock reservoirs with permeability of 0.1-0.5 mD; and high-viscosity fracturing fluid 3 is used for coal and rock reservoirs with permeability of 0.5-5 mD. The reason for using high-viscosity fracturing fluid in the first stage of fracture creation is that high-viscosity fracturing fluid has a very small filtrate loss, which can avoid activating cleavage when the initial fracture encounters cleavage.

[0076] Phase Two:

[0077] a. High-viscosity sand-carrying fluid plugging stage: Inject high-viscosity sand-carrying fluid with a sand ratio of 5% into the bottom of the coal-rock gas well at a discharge rate of 16 m3 / min. Observe the fracturing construction curve monitored on site. When the bottom pressure rises at a rate of 0 < Pw ≤ 0.01 MPa / s, the injection of high-viscosity sand-carrying fluid is stopped, and the coal seam cleavage plugging of this stage is completed.

[0078] Specifically, for coal and rock reservoirs with permeability of 0.01-0.1 mD, high-viscosity fracturing fluid 1 and 200-mesh quartz sand are used; for coal and rock reservoirs with permeability of 0.1-0.5 mD, high-viscosity fracturing fluid 2 and 200-mesh quartz sand are used; and for coal and rock reservoirs with permeability of 0.5-5 mD, high-viscosity fracturing fluid 3 and 200-mesh quartz sand are used.

[0079] b. Low-viscosity fracturing fluid main fracture creation stage: Low-viscosity fracturing fluid is continuously injected into the bottom of the coal-rock gas well at a flow rate of 16 m³ / min, and the fracturing operation curve monitored on-site is observed. When the bottom hole pressure decreases at a rate of 0.015 MPa / s ≤ Pw < 0.12 MPa / s, it indicates that the fracture has encountered coal seam cleavage during its extension along the tip of the main fracture. At this point, the injection of low-viscosity fracturing fluid is terminated, completing the low-viscosity fracturing fluid main fracture creation stage.

[0080] Specifically, for coal and rock reservoirs with permeability of 0.01-0.1 mD, low-viscosity fracturing fluid 1 is used; for coal and rock reservoirs with permeability of 0.1-0.5 mD, low-viscosity fracturing fluid 2 is used; and for coal and rock reservoirs with permeability of 0.5-5 mD, low-viscosity fracturing fluid 3 is used.

[0081] c. Cyclic steps: Repeat construction steps (a)-(b) until the length of the main crack reaches the designed crack length. At the same time, the sand ratio of the high-viscosity sand liquid is increased by 1% in the cleavage stage of the high-viscosity sand liquid sealing.

[0082] For coal and rock reservoirs with permeability of 0.01-0.1 mD, the designed main fracture length is 300-400 m, and the total amount of pre-flush fluid injected per cluster is 160-180 m3; for coal and rock reservoirs with permeability of 0.1-0.5 mD, the designed main fracture length is 210-300 m, and the total amount of pre-flush fluid injected per cluster is 140-160 m3; for coal and rock reservoirs with permeability of 0.5-5 mD, the designed main fracture length is 150-210 m, and the total amount of pre-flush fluid injected per cluster is 120-140 m3.

[0083] The third stage involves injecting medium-viscosity fracturing fluid (40-70 mesh quartz sand) at a flow rate of 16 m³ / min, gradually increasing the sand ratio from 10% to 18% until the required amount of sand is achieved. Finally, a volume of medium-viscosity fracturing fluid (one wellbore volume) is injected into the wellbore at a flow rate of 16 m³ / min to displace all the proppant in the wellbore into the fractures.

[0084] For coal and rock reservoirs with permeability of 0.01-0.1 mD, the designed main fracture length is 300-400 m, and 90-120 m3 of 40-70 mesh quartz sand needs to be added during the single-cluster proppant-carrying fluid stage. For coal and rock reservoirs with permeability of 0.1-0.5 mD, when the designed main fracture length is 210-300 m, 63-90 m3 of 40-70 mesh quartz sand needs to be added during the single-cluster proppant-carrying fluid stage. For coal and rock reservoirs with permeability of 0.5-5 mD, when the designed main fracture length is 150-210 m, 45-63 m3 of 40-70 mesh quartz sand needs to be added during the single-cluster proppant-carrying fluid stage.

[0085] Example

[0086] like Figures 9-10The reservoir stimulation of well Yi 10-23-56 was carried out using a uniform fracture network fracturing method for coal and rock reservoirs provided in this application. The specific steps are as follows:

[0087] (1) First, the basic physical properties and rock mechanical properties of a total of 13 coal cores from the coal reservoir to be modified were tested, including rock permeability k, porosity Φ, XRD whole-rock analysis, and scanning electron microscopy analysis; the rock mechanical parameters tested included the rock's elastic modulus E, Poisson's ratio υ, and compressive strength σf.

[0088] (2) The core sample of this reservoir has a maximum permeability of 0.1 mD, a maximum porosity of 10%, a minimum total clay content of 31%, and a dense distribution of fractures with a width of more than 1 μm. The rock has a minimum elastic modulus of 1.2 GPa and a maximum of 6.4 GPa, a minimum Poisson's ratio of 0.21 and a maximum of 0.34, and a maximum compressive strength σf of 6.08 MPa. These properties meet the requirements of a coal seam and are therefore classified as a coal seam.

[0089] (3) Inject 10-15 m3 of 15% hydrochloric acid into the bottom of the well at a flow rate of 2 m2 / min to improve the connectivity of coal seam cleavage. Start fracturing 30 min after the hydrochloric acid injection.

[0090] (4) Target stratum fracture rock mass stage: According to the rock mechanical property test results, the reservoir permeability of this fractured coal seam section is 0.1mD. Therefore, high viscosity fracturing fluid 1 is used for fracturing in this stage. In the early stage of fracturing, the fracturing construction curve shows that the bottom hole pressure rises steadily. When the bottom hole pressure Pw drops at a rate of ≤0.12MPa / s, it indicates that the target stratum rock mass has fractured. At this time, continue to inject high viscosity fracturing fluid. When the bottom hole pressure drops again at a rate of 0.015MPa / s≤Pw<0.12MPa / s, it indicates that the main fracture propagation encounters coal seam cleavage. At this time, the injection of high viscosity fracturing fluid ends, the main fracture creation stage of high viscosity fracturing fluid is completed, and the cleavage sealing stage of high viscosity sand-carrying fluid begins.

[0091] (5) High-viscosity sand-carrying fluid plugging stage: The reservoir permeability of this fracturing coal seam section is 0.1mD. Therefore, high-viscosity fracturing fluid 1 is used for fracturing in this stage. High-viscosity sand-carrying fluid with a sand ratio of 5% is injected into the bottom of the well at a discharge rate of 16m3 / min. The fracturing construction curve monitored on site is observed. When the bottom pressure rises at a rate of 0<Pw≤0.01MPa / s, the injection of high-viscosity sand-carrying fluid is stopped, and the coal seam cleavage plugging in this stage is completed.

[0092] (6) Low-viscosity fracturing fluid for main fracture creation stage: The reservoir permeability of this fracturing coal seam section is 0.1 mD, therefore, low-viscosity fracturing fluid 1 is used for fracturing in this stage. Low-viscosity fracturing fluid is continuously injected into the bottom hole at a flow rate of 16 m³ / min, and the fracturing operation curve monitored on site is observed. When the bottom hole pressure decreases at a rate of 0.015 MPa / s ≤ Pw < 0.12 MPa / s, it indicates that the fracture encountered coal seam cleavage during its extension along the tip of the main fracture. At this point, the injection of low-viscosity fracturing fluid is stopped, and the low-viscosity fracturing fluid for main fracture creation stage is completed.

[0093] (7) Cyclic steps: The reservoir permeability of this fracturing coal seam section is 0.1mD, so the amount of pre-fracturing fluid used in this stage is 160-180m3. Repeat the construction steps (3)-(4) with the total amount of pre-fracturing fluid until the length of the main fracture reaches the designed fracture length. At the same time, the sand ratio is increased by 1% in the high-viscosity sand-carrying fluid sealing and cutting stage for each cycle.

[0094] (8) During the continuous injection of sand-carrying fluid, the permeability of the reservoir in this fractured coal seam section is 0.1mD. For this type of coal and rock reservoir, the designed length of the main fracture is 300-400m. Quartz sand needs to be added during the single-cluster sand-carrying fluid stage. The types of quartz sand are 200 mesh quartz sand, 100 mesh quartz sand, and 40-70 mesh quartz sand. The addition ratio is 1:2:1. For this type of coal and rock reservoir, add 103m3 of 40-70 mesh quartz sand, 206m3 of 100 mesh quartz sand, and 103m3 of 200 mesh quartz sand. At the beginning of the sand-carrying fluid injection stage, inject medium-viscosity sand-carrying fluid with quartz sand mesh of 40-70 mesh at a discharge rate of 16m3 / min. The sand ratio increases uniformly from 12% to 22% until the sand addition reaches the design requirement.

[0095] (9) Replacement stage of residual proppant in wellbore: inject medium-viscosity fracturing fluid of one wellbore volume into the bottom of the well at a flow rate of 16 m3 / min to replace all the proppant in the wellbore into the fracture.

[0096] (10) The fracturing operation is completed.

[0097] (11) The fracturing operation of well Yi 10-32-56 was carried out using the final optimized fracturing method of creating a uniform fracture network in the reservoir. The monitoring results showed that the length of the main fracture after the coal seam section was modified met the design requirements, and the reservoir modification effect was very good.

[0098] like Figure 2 This application provides a fracturing device for creating a uniform fracture network in coal and rock reservoirs, comprising:

[0099] Module 10 is equipped for preparing fracturing fluid according to the permeability of coal and rock reservoirs;

[0100] Cleaning module 20 is used to clean the wellbore of a coal gas well;

[0101] Injection module 30 is used to inject hydrochloric acid into the bottom of the coal gas well;

[0102] Fracturing module 40 is used for fracturing coal and rock reservoirs.

[0103] The uniform fracture network fracturing device for coal and rock reservoirs provided in this application can perform the uniform fracture network fracturing method for coal and rock reservoirs provided in the above steps.

[0104] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

[0105] The following is for reference. Figure 3 The diagram illustrates a structural schematic of an electronic device 100 suitable for implementing embodiments of the present disclosure. The electronic devices in the embodiments of the present disclosure may include, but are not limited to, mobile terminals such as mobile phones, laptops, digital broadcast receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), in-vehicle terminals (e.g., in-vehicle navigation terminals), and fixed terminals such as digital TVs and desktop computers. Figure 3 The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of the embodiments disclosed herein.

[0106] like Figure 3 As shown, the electronic device 100 may include a processing unit (e.g., a central processing unit, a graphics processing unit, etc.) 101, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 102 or a program loaded from a storage device 108 into a random access memory (RAM) 103. The RAM 103 also stores various programs and data required for the operation of the electronic device 100. The processing unit 101, ROM 102, and RAM 103 are interconnected via a bus 104. An input / output (I / O) interface 105 is also connected to the bus 104.

[0107] Typically, the following devices can be connected to I / O interface 105: input devices 106 including, for example, touchscreens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices 107 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 108 including, for example, magnetic tapes, hard disks, etc.; and communication devices 109. Communication device 109 allows electronic device 100 to communicate wirelessly or wiredly with other devices to exchange data. Although electronic device 100 with various devices is shown in the figure, it should be understood that it is not required to implement or possess all of the devices shown. More or fewer devices may be implemented or possessed alternatively.

[0108] In particular, according to embodiments of this disclosure, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this disclosure include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication device 109, or installed from storage device 108, or installed from ROM 102. When the computer program is executed by processing device 101, it performs the functions defined in the methods of embodiments of this disclosure.

[0109] The following is for reference. Figure 4 The diagram illustrates a computer-readable storage medium suitable for implementing embodiments of the present disclosure, the computer-readable storage medium storing a computer program that, when executed by a processor, enables the implementation of the uniform fracture network fracturing method for coal and rock reservoirs as described above.

[0110] This application also provides a computer program product. It includes a computer program / computer-executable instructions that, when executed by a processor of an electronic device, implement the steps of the uniform fracture network fracturing method for coal and rock reservoirs described in any of the preceding claims.

[0111] The method, apparatus, and storage medium for creating a uniform fracture network in coal and rock reservoirs provided in this application have a simple and easy-to-implement operation process, do not require complex technology and equipment, and can be widely used in coal and rock reservoir mining; it can effectively improve the complexity of far-well fractures in coal and rock reservoirs with well-developed cleavage, and further improve the recovery rate and production benefits.

[0112] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0113] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for creating a uniform fracture network in coal and rock reservoirs, characterized in that, The method comprises the steps of: equipping fracturing fluid according to permeability of coal rock reservoir; cleaning wellbore of coal gas well; injecting hydrochloric acid into bottom of the coal gas well; fracturing coal rock reservoir.

2. The method of claim 1, wherein the method further comprises, The step of equipping fracturing fluid according to permeability of coal rock reservoir comprises the steps of: when the permeability of the coal rock reservoir is 0.01-0.1 mD, equipping first fracturing fluid with viscosity of 33-38 mPa·s, equipping second fracturing fluid with viscosity of 14.5-17 mPa·s, equipping third fracturing fluid with viscosity of 5.5-6 mPa·s, and preparing 100 mesh and 40-70 mesh quartz sand.

3. The method of claim 1, wherein the method further comprises, The step of equipping fracturing fluid according to permeability of coal rock reservoir comprises the steps of: when the permeability of the coal rock reservoir is 0.1-0.5 mD, equipping fourth fracturing fluid with viscosity of 70-74.5 mPa·s, equipping fifth fracturing fluid with viscosity of 25.5-27.5 mPa·s, equipping sixth fracturing fluid with viscosity of 9.5-12 mPa·s, and preparing 100 mesh and 40-70 mesh quartz sand.

4. The method of claim 1, wherein the method further comprises, The step of equipping fracturing fluid according to permeability of coal rock reservoir comprises the steps of: when the permeability of the coal rock reservoir is 0.5-5 mD, equipping seventh fracturing fluid with viscosity of 75-78 mPa·s, equipping eighth fracturing fluid with viscosity of 27.5-30 mPa·s, equipping ninth fracturing fluid with viscosity of 12-13.5 mPa·s, and preparing 200 mesh and 40-70 mesh quartz sand.

5. The method of claim 1, wherein the method further comprises, The step of cleaning wellbore of coal gas well comprises the steps of: cleaning wellbore by injecting clean water into the coal gas well through casing at a rate of 2 m3 / min; injecting clean water into the coal gas well to test and stabilize pressure of wellhead and high-pressure pipeline for 10 minutes.

6. The method of claim 1, wherein the method further comprises, The step of injecting hydrochloric acid into bottom of the coal gas well comprises the steps of: injecting 10-15 m3 of hydrochloric acid with concentration of 15% into bottom of the coal gas well at a rate of 2 m3 / min; starting fracturing operation after 30 minutes of injection of hydrochloric acid.

7. The method of claim 1, wherein the method further comprises, The step of fracturing coal rock reservoir comprises the steps of: fracturing coal rock reservoir using fracturing fluid.

8. A device for creating a uniform fracture network in a coal reservoir, the device comprising: It comprises: an equipping module for equipping fracturing fluid according to permeability of coal rock reservoir; a cleaning module for cleaning wellbore of coal gas well; an injecting module for injecting hydrochloric acid into bottom of the coal gas well; a fracturing module for fracturing coal rock reservoir.

9. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the steps of the method of any one of claims 1-7 when executing the program.

10. A storage medium having stored thereon a computer program, characterized in that The program, when executed by the processor, implements the steps of the method of any one of claims 1-7.

Images