Methods and devices for preventing shear deformation of casing in horizontal wells during shale gas development

Abstract

This application provides a method and apparatus for preventing shear deformation of casing in horizontal wells used in shale gas development. Targeting the fault where the horizontal well is located, this application determines the discharge rate and fluid intensity for each section of the horizontal well based on the quantitative relationship between the average slip of the fracture and pump pressure, total fluid volume, and fracture scale, as well as the casing deformation risk level of the fracture. Then, based on the discharge rate and fluid intensity of each section, temporary plugging measures are determined for each section. Finally, based on the temporary plugging measures, on-site equipment is controlled to temporarily plug the horizontal well. This achieves the prevention and control of shear deformation of casing in horizontal wells used in shale gas development. It avoids or reduces shear slip during fracturing, effectively preventing casing deformation and reducing its impact on the economical and efficient development of shale gas.

Description

Technical Field

[0001] This application relates to the field of shale gas resource development technology, and in particular to a method and device for preventing shear deformation of casing in horizontal wells for shale gas development. Background Technology

[0002] China possesses enormous shale gas reserves and immense development potential. Shale gas development utilizes large-scale horizontal well hydraulic fracturing technology; however, casing deformation is a serious problem during large-scale hydraulic fracturing. Casing deformation not only prevents bridge plugs from setting properly, leading to multi-stage pressure failure or even stage loss, thus affecting fracturing effectiveness, but also increases construction costs and difficulty, shortens the wellbore lifespan, and consequently reduces the overall economic benefits of shale gas development. It has become a major factor restricting shale gas development.

[0003] In existing technologies, by analyzing and calculating the sliding risk and sliding force of shale bedding, fractures and faults in the shale reservoir of the target well area, the distribution area of ​​casing deformation risk in the target well area is determined, and then the wellbore trajectory in the target well area is designed to be located in a low-risk area below the preset benchmark risk.

[0004] However, recent studies have revealed that shale bedding, fractures, and faults are widely developed in the target well area in most cases and cannot be accurately identified. Therefore, it is impossible to completely avoid these areas with bedding, fractures, and faults during actual drilling. As a result, the above-mentioned scheme cannot actually achieve the purpose of preventing casing deformation. Summary of the Invention

[0005] This application provides a method and device for preventing shear deformation of casing in horizontal wells for shale gas development, which can solve the problem of severe casing deformation during hydraulic fracturing.

[0006] In a first aspect, embodiments of this application provide a method for preventing shear deformation of casing in horizontal wells used in shale gas development, applied to computer equipment, the method comprising:

[0007] For the fault where the horizontal well is located, the discharge rate and fluid intensity of each well section of the horizontal well are determined based on the quantitative relationship between the average slip of the fault-fracture and the pump pressure, total fluid volume and fracture scale, as well as the casing deformation risk level of the fault-fracture.

[0008] The temporary plugging measures for each well section are determined based on the discharge rate and fluid intensity of each well section.

[0009] The temporary plugging measures are used to control the field equipment to temporarily plug the horizontal well.

[0010] In conjunction with the first aspect, in some embodiments, the quantitative relationship between the average fracture slip and the pump pressure, total fluid volume, and fracture scale is expressed as follows: ;

[0011] Where D represents the average slip of the fracture, k is a proportionality coefficient representing the ratio of energy required for the target fracture slip to the input energy, P represents the pump pressure, Q represents the total fluid input for hydraulic fracturing, μ represents the friction coefficient of the fracture surface, L represents the fracture length, and W represents the fracture width. This represents normal stress.

[0012] In conjunction with the first aspect, in some embodiments, determining the discharge rate and fluid intensity of each section of the horizontal well based on the quantitative relationship between the average slip of the fracture and the pump pressure, total fluid volume, and fracture scale, as well as the casing deformation risk level of the fracture, includes:

[0013] In well sections with fault development, the discharge rate between adjacent sections is less than or equal to 11m³. 3 / min, with liquid strength less than or equal to 20m 3 / min;

[0014] The discharge rate for well sections containing Class I casing deformation risk fractures shall not exceed 11m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of the two adjacent sections are handled according to the Class II risk standard for casing deformation;

[0015] The discharge rate for well sections containing Class II casing deformation risk fractures shall not exceed 12m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of the two adjacent sections are handled according to the Class III risk standard for casing deformation;

[0016] The discharge rate for well sections containing Class III casing deformation risk fractures shall not exceed 12m³. 3 / min, liquid strength not exceeding 22m 3 / min, the displacement of two adjacent sections does not exceed 13m 3 / min, liquid strength not exceeding 24m 3 / min;

[0017] For other well sections not containing casing deformation risk fractures, the discharge rate shall not exceed 14m³. 3 / min, liquid strength not exceeding 25m 3 / min.

[0018] In conjunction with the first aspect, in some embodiments, determining the temporary plugging measures for each well section based on the discharge rate and fluid intensity of each well section includes:

[0019] In well sections with fault development, the fluid volume reaches 300-400m³. 3 Then a temporary blockage was initiated;

[0020] In well sections containing Class I casing deformation risk fractures, the fluid volume reaches 500-600m³. 3 Then, temporary blocking begins, and the temporary blocking measures for adjacent sections are handled according to the Level II risk standard.

[0021] The well section containing Class II casing deformation risk fracture has a fluid volume of 700-800m³. 3 Then, temporary blocking begins, and the temporary blocking measures for adjacent sections are handled according to the Level III risk standard.

[0022] Well sections containing Class III casing deformation risk fractures, and other well sections not containing casing deformation risk fractures, with a fluid usage of 1000m³. 3 Temporary clogging begins after / min, with the liquid usage in the adjacent sections reaching 1200m³. 3 A temporary blockage was then initiated.

[0023] Secondly, embodiments of this application also provide a device for preventing shear and compression deformation of casing in horizontal wells for shale gas development, the device comprising:

[0024] The first processing module is used to determine the discharge rate and fluid intensity of each well section of the horizontal well based on the quantitative relationship between the average slip of the fault-fracture and the pump pressure, total fluid volume and fracture scale, as well as the casing deformation risk level of the fault-fracture.

[0025] The second processing module is used to determine the temporary plugging measures for each well section based on the discharge rate and fluid intensity of each well section.

[0026] The third processing module is used to control the field equipment to temporarily plug the horizontal well according to the temporary plugging measures.

[0027] In conjunction with the second aspect, in some embodiments, the quantitative relationship between the average fracture slip and the pump pressure, total fluid volume, and fracture scale is expressed as follows: ;

[0028] Where D represents the average slip of the fracture, k is a proportionality coefficient representing the ratio of energy required for the target fracture slip to the input energy, P represents the pump pressure, Q represents the total fluid input for hydraulic fracturing, μ represents the friction coefficient of the fracture surface, L represents the fracture length, and W represents the fracture width. This represents normal stress.

[0029] In conjunction with the second aspect, in some embodiments, the first processing module includes:

[0030] The first processing unit is used for well sections with fault development, where the discharge rate between adjacent sections is less than or equal to 11m³. 3 / min, with liquid strength less than or equal to 20m 3 / min;

[0031] The second processing unit, used for well sections containing Class I casing deformation risk fractures, has a discharge capacity not exceeding 11m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of the two adjacent sections are handled according to the Class II risk standard for casing deformation;

[0032] The third processing unit, used for well sections containing Class II casing deformation risk fractures, has a discharge capacity not exceeding 12m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of the two adjacent sections are handled according to the Class III risk standard for casing deformation;

[0033] The fourth processing unit, used for well sections containing Class III casing deformation risk fractures, has a discharge rate not exceeding 12m³. 3 / min, liquid strength not exceeding 22m 3 / min, the displacement of two adjacent sections does not exceed 13m 3 / min, liquid strength not exceeding 24m 3 / min;

[0034] The fifth processing unit is used for other well sections that do not contain casing deformation risk fractures, with a discharge capacity not exceeding 14m³. 3 / min, liquid strength not exceeding 25m 3 / min.

[0035] In conjunction with the second aspect, in some embodiments, the second processing module includes:

[0036] In the first processing unit, in well sections with fault development, the fluid volume reaches 300-400m³. 3 Then a temporary blockage was initiated;

[0037] The second processing unit includes well sections with Class I casing deformation risk and fracture, with a fluid volume of 500-600 m³. 3 Then, temporary blocking begins, and the temporary blocking measures for adjacent sections are handled according to the Level II risk standard.

[0038] The third processing unit includes well sections with Class II casing deformation risk and fracture, with a fluid volume of 700-800 m³. 3 Then, temporary blocking begins, and the temporary blocking measures for adjacent sections are handled according to the Level III risk standard.

[0039] The fourth treatment unit includes well sections with Class III casing deformation risk fractures, as well as other well sections without casing deformation risk fractures, with a fluid usage of 1000m³. 3 Temporary clogging begins after / min, with the liquid usage in the adjacent sections reaching 1200m³. 3 A temporary blockage was then initiated.

[0040] Thirdly, this application also provides a computer device, including: a processor, a memory, and a display;

[0041] The memory stores computer-executed instructions;

[0042] The processor executes computer execution instructions stored in the memory to implement the method described in the first aspect.

[0043] Fourthly, this application also provides a computer storage medium storing computer execution instructions, which, when executed by a processor, are used to implement the method described in the first aspect.

[0044] The method and apparatus for preventing casing shear deformation in shale gas development horizontal wells provided in this application embodiment, in this scheme, for the fault where the horizontal well is located, determines the discharge rate and fluid intensity of each well section based on the quantitative relationship between the average slip of the fracture and pump pressure, total fluid volume and fracture scale, as well as the casing deformation risk level of the fracture. Then, based on the discharge rate and fluid intensity of each well section, temporary plugging measures are determined for each well section. Finally, based on the temporary plugging measures, the on-site equipment is controlled to temporarily plug the horizontal well. This scheme alleviates adverse situations such as inter-well pressure channeling, induced earthquakes and groundwater pollution during hydraulic fracturing, ensures the smooth progress of fracturing operations, and to a certain extent avoids the harmful impacts of hydraulic fracturing on the environment and society. Attached Figure Description

[0045] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0046] Figure 1 An application scenario diagram of the method for preventing shear and compression deformation of horizontal well casing in shale gas development provided in the embodiments of this application;

[0047] Figure 2 This is a schematic flowchart of an embodiment of the method for preventing shear and compression deformation of horizontal well casing in shale gas development provided in this application.

[0048] Figure 3 This is a schematic diagram of hydraulic fracturing before temporary plugging of the fracture.

[0049] Figure 4 This is a schematic diagram of fracturing after temporary plugging of the fracture.

[0050] Figure 5 Plan view for risk prediction and evaluation of platform Z;

[0051] Figure 6 This is a schematic diagram of the structure of Embodiment 1 of the shale gas development horizontal well casing shear and compression deformation prevention device provided in this application.

[0052] Figure 7 This is a schematic diagram of the second embodiment of the shale gas development horizontal well casing shear and compression deformation prevention device provided in this application.

[0053] Figure 8 This is a schematic diagram of the structure of Embodiment 3 of the shale gas development horizontal well casing shear and compression deformation prevention device provided in this application.

[0054] Figure 9 A schematic diagram of the structure of a computer device provided in an embodiment of this application.

[0055] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0056] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0057] By analyzing and calculating the sliding risk and sliding force of shale bedding, fractures, and faults in the shale reservoir of the target well area, the distribution area of ​​casing deformation risk in the target well area can be determined, and the wellbore trajectory within the target well area can be designed to be located in a low-risk area below the preset benchmark risk. However, recent studies have found that in most cases, shale bedding, fractures, and faults are widely developed in the target well area and cannot be accurately identified. Therefore, it is impossible to completely avoid these areas with developed bedding, fractures, and faults during actual drilling, making it practically impossible to achieve the goal of casing deformation prevention. Another approach is to identify active faults in the target well area based on four-dimensional geostress field and fault data, and then optimize the horizontal section trajectory of the wellbore to control drilling operations to avoid active faults. Alternatively, a quantitative relationship can be established between construction parameters and the active area of ​​active faults, and construction parameters can be optimized during fracturing operations to control the active area of ​​faults, thereby reducing the probability of casing deformation in shale gas horizontal well casing during drilling and fracturing operations. However, the theoretical basis of this method has limitations, leading to inaccurate prediction of fault sliding risk. If the slip risk of fractures / faults in the target well area is assessed in advance before fracturing operations, and fractures / faults at the target risk level are sealed, casing deformation can be effectively prevented. However, this method requires the installation of too many oil layer casing protection devices, increasing construction costs. On the other hand, for those cross-well fractures that are not accurately identified (including those with location deviations and those that are not identified), they may still be activated during subsequent fracturing operations, causing slip and resulting in casing deformation.

[0058] To address the aforementioned problems, this application provides a method for preventing shear deformation of casing in horizontal wells used for shale gas development, achieving the prevention and control of shear deformation in horizontal well casings. Specifically, currently there is no particularly effective method for preventing shear deformation of casing in horizontal wells used for shale gas development. During the research process, the inventors discovered that identifying active faults in the target well area before drilling and controlling fault activation in the drilling and construction design can reduce the probability of casing deformation during construction, making fracturing operations safer and more reasonable. However, recent studies have revealed that faults and fractures are widely developed in shale reservoirs, and are often subseismically resolvable. Therefore, it is impossible to completely avoid these faults and fractures during drilling, and the slip trend analysis theory still has certain shortcomings. If the slip risk of fractures / faults in the target well area is assessed in advance before fracturing operations, and fractures / faults at the target risk level are sealed, casing deformation can be effectively prevented. However, in most cases, shale reservoirs have widespread fractures and faults that cannot be accurately identified. In addition, too many oil layer casing protection devices need to be installed, increasing construction costs. For those fractures and faults that are not accurately identified, they may still be activated during subsequent fracturing operations, causing slip and casing deformation. Considering these problems, the inventors studied whether, based on the generalized fault theory, the average slip of fractures and faults can be quantitatively studied in relation to pump pressure, total fluid volume, and fracture scale. Based on this quantitative relationship, the pumping rate, fluid intensity, and temporary plugging measures for well sections with different risk levels can be determined. Based on this, the technical solution of this application is proposed.

[0059] Figure 1 This diagram illustrates an application scenario of the method for preventing shear and compression deformation of casing in horizontal wells for shale gas development, as provided in the embodiments of this application. Figure 1 As shown in the embodiments of this application, the method for preventing shear deformation of casing in horizontal wells for shale gas development can be applied to actual shale gas development. An actual shale gas development scenario includes at least extraction equipment, computer equipment, and at least one fracture overlapping with the extraction equipment. The extraction equipment can be a series of shale gas extraction devices such as horizontal wells, and the computer equipment can be computers, personal computers, smart terminals, or other devices that can control the operation of the extraction equipment and perform data processing and content display. This solution does not limit the specific form of the above equipment.

[0060] In this scheme, it should also be understood that at least one fracture overlapping with the mining equipment can be a fracture with any orientation and any shape. This application does not impose any restrictions on the orientation and shape of the fracture.

[0061] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0062] This application also provides a method for preventing shear deformation of casing in horizontal wells used in shale gas development, applied to computer equipment. Figure 2 This is a schematic flowchart of an embodiment of the method for preventing shear and compression deformation of casing in horizontal wells for shale gas development provided in this application. Figure 2 As shown, the specific steps include:

[0063] S101: Determine the discharge rate and fluid intensity for each section of the horizontal well.

[0064] In this step, based on the generalized shear activity criterion, and considering the section where the horizontal well is located, research revealed that when the relative activity coefficient of the fracture-fracturing reaches 1.0, shear slip activity will occur on the weak surface where the fracture-fracturing occurs. If the slip across the weak surface of the wellbore reaches a certain level, it will cause casing deformation. The degree of casing deformation depends on the magnitude of the slip across the weak surface, which is positively correlated with the activity coefficient and scale of the weak surface. Therefore, a quantitative relationship was established between the average slip across the fracture-fracturing and the pump pressure, total fluid volume, and fracture scale. Based on the casing deformation risk level of the fracture-fracturing, the discharge rate and fluid intensity for each section of the horizontal well were determined.

[0065] In one specific implementation, it is assumed that: the energy required for fracture-slip during hydraulic fracturing is all externally input energy, i.e., the energy contained in the fracturing fluid; the fracture-slip is a steady-slip mechanism; and the fracture shape is rectangular. The total energy input for hydraulic fracturing, i.e., the work done by the pump on the fracturing fluid, is expressed as follows:

[0066] (1)

[0067] in, This represents the total energy input for hydraulic fracturing, where P represents pump pressure and S represents the wellbore cross-sectional area. This indicates the total length of the pumped-in column.

[0068] The total fluid input for hydraulic fracturing is:

[0069] (2)

[0070] Where Q represents the total fluid input for hydraulic fracturing, and S represents the wellbore cross-sectional area. This indicates the total length of the pumped-in column.

[0071] The frictional force experienced during fracture-slip is:

[0072] (3)

[0073] in, This represents the frictional force experienced during fracture-slip. Let represent the coefficient of friction of the fracture surface, and L represent the length of the fracture. W represents normal stress, and W represents the fracture width.

[0074] The energy released by fracture-slip is:

[0075] (4)

[0076] Where D represents the average slip of the fracture.

[0077] The energy consumption of hydraulic fracturing includes: overcoming frictional resistance during fracturing fluid flow; fracture generation, propagation, and slippage; various seepage and leakage; and shear slippage through the well. Thus, the total energy input for fracturing, minus the energy consumed in overcoming frictional resistance during fracturing fluid flow, fracture generation, propagation, and slippage, and various seepage and leakage, equals the energy released by the target fracture slippage. Therefore, let:

[0078] (5)

[0079] in, It is a proportionality coefficient, determined according to the region, representing the ratio of the energy required for the target fracture-slip to the input energy, which is jointly determined by geological and engineering conditions.

[0080] Finally, by combining formulas 1, 2, 3, 4, and 5, we can obtain a quantitative relationship between the average slip of the fracture and the pump pressure, total fluid volume, and fracture scale:

[0081] (6)

[0082] Where D represents the average slip of the fracture. The proportionality coefficient is P, where P represents pump pressure and Q represents the total fluid input for hydraulic fracturing. Let represent the coefficient of friction of the fracture surface, and L represent the length of the fracture. W represents normal stress, and W represents the fracture width.

[0083] As can be seen from Formula 6, the average slip-to-fracture ratio is directly proportional to the pump pressure and total fluid volume. Since the discharge rate is positively correlated with pump pressure, fluid intensity, and total fluid volume, the average slip-to-fracture ratio is also positively correlated with the discharge rate and fluid intensity. The critical slip-to-fracture ratio for shear slip is 10-15 mm. Therefore, based on the relationship between the average slip-to-fracture ratio, discharge rate, and fluid intensity, as well as the critical slip-to-fracture ratio, the discharge rate and fluid intensity for each section of the horizontal well are ultimately determined.

[0084] Specifically, in well sections with fault development, the discharge rate between adjacent sections is less than or equal to 11m³. 3 / min, with liquid strength less than or equal to 20m 3 / min.

[0085] The discharge rate for well sections containing Class I casing deformation risk fractures shall not exceed 11m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of adjacent sections are handled according to the Class II risk standard.

[0086] The discharge rate for well sections containing Class II casing deformation risk fractures shall not exceed 12m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of adjacent sections are handled according to the Class III risk standard.

[0087] The discharge rate for well sections containing Class III casing deformation risk fractures shall not exceed 12m³. 3 / min, liquid strength not exceeding 22m 3 / min, the displacement of two adjacent sections does not exceed 13m 3 / min, liquid strength not exceeding 24m 3 / min.

[0088] For other well sections not containing casing deformation risk fractures, the discharge rate shall not exceed 14m³. 3 / min, liquid strength not exceeding 25m 3 / min.

[0089] S102: Determine the temporary plugging measures for each well section based on the discharge rate and fluid intensity of each well section.

[0090] In this step, when the cohesion on the natural fracture surface... and the normal stress it is subjected to The sum is less than the tensile strength of the shale layer. With minimum horizontal principal stress The sum of In such cases, fracturing fluid preferentially flows along natural fractures. Furthermore, all other things being equal, the potential flow capacity of the fluid within a natural fracture is proportional to the cube of its size. For example... Figure 3 As shown, during the fracturing process, when the fracturing fluid meets the following conditions... After large-scale fracture-fracture communication, fracturing fluid preferentially converges towards the associated perforation, forming a pressure drop funnel. For example... Figure 4 As shown, a certain number of temporary plugging balls and temporary plugging agents are then deployed into the well for combined temporary plugging. Driven by the fracturing fluid, the plugging balls preferentially plug the perforations with the highest flow rates, thus sealing the fracture openings. The plugging agent, on the other hand, enters the perforations with slightly lower flow rates, flows into the fracture interior to a certain depth, and deposits to form a barrier, thus sealing the fracture interior. Both plugging methods hinder fracturing fluid loss, controlling the fracture to prevent (or minimize) shear slip, thereby achieving the goal of preventing casing deformation. Therefore, the temporary plugging measures for each well section should be determined based on the flow rate and fluid intensity of each section.

[0091] In one specific implementation, in well sections with fault development, the fluid volume reaches 300-400 m³. 3 A temporary blockage was then initiated.

[0092] In well sections containing Class I casing deformation risk fractures, the fluid volume reaches 500-600m³. 3 Temporary blocking will then begin, and the temporary blocking measures for adjacent sections before and after will be handled according to the Level II risk standard.

[0093] The well section containing Class II casing deformation risk fracture has a fluid volume of 700-800m³. 3 Temporary blocking will then begin, and the temporary blocking measures for adjacent sections before and after will be handled according to the Level III risk standard.

[0094] Well sections containing Class III casing deformation risk fractures, and other well sections not containing casing deformation risk fractures, with a fluid usage of 1000m³. 3 Temporary clogging was then initiated, with the liquid usage in the adjacent sections reaching 1200m³. 3 A temporary blockage was then initiated.

[0095] S103: Control the on-site equipment to temporarily plug the horizontal well according to the temporary plugging measures.

[0096] In the specific implementation of this step, after determining the discharge rate and fluid intensity of each well section of the horizontal well, as well as the temporary plugging measures for each well section, before shale gas development in the study area, the equipment controlling the thread performs the temporary plugging treatment of the horizontal well as described above. The specific temporary plugging measures are set according to the actual situation of the study area and are not specifically limited in this scheme.

[0097] This application embodiment also provides a method for preventing casing shear and pressure deformation in horizontal wells for shale gas development. In step S101, based on the quantitative relationship between the average slippage of the fracture and pump pressure, total fluid volume, and fracture scale, as well as the casing deformation risk level of the fracture, the discharge rate and fluid intensity of each section of the horizontal well are determined. Specifically, this includes:

[0098] In well sections with fault development, the discharge rate between adjacent sections is less than or equal to 11m³. 3 / min, with liquid strength less than or equal to 20m 3 / min.

[0099] The discharge rate for well sections containing Class I casing deformation risk fractures shall not exceed 11m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of adjacent sections are handled according to the Class II risk standard.

[0100] The discharge rate for well sections containing Class II casing deformation risk fractures shall not exceed 12m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of adjacent sections are handled according to the Class III risk standard.

[0101] The discharge rate for well sections containing Class III casing deformation risk fractures shall not exceed 12m³. 3 / min, liquid strength not exceeding 22m 3 / min, the displacement of two adjacent sections does not exceed 13m 3 / min, liquid strength not exceeding 24m 3 / min.

[0102] For other well sections not containing casing deformation risk fractures, the discharge rate shall not exceed 14m³. 3 / min, liquid strength not exceeding 25m 3 / min.

[0103] The method for preventing shear deformation of casing in horizontal wells for shale gas development provided in this application, based on the generalized shear activity criterion, derives the average slip-to-fracturing amount, displacement rate, and fluid intensity. Furthermore, it determines the displacement rate and fluid intensity for each section of the horizontal well based on the adjacent slip and the actual conditions of the study area. This targeted optimization of displacement rate and fluid intensity mitigates adverse effects such as inter-well cross-flow, induced earthquakes, and groundwater pollution during hydraulic fracturing, ensuring the smooth progress of fracturing operations and, to a certain extent, avoiding the harmful environmental and social impacts of hydraulic fracturing.

[0104] In the method for preventing shear and pressure deformation of casing in horizontal wells for shale gas development provided in this application embodiment, step S102 involves determining temporary plugging measures for each well section based on the discharge rate and fluid intensity of each section, specifically including:

[0105] In well sections with fault development, the fluid volume reaches 300-400m³. 3 A temporary blockage was then initiated.

[0106] In well sections containing Class I casing deformation risk fractures, the fluid volume reaches 500-600m³. 3 Temporary blocking will then begin, and the temporary blocking measures for adjacent sections before and after will be handled according to the Level II risk standard.

[0107] The well section containing Class II casing deformation risk fracture has a fluid volume of 700-800m³. 3 Temporary blocking will then begin, and the temporary blocking measures for adjacent sections before and after will be handled according to the Level III risk standard.

[0108] Well sections containing Class III casing deformation risk fractures, and other well sections not containing casing deformation risk fractures, with a fluid usage of 1000m³. 3 Temporary clogging begins after / min, with the liquid usage in the adjacent sections reaching 1200m³. 3 A temporary blockage was then initiated.

[0109] The method for preventing casing shear deformation in shale gas development horizontal wells provided in this application determines the temporary plugging measures for each well section based on the discharge rate and fluid intensity of each section. This avoids relying on a single temporary plugging measure. By analyzing the two flow paths of fracturing fluid and combining the discharge rate and fluid intensity of each well section, a comprehensive temporary plugging measure is formulated to prevent fracturing fluid leakage and solve the casing deformation problem at its source.

[0110] The following example illustrates the casing deformation prevention method for horizontal wells in the Z platform of the Weiyuan shale gas block in Sichuan Province. Specifically, it includes:

[0111] like Figure 5 As shown, based on the casing deformation risk prediction and evaluation results of the Z platform, the casing deformation risk of well-to-well fracture is divided into levels I, II and III;

[0112] For well sections containing Class I casing deformation risk fractures, the discharge rate and fluid intensity for this section shall not exceed 11m³. 3 / min and 20m 3 / min, and when the liquid volume reaches 500-600m 3 Temporary plugging then begins. The discharge rate, liquid intensity, and temporary plugging measures for adjacent sections are handled according to the Level II transformer risk standard.

[0113] For well sections containing Class II casing deformation risk fractures, the discharge rate and fluid intensity for this section shall not exceed 12m³. 3 / min and 20m 3 / min, and when the liquid volume reaches 700-800m 3 Temporary plugging then begins. The discharge rate, liquid intensity, and temporary plugging measures for adjacent sections are handled according to the Level III transformer risk standard.

[0114] For well sections containing Class III casing deformation risk fractures, the discharge rate and fluid intensity for this section shall not exceed 12m³. 3 / min and 22m 3 / min, and when the liquid volume reaches 1000m 3 Temporary clogging begins after [time / min]. The discharge rate and liquid intensity of the two adjacent sections should not exceed 13m³. 3 / min and 24m 3 / min, and when the liquid volume reaches 1200m 3 Then a temporary blockage was initiated;

[0115] For other well sections not containing casing deformation risk fractures, the discharge rate and fluid intensity shall not exceed 14m³. 3 / min and 25m 3 / min, and when the liquid volume reaches 1200m 3 Then a temporary blockage was initiated;

[0116] Based on the above principles, the fracturing parameters for each well section of each well on the Z platform were designed. Table 1 shows the fracturing parameters for well Z1. With this, the casing deformation prevention measures for the Z platform were completed.

[0117] Table 1 Design Parameters for Fracturing Construction in Well Z1

[0118]

[0119] Table 1 (continued)

[0120]

[0121] This application also provides a device for preventing shear deformation of casing in horizontal wells used in shale gas development, which is applied to computer equipment. Figure 6 This is a schematic diagram of the structure of Embodiment 1 of the shale gas development horizontal well casing shear and compression deformation prevention device provided in this application. Figure 6 As shown, the shale gas development horizontal well casing shear deformation prevention device 200 includes:

[0122] The first processing module 201 is used to determine the discharge rate and fluid intensity of each section of the horizontal well based on the quantitative relationship between the average slip of the fracture and the pump pressure, total fluid volume and fracture scale, as well as the casing deformation risk level of the fracture, for the fault where the horizontal well is located.

[0123] The second processing module 202 is used to determine the temporary plugging measures for each well section based on the discharge rate and fluid intensity of each well section.

[0124] The third processing module 203 is used to control the field equipment to perform temporary plugging treatment on the horizontal well according to the temporary plugging measures.

[0125] This application embodiment also provides a device for preventing shear and compression deformation of casing in horizontal wells for shale gas development. In the first processing module, the quantitative relationship between the average fracture slip and pump pressure, total fluid volume, and fracture scale is expressed as follows:

[0126]

[0127] Where D represents the average slip of the fracture, k is a proportionality coefficient representing the ratio of energy required for the target fracture slip to the input energy, P represents the pump pressure, Q represents the total fluid input for hydraulic fracturing, μ represents the friction coefficient of the fracture surface, L represents the fracture length, and W represents the fracture width. This represents normal stress.

[0128] Figure 7 This is a schematic diagram of the second embodiment of the shale gas development horizontal well casing shear and compression deformation prevention device provided in this application. Figure 7 As shown, the first processing module 201 includes:

[0129] The first processing unit 2011 is used in well sections with fault development, where the discharge rate between adjacent sections is less than or equal to 11m³. 3 / min, with liquid strength less than or equal to 20m 3 / min.

[0130] The second processing unit 2012 is used for well sections containing Class I casing deformation risk fractures with a discharge rate not exceeding 11m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of adjacent sections are handled according to the Class II risk standard.

[0131] The third processing unit 2013 is used for well sections containing Class II casing deformation risk fractures with a discharge rate not exceeding 12m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of adjacent sections are handled according to the Class III risk standard.

[0132] The fourth processing unit 2014 is used for well sections containing Class III casing deformation risk fractures with a discharge rate not exceeding 12m³. 3 / min, liquid strength not exceeding 22m 3 / min, the displacement of two adjacent sections does not exceed 13m 3 / min, liquid strength not exceeding 24m 3 / min.

[0133] The fifth processing unit, 2015, is used for other well sections that do not contain casing deformation risk fractures, with a discharge capacity not exceeding 14m³. 3 / min, liquid strength not exceeding 25m 3 / min.

[0134] Figure 8 This is a schematic diagram of the structure of Embodiment 3 of the shale gas development horizontal well casing shear and compression deformation prevention device provided in this application. Figure 8 As shown, the second processing module 202 includes:

[0135] In the first processing unit 2021, the fluid volume reached 300-400 m³ in the well section with fault development. 3 A temporary blockage was then initiated.

[0136] The second processing unit, 2022, includes well sections with Class I casing deformation risk and fracture, with a fluid volume reaching 500-600 m³. 3 Temporary blocking will then begin, and the temporary blocking measures for adjacent sections before and after will be handled according to the Level II risk standard.

[0137] The third processing unit, 2023, includes well sections with Class II casing deformation risk and fracture, with a fluid volume reaching 700-800 m³. 3 Temporary blocking will then begin, and the temporary blocking measures for adjacent sections before and after will be handled according to the Level III risk standard.

[0138] The fourth processing unit 2024 includes well sections with Class III casing deformation risk fractures, as well as other well sections without casing deformation risk fractures, with a fluid usage of 1000m³. 3 Temporary clogging begins after / min, with the liquid usage in the adjacent sections reaching 1200m³. 3 A temporary blockage was then initiated.

[0139] This application also provides a computer device. Figure 9 A schematic diagram of the structure of the computer device provided in the embodiments of this application, such as... Figure 9 As shown, the computer device 300 includes a processor 301, a memory 302, and a display 303;

[0140] Memory 301 stores computer-executed instructions.

[0141] The processor 302 executes computer execution instructions stored in the memory to implement any of the method embodiments described above.

[0142] The display 303 is used to display image information such as cross-sections and plan views.

[0143] This application also provides a computer storage medium storing computer execution instructions, which, when executed by a processor, are used to implement any of the method embodiments described above.

[0144] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0145] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for preventing shear deformation of casing in horizontal wells for shale gas development, characterized in that, Applied to a computer device, the method includes: For the fault where the horizontal well is located, the discharge rate and fluid intensity of each well section of the horizontal well are determined based on the quantitative relationship between the average slip of the fault-fracture and the pump pressure, total fluid volume and fracture scale, as well as the casing deformation risk level of the fault-fracture. The casing deformation risk of the fault-fracture is divided into three levels: I, II and III. The temporary plugging measures for each well section are determined based on the discharge rate and fluid intensity of each well section. According to the aforementioned temporary plugging measures, the field equipment is controlled to perform temporary plugging treatment on the horizontal well. The temporary plugging treatment is to seal the fracture opening and inside the fracture by using temporary plugging balls and temporary plugging agents, so as to control fracture shear slip and prevent casing deformation. The determination of the discharge rate and fluid intensity for each section of the horizontal well based on the quantitative relationship between the average slip of the fracture and pump pressure, total fluid volume, and fracture scale, as well as the casing deformation risk level of the fracture, includes: In well sections with fault development, the discharge rate between adjacent sections is less than or equal to 11m³. 3 / min, with liquid strength less than or equal to 20m 3 / min; The discharge rate for well sections containing Class I casing deformation risk fractures shall not exceed 11m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of the two adjacent sections are handled according to the Class II risk standard for casing deformation; The discharge rate for well sections containing Class II casing deformation risk fractures shall not exceed 12m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of the two adjacent sections are handled according to the Class III risk standard for casing deformation; The discharge rate for well sections containing Class III casing deformation risk fractures shall not exceed 12m³. 3 / min, liquid strength not exceeding 22m 3 / min, the displacement of two adjacent sections does not exceed 13m 3 / min, liquid strength not exceeding 24m 3 / min; For other well sections not containing casing deformation risk fractures, the discharge rate shall not exceed 14m³. 3 / min, liquid strength not exceeding 25m 3 / min.

2. The method according to claim 1, characterized in that, The quantitative relationship between the average fracture slip and pump pressure, total fluid volume, and fracture scale is expressed as follows: ; Where D represents the average slip of the fracture, k is a proportionality coefficient representing the ratio of energy required for the target fracture slip to the input energy, P represents the pump pressure, Q represents the total fluid input for hydraulic fracturing, μ represents the friction coefficient of the fracture surface, L represents the fracture length, and W represents the fracture width. This represents normal stress.

3. The method according to claim 1, characterized in that, The determination of temporary plugging measures for each well section based on the discharge rate and fluid intensity of each well section includes: In well sections with fault development, the fluid volume reaches 300-400m³. 3 Then a temporary blockage was initiated; In well sections containing Class I casing deformation risk fractures, the fluid volume reaches 500-600m³. 3 Then, temporary blocking begins, and the temporary blocking measures for adjacent sections are handled according to the Level II risk standard. The well section containing Class II casing deformation risk fracture has a fluid volume of 700-800m³. 3 Then, temporary blocking begins, and the temporary blocking measures for adjacent sections are handled according to the Level III risk standard. Well sections containing Class III casing deformation risk fractures, and other well sections not containing casing deformation risk fractures, with a fluid usage of 1000m³. 3 Temporary clogging begins after a certain number of minutes, with the fluid usage in the two adjacent sections reaching 1200 m³. 3 A temporary blockage was then initiated.

4. A device for preventing shear and compression deformation of casing in horizontal wells for shale gas development, characterized in that, The device includes: The first processing module is used to determine the discharge rate and fluid intensity of each well section of the horizontal well based on the quantitative relationship between the average slip of the fracture and the pump pressure, total fluid volume and fracture scale, as well as the casing deformation risk level of the fracture, for the fault where the horizontal well is located. The casing deformation risk of the fracture is divided into three levels: I, II and III. The second processing module is used to determine the temporary plugging measures for each well section based on the discharge rate and fluid intensity of each well section. The third processing module is used to control the field equipment to perform temporary plugging treatment on the horizontal well according to the temporary plugging measures. The temporary plugging treatment is to seal the fracture opening and inside the fracture by using a temporary plugging ball and a temporary plugging agent to control fracture shear slip and prevent casing deformation. The first processing module includes: The first processing unit is used for well sections with fault development, where the discharge rate between adjacent sections is less than or equal to 11m³. 3 / min, with liquid strength less than or equal to 20m 3 / min; The second processing unit, used for well sections containing Class I casing deformation risk fractures, has a discharge capacity not exceeding 11m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of the two adjacent sections are handled according to the Class II risk standard for casing deformation; The third processing unit, used for well sections containing Class II casing deformation risk fractures, has a discharge capacity not exceeding 12m³. 3 / min, liquid strength not exceeding 20m 3 / min, the discharge rate and liquid intensity of the two adjacent sections are handled according to the Class III risk standard for casing deformation; The fourth processing unit, used for well sections containing Class III casing deformation risk fractures, has a discharge rate not exceeding 12m³. 3 / min, liquid strength not exceeding 22m 3 / min, the displacement of two adjacent sections does not exceed 13m 3 / min, liquid strength not exceeding 24m 3 / min; The fifth processing unit is used for other well sections that do not contain casing deformation risk fractures, with a discharge capacity not exceeding 14m³. 3 / min, liquid strength not exceeding 25m 3 / min.

5. The apparatus according to claim 4, characterized in that, The quantitative relationship between the average fracture slip and pump pressure, total fluid volume, and fracture scale is expressed as follows: ; Where D represents the average slip of the fracture, k is a proportionality coefficient representing the ratio of energy required for the target fracture slip to the input energy, P represents the pump pressure, Q represents the total fluid input for hydraulic fracturing, μ represents the friction coefficient of the fracture surface, L represents the fracture length, and W represents the fracture width. This represents normal stress.

6. The apparatus according to claim 4, characterized in that, The second processing module includes: In the first processing unit, in well sections with fault development, the fluid volume reaches 300-400m³. 3 Then a temporary blockage was initiated; The second processing unit includes well sections with Class I casing deformation risk and fracture, with a fluid volume of 500-600 m³. 3 Then, temporary blocking begins, and the temporary blocking measures for adjacent sections are handled according to the Level II risk standard. The third processing unit includes well sections with Class II casing deformation risk and fracture, with a fluid volume of 700-800 m³. 3 Then, temporary blocking begins, and the temporary blocking measures for adjacent sections are handled according to the Level III risk standard. The fourth treatment unit includes well sections with Class III casing deformation risk fractures, as well as other well sections without casing deformation risk fractures, with a fluid usage of 1000m³. 3 Temporary clogging begins after a certain number of minutes, with the fluid usage in the two adjacent sections reaching 1200 m³. 3 A temporary blockage was then initiated.

7. A computer device, comprising: Processor, memory, and display; The memory is connected to the processor and is used to store computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the method as described in any one of claims 1 to 3.

8. A computer storage medium, characterized in that, The computer storage medium stores computer execution instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1 to 3.

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