Fault slippage shear casing deformation simulation and evaluation device in hydraulic fracturing process

Abstract

The invention relates to a fault slippage shear casing deformation simulation and evaluation device in a hydraulic fracturing process. The fault slippage shear casing deformation simulation and evaluation device comprises a shaft simulation system, a fluid circulation system, a heating system, a displacement load applying system and a measuring system, the shaft simulation system comprises a sleeve and an outer frame arranged on the periphery of the sleeve, and cement is poured into the outer frame on the periphery of the sleeve to form a simulation stratum; the fluid circulating system comprises a liquid storage tank, pressure regulating valves and a water pump, the liquid storage tank, the water pump and the sleeve are connected through a circulating pipeline, and the pressure regulating valves are arranged at the two ends of the sleeve respectively; the displacement load applying system comprises a fixing mechanism, a moving mechanism and a hydraulic cylinder, and is used for pushing a fault of a simulated stratum to slide along a weak plane so as to apply shear deformation to a sleeve; the measuring system is used for capturing fault slippage parameters and shear deformation parameters of the casing pipe. The monitoring and the evaluation on the shear deformation of the horizontal casing under the stratum caused by various factors in the hydraulic fracturing process are realized in a real working condition environment.

Description

Technical Field

[0001] The invention relates to a fault slip shear casing deformation simulation and evaluation device in a hydraulic fracturing process. Background Art

[0002] Shale gas exploration and development face many difficulties and challenges. Among them, casing deformation during multi-stage fracturing of shale gas horizontal wells is one of the bottlenecks that urgently needs to be overcome. The measurement data of the engineering site show that shear deformation is the main form of casing deformation, and fault slip along natural fractures is the main cause of casing shear deformation. Its main mechanism of action is: during the multi-stage fracturing of shale gas horizontal wells, a large amount of fracturing fluid enters the natural fractures. The high net pressure in the fracture caused by the large displacement and the low friction coefficient of the fracture surface caused by the slick water cause the fault to be activated and then slip along the natural fractures, causing shear deformation of the casing that passes through the natural fractures.

[0003] After the casing is shear-deformed, the bridge plug of the original design size cannot be set in place, and a smaller diameter bridge plug (secondary bridge plug or even tertiary bridge plug) needs to be replaced and repeatedly inserted, which increases construction time and construction costs; in severe cases, the tertiary bridge plug still cannot be set, resulting in the abandonment of the designed fracturing stage, thereby reducing the production of a single well. Moreover, based on the experience of casing deformation in conventional oil and gas fields, casing deformation will become more serious in the long-term production process of subsequent shale gas wells, significantly shortening the life cycle of the well.

[0004] At present, in actual engineering operations, the multi-arm caliper measurement device is mainly used to analyze the shear deformation of the casing. However, a measurement takes a lot of time and money, and given that the shear deformation of the casing often increases over time, the final change in the inner diameter of the casing is inconsistent with the measurement result, which has a great impact on the selection of bridge plugs. In the laboratory environment, it mainly relies on the use of computer simulation modeling software such as Abaqus and Ansys to simulate the shear deformation of the casing caused by fault slip under multi-stage fracturing, but there is a large gap between the calculated simulation results and the actual results.

[0005] Therefore, it is urgent to establish an indoor simulation analysis device to analyze the change of the inner diameter of the casing after shear deformation, and it is also necessary to consider the actual hydraulic fracturing project. It can analyze relevant parameters such as the distance of fault slip, the change of formation temperature, the specifications of the casing, the pressure during fracturing, etc., to restore the actual bottom hole engineering to the maximum extent, and establish the relationship between the fault slip parameters and the change of the inner diameter of the casing after shear deformation. At the same time, it can also evaluate whether the bridge plug can pass after the casing deformation, which can be used as the basis for the selection of the bridge plug. Summary of the invention

[0006] In order to enrich the types of indoor simulation and analysis devices in the prior art, considering the actual hydraulic fracturing project, the change of the inner diameter of the casing after shear deformation is analyzed, and the present invention proposes a fault slip shear casing deformation simulation and evaluation device during hydraulic fracturing. The technical solution proposed by the present invention is as follows:

[0007] In a first aspect, the present invention provides a fault slip shear casing deformation simulation and evaluation device during hydraulic fracturing, comprising: a wellbore simulation system, a fluid circulation system, a heating system, a displacement load application system and a measurement system;

[0008] The wellbore simulation system includes a casing and an outer frame arranged outside the casing, and the outer frame outside the casing is poured with cement to form a simulated formation to simulate the cement ring and rock mass around the casing under actual engineering conditions;

[0009] The fluid circulation system comprises a liquid storage tank, a pressure regulating valve and a water pump. The liquid storage tank, the water pump and the casing are connected through a circulation pipeline, and the pressure regulating valves are respectively provided at both ends of the casing;

[0010] The heating system includes a heating device embedded in the simulated formation;

[0011] The displacement load application system comprises a fixing mechanism, a moving mechanism and a hydraulic cylinder, wherein the fixing mechanism is connected to the outer frame, and the hydraulic cylinder is connected to the moving mechanism, and is used to push the fault of the simulated formation to slide along the weak surface, so that the casing is subjected to shear deformation;

[0012] The measurement system is arranged outside the wellbore simulation system to capture fault slip parameters, and is arranged inside or outside the casing to collect shear deformation parameters of the casing.

[0013] In one or some embodiments, the fault slip parameter includes the fault slip distance, and the shear deformation parameter includes the temperature, the pressure on the casing, the flow rate in the casing pipeline, and the inner diameter of the casing;

[0014] The measurement system includes a temperature measurement module, a pressure measurement module, a slip distance measurement module, a flow measurement module and a well diameter measurement module;

[0015] The temperature measurement module includes a thermocouple and a temperature control instrument laid on the casing wall, wherein the thermocouple is connected to the temperature control instrument and is used to measure the casing temperature;

[0016] The pressure measuring module is arranged on the outer wall of the casing and is used to detect the pressure on the casing;

[0017] The slip distance measurement module is arranged outside the wellbore simulation system and is used to measure the fault slip distance of the simulated formation according to the pressure measurement module;

[0018] The flow measurement module is used to measure the flow in the casing pipeline;

[0019] The well diameter measurement module is arranged on the inner wall of the casing and is used to measure the inner diameter of the casing.

[0020] In one or some embodiments, the shear deformation parameter includes a degree of deformation of the casing, and the measurement system further includes a strain measurement module disposed on an outer layer of the casing for measuring the degree of deformation of the casing.

[0021] In one or some embodiments, the strain measurement module includes a distributed optical fiber sensor and a strain detector connected thereto;

[0022] The distributed optical fiber sensor is packaged in the outer layer of the casing, and the strain detector is connected to the strain gauge of the distributed optical fiber sensor.

[0023] In one or some embodiments, the measurement system further includes: an electromagnetic ultrasonic measurement module disposed in the casing, for detecting whether cracks appear inside the casing.

[0024] In one or some embodiments, the slip distance measurement module is a DIC measurement device, and the DIC measurement device is installed at a position corresponding to the middle of the casing.

[0025] In one or some embodiments, the caliper measurement module is a multi-arm caliper.

[0026] In one or some embodiments, the measurement system further includes a thermometer and a pressure gauge disposed at both ends of the sleeve, for measuring the temperature and pressure in the circulation pipeline, respectively.

[0027] In one or some embodiments, the device further comprises a pressure relief channel connected between the sleeve inlet and the liquid storage tank.

[0028] In one or some embodiments, safety valves are respectively provided on the circulation pipeline and the pressure relief channel.

[0029] In one or some embodiments, flow meters are provided at the parts of the circulation channel located at both ends of the casing.

[0030] In a second aspect, the present invention provides a test method for simulating and evaluating the deformation of fault slip shear casing during hydraulic fracturing as described in the first aspect, comprising:

[0031] Prepare corresponding cement slurry according to engineering requirements and actual formation mechanical properties;

[0032] A casing with an outer diameter the same as that of the wellbore is used and pre-set in the displacement load application system, and the prepared cement slurry is poured between the pre-set casing and the outer frame. During the pouring of the cement slurry, a heating device is evenly embedded to apply temperature to the simulated formation, and a weak surface is set at the slip interface of the simulated formation.

[0033] After the cement slurry solidifies, the pre-set casing is removed to obtain a wellbore of the same size as the actual project;

[0034] Install casing and adjust the centering degree between casing and wellbore. By adjusting the eccentric angle and eccentricity, simulate the different conditions of casing in horizontal well section.

[0035] Injecting the prepared cement slurry into the annulus between the casing and the wellbore, using a heating device to heat the simulated formation during the injection process, and pressurizing the annular fluid to form a casing-cement annulus-simulated formation combination system;

[0036] Turning on the heating device in the simulated formation and heating it to the simulated formation temperature;

[0037] Start the water pump and adjust it to the same displacement as the actual fracturing project. Use the measurement system to measure the parameters of the casing, cement sheath, and simulated formation during the process.

[0038] Start the displacement load application system, push the fault to slide along the weak plane according to the test requirements, and use the measurement system to capture the fault sliding process;

[0039] After the test is completed, the shear deformation parameters of the casing after shear deformation are measured by the measuring system.

[0040] In one or some embodiments, the shear deformation parameter includes the inner diameter of the casing, and the inner diameter of the casing is measured in the following manner:

[0041] A multi-arm caliper was used to measure the inner diameter of the casing after shear deformation. At the same time, bridge plugs of different specifications were used for testing to determine whether the bridge plugs could pass through the deformed position.

[0042] In one or some embodiments, the method includes using a DIC measurement device to capture the fault slip process.

[0043] In one or some embodiments, the method further comprises:

[0044] Adjust the cement slurry formula to change the mechanical properties of the simulated formation, change the cement slurry formula to change the mechanical properties of the cement sheath, control the heating device in the simulated formation to change the simulated formation temperature, select casing of different specifications to change the casing parameters, change the pumping parameters of the water pump to change the pump pressure and displacement, control the displacement load application system to change the fault slip distance, so as to obtain the change of casing inner diameter under different engineering and geological parameters.

[0045] In one or some embodiments, the method further includes: during the test, starting the pressure measurement module and the strain measurement module to detect the pressure on the casing and the degree of deformation of the casing.

[0046] In one or some embodiments, the method further includes: starting the electromagnetic ultrasonic measurement module to detect whether the casing is damaged or broken.

[0047] In one or some embodiments, the method further comprises: measuring the flow rate in the circulation channel by means of a flow measurement module.

[0048] In one or some embodiments, the method further includes: during the test, adjusting and controlling the pressure of the circulation pipeline by means of a pressure regulating valve and a safety valve; when the pressure of the circulation pipeline is greater than a preset pressure value, opening the safety valve to allow the fracturing fluid to flow back to the storage tank via the pressure relief pipeline.

[0049] In one or some embodiments, before using a casing having an outer diameter the same as that of the wellbore and pre-setting it in the displacement load application system, the method further includes: applying butter on the outer wall of the pre-set casing.

[0050] Based on the above technical solution, the beneficial effects of the present invention compared with the prior art are as follows:

[0051] The present invention provides a simulation and evaluation device for fault slip shear casing deformation during hydraulic fracturing, wherein the wellbore simulation system comprises a casing and an outer frame arranged on the periphery of the casing, the casing is a full-size casing consistent with engineering practice, and the outer frame on the periphery of the casing can be poured with cement to simulate the cement ring and rock mass around the casing under actual engineering conditions, forming a casing-cement ring-simulated formation combination system; the fluid circulation system comprises a liquid storage tank, a pressure regulating valve and a water pump, the liquid storage tank, the water pump and the casing are connected by a circulation pipeline, and the pressure regulating valves are respectively arranged at both ends of the casing; the casing can be pressurized by the water pump. During the test, the fluid circulation system pumps the fracturing fluid stored in the storage tank into the circulation pipeline through a water pump, so that the fracturing fluid circulates in the entire pipeline, and the pressure regulating valve can be used to adjust its pressure to simulate the engineering practice of the fluid entering the formation through the casing during hydraulic fracturing; the heating system includes a heating device embedded in the cement, and the heating device is embedded in the cement to change the temperature of the simulated formation; the displacement load application system includes a hydraulic cylinder that applies shear deformation, pushing the fault of the simulated formation to slide along the weak surface, so that the casing is subjected to shear deformation, and the measurement system is set outside the wellbore simulation system, inside or outside the casing, for obtaining fault slip parameters and casing shear deformation parameters. The present invention can simulate the shear deformation of the casing under different circulating pipe pressures, different formation slip distances, different casing specifications, different formation temperatures, and different rock strengths, measure the change in the inner diameter of the casing after shear deformation, and can use a full-size bridge plug to test whether the deformed casing can allow the bridge plug to pass smoothly, so as to evaluate the impact of the casing shear deformation on the actual production increase operation. It can provide a basis for the optimization of casing specifications and provide technical support for the prevention and control of casing deformation problems. It can monitor and evaluate the shear deformation of horizontal casing under the formation caused by various factors during hydraulic fracturing under real working conditions.

[0052] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0053] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0055] Figure 1 Schematic diagram of the structure of a device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to an embodiment of the present application;

[0056] Figure 2 It is a 3D structural schematic diagram of a fault slip shear casing deformation simulation and evaluation device in a hydraulic fracturing process according to an embodiment of the present application;

[0057] Figure 3 A system structure block diagram of a device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to an embodiment of the present application;

[0058] Figure 4 It is a structural block diagram of a measurement system of a device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to an embodiment of the present application;

[0059] Figure 5 A second structural block diagram of a measurement system of a device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to an embodiment of the present application;

[0060] Figure 6 This is the system diagram of the test device;

[0061] Figure 7 It is the system fluid circulation state diagram of the test device;

[0062] Figure 8 This is the system casing shear state diagram of the test device.

[0063] In the figure: 1 is the casing mouth; 2 is the casing; 3 is the strain measurement module; 4 is the sliding distance measurement module; 5 is the pressure measurement module; 6 is the moving mechanism; 7 is the fixing mechanism; 8 is the temperature measurement module; 9 is the simulated formation; 10 is the hydraulic cylinder; 11 is the outer frame; 12 is the first support frame; 13 is the second support frame; 14 is the flow measurement module; 15 is the wellbore measurement module; 16 is the electromagnetic ultrasonic measurement module. DETAILED DESCRIPTION

[0064] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0065] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

[0066] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0067] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] In order to avoid casing deformation during well completion and production increase of oil and gas wells, it is necessary to simulate the shear deformation of casing under different well depths and different working conditions. The inventor found in his work that, at present, in actual engineering operations, a multi-arm wellbore measurement device is mainly used to analyze the shear deformation of casing, but it takes a lot of time and money to measure once, and given that the shear deformation of casing often increases with the passage of time, the change in the final casing inner diameter is inconsistent with the measurement result, which has a great impact on the selection of bridge plugs. In the laboratory environment, it mainly relies on the use of computer simulation modeling software such as Abaqus and Ansys to simulate the shear deformation of fault slip under multi-stage fracturing, but there is a large gap between the calculated simulation results and the actual results, which cannot meet the expectations of the inventor.

[0069] Therefore, it is urgent to establish an indoor simulation analysis device to analyze the change of the inner diameter of the casing after shear deformation, and it is also necessary to consider the actual hydraulic fracturing project. It can analyze relevant parameters such as the distance of fault slip, the change of formation temperature, the specifications of the casing, the pressure during fracturing, etc., to restore the actual bottom hole engineering to the maximum extent, and establish the relationship between the fault slip parameters and the change of the inner diameter of the casing after shear deformation. At the same time, it can also evaluate whether the bridge plug can pass after the casing deformation, which can be used as the basis for the selection of the bridge plug.

[0070] Patent publication CN114184496A discloses a casing shear strength and deformation test device, which can simulate the casing bearing the shear load of the formation rock, test the shear strength and shear deformation, so as to solve the technical problem that the casing strength and deformation cannot be accurately determined under the shear sliding of the formation rock, but there is no complete fluid circulation system, and the circulation pressure cannot be adjusted. At the same time, there is no heating system, and the real temperature change of the formation cannot be simulated. Patent publication CN106018125 discloses a drilling cementing casing shear test system, which can simulate the casing shear deformation and can apply a shear force of 3000kN, which is suitable for shearing cementing casings of different specifications and diameters, but it cannot simulate and test the influence of shear force on casing deformation under different formation conditions according to different formation rocks and cementing quality.

[0071] At present, the commercial numerical simulation software used in calculating casing shear deformation has the disadvantages of complex parameter adjustment, slow calculation speed, post-processing, and inconsistent results with reality, which cannot directly serve oil and gas well completion and production increase engineering. In order to overcome this problem, it is proposed to establish an indoor simulation analysis device to analyze the changes after casing shear deformation, and it is also necessary to consider the actual hydraulic fracturing project. It can analyze relevant parameters such as the distance of fault slip, the change of formation temperature, the specifications of casing, and the pressure during fracturing. Parameters, so as to restore the actual bottom hole engineering to the maximum extent, establish the relationship between the fault slip parameter and the change of the inner diameter after the shear deformation of the casing. It can evaluate whether the bridge plug can pass after the casing deformation, so as to provide a basis for the optimization of the specifications of the bridge plug and casing, and provide technical support for the prevention and control of casing deformation problems. In view of this, the inventor has further developed a fault slip shear casing deformation simulation and evaluation device during hydraulic fracturing, which is used to measure the change value of the casing inner diameter under different fault slip parameters, and to evaluate whether the bridge plug can pass the deformation position.

[0072] Embodiment 1

[0073] The embodiment of the present invention provides a fault slip shear casing deformation simulation and evaluation device during hydraulic fracturing, referring to Figure 3As shown, it includes: a wellbore simulation system 101, a fluid circulation system 102, a heating system 103, a displacement load application system 104 and a measurement system 105;

[0074] Reference Figure 1 and Figure 2 As shown, the wellbore simulation system 101 includes a casing 2 and an outer frame 11 arranged outside the casing. The outer frame 11 outside the casing 2 is poured with cement to form a simulated formation 9 to simulate the cement ring and rock mass around the casing 2 under actual engineering conditions; both ends of the casing are provided with casing ports 1, and the casing can be connected to the circulation channel through the casing ports 1. The casing 2 is a full-size casing that conforms to the actual engineering practice. The full-size casing can be used, and the specifications, such as the diameter, steel grade, and wall thickness of the casing, can be adjusted according to actual conditions. The internal pressure of the casing can be adjusted to simulate different pressures. By adjusting the formula of cement, the rock mechanical properties of the fault are adjusted to simulate different formations. The present invention can change the rock and cementing quality through cement slurries of different formulas, and simulate and test the influence of shear force on casing deformation under formation conditions of different conditions according to different formation rocks and cementing quality. The present invention can be used to simulate different friction coefficients by setting different artificial damages on the contact surface between the upper plate and the lower plate of the fault.

[0075] Reference Figure 7 As shown, the fluid circulation system 102 includes a liquid storage tank, a pressure regulating valve and a water pump. The liquid storage tank, the water pump and the casing 2 are connected by a circulation pipeline. The pressure regulating valves are respectively provided at both ends of the casing 2; the casing 2 can be pressurized by the water pump. The fracturing fluid is pumped out from the liquid storage tank by the water pump and injected into the device, and then flows back to the liquid storage tank through the multi-stage pressure regulating valve to form a circulation loop. During the test, the above-mentioned fluid circulation system 102 pumps the fracturing fluid stored in the liquid storage tank into the circulation pipeline through the water pump, so that the fracturing fluid circulates in the entire pipeline, and the pressure can be adjusted by a pressure regulating valve to simulate the engineering practice of the fluid entering the formation through the casing 2 during hydraulic fracturing;

[0076] The heating system 103 includes a heating device embedded in the simulated stratum 9; the heating device is embedded in cement to increase the temperature, and a tubular electric heating element is used as a heating element. The tubular electric heating element is a high-temperature resistance wire placed in a metal tube, and the gap is tightly filled with crystalline magnesium oxide powder with good insulation and thermal conductivity to achieve a good heating effect. The heating device can be a heating coil;

[0077] The displacement load application system 104 includes a fixed mechanism 7, a mobile mechanism 6 and a hydraulic cylinder 10. The fixed mechanism 7 is connected to the outer frame 11, and the hydraulic cylinder 10 is connected to the mobile mechanism 6, and is used to push the fault of the simulated stratum 9 to slide along the weak surface, so that the casing 2 is subjected to shear deformation. The present invention simulates different sliding speeds and sliding lengths through the setting of the displacement load application system 104, and specifically can achieve the change of sliding speed and sliding length by adjusting the hydraulic cylinder 10 below. The displacement load application system 104 also includes a first support frame 12 arranged outside the mobile mechanism, the bottom end of the first support frame 12 is fixed to the ground, and the first support frame 12 is used to limit the moving distance of the mobile mechanism 6. It also includes a second support frame 13 fixed to the fixed mechanism 7 at one end, and the other end of the second support frame 13 is connected to the mobile mechanism 6. The moving part relies on the thrust provided by the hydraulic cylinder to push the bottom of the structure. The hydraulic cylinder 10 drives the moving mechanism 6 on the left side of the second support frame 13 to move, and then pushes the entire poured cement body, i.e., the simulated stratum 9. In this process, the moving mechanism 6 will continue to rise along the slope, shearing the casing 2, causing the casing to deform.

[0078] The measurement system 105 is disposed outside the wellbore simulation system 101 to capture fault slip parameters, and is disposed inside or outside the casing 2 to collect shear deformation parameters of the casing 2 .

[0079] The present invention relates to the technical field of shale gas drilling exploration and exploitation, and in particular to a fault slip shear casing deformation measurement and evaluation device under hydraulic fracturing conditions. Its wellbore simulation system 101 includes a casing and an outer frame 11 arranged on the outer periphery of the casing, the casing 2 is a full-size casing that conforms to the actual project, and the outer frame 11 on the outer periphery of the casing 2 can be poured with cement to simulate the cement ring and rock mass around the casing under actual project conditions, forming a casing-cement ring-simulated formation 9 combination system; the fluid circulation system 102 includes a liquid storage tank, a pressure regulating valve and a water pump, the liquid storage tank, the water pump and the casing 2 are connected by a circulation pipeline, and the pressure regulating valves are respectively arranged at both ends of the casing 2; the casing 2 can be pressurized by the water pump. During the test, the fluid circulation system 102 pumps the fracturing fluid stored in the fluid storage tank into the circulation pipeline through a water pump, so that the fracturing fluid circulates in the entire pipeline, and the pressure regulating valve can be used to adjust its pressure to simulate the engineering practice of the fluid entering the formation through the casing 2 during hydraulic fracturing; the heating system 103 includes a heating device embedded in the cement, and the heating device is embedded in the cement to change the temperature of the simulated formation 9; the displacement load application system 104 includes a hydraulic cylinder 10 for applying shear deformation, which pushes the fault of the simulated formation 9 to slide along the weak surface, so that the casing 2 applies shear deformation, and the measurement system 105 is arranged outside the wellbore simulation system 101, inside or outside the casing 2, and is used to obtain fault slip parameters and casing shear deformation parameters. The present invention can simulate the shear deformation of casing under different circulating pipe pressures, different formation slip distances, different casing specifications, different formation temperatures, and different rock strengths, measure the change in the inner diameter of the casing after shear deformation, and use a full-size bridge plug to test whether the deformed casing can allow the bridge plug to pass smoothly, so as to evaluate the impact of casing shear deformation on actual production increase operations. It can provide a basis for the optimization of casing specifications and provide technical support for the prevention and control of casing deformation problems. It realizes the monitoring and evaluation of the shear deformation of the horizontal casing under the formation caused by various factors during the hydraulic fracturing process under real working conditions.

[0080] In one embodiment, the size of the outer frame 11 is more than ten times the diameter of the sleeve, which can effectively avoid the size effect that may exist in the sleeve deformation. The size effect means that under the same conditions, objects of different sizes or shapes may be subjected to different forces. This difference is usually caused by the proportional relationship between the surface area or volume of the object.

[0081] In one embodiment, the fault slip parameter includes the fault slip distance, and the shear deformation parameter includes the temperature, the pressure on the casing, the flow rate in the casing pipeline, and the inner diameter of the casing;

[0082] Reference Figure 4As shown, the measurement system 105 includes a temperature measurement module 8, a pressure measurement module 5, a slip distance measurement module 4, a flow measurement module 14 and a well diameter measurement module 15;

[0083] The temperature measurement module 8 includes a thermocouple and a temperature control instrument laid on the casing wall. The thermocouple is connected to the temperature control instrument to measure the casing temperature. The temperature change can be measured by continuously collecting data at preset time intervals.

[0084] The pressure measuring module 5 is arranged on the outer wall of the casing 2, and is used to detect the pressure on the casing. The pressure measuring module 5 uses an optical fiber sensor to detect the pressure on the casing, and the optical fiber sensor is packaged on the casing 2.

[0085] The slip distance measurement module 4 is disposed outside the wellbore simulation system 101 and is used to measure the fault slip distance of the simulated formation 9;

[0086] The flow measurement module 14 is used to measure the flow in the casing pipeline. The flow measurement module 14 is a flow meter that collects and measures the change of the flow in the casing pipeline at a preset time interval.

[0087] The caliper measurement module 15 is arranged on the inner wall of the casing to measure the inner diameter of the casing. The change of the inner diameter of the casing can be measured by continuously collecting data at preset time intervals. For the casing after shear deformation, the caliper measurement module 15 can be used to measure the change of the inner diameter of the casing, and the relationship between the fault slip distance and the change of the inner diameter of the casing can be established by combining the measurement of the fault slip distance. The caliper measurement module 15 can be a multi-arm caliper.

[0088] In one embodiment, the shear deformation parameter includes the degree of casing deformation, referring to Figure 5 As shown, the measurement system 105 further includes a strain measurement module 3 disposed on the outer layer of the casing, for measuring the deformation degree of the casing.

[0089] In one embodiment, the strain measurement module 3 includes a distributed optical fiber sensor and a strain detector connected thereto;

[0090] The distributed optical fiber sensor is encapsulated in the outer layer of the casing, and the strain detector is connected to the strain gauge of the distributed optical fiber sensor. The distributed optical fiber sensor is encapsulated in the outer layer of the casing, and the principle of the distributed optical fiber sensor axial strain monitoring the casing stress downhole and the principle of optical fiber monitoring the casing external pressure are used to complete the online monitoring of casing deformation and casing external pressure through computer data acquisition and processing.

[0091] In one embodiment, referring to Figure 5As shown, the measuring system 105 also includes: an electromagnetic ultrasonic measuring module 16 disposed in the casing, which is used to detect whether cracks appear inside the casing. The module is to bind the excitation coil to the conductive metal. After power is turned on, the coil will generate a corresponding current and form an alternating magnetic field. Through the reaction between the magnetic field and the metal, ultrasonic waves are generated, which can effectively detect whether cracks appear inside the casing 2.

[0092] In one embodiment, the sliding distance measuring module 4 is a DIC measuring device, and the DIC measuring device is installed at a position corresponding to the middle of the sleeve. If the DIC measuring device is set at the end of the sleeve, the position restriction at the end will be more obvious as the spatial motion size is reduced. The DIC measuring device is installed at a position corresponding to the middle of the sleeve to avoid the position restriction effect of the end, so that a more complete image can be obtained.

[0093] The DIC measuring device includes an image acquisition device and a data acquisition processing module. The image acquisition device is connected to the data acquisition processing module. The image acquisition device is used to capture digital images, and the movement of each image point is calculated by the data acquisition processing module. The strain and displacement of the rock are calculated by tracking the movement of each image point to calculate the fault slip distance, laying the foundation for the subsequent establishment of the change in the inner diameter of the casing. The DIC measuring device is installed in addition to the entire fault slip device, i.e., the wellbore simulation system 101 and the displacement load application system 104. The final slip distance of the fault is determined by the simulated rock displacement captured by the high-speed camera. During the test, the side of the entire cement body, i.e., the simulated stratum 9, will be speckled to avoid reflection on the surface of the object to be measured. The spray paint used to make the speckle is matte white paint (primer) and matte black paint (speckle paint). Before spraying, the surface of the object to be measured needs to be cleaned with an organic solvent (alcohol, etc.) to remove the grease on the surface of the object to be measured, thereby improving the adhesion of the speckle on the surface of the object to be measured. The speckle deforms with the object to be measured and is not easy to fall off. The image acquisition device is a high-definition camera. After speckle processing, the high-speed camera will capture the movement process of the entire fault, and then the software will identify the movement distance or deformation size.

[0094] In one embodiment, referring to Figure 6 and Figure 7 As shown, the measuring system 105 also includes a thermometer and a pressure gauge disposed at both ends of the sleeve, which are used to measure the temperature and pressure in the circulation pipeline respectively.

[0095] In one embodiment, referring to Figure 6 and Figure 7 As shown, the device also includes a pressure relief channel connected between the sleeve inlet and the liquid storage tank. When the pressure is too high, the safety valve can be opened to allow the liquid to flow back to the liquid storage tank via the pressure relief pipeline.

[0096] In one embodiment, referring to Figure 6 and Figure 7 As shown, the circulation pipeline and the pressure relief channel are respectively provided with safety valves to avoid accidents caused by excessive pressure. When the pressure is too high, part of the pressure can be released by opening the safety valve.

[0097] In one embodiment, referring to Figure 6 and Figure 7 As shown, the parts of the circulation channel located at both ends of the sleeve are provided with flow meters, and the flow meters are used to measure the flow in the circulation pipeline.

[0098] In the embodiment of the present application, a full-size bridge plug can be used to test whether the deformed casing can allow the bridge plug to pass smoothly, so as to evaluate the impact of the shear deformation of the casing on the actual production increase operation.

[0099] Embodiment 2

[0100] The embodiment of the present invention provides a test method for simulating and evaluating a fault slip shear casing deformation during hydraulic fracturing, comprising:

[0101] First, perform comprehensive initialization preparations on the device. This includes checking the structural firmness and subsequent cement filling, as well as checking whether the hydraulic cylinder 10, safety valve, pressure regulating valve, and various measurement modules are ready. Any problem in any link will trigger an alarm and shutdown mechanism. After the inspection is completed, perform the following steps:

[0102] S201. According to the engineering requirements and the actual mechanical properties of the stratum, the corresponding cement slurry is prepared to ensure that the mechanical properties of the cement slurry after solidification are the same as those of the stratum;

[0103] S202, using a casing with an outer diameter the same as that of the wellbore, pre-set in the displacement load application system 104, pouring the prepared cement slurry between the pre-set casing and the outer frame 11, during the pouring of the cement slurry, uniformly embedding a heating device to apply temperature to the simulated formation 9, and setting a weak surface at the sliding interface of the simulated formation 9;

[0104] S203, after the cement slurry solidifies, the pre-set casing is removed to obtain a wellbore of the same size as the actual project;

[0105] S204, erecting the casing, and adjusting the degree of centering between the casing and the wellbore, simulating different conditions of the casing in the horizontal well section by adjusting the eccentric angle and the eccentric distance; pasting strain gauges and temperature sensors on the outer wall of the erected casing to measure the casing temperature change during the test and the casing strain during the fault slip process;

[0106] S205. Inject the prepared cement slurry into the annulus between the casing and the wellbore. During the injection process, use a heating device to heat the simulated formation 9 and pressurize the annular fluid to form a casing-cement ring-simulated formation 9 combination system. During the injection of cement slurry, the annular fluid is pressurized to ensure that high temperature and high pressure maintenance is achieved during the process of the cement slurry solidifying into the cement ring, and finally a casing-cement ring-simulated formation 9 combination system is formed. On this basis, the liquid storage tank, pressure regulating valve, thermometer, pressure gauge, flow meter, circulation pipeline, pressure relief pipeline, etc. are connected in sequence to form a complete simulation device, refer to Figure 6 After the simulation device is installed, perform the following operations:

[0107] S206, turning on the heating device in the simulated formation 9 and heating it to the temperature of the simulated formation 9;

[0108] S207, start the water pump, adjust the water pump to the same displacement as the actual fracturing project, and use the measurement system 105 to measure the parameters of the casing, cement ring, and simulated formation 9 during the process;

[0109] S208, start the displacement load application system 104, push the fault to slide along the weak plane according to the test requirements, and use the measurement system 105 to capture the fault sliding process; refer to Figure 8 As shown, the upward movement of the device causes shear deformation of the casing.

[0110] S209 , after the test is completed, the shear deformation parameters of the casing after shear deformation are measured by the measuring system 105 .

[0111] When all the above work is completed, the hydraulic cylinder 10 pushes the moving mechanism 6 to reset, the device stops running, and then subsequent work such as disassembling the cement ring and casing is carried out.

[0112] In one embodiment, the shear deformation parameter in the above step S209 includes the inner diameter of the casing, and the inner diameter of the casing is measured in the following manner:

[0113] A multi-arm caliper was used to measure the inner diameter of the casing after shear deformation. At the same time, bridge plugs of different specifications were used for testing to determine whether the bridge plugs could pass through the deformed position.

[0114] In one embodiment, the method described in step S208 includes using a DIC measurement device to capture the fault slip process, thereby laying a foundation for subsequent DIC analysis.

[0115] In one embodiment, the method further comprises:

[0116] Adjust the cement slurry formula to change the mechanical properties of the simulated formation 9, change the cement slurry formula to change the mechanical properties of the cement sheath, control the heating device in the simulated formation 9 to change the temperature of the simulated formation 9, select different specifications of casing to change the parameters of the casing, change the pumping parameters of the water pump to change the pump pressure and displacement, and control the displacement load application system 104 to change the fault slip distance to obtain the change of the inner diameter of the casing under different engineering and geological parameters. Through the above technical scheme, it is realized to monitor and evaluate the shear deformation of the horizontal casing under the formation caused by various factors during the hydraulic fracturing process under real working conditions. It can simulate the shear deformation of the casing under different circulating pipe pressures, different formation slip distances, different casing specifications, different formation temperatures, and different rock strengths, measure the change of the inner diameter of the casing after shear deformation, and use a full-size bridge plug to test whether the deformed casing can allow the bridge plug to pass smoothly, so as to evaluate the impact of the shear deformation of the casing on the actual production increase operation. It can provide a basis for the optimization of casing specifications and provide technical support for the prevention and control of casing deformation problems. On this basis, relevant equipment is developed so that after simple training of on-site technicians, the method can be used to detect and control the shear deformation of the wellbore casing, so that the casing shear deformation simulation and analysis device can truly serve on-site drilling and completion operations, and escort the completion and production increase operations of oil and gas wells, which has certain engineering significance.

[0117] In one embodiment, the method further comprises: during the test, starting the pressure measurement module 5 and the strain measurement module 3 to detect the pressure on the casing and the degree of deformation of the casing.

[0118] In one embodiment, the method further comprises: starting the electromagnetic ultrasonic measuring module 16 to detect whether the casing is damaged or broken.

[0119] In one embodiment, the method further comprises: measuring the flow rate in the circulation channel by means of a flow measurement module 14 .

[0120] In one embodiment, the method further includes: during the test, adjusting and controlling the pressure of the circulation pipeline by means of a pressure regulating valve and a safety valve, and when the pressure of the circulation pipeline is greater than a preset pressure value, opening the safety valve to allow the fracturing fluid to flow back to the fluid storage tank via the pressure relief pipeline.

[0121] In one embodiment, before using a casing with an outer diameter the same as that of the wellbore and pre-setting it in the displacement load application system 104, the method further includes: coating the outer wall of the pre-set casing with butter to facilitate stripping after the cement slurry solidifies.

[0122] In the embodiment of the present invention, the test method of the device for simulating and evaluating the deformation of fault slip shear casing during hydraulic fracturing corresponds to the device for simulating and evaluating the deformation of fault slip shear casing during hydraulic fracturing described in the above-mentioned embodiment 1. The specific implementation process can refer to the description of the device for simulating and evaluating the deformation of fault slip shear casing during hydraulic fracturing in the above-mentioned embodiment 1, and the repeated parts will not be repeated here.

[0123] In this document, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. The orientation or position relationship indicated by the terms "upper", "lower", etc. is based on the orientation or position relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0124] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. The present invention is not limited to any single aspect, any single embodiment, or any combination and / or permutation of these aspects and / or embodiments. Each aspect and / or embodiment of the present invention can be used alone, or in combination with one or more other aspects and / or other embodiments.

[0125] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing, characterized in that: include: Wellbore simulation system, fluid circulation system, heating system, displacement load application system and measurement system; The wellbore simulation system includes a casing and an outer frame arranged outside the casing, and the outer frame outside the casing is poured with cement to form a simulated formation to simulate the cement ring and rock mass around the casing under actual engineering conditions; The fluid circulation system comprises a liquid storage tank, a pressure regulating valve and a water pump. The liquid storage tank, the water pump and the casing are connected through a circulation pipeline, and the pressure regulating valves are respectively provided at both ends of the casing; The heating system includes a heating device embedded in the simulated formation; The displacement load application system comprises a fixing mechanism, a moving mechanism and a hydraulic cylinder, wherein the fixing mechanism is connected to the outer frame, and the hydraulic cylinder is connected to the moving mechanism, and is used to push the fault of the simulated formation to slide along the weak surface, so that the casing is subjected to shear deformation; The measurement system is arranged outside the wellbore simulation system to capture fault slip parameters, and is arranged inside or outside the casing to collect shear deformation parameters of the casing.

2. The device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to claim 1, characterized in that: The fault slip parameters include fault slip distance, and the shear deformation parameters include temperature, casing pressure, casing flow rate, and casing inner diameter; The measurement system includes a temperature measurement module, a pressure measurement module, a slip distance measurement module, a flow measurement module and a well diameter measurement module; The temperature measurement module includes a thermocouple and a temperature control instrument laid on the casing wall, wherein the thermocouple is connected to the temperature control instrument and is used to measure the casing temperature; The pressure measuring module is arranged on the outer wall of the casing and is used to detect the pressure on the casing; The slip distance measurement module is arranged outside the wellbore simulation system and is used to measure the fault slip distance of the simulated formation according to the pressure measurement module; The flow measurement module is used to measure the flow in the casing pipeline; The well diameter measurement module is arranged on the inner wall of the casing and is used to measure the inner diameter of the casing.

3. The device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to claim 1, characterized in that: The shear deformation parameter includes the degree of deformation of the casing, and the measurement system further includes a strain measurement module arranged on the outer layer of the casing, for measuring the degree of deformation of the casing.

4. The device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to claim 3, characterized in that: The strain measurement module includes a distributed optical fiber sensor and a strain detector connected thereto; The distributed optical fiber sensor is packaged in the outer layer of the casing, and the strain detector is connected to the strain gauge of the distributed optical fiber sensor.

5. The device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to claim 1, characterized in that: The measuring system further comprises: an electromagnetic ultrasonic measuring module arranged in the casing, for detecting whether cracks appear inside the casing.

6. The device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to claim 2, characterized in that: The slip distance measuring module is a DIC measuring device, and the DIC measuring device is installed at a position corresponding to the middle of the sleeve.

7. The device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to claim 2, characterized in that: The caliper measurement module is a multi-arm caliper.

8. The device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to claim 2, characterized in that: The measuring system further comprises a thermometer and a pressure gauge arranged at both ends of the sleeve, which are used to measure the temperature and pressure in the circulation pipeline respectively.

9. The device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to claim 1, characterized in that: The device also includes a pressure relief channel connected between the sleeve inlet and the liquid storage tank.

10. The device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to claim 9, characterized in that: The circulation pipeline and the pressure relief channel are respectively provided with safety valves.

11. The device for simulating and evaluating fault slip shear casing deformation during hydraulic fracturing according to claim 1, characterized in that: The parts of the circulation channel located at both ends of the sleeve are provided with flow meters.

12. A test method for the fault slip shear casing deformation simulation and evaluation device during hydraulic fracturing according to any one of claims 1 to 11, characterized in that: include: Prepare corresponding cement slurry according to engineering requirements and actual formation mechanical properties; A casing with an outer diameter the same as that of the wellbore is used and pre-set in the displacement load application system, and the prepared cement slurry is poured between the pre-set casing and the outer frame. During the pouring of the cement slurry, a heating device is evenly embedded to apply temperature to the simulated formation, and a weak surface is set at the slip interface of the simulated formation. After the cement slurry solidifies, the pre-set casing is removed to obtain a wellbore of the same size as the actual project; Install casing and adjust the centering degree between casing and wellbore. By adjusting the eccentric angle and eccentricity, simulate the different conditions of casing in horizontal well section. Injecting the prepared cement slurry into the annulus between the casing and the wellbore, using a heating device to heat the simulated formation during the injection process, and pressurizing the annular fluid to form a casing-cement annulus-simulated formation combination system; Turning on the heating device in the simulated formation and heating it to the simulated formation temperature; Start the water pump and adjust it to the same displacement as the actual fracturing project. Use the measurement system to measure the parameters of the casing, cement sheath, and simulated formation during the process. Start the displacement load application system, push the fault to slide along the weak plane according to the test requirements, and use the measurement system to capture the fault sliding process; After the test is completed, the shear deformation parameters of the casing after shear deformation are measured by the measuring system.

13. The test method of the fault slip shear casing deformation simulation and evaluation device during hydraulic fracturing according to claim 12, characterized in that: The shear deformation parameter includes the inner diameter of the casing, which is measured in the following manner: A multi-arm caliper was used to measure the inner diameter of the casing after shear deformation. At the same time, bridge plugs of different specifications were used for testing to determine whether the bridge plugs could pass through the deformed position.

14. The test method of the fault slip shear casing deformation simulation and evaluation device during hydraulic fracturing according to claim 12, characterized in that: The method includes using a DIC measurement device to capture the fault slip process.

15. The test method of the fault slip shear casing deformation simulation and evaluation device during hydraulic fracturing according to claim 12, characterized in that: The method further comprises: Adjust the cement slurry formula to change the mechanical properties of the simulated formation, change the cement slurry formula to change the mechanical properties of the cement sheath, control the heating device in the simulated formation to change the simulated formation temperature, select casing of different specifications to change the casing parameters, change the pumping parameters of the water pump to change the pump pressure and displacement, control the displacement load application system to change the fault slip distance, so as to obtain the change of casing inner diameter under different engineering and geological parameters.

16. The test method of the fault slip shear casing deformation simulation and evaluation device during hydraulic fracturing according to claim 12, characterized in that: The method further comprises: during the test, starting the pressure measurement module and the strain measurement module to detect the pressure on the casing and the degree of deformation of the casing.

17. The test method of the fault slip shear casing deformation simulation and evaluation device during hydraulic fracturing according to claim 12, characterized in that: The method further comprises: starting the electromagnetic ultrasonic measuring module to detect whether the casing is damaged or broken.

18. The test method of the fault slip shear casing deformation simulation and evaluation device during hydraulic fracturing according to claim 12, characterized in that: The method further includes: measuring the flow rate in the circulation channel by using a flow measurement module.

19. The test method of the fault slip shear casing deformation simulation and evaluation device during hydraulic fracturing according to claim 12, characterized in that: The method further includes: during the test, adjusting and controlling the pressure of the circulation pipeline by means of a pressure regulating valve and a safety valve, and when the pressure of the circulation pipeline is greater than a preset pressure value, opening the safety valve to allow the fracturing fluid to flow back to the fluid storage tank via the pressure relief pipeline.

20. The test method of the fault slip shear casing deformation simulation and evaluation device during hydraulic fracturing according to claim 12, characterized in that: Before using a casing with an outer diameter the same as that of the wellbore and presetting it in the displacement load application system, the method further comprises: coating the outer wall of the pre-set casing with butter.

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