High temperature and high pressure crack regulator, plugging evaluation experimental device and experimental method

Abstract

The present invention provides a high-temperature and high-pressure crack regulator, a plugging evaluation experimental device and an experimental method, wherein the regulator comprises a plugging unit, the plugging unit comprises a shell and a crack regulation component, the shell is provided with a first chamber, a second chamber, a first drainage hole, a second drainage hole and a third drainage hole, wherein the first drainage hole can connect the first chamber with the outside, the second drainage hole can connect the first and second chambers, and the third drainage hole can connect the second chamber with the outside; the crack regulation component is installed in the second chamber, comprises an upper and lower fixed block and an adjustment block, the adjustment block is arranged between the upper and lower fixed blocks, a crack can be formed between the adjustment block and the lower fixed block, the crack is connected with the second and third drainage holes, the adjustment block can move up and down along the axial direction to adjust the width of the crack, the fluid pressure increases and the crack opens, and the fluid pressure decreases and the crack closes, thereby realizing the simulation of the plugging process of pressure-sensitive induced fracture leakage and extended fracture leakage.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas well leakage simulation experiments, and in particular to a high-temperature and high-pressure crack regulator, a plugging evaluation experimental device and an experimental method. Background Art

[0002] Well leakage is a phenomenon in which working fluid (including drilling fluid, cement slurry, completion fluid and other fluids) leaks into the formation under the action of positive pressure difference during various downhole operations such as drilling, cementing, testing, completion or repair. Drilling fluid leakage is a common downhole complex situation in drilling operations. Most drilling processes have different degrees of leakage, causing huge economic losses and non-productive time. Severe well leakage will cause the pressure in the well to drop, affecting normal drilling, causing wellbore instability, inducing formation fluid to flow into the wellbore and causing blowouts. Fractures are the main leakage channels. The most commonly used indoor plugging evaluation method is to evaluate the plugging effect of plugging materials by simulating formation fractures. In addition to natural fractures, induced fractures and extended fractures that open, expand, extend and close with changes in wellbore pressure are also important leakage channels. The pressure-sensitive nature of induced fractures and extended fractures brings great challenges to indoor plugging evaluation.

[0003] Existing indoor plugging test devices mostly use small core columns or flat cracks to simulate crack leakage channels, such as a full-diameter high-pressure intelligent plugging tester with application number 201420156814X, whose booster pump, intermediate container, core clamping device, and condenser are connected in series by connecting pipelines; wherein, the intermediate container is a piston structure, a first control valve is arranged between the intermediate container and the core clamping device, a second control valve is arranged downstream of the core clamping device, a third control valve is arranged between the first control valve and the core clamping device, and heating devices are arranged in the intermediate container and the core clamping device respectively. The intermediate container is connected to a stirrer, which can effectively prevent the plugging particles in the experimental fluid from precipitating; the core clamping device is provided with a core clamp heating sleeve, which can heat and simulate various formation temperatures, and conduct plugging evaluation on artificial cores or natural cores with a diameter of 100 mm.

[0004] The above-mentioned full-diameter high-pressure intelligent plugging tester patent uses rock cores to conduct plugging experiments. However, the plugging experiments are smaller in size than the actual fracture leakage channels and cannot truly reflect the dynamic changes in the fracture width, which seriously affects the dynamic simulation of leakage and the accurate evaluation of plugging materials, resulting in inconsistencies between indoor experimental results and on-site plugging effects.

[0005] A gap simulation mechanism, a crack simulation test instrument and a plugging evaluation experimental device with application number CN2020112522652 disclose a gap simulation mechanism, a crack simulation test instrument and a plugging evaluation experimental device, wherein the gap simulation mechanism includes a rock sample, a fixed plate, two crack plates, multiple sets of springs and a sealing rubber sleeve. When the plugging slurry enters the hollow groove of the rock sample from the liquid inlet channel of the gap simulation mechanism, the plugging slurry enters the chamfered corners at the top of the two crack plates, opens the two crack plates and rotates to both sides around the fixed plate to dynamically simulate the pore cracking process.

[0006] The above patent simulates the process of plugging leaks with variable cracks by cooperating with two seam plates and a spring. However, the variable pressure-bearing method of the cracks in the experimental device is a spring, and the detection is prone to errors and lacks accuracy. In addition, the patent can only perform limited detection of pressure-bearing capacity, and the research impact is limited.

[0007] In summary, the existing conventional plugging tester realizes the dynamic change behavior of cracks through springs, the change is single, and it is inconvenient to detect pressure data; it cannot effectively simulate the characteristic behavior of induced cracks and extended cracks opening and closing with the change of wellbore pressure, and there are experimental limitations such as the original absence of cracks and the inability to monitor the crack width in real time; in addition, the conventional experimental device only considers the positive plugging and pressure-bearing process of the crack, and no backflow experimental device is designed. There is a lack of reverse pressure-bearing test operations in the backflow process and normal pressure-bearing test operations in the crack closing process, and it is impossible to simulate the stress and pressure state of the plugging layer under real working conditions, and it is impossible to realize the quantitative evaluation of the three-way pressure-bearing capacity of the plugging material to plug the crack. Summary of the invention

[0008] The purpose of the present invention is to solve at least one of the above-mentioned deficiencies in the prior art. For example, one of the purposes of the present invention is to provide a high temperature and high pressure crack regulator, a plugging evaluation experimental device and an experimental method.

[0009] In order to achieve the above-mentioned purpose, the present invention provides a high-temperature and high-pressure crack regulator, including a pressurized injection unit and a plugging unit, wherein the plugging unit includes a shell and a crack regulation component, and the shell is provided with a first chamber and a second chamber that are connected vertically, and a first drainage hole, a second drainage hole and a third drainage hole that are connected horizontally, wherein the first drainage hole can connect the first chamber with the outside world, the second drainage hole can connect the first and second chambers, and the third drainage hole can connect the second chamber with the outside world; the crack regulation component is installed in the second chamber, It includes an upper fixed block, a lower fixed block and an adjusting block, wherein the adjusting block is arranged between the upper fixed block and the lower fixed block, a crack can be formed between the adjusting block and the lower fixed block, the crack is connected with the second and third drainage holes, and the adjusting block can move up and down along the axis of the second chamber to adjust the width of the crack; the pressurized injection unit includes a cylinder and a piston, the piston is penetrated in the cylinder, the lower end of the cylinder is fixedly connected to the upper end of the shell, so that the inner cavity of the cylinder is connected with the first chamber, and the piston can move downward along the axis of the cylinder to press the plugging slurry into the first chamber, the second drainage hole and the crack.

[0010] Optionally, the regulator may further include a stirring unit, which may be fixedly connected to the lower end of the shell and include stirring blades, which may extend into the first chamber and the cylinder to stir the plugging slurry.

[0011] Optionally, the crack adjustment assembly may further include an adjustment rod, the lower end of which is fixedly connected to the adjustment block, the upper end of which passes through the upper fixed block and extends above the shell, and the adjustment rod can control the up and down movement of the adjustment block.

[0012] Optionally, the leak-stopping unit may further include an upper pressure cover and a lower pressure cover, wherein the upper pressure cover is fixedly connected to the upper end of the upper fixing block, and the lower pressure cover is fixedly connected to the lower end of the lower fixing block.

[0013] Optionally, the leak-plugging unit may further include a left end cover and a right end cover, which are respectively fixedly connected to the left and right sides of the shell, and are respectively provided with a first connecting hole and a second connecting hole that pass through the left and right sides, the first connecting hole is connected to the first drainage hole, and the second connecting hole is connected to the third drainage hole.

[0014] Optionally, the pressurized liquid injection unit may further include a heating ring, which is sleeved on the outside of the cylinder to heat the plugging slurry in the cylinder.

[0015] Optionally, the plugging unit may further include a heating plate installed on the outside of the shell to heat the cracks and the plugging slurry in the cracks to simulate a high temperature underground environment.

[0016] On the other hand, the present invention provides a plugging evaluation experimental device, including the high-temperature and high-pressure crack regulator, a forward injection metering unit and a reverse injection metering unit as described above, the forward injection metering unit is connected to the pressurized injection unit through a pipeline, and the reverse injection metering unit is connected to the plugging unit through a pipeline; the forward injection metering unit includes a first liquid storage tank, a first intermediate container, a horizontal flow pump and a sealed measuring cylinder connected in sequence, wherein the sealed measuring cylinder can measure the amount of plugging slurry injected into the pressurized injection unit.

[0017] Optionally, the reverse injection metering unit may include an injection component and a metering component, the injection component includes a second liquid storage tank, a second intermediate container, an injection pump and a piston container connected in sequence, the injection component can reversely press the liquid into the plugging unit to measure the reverse pressure bearing capacity of the plugging unit;

[0018] The metering assembly is connected to the piston container and comprises a connected measuring cup and a balance, and the metering assembly is capable of measuring volume and weight parameters of the liquid flowing into the piston container.

[0019] Optionally, the experimental device may further include a constant speed pump connected to the upper fixed block, and the constant speed pump can continuously and uninterruptedly supply liquid to the plugging unit to keep the pressure in the plugging unit constant.

[0020] Optionally, the experimental device may also include a parameter measuring unit, which includes a first temperature sensor, a second temperature sensor, a first pressure gauge, a second pressure gauge and a third pressure gauge, wherein the first temperature sensor is connected to the cylinder to measure the temperature of the plugging slurry in the cylinder, and the second temperature sensor is connected to the plugging unit to measure the temperature of the plugging slurry in the plugging unit; the first pressure gauge is connected between the forward injection metering unit and the pressurized injection unit to detect the plugging pressure; the second pressure gauge is connected to the piston container to detect the return pressure; the third pressure gauge is connected to the constant speed pump to detect the driving pressure of the constant speed pump.

[0021] Optionally, the experimental device may further include a pressure control unit, which includes a first valve, a second valve and a third valve, wherein the first valve is arranged between the forward injection metering unit and the pressurized injection unit, and the injection pressure from the forward injection metering unit to the pressurized injection unit can be adjusted by controlling the opening of the first valve; the second valve is arranged between the injection pump and the piston container, and the injection pressure from the injection pump to the piston container can be adjusted by controlling the opening of the second valve; the third valve is arranged between the piston container and the metering component, and the injection pressure from the piston container to the metering component can be adjusted by controlling the opening of the third valve.

[0022] Optionally, the experimental device may further include a data acquisition system, and the forward liquid injection metering unit, the reverse liquid injection metering unit and the parameter measurement unit are all connected to the data acquisition system, and the data acquisition system can collect the measurement data of each unit and perform analysis and processing.

[0023] On the other hand, the present invention provides a plugging evaluation experimental method, which uses the plugging evaluation experimental device as described above to conduct experiments. The experimental method includes injecting the plugging slurry in the forward injection metering unit into the high-temperature and high-pressure crack regulator by adjusting the first valve, and measuring the injection pressure and temperature parameters at the same time; injecting the plugging slurry leaked from the high-temperature and high-pressure crack regulator into the piston container, converting the plugging slurry with solid plugging material into a liquid that is easy to measure through the piston container, and adjusting the third valve to inject the liquid in the piston container into the metering component to measure the weight and volume parameters; by adjusting the second valve, the fluid in the injection component is reversely pressed into the plugging unit, and measuring the reverse pressure-bearing temperature and pressure parameters of the plugging unit; transmitting the above-mentioned measurement parameters to the data acquisition system for analysis and processing.

[0024] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0025] 1) The present invention forms a variable width fracture with fluid pressure response characteristics through the coupling of a constant speed pump, a movable adjustment block and a dynamic fracture. Under the condition of simulating the change of fluid pressure in the wellbore, the fracture width is automatically adjusted. When the fluid pressure increases, the fracture opens, and when the fluid pressure decreases, the fracture closes, thereby simulating the plugging process of induced fracture leakage and extended fracture leakage with pressure sensitivity;

[0026] 2) The present invention can realize the functions of forward pressurization and reverse pressurization of wellbore cracks by adjusting the injection pressure. Reverse pressurization of cracks can be achieved through the backflow system, simulating the forward plugging, crack closure pressure and backflow pressure stages in the plugging process, and realizing quantitative evaluation of the three-way pressure bearing capacity of plugging materials for plugging cracks, which is more in line with the influence of real wellbore pressure fluctuations on the crack plugging effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects and / or features of the present invention will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0028] Figure 1 A schematic structural diagram of a high-temperature and high-pressure crack regulator according to an exemplary embodiment of the present invention is shown.

[0029] Figure 2 A schematic diagram of a shell in a high-temperature and high-pressure crack regulator according to an exemplary embodiment of the present invention is shown.

[0030] Figure 3 A top view of a high-temperature and high-pressure fracture conditioner according to an exemplary embodiment of the present invention is shown.

[0031] Figure 4 A schematic diagram of a leak plugging evaluation experimental device according to an exemplary embodiment of the present invention is shown.

[0032] Description of reference numerals:

[0033] A-High temperature and high pressure crack regulator;

[0034] 1- pressurized liquid injection unit, 11- cylinder, 12- piston, 13- plug, 14- pressure cap, 15- dead plug, 16- heating coil;

[0035] 2-leakage plugging unit, 21-shell, 211-first chamber, 212-second chamber, 213-first drainage hole, 214-second drainage hole, 215-third drainage hole, 22-crack adjustment assembly, 221-upper fixed block, 222-lower fixed block, 223-adjustment block, 224-adjustment rod, 225-crack, 23-upper pressure cover, 24-lower pressure cover, 25-left end cover, 251-first communication hole, 26-right end cover, 261-second communication hole, 27-heating plate;

[0036] 3-stirring unit, 31-stirring blade;

[0037] 4-forward injection metering unit, 41-first liquid storage tank, 42-first intermediate container, 43-advection pump, 44-sealed measuring cylinder;

[0038] 5-reverse injection metering unit, 51-injection assembly, 511-second liquid storage tank, 512-second intermediate container, 513-injection pump, 514-piston container, 52-metering assembly, 521-measuring cup, 522-balance;

[0039] 6-Constant speed pump;

[0040] 7- parameter measurement unit, 71- first temperature sensor, 72- second temperature sensor, 73- first pressure gauge, 74- second pressure gauge, 75- third pressure gauge;

[0041] 8-pressure control unit, 81-first valve, 82-second valve, 83-third valve, 84-back pressure valve, 85-drain valve;

[0042] 9-Data acquisition system. DETAILED DESCRIPTION

[0043] Hereinafter, the high-temperature and high-pressure crack regulator, the plugging evaluation experimental device and the experimental method of the present invention will be described in detail in conjunction with exemplary embodiments.

[0044] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0045] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0046] In the description of this application, 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 direct connection, or an indirect connection 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.

[0047] In the related technology, the dynamic change behavior of cracks is realized by springs in conventional plugging testers, the changes are single, and it is inconvenient to detect pressure data; it cannot effectively simulate the characteristic behavior of induced cracks and extended cracks opening and closing with the change of wellbore pressure, and there are experimental limitations such as the original absence of cracks and the inability to monitor the crack width in real time; in addition, the conventional experimental device only considers the positive plugging and pressure-bearing process of the crack, and no backflow experimental device is designed. There is a lack of reverse pressure-bearing test operations in the backflow process and normal pressure-bearing test operations in the crack closing process, and it is impossible to simulate the stress and pressure state of the plugging layer under real working conditions, and it is impossible to realize the quantitative evaluation of the three-way pressure-bearing capacity of the plugging material to plug the crack.

[0048] Based on this, the present invention provides a high-temperature and high-pressure crack regulator and a plugging evaluation experimental device, wherein the high-temperature and high-pressure crack regulator includes a pressurized injection unit and a plugging unit, wherein the plugging unit includes a shell and a crack regulation component, and the shell is provided with a first chamber and a second chamber that are vertically connected, and a first drainage hole, a second drainage hole and a third drainage hole that are horizontally connected, wherein the first drainage hole can connect the first chamber with the outside world, the second drainage hole can connect the first and second chambers, and the third drainage hole can connect the second chamber with the outside world; the crack regulation component is arranged It is installed in the second chamber, including an upper fixed block, a lower fixed block and an adjusting block. The adjusting block is arranged between the upper fixed block and the lower fixed block. A crack can be formed between the adjusting block and the lower fixed block. The crack is connected with the second and third drainage holes. The adjusting block can move up and down along the axis of the second chamber to adjust the width of the crack; the pressurized injection unit includes a cylinder and a piston. The piston is inserted into the cylinder. The lower end of the cylinder is fixedly connected to the upper end of the shell so that the inner cavity of the cylinder is connected with the first chamber. The piston can move downward along the axis of the cylinder to press the plugging slurry into the first chamber, the second drainage hole and the crack.

[0049] The plugging evaluation experimental device includes the above-mentioned high-temperature and high-pressure crack regulator, a forward injection metering unit and a reverse injection metering unit. The forward injection metering unit is connected to the pressurized injection unit through a pipeline, and includes a first liquid storage tank, a first intermediate container, a horizontal flow pump and a sealed measuring cylinder connected in sequence, wherein the sealed measuring cylinder can measure the amount of plugging slurry injected into the pressurized injection unit. The reverse injection metering unit is connected to the plugging unit through a pipeline, and includes an injection component and a metering component. The injection component includes a second liquid storage tank, a second intermediate container, an injection pump and a piston container connected in sequence. The injection component can reversely press the liquid into the plugging unit to measure the reverse pressure bearing capacity of the plugging unit; the metering component is connected to the piston container, including a connected measuring cup and a balance, and the metering component can measure the volume and weight parameters of the liquid flowing into the piston container.

[0050] The present invention forms a variable-width crack with fluid pressure response characteristics through a constant-speed pump, a movable adjustment block and a dynamic crack coupling. Under the condition of simulated fluid pressure changes in a wellbore, the crack width is automatically adjusted. When the fluid pressure increases, the crack opens, and when the fluid pressure decreases, the crack closes, thereby realizing the simulation of the plugging process of pressure-sensitive induced fracture leakage and extended fracture leakage. The present invention can realize the functions of forward pressurization of wellbore fractures and reverse pressurization of fractures by adjusting the injection pressure, and can realize reverse pressurization of fractures through a backflow system, simulating the forward plugging, fracture closure pressure bearing and backflow pressure bearing stages in the plugging process, thereby realizing quantitative evaluation of the three-way pressure bearing capacity of plugging materials for plugging fractures, which is more in line with the influence of real wellbore pressure fluctuations on the crack plugging effect.

[0051] Exemplary Embodiment 1

[0052] The present exemplary embodiment provides a high temperature and high pressure crack regulator.

[0053] Figure 1 A schematic diagram of the structure of a high-temperature and high-pressure crack regulator according to an exemplary embodiment of the present invention is shown. Figure 2 A schematic diagram showing a shell in a high-temperature and high-pressure crack regulator according to an exemplary embodiment of the present invention is shown. Figure 3 A top view of a high-temperature and high-pressure fracture conditioner according to an exemplary embodiment of the present invention is shown.

[0054] like Figures 1 to 3 As shown in the figure, the high-temperature and high-pressure crack regulator described in this exemplary embodiment may include a pressurized liquid injection unit 1, a leak-plugging unit 2 and a stirring unit 3, wherein the leak-plugging unit 2 may include a shell 21, a crack adjustment component 22, an upper pressure cover 23, a lower pressure cover 24, a left end cover 25, a right end cover 26 and a heating plate 27, and the pressurized liquid injection unit 1 may include a cylinder 11, a piston 12, a plug 13, a pressure cap 14, a dead plug 15 and a heating coil 16.

[0055] In this embodiment, the housing 21 may be provided with a first chamber 211 and a second chamber 212, the first chamber 211 and the second chamber 212 respectively pass through the upper and lower sides of the housing 21, and the axes of the first chamber 211 and the second chamber 212 are parallel to each other and extend in the radial direction (i.e. Figure 1 The cylinder 11 and the shell 21 are spaced apart from each other by a distance (in a direction perpendicular to the axis), and the lower end of the cylinder 11 can be inserted into the upper end of the first chamber 211 and fixedly connected to the shell 21 by threaded fitting, but the present invention is not limited thereto, and the cylinder 11 and the shell 21 can also be welded, integrally formed or otherwise fixedly connected.

[0056] Furthermore, the cylinder 11 can be a hollow cylindrical structure, and the piston 12 can be a cylindrical structure with a certain height. The piston 12 is inserted into the cylinder 11, and its outer diameter matches the inner diameter of the cylinder 11. The piston 12 can move up and down along the axis of the cylinder 11. The inner cavity of the cylinder 11 is connected to the first chamber 211. When the piston 12 moves downward, the fluid in the cylinder 11 can be pressed into the first chamber 211, but the present invention is not limited to this. The cylinder 11 can also be a square cylinder, an elliptical cylinder or other shaped cylindrical structure, and the piston 12 can also be a square column, an elliptical column or other shaped column structure, as long as the outer wall of the piston 12 matches the inner wall of the cylinder 11.

[0057] Furthermore, a through hole extending from top to bottom may be opened on the piston 12, and a dead plug 15 may be inserted into the through hole to block the through hole. When the piston 12 is installed into the cylinder 11, the dead plug 15 needs to be removed from the through hole so that the piston has the function of ventilation up and down, which is convenient for the installation of the piston 12. When the piston 12 is used to press down the fluid in the cylinder 11, the dead plug 15 needs to be inserted into the through hole to block the through hole so that the fluid is always kept below the piston 12; a threaded blind hole is opened in the axial direction on the upper end face of the piston 12 to facilitate the screw to be screwed into the threaded blind hole to facilitate the loading and unloading of the piston 12.

[0058] Furthermore, a plug 13 and a pressure cap 14 are installed at the upper end of the cylinder 11. The plug 13 is inserted into the upper end of the cylinder 11 and keeps the relative position with the cylinder 11 fixed. The pressure cap 14 is sleeved outside the upper end of the cylinder 11 and is fixedly connected with the cylinder 11 by threads. The plug 13 and the pressure cap 14 are fixedly connected by a clamping ring provided at the upper end of the pressure cap 14. The plug 13 is provided with a through hole that passes through from top to bottom, and the fluid can flow into the cylinder 11 from the outside along the through hole. However, the present invention is not limited to this. The pressure cap 14 and the cylinder 11 can also be fixedly connected by other means such as screws or bolts, and the pressure cap 14 and the plug 13 can also be fixedly connected by other means such as threads, screws or bolts.

[0059] During the installation of the pressurized injection unit 1, the lower end of the cylinder 11 is first screwed into the upper end of the first chamber 211 to fix the cylinder 11 to the shell 21, and then the piston 12 is pressed in from the upper end of the cylinder 11, and finally the plug 13 and the pressure cap 14 are installed on the upper end of the cylinder 11.

[0060] Furthermore, a heating coil 16 is sleeved on the outer side of the cylinder 11. The heating coil 16 is made of a metal resistance wire. The heating coil 16 can heat the fluid in the cylinder 11, thereby simulating the situation in which the plugging slurry is heated during the process of entering the wellbore in an actual plugging operation. However, the present invention is not limited to this. The heating coil 16 can also be any other form of heating device besides the metal resistance wire, as long as it can heat the fluid in the cylinder 11.

[0061] In this embodiment, the stirring unit 3 is installed at the lower end of the shell 21, and the upper end thereof is threadedly inserted into the first chamber 211, thereby being fixedly connected to the shell 21. The stirring unit 3 includes a stirring blade 31 and a motor. The stirring blade 31 can extend upward along the first chamber 211 into the cylinder 11, and stir the fluid in the cylinder 11 under the drive of the motor to avoid sedimentation and stratification of the fluid in the cylinder 11 due to long-term static state.

[0062] In this embodiment, the crack adjustment assembly 22 is installed in the second chamber 212, and includes an upper fixed block 221, a lower fixed block 222, an adjustment block 223 and an adjustment rod 224. The upper fixed block 221, the lower fixed block 222 and the adjustment block 223 are all penetrated in the second chamber 212. The upper fixed block 221 and the lower fixed block 222 are respectively located at the upper and lower ends of the second chamber 212, and are separated from each other by a distance along the axial direction of the second chamber 212.

[0063] Furthermore, the upper end of the upper fixing block 221 (that is, the upper end of the shell 21) is fixedly connected to the upper pressure cover 23 by bolts, and the upper pressure cover 23 can keep the upper fixing block 221 fixed in the second chamber 212 relative to the shell 21; the lower end of the lower fixing block 222 (that is, the lower end of the shell 21) is fixedly connected to the lower pressure cover 24 by bolts, and the lower pressure cover 24 can keep the lower fixing block 222 fixed in the second chamber 212 relative to the shell 21, but the present invention is not limited to this, and the fixed connection between the upper fixing block 221, the lower fixing block 222 and the shell 21 can also be achieved by other fixed connection methods such as expansion connection, welding, and one-piece molding.

[0064] Furthermore, the adjustment block 223 is located between the upper fixed block 221 and the lower fixed block 222; the distance between the upper fixed block 221 and the lower fixed block 222 is greater than the height dimension of the adjustment block 223, so the adjustment block 223 can move up and down between the upper fixed block 221 and the lower fixed block 222, and a crack 225 is formed between the adjustment block 223 and the lower fixed block 222, and the width dimension of the crack 225 can change with the up and down movement of the adjustment block 223.

[0065] Furthermore, the adjusting rod 224 is fixedly connected to the adjusting block 223 by threads, and the adjusting rod 224 can pass through the upper fixing block 221 and the upper pressure cover 23 and extend to the shell 21. By pulling the adjusting rod 224 up and down, the adjusting block 223 can be moved to adjust the width of the crack 225, but the present invention is not limited to this. The adjusting rod 224 and the adjusting block 223 can also be fixedly connected by other methods such as welding, expansion joint, integral molding, etc., and the adjusting block 223 can also be moved up and down by setting other forms of adjustment mechanisms, which is not limited to setting one form of adjusting rod 224.

[0066] Furthermore, a first drainage hole 213, a second drainage hole 214 and a third drainage hole 215 are provided in the middle of the shell 21 along the radial direction of the first chamber 211 and the second chamber 212 (that is, perpendicular to the axial direction of the cylinder 11), and the left and right ends of the first drainage hole 213 are respectively connected to the left side of the shell 21 and the first chamber 211, the left and right ends of the first drainage hole 213 are respectively connected to the first chamber 211 and the second chamber 212, and the left and right ends of the third drainage hole 215 are respectively connected to the second chamber 212 and the right side of the shell 21. When the crack adjustment assembly 22 is installed in the second chamber 212, the second drainage hole 214 and the third drainage hole 215 can be connected to the crack 225.

[0067] Furthermore, a left end cover 25 and a right end cover 26 are installed on the outer walls on the left and right sides of the shell 21. The left end cover 25 and the right end cover 26 are fixedly connected to the shell 21 by bolts. The left end cover 25 covers the hole opening at the left end of the first drainage hole 213, and the right end cover 26 covers the hole opening at the right end of the third drainage hole 215. The left end cover 25 is provided with a first connecting hole 251 that can be communicated with the first drainage hole 213, and the right end cover 26 is provided with a second connecting hole 261 that can be communicated with the third drainage hole 215. The fluid in the shell 21 can be discharged to the outside of the shell 21 along the first drainage hole 213, the first connecting hole 251 and the third drainage hole 215, and the second connecting hole 261, but the present invention is not limited to this. The left end cover 25, the right end cover 26 and the shell 21 can also be fixedly connected by other methods such as welding and integral molding.

[0068] Furthermore, heating plates 27 are installed on the front and rear sides of the shell 21. The heating plates 27 are heat-conducting metal plates. The heating plates 27 cover the walls on the front and rear sides of the shell 21, and can heat the entire plugging unit, thereby simulating the high-temperature environment underground in actual plugging operations. However, the present invention is not limited to this, and the heating plates 27 can also be any other form of heating device except for the heat-conducting metal plate, as long as the internal environment of the shell 21 can be heated.

[0069] The working process of the high temperature and high pressure crack regulator according to this exemplary embodiment is described in detail below:

[0070] During the plugging experiment, the plugging slurry is first injected into the cylinder 11 and the first chamber 211, and then the piston 12 is installed in the cylinder 11, and then the plug 13 and the pressure cap 14 are installed at the upper end of the cylinder 11 to seal the cylinder 11. At this time, the stirring unit 3, the heating ring 16 and the heating plate 27 are turned on to stir and heat the plugging slurry in the first chamber 211 and the cylinder 11, and also heat the crack 225. When the temperature rises to the preset temperature, the piston 12 is pressed down, and the plugging slurry in the cylinder 11 and the first chamber 211 is injected into the crack 225 through the second drainage hole 214 according to the preset pressure. When the injection pressure increases, the adjustment rod 224 pulls the adjustment block 223 to move upward, and the crack 225 opens. When the injection pressure decreases, the adjustment rod 224 pushes the adjustment block 223 to move downward, and the crack 225 closes. A part of the plugging slurry will flow out of the high-temperature and high-pressure crack regulator through the right end cover 26 and enter the measuring container to measure the leakage amount.

[0071] Exemplary Embodiment 2

[0072] This exemplary embodiment provides a leak plugging evaluation experimental device.

[0073] Figure 4 A schematic diagram of a leak plugging evaluation experimental device according to an exemplary embodiment of the present invention is shown.

[0074] like Figures 1 to 4 As shown in , the plugging evaluation experimental device of this exemplary embodiment includes the high-temperature and high-pressure crack regulator A described in exemplary embodiment 1, as well as a forward injection metering unit 4, a reverse injection metering unit 5, a constant speed pump 6, a parameter measurement unit 7, a pressure control unit 8 and a data acquisition system 9.

[0075] In this embodiment, the forward injection metering unit 4 includes a first liquid storage tank 41, a first intermediate container 42, a horizontal flow pump 43 and a sealed measuring cylinder 44. The first liquid storage tank 41, the first intermediate container 42, the horizontal flow pump 43 and the sealed measuring cylinder 44 are connected to each other through pipelines, and then the sealed measuring cylinder 44 is connected to the pressurized injection unit 1 through a pipeline. The first intermediate container 42 is a filter, which can be used to filter impurities in the liquid. The first liquid storage tank 41 stores plugging slurry, and the plugging slurry in the first liquid storage tank 41 can be sucked into the first intermediate container 42 by the horizontal flow pump 43 for filtration and then enters the sealed measuring cylinder 44 for measurement. The plugging slurry is then sucked out of the sealed measuring cylinder 44 and injected into the pressurized injection unit 1 for plugging experiments, but the present invention is not limited thereto. The forward injection metering unit 4 may also include other components as long as the function of injecting the plugging slurry into the pressurized injection unit 1 and measuring can be realized.

[0076] In this embodiment, the reverse injection metering unit 5 includes an injection assembly 51 and a metering assembly 52, wherein the injection assembly 51 includes a second liquid storage tank 511, a second intermediate container 512, an injection pump 513 and a piston container 514. The second liquid storage tank 511, the second intermediate container 512, the injection pump 513 and the piston container 514 are connected to each other through pipelines, and then the piston container 514 is connected to the right end cover 26 in the plugging unit 2 through a pipeline. The second intermediate container 512 is a filter that can be used to filter impurities in the liquid. The second liquid storage tank 511 stores plugging slurry. The injection pump 513 can suck the plugging slurry out of the second liquid storage tank 511, and after filtering in the second intermediate container 512, inject it into the piston container 514, and then press the plugging slurry from the second connecting hole 261 on the right end cover 26 into the crack 225 through the piston container 514, so as to measure the reverse pressure bearing capacity of the plugging layer formed during the plugging experiment in the backflow process.

[0077] Furthermore, the metering component 52 includes a measuring cup 521 and a balance 522. The measuring cup 521 is placed on the balance 522. The piston container 514 is connected to the measuring cup 521 through a pipeline. In the plugging experiment, the plugging slurry leaked from the plugging unit 2 will enter the piston container 514. Since the plugging slurry contains solid plugging materials, the plugging slurry containing solids is converted into a liquid that is easy to measure in the piston container 514, and then input into the measuring cup 521 for volume measurement, and weighed using the balance 522 for accurate statistics.

[0078] The components included in the injection assembly 51 and the metering assembly 52 of the reverse injection metering unit 5 in the present invention are not limited to those described above, and may also include other components, as long as the plugging slurry can be injected into the plugging unit 2 for a reverse pressure test, and the volume and weight parameters of the lost plugging slurry can be measured.

[0079] In this embodiment, the constant speed pump 6 can be connected to the upper fixed block 221 through a pipeline, and the constant speed pump 6 can continuously and uninterruptedly supply liquid to the plugging unit 2 at a constant pressure. That is, the constant speed pump 6 can inject liquid between the upper fixed block 221 and the adjustment block 223 to keep the pressure above the adjustment block 223 and between the crack 225 constant, thereby realizing the function that the width of the crack 225 changes with the pressure in the crack in the experiment.

[0080] In this embodiment, the parameter measurement unit 7 includes a first temperature sensor 71, a second temperature sensor 72, a first pressure gauge 73, a second pressure gauge 74 and a third pressure gauge 75, wherein the first temperature sensor 71 is installed on the cylinder 11, and can be used to measure the temperature of the plugging slurry in the cylinder 11, and the second temperature sensor 72 is installed on the plugging unit 2, and can be used to measure the temperature of the plugging slurry in the plugging unit 2; the first pressure gauge 73 is installed on the pipeline between the forward injection metering unit 4 and the pressurized injection unit 1, and can be used to detect the plugging pressure when the plugging slurry is injected into the pressurized injection unit 1; the second pressure gauge 74 is installed on the piston container 514, and can be used to detect the return pressure when the plugging slurry is reversely pressed into the plugging unit 2; the third pressure gauge 75 is connected to the constant speed pump, and can be used to detect the outlet pressure of the constant speed pump 6.

[0081] In this embodiment, the pressure control unit 8 includes a first valve 81, a second valve 82, a third valve 83, a back pressure valve 84 and a drain valve 85, wherein the first valve 81 is installed on the pipeline between the forward injection metering unit 4 and the pressurized injection unit 1, and the injection pressure from the forward injection metering unit 4 to the pressurized injection unit 1 can be adjusted by controlling the opening of the first valve 81; the second valve 82 is installed on the pipeline between the injection pump 513 and the piston container 514, and the injection pressure from the injection pump 513 to the piston container 514 can be adjusted by controlling the opening of the second valve 82; The valve 83 is installed on the pipeline between the piston container 514 and the metering component 52. The injection pressure of the piston container 514 to the metering component 52 can be adjusted by controlling the opening of the third valve 83; the back pressure valve 84 is installed at the outlet position of the forward injection metering unit 4, and can be used to relieve pressure when the pressure in the pipeline increases abnormally to ensure the safety of the experimental device; the drain valve 85 is installed at the position of the left end cover 25 in the high-temperature and high-pressure crack regulator A, and is connected to the first connecting hole 251 on the left end cover 25. The drain valve 85 can be used to discharge the plugging slurry in the high-temperature and high-pressure crack regulator A.

[0082] In this embodiment, the forward injection metering unit 4, the reverse injection metering unit 5 and the parameter measurement unit 7 are all connected to the data acquisition system 9. The forward injection metering unit 4 can transmit the volume data of the plugging liquid measured by it to the data acquisition system 9, the reverse injection metering unit 5 can transmit the weight and volume data of the plugging liquid measured by it to the data acquisition system 9, and the parameter measurement unit 7 can transmit the temperature and pressure data measured at various locations to the data acquisition system 9. After receiving the above parameters, the data acquisition system 9 can perform analysis and processing as data support for subsequent plugging evaluation.

[0083] Exemplary Embodiment 3

[0084] This exemplary embodiment provides a leak plugging evaluation experimental method.

[0085] The plugging evaluation experimental method described in this exemplary embodiment uses the plugging evaluation experimental device described in exemplary embodiment 2 to conduct the experiment.

[0086] The plugging evaluation experimental method described in this exemplary embodiment includes:

[0087] like Figures 1 to 4 As shown in the figure, first open the back pressure valve 84 and the first valve 81, suck the plugging slurry into the sealed measuring cylinder 44 through the horizontal flow pump 43 for measurement, then inject the plugging slurry into the cylinder 11 and the first chamber 211, install the piston 12 in the cylinder 11, and then install the plug 13 and the pressure cap 14 at the upper end of the cylinder 11 to seal the cylinder 11, then turn on the stirring unit 3, the heating coil 16 and the heating plate 27, stir and heat the plugging slurry in the first chamber 211 and the cylinder 11, and also heat the crack 225.

[0088] When the temperature rises to the preset temperature, the piston 12 is pressed down, and the plugging slurry in the cylinder 11 and the first chamber 211 is injected into the crack 225 through the second drainage hole 214 according to the preset pressure, and a crack plugging simulation experiment is carried out. When the injection pressure increases, the adjusting rod 224 pulls the adjusting block 223 to move upward, and the crack 225 opens. When the injection pressure decreases, the adjusting rod 224 pushes the adjusting block 223 to move downward, and the crack 225 closes.

[0089] In the crack plugging simulation experiment, a portion of the plugging slurry will flow out of the high-temperature and high-pressure crack regulator A through the right end cover 26 and enter the piston container 514. Since the plugging slurry contains solid plugging materials, the plugging slurry containing solids is converted into a liquid that is easy to measure in the piston container 514, and then input into the measuring cup 521 for volume measurement, and weighed using a balance 522.

[0090] When conducting a backflow experiment, first unload the injection pressure of the forward injection metering unit 4 to the pressurized injection unit 1 to 0, close the back pressure valve 84, the first valve 81 and the third valve 83, open the second valve 82, and press the plugging slurry in the second liquid storage tank 511 into the piston container 514 through the injection pump 513, and reversely press the plugging slurry into the plugging unit 2 through the piston container 514. At the same time, record the breakthrough pressure of the backflow process, that is, the maximum value of the second pressure gauge 74 during the backflow experiment. In the plugging experiment and the backflow experiment, the data acquisition system 9 is used to receive various parameters such as pressure, temperature, weight, volume, etc. measured by the forward injection metering unit 4, the reverse injection metering unit 5 and the parameter measurement unit 7, and collect, summarize and analyze them.

[0091] After the experiment, the drain valve 85 is opened to drain the plugging slurry in the high-temperature and high-pressure fracture regulator A and clean the device.

[0092] In summary, the present invention forms a variable-width crack with fluid pressure response characteristics through a constant speed pump, a movable adjustment block and a dynamic crack coupling. Under the condition of simulated fluid pressure changes in the wellbore, the crack width is automatically adjusted. When the fluid pressure increases, the crack opens, and when the fluid pressure decreases, the crack closes, thereby realizing the simulation of the plugging process of pressure-sensitive induced fracture leakage and extended fracture leakage; the present invention can realize the functions of forward pressurization of wellbore fractures and reverse pressurization of fractures by adjusting the injection pressure, and can realize reverse pressurization of fractures through the backflow system, simulating the forward plugging, crack closure pressure bearing and backflow pressure bearing stages in the plugging process, and realizing quantitative evaluation of the three-way pressure bearing capacity of plugging materials for plugging cracks, which is more in line with the influence of real wellbore pressure fluctuations on the crack plugging effect.

[0093] Although the present invention has been described above in conjunction with the exemplary embodiments and the accompanying drawings, it should be apparent to those skilled in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.

Claims

1. A high temperature and high pressure crack regulator, It is characterized in that The regulator includes a pressurized liquid injection unit and a leak plugging unit, wherein: The plugging unit includes a shell and a crack adjustment component, the shell is provided with a first chamber and a second chamber which are connected vertically, and a first drainage hole, a second drainage hole and a third drainage hole which are connected horizontally, wherein the first drainage hole can connect the first chamber with the outside, the second drainage hole can connect the first and second chambers, and the third drainage hole can connect the second chamber with the outside; the crack adjustment component is installed in the second chamber, and includes an upper fixed block, a lower fixed block, an adjustment block and an adjustment rod, the upper fixed block, the lower fixed block and the adjustment block are all arranged in the second chamber, the upper fixed block and the lower fixed block are respectively located at the upper and lower ends of the second chamber, and are separated from each other by an end distance along the axial direction of the second chamber, and the adjustment block is arranged on the upper fixed block and A crack can be formed between the lower fixed block and the adjusting block and the lower fixed block, the crack is connected to the second and third drainage holes, the adjusting block can move up and down along the axis of the second chamber to adjust the width of the crack, the lower end of the adjusting rod is fixedly connected to the adjusting block, the upper end of the adjusting rod passes through the upper fixed block and extends to the top of the shell, and the adjusting rod can control the up and down movement of the adjusting block; the plugging unit also includes an upper pressure cover and a lower pressure cover, the upper pressure cover is fixedly connected to the upper end of the upper fixed block, and the lower pressure cover is fixedly connected to the lower end of the lower fixed block, the upper pressure cover can keep the upper fixed block in a fixed position relative to the shell in the second chamber, and the lower pressure cover can keep the lower fixed block in a fixed position relative to the shell in the second chamber; The pressurized injection unit includes a cylinder and a piston. The piston is inserted into the cylinder. The lower end of the cylinder is fixedly connected to the upper end of the shell so that the inner cavity of the cylinder is connected to the first chamber. The piston can move downward along the axis of the cylinder to press the plugging slurry into the first chamber, the second drainage hole and the crack.

2. The high temperature and high pressure crack regulator according to claim 1, It is characterized in that The regulator also includes a stirring unit, which is fixedly connected to the lower end of the shell and includes stirring blades. The stirring blades can extend into the first chamber and the cylinder to stir the plugging slurry.

3. The high temperature and high pressure crack regulator according to claim 1, It is characterized in that The leak-proof unit also includes a left end cover and a right end cover, which are respectively fixedly connected to the left and right sides of the shell, and are respectively provided with a first connecting hole and a second connecting hole that pass through the left and right sides, the first connecting hole is connected to the first drainage hole, and the second connecting hole is connected to the third drainage hole.

4. The high temperature and high pressure crack regulator according to claim 1, It is characterized in that The pressurized liquid injection unit also includes a heating ring, which is sleeved on the outside of the cylinder to heat the plugging slurry in the cylinder.

5. The high temperature and high pressure crack regulator according to claim 1, It is characterized in that The plugging unit further comprises a heating plate, which is mounted on the outside of the shell to heat the cracks and the plugging slurry in the cracks to simulate a high temperature underground environment.

6. A leak plugging evaluation experimental device, It is characterized in that The experimental device comprises a high-temperature and high-pressure crack regulator according to any one of claims 1 to 5, a forward injection metering unit and a reverse injection metering unit, the forward injection metering unit is connected to the pressurized injection unit through a pipeline, and the reverse injection metering unit is connected to the plugging unit through a pipeline; The forward injection metering unit comprises a first liquid storage tank, a first intermediate container, a horizontal flow pump and a sealed measuring cylinder which are connected in sequence, wherein the sealed measuring cylinder can measure the amount of plugging slurry injected into the pressurized injection unit; The reverse injection metering unit includes an injection component and a metering component. The injection component includes a second liquid storage tank, a second intermediate container, an injection pump and a piston container which are connected in sequence through pipelines, and the piston container is connected to the right end cover in the plugging unit through a pipeline; the second intermediate container is a filter for filtering impurities in the liquid, and the second liquid storage tank stores plugging slurry. The injection pump sucks the plugging slurry out of the second liquid storage tank, and after filtering through the second intermediate container, injects it into the piston container, and then presses the plugging slurry into the crack from the second connecting hole on the right end cover through the piston container, so as to measure the reverse pressure bearing capacity of the plugging layer formed during the plugging experiment during the backflow process; A metering assembly is connected to the piston container and includes a connected measuring cup and a balance, and the metering assembly is capable of measuring volume and weight parameters of the liquid flowing into the piston container; The experimental device also includes a pressure control unit, which includes a first valve, a second valve and a third valve, wherein: The first valve is arranged between the forward injection metering unit and the pressurized injection unit, and the injection pressure of the forward injection metering unit to the pressurized injection unit can be adjusted by controlling the opening of the first valve; The second valve is arranged between the injection pump and the piston container, and the injection pressure of the injection pump to the piston container can be adjusted by controlling the opening of the second valve; The third valve is arranged between the piston container and the metering component, and the injection pressure of the piston container to the metering component can be adjusted by controlling the opening of the third valve; The experimental device also includes a data acquisition system. The forward liquid injection metering unit, the reverse liquid injection metering unit and the parameter measurement unit are all connected to the data acquisition system. The data acquisition system can collect the measurement data of each unit and perform analysis and processing.

7. The leak plugging evaluation experimental device according to claim 6, It is characterized in that The experimental device also includes a constant speed pump, which is connected to the upper fixed block. The constant speed pump can continuously and uninterruptedly supply liquid to the plugging unit to keep the pressure in the plugging unit constant.

8. The leak plugging evaluation experimental device according to claim 7, It is characterized in that The experimental device further includes a parameter measurement unit, which includes a first temperature sensor, a second temperature sensor, a first pressure gauge, a second pressure gauge, and a third pressure gauge, wherein: A first temperature sensor is connected to the cylinder to measure the temperature of the plugging slurry in the cylinder; A second temperature sensor is connected to the plugging unit to measure the temperature of the plugging slurry in the plugging unit; A first pressure gauge is connected between the forward injection metering unit and the pressurized injection unit to detect the plugging pressure; A second pressure gauge is connected to the piston container to detect the flowback pressure; The third pressure gauge is connected to the constant speed pump to detect the driving pressure of the constant speed pump.

9. A leak plugging evaluation experimental method, It is characterized in that The experimental method uses the plugging evaluation experimental device as described in any one of claims 6 to 8 to conduct the experiment.

10. The leak plugging evaluation experimental method according to claim 9, It is characterized in that The experimental method comprises: when the plugging evaluation experimental device includes the first valve, injecting the plugging slurry in the forward injection metering unit into the high-temperature and high-pressure fracture regulator by adjusting the first valve, and measuring the injected pressure and temperature parameters at the same time; In the case where the plugging evaluation experimental device includes the piston container, the third valve and the metering component, the plugging slurry leaking from the high-temperature and high-pressure crack regulator is injected into the piston container, the plugging slurry containing solid plugging materials is converted into a liquid that is easy to measure through the piston container, and the third valve is adjusted to inject the liquid in the piston container into the metering component to measure the weight and volume parameters; When the plugging evaluation experimental device includes the second valve and the injection assembly, the fluid in the injection assembly is reversely pressed into the plugging unit by adjusting the second valve, and the temperature and pressure parameters of the reverse pressure of the plugging unit are measured; When the plugging evaluation experimental device includes the data acquisition system, the above-mentioned measurement parameters are transmitted to the data acquisition system for analysis and processing.

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