Indoor evaluation device and method for original leakage pressure and leakage pressure after leakage stoppage

Abstract

The invention discloses an indoor evaluation device and method for original leakage pressure and leakage pressure after leakage stoppage, and the device comprises a pressure chamber assembly, a confining pressure pipeline assembly, a confining pressure liner, a simulation sleeve pipeline assembly, a slotting insertion block and a controller, and the two ends of the confining pressure pipeline assembly are connected with a hydraulic oil source and a containing cavity respectively; the confining pressure liner is arranged in the accommodating cavity of the pressure chamber assembly, is used for sleeving the outer side of the rock core sample and is used for applying confining pressure to the rock core sample through hydraulic oil; the two ends of the simulation casing pipeline assembly are connected with a drilling fluid source and a sample deep hole of the rock core sample respectively and used for conveying drilling fluid to the sample deep hole. The kerf insertion block is used for being inserted into the kerf; the controller is in communication connection with the confining pressure pipeline assembly and the simulation casing pipeline assembly and used for determining the original leakage pressure of the rock core sample and the leakage pressure after leakage stoppage. The device has the advantages that operation is easy, convenient and rapid, the evaluation difficulty is lowered, and the simulation effect of drilling fluid leakage pressure measurement under different conditions can be improved.

Description

Technical Field

[0001] The present application belongs to the field of leakage pressure measurement, and specifically relates to an indoor evaluation device and method for original leakage pressure and leakage pressure after plugging. Background Art

[0002] With the rapid development of oil and gas exploration and development technologies, drilling has become a critical component of oil and gas field development. Currently, drilling fluid loss is a frequent problem, becoming a key factor hindering the safe and efficient conduct of drilling operations. Drilling fluid loss refers to the inflow of drilling fluid into the formation when the drilling fluid pressure exceeds the formation pressure. Loss pressure refers to the minimum pressure required for drilling fluid to enter the pores or fractures of the formation. To prevent drilling fluid loss, it is first necessary to determine the loss pressure at which lost circulation occurs and then control the drilling fluid pressure.

[0003] However, due to the complex formation parameters, the measurement of drilling fluid loss pressure under different conditions is difficult and the results are less accurate. Summary of the Invention

[0004] The purpose of this application is to provide an indoor evaluation device for original leakage pressure and leakage pressure after plugging, so as to improve the simulation effect of drilling fluid leakage pressure measurement under different conditions.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides an indoor evaluation device for original leakage pressure and leakage pressure after plugging, the indoor evaluation device for original leakage pressure and leakage pressure after plugging comprising: A pressure chamber assembly, wherein a receiving cavity for receiving a core sample is formed in the pressure chamber assembly; A confining pressure pipeline assembly, with both ends of the confining pressure pipeline assembly connected to a hydraulic oil source and a receiving chamber, respectively, for delivering hydraulic oil to the receiving chamber; The confining pressure liner is arranged in the accommodating cavity and is used to be sleeved on the outside of the core sample, and is used to apply confining pressure to the core sample through hydraulic oil; A simulated casing pipeline assembly, wherein both ends of the simulated casing pipeline assembly are respectively connected to a drilling fluid source and a sample deep hole of a core sample, and are used to transport drilling fluid to the sample deep hole; A slit inserting block, used for being inserted into the slit; The controller is connected to the confining pressure pipeline assembly and the simulated casing pipeline assembly and is used to determine the loss pressure array of the core sample. The loss pressure array includes the original loss pressure and the loss pressure after plugging.

[0006] In an embodiment of the present application, the confined pressure pipeline assembly includes: a first pipeline connected between the hydraulic oil source and the accommodating chamber; The first regulating member is provided on the first pipeline and is used for regulating the pressure of the hydraulic oil.

[0007] In an embodiment of the present application, the simulated casing pipeline assembly includes: a second pipeline connected between the drilling fluid source and the sample deep hole; The second regulating member is arranged on the second pipeline and is used to regulate the pressure of the drilling fluid.

[0008] In an embodiment of the present application, the pressure chamber assembly includes a top plate, a bottom plate, a shell, a first sealing rubber ring and a second sealing rubber ring. The top plate and the bottom plate are vertically spaced apart. The shell is arranged between the top plate and the bottom plate and the two ends of the shell are detachably connected to the top plate and the bottom plate respectively. The top plate, the bottom plate and the shell together enclose a accommodating cavity. The first sealing rubber ring is arranged between the top plate and the confining pressure inner liner and is used to seal the gap between the top plate and the confining pressure inner liner. The second sealing rubber ring is arranged between the bottom plate and the confining pressure inner liner and is used to seal the gap between the bottom plate and the confining pressure inner liner.

[0009] In an embodiment of the present application, the horizontal cross-section of the slit insert is wedge-shaped.

[0010] In a second aspect of the present application, a method for indoor evaluation of original leakage pressure and leakage pressure after plugging is provided. The method for indoor evaluation of original leakage pressure and leakage pressure after plugging is applicable to the above-mentioned indoor evaluation device for original leakage pressure and leakage pressure after plugging and comprises: Controlling the confining pressure pipeline assembly to deliver hydraulic oil into the accommodating chamber to apply a first confining pressure to the core sample and place the slit in a first closed state; Controlling the simulated casing and pipeline assembly to deliver drilling fluid with gradually increasing pressure to the deep hole of the core sample; Make sure the drilling fluid flows out of the cut; obtaining a first pressure of the drilling fluid; Controlling the confining pressure pipeline assembly to stop delivering hydraulic oil into the accommodation cavity and controlling the simulated casing pipeline assembly to stop delivering drilling fluid into the sample deep hole; Insert the slit insertion block into the slit; Controlling the confining pressure pipeline assembly to deliver hydraulic oil into the accommodating chamber to apply a second confining pressure to the core sample and place the slit in a second closed state; Controlling the simulated casing pipeline assembly to deliver drilling fluid to the sample deep hole of the core sample again; Make sure the drilling fluid flows out of the cut again; obtaining a second pressure of the drilling fluid; A leak pressure array is determined based on the first pressure and the second pressure.

[0011] In an embodiment of the present application, the indoor evaluation of the original leakage pressure and the leakage pressure after plugging further includes a first adjustment member and a second adjustment member, and the indoor evaluation method of the original leakage pressure and the leakage pressure after plugging further includes: After controlling the confining pressure pipeline assembly to deliver hydraulic oil into the accommodating chamber, controlling the first regulating member to regulate the pressure of the hydraulic oil to a first confining pressure so that the slit is in a first closed state; and After controlling the confining pressure pipeline assembly to deliver hydraulic oil to the accommodating chamber again, controlling the first regulating member to regulate the pressure of the hydraulic oil to the second confining pressure, so that the slit is in the second closed state.

[0012] In the embodiment of the present application, the first confining pressure is determined according to the following method:

[0013]

[0014] in, is a first preset wellbore stress; is a second preset wellbore stress; The third preset wellbore stress; is the preset well surface shear stress; is the preset wellbore radius; is the preset wellbore pressure; is the angle of the core sample in the cylindrical coordinate system; is the distance between the core sample and the origin in the cylindrical coordinate system; is the first confining pressure.

[0015] In an embodiment of the present application, determining that the drilling fluid has flowed out of the cut or determining that the drilling fluid has flowed out of the cut again includes: Obtaining the flow rate value of the drilling fluid at the output end of the slot; When the flow rate value reaches a preset overflow flow rate value, it is determined that the drilling fluid flows out from the cut of the core sample.

[0016] In an embodiment of the present application, determining that the drilling fluid has flowed out of the cut or determining that the drilling fluid has flowed out of the cut again includes: Obtaining the pressure value of the drilling fluid at the output end of the slot; When the pressure value reaches a preset overflow pressure value, it is determined that the drilling fluid flows out of the cut of the core sample.

[0017] It can be seen from the above technical scheme that the indoor evaluation device for the original loss pressure and the loss pressure after plugging includes a pressure chamber assembly, a confining pressure pipeline assembly, a confining pressure liner, a simulated casing pipeline assembly, a slit insert block and a controller. A accommodating cavity for accommodating a core sample is formed in the pressure chamber assembly; the two ends of the confining pressure pipeline assembly are respectively connected to the hydraulic oil source and the accommodating cavity for conveying hydraulic oil into the accommodating cavity; the confining pressure liner is arranged in the accommodating cavity and is used to be sleeved on the outside of the core sample for applying confining pressure to the core sample through hydraulic oil; the two ends of the simulated casing pipeline assembly are respectively connected to the drilling fluid source and the sample deep hole of the core sample for conveying drilling fluid to the sample deep hole; the slit insert block is used to be inserted in the slit; the controller is communicated with the confining pressure pipeline assembly and the simulated casing pipeline assembly and is used to determine the loss pressure array of the core sample, wherein the loss pressure array includes the original loss pressure and the loss pressure after plugging. The device for evaluating the original loss pressure and the loss pressure after plugging has a simple structure. The original loss pressure of the core sample can be evaluated by arranging a pressure chamber assembly, a confining pressure pipeline assembly, a confining pressure liner, a simulated casing pipeline assembly, and a controller. The device can also evaluate the loss pressure of the core sample after plugging by adding a slit insert block on the basis of the above components. The device can ensure the evaluation accuracy of the loss pressure array and is easy and quick to operate, thereby reducing the difficulty of evaluating the loss pressure array and improving the simulation effect of drilling fluid loss pressure measurement under different conditions.

[0018] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without inventive work. In the drawings: Figure 1 Schematic diagram of the structure of an indoor evaluation device for original leakage pressure and leakage pressure after plugging according to a specific embodiment of the present application; Figure 2 for Figure 1 The main view of the indoor evaluation device for the original leakage pressure and the leakage pressure after plugging; Figure 3 for Figure 1 A top view of the indoor evaluation device for the original leakage pressure and the leakage pressure after plugging; Figure 4 for Figure 1 Schematic diagram of the structure of the pressure vessel of the indoor evaluation device for the original leakage pressure and the leakage pressure after plugging; Figure 5 for Figure 4 The main view of the pressure vessel in FIG. Figure 6 for Figure 5 A cross-sectional view of the pressure vessel in direction II; Figure 7 This is a top view of a conventional core; Figure 8 for Figure 7 Cross-section view of conventional core in AA direction; Figure 9 It is the top view of the interface type core; Figure 10 for Figure 7 Cross-sectional view of the middle interface type core in the BB direction; Figure 11 This is a top view of the fracture-cavity core; Figure 12 for Figure 7 Cross-sectional view of the fracture-cavity core in the CC direction; Figure 13 This is a top view of the sandwich core; Figure 14 for Figure 7 Cross-sectional view of the medium-interlayer core in the DD direction; Figure 15 for Figure 1 Schematic diagram of the structure of the middle slit insertion block.

[0020] Description of Reference Numerals 1-top plate; 2-confining pressure stabilization assembly; 3-second motor; 4-second regulating member; 5-drilling fluid storage tank; 6-valve; 7-opening and closing valve; 8-regulating valve; 9-third pressure gauge; 10-second pressure gauge; 11-first pressure gauge; 12-overflow pressure gauge; 13-overflow flow meter; 14-beaker; 15-second pipeline; 16-first pipeline; 17-third pipeline; 18-second coupling; 19-core sample; 20-confining pressure liner; 21-bottom plate; 22-shell; 23-first motor; 24-first coupling; 25-first regulating member; 26-hydraulic oil tank; 27-slit insert block; G-slit; H-sample deep hole; a-first connecting port; b-second connecting port; c-third connecting port. DETAILED DESCRIPTION

[0021] The following describes the specific embodiments of the present application in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application and are not intended to limit the present application.

[0022] The first aspect of the present application provides an indoor evaluation device for original leakage pressure and leakage pressure after plugging, such as Figure 1As shown in the figure, the indoor evaluation device for the original leakage pressure and the leakage pressure after plugging includes: A pressure chamber assembly, wherein a receiving cavity for receiving the core sample 19 is formed in the pressure chamber assembly; A confining pressure pipeline assembly, with both ends of the confining pressure pipeline assembly connected to a hydraulic oil source and a receiving chamber, respectively, for delivering hydraulic oil to the receiving chamber; The confining pressure liner 20 is provided in the accommodating cavity and is used to be sleeved on the outside of the core sample 19, and is used to apply confining pressure to the core sample 19 through hydraulic oil; A simulated casing pipeline assembly, the two ends of which are respectively connected to a drilling fluid source and a sample deep hole H of the core sample 19, for transporting drilling fluid to the sample deep hole H; A slit inserting block 27 is used to be inserted into the slit G; The controller is in communication with the confining pressure pipeline assembly and the simulated casing pipeline assembly and is used to determine the loss pressure array of the core sample 19, wherein the loss pressure array includes the original loss pressure and the loss pressure after plugging.

[0023] Specifically, in this embodiment, the core sample 19 can be a full-diameter core sample 19, i.e., a core extracted from an oil (gas) reservoir using coring techniques, without cutting or splitting, and used in its entirety in the laboratory for analysis and determination of relevant parameters. In this embodiment, the full-diameter core sample 19 has a diameter of 100 mm and a height of 5 cm. A deep hole with a diameter ranging from 5 mm to 80 mm and a depth ranging from 0 to 4 cm is drilled in the center of the full-diameter core. A single slit G is provided in the full-diameter core sample 19 and is distributed radially along the full-diameter core sample 19. The slit G has a thickness of 1 mm and its depth is the same as the depth of the sample deep hole H. Furthermore, the core sample 19 is replaceably accommodated in the accommodating chamber. Hydraulic oil is injected into the pressure chamber assembly via the confining pressure pipeline assembly, thereby applying pressure to the confining pressure liner 20 surrounding the core sample 19 within the pressure chamber assembly, thereby achieving uniform application of confining pressure to the outer peripheral wall of the core sample 19. Due to the effect of the confining pressure, the slit G on the core sample 19 will close, and drilling fluid will be injected into the sample deep hole H of the core sample 19 through the simulated casing pipeline assembly, while the pressure of the drilling fluid will be evenly increased. After the pressure of the drilling fluid increases to a certain level, the high-pressure drilling fluid will exert pressure on the wall of the sample deep hole H and open the slit G on the core sample 19, so that the drilling fluid can flow out of the slit G of the core sample 19, that is, simulating drilling fluid loss.

[0024] When the original leakage pressure and the leakage pressure after plugging are evaluated by the indoor evaluation device of the present embodiment, the core sample 19 is placed in the accommodating chamber, and the confining pressure pipeline assembly is controlled to inject hydraulic oil into the pressure chamber assembly, thereby applying pressure to the confining pressure liner 20 on the side of the core sample 19 in the pressure chamber assembly, and then uniformly applying confining pressure to the outer peripheral wall of the core sample 19 to close the slit G on the core sample 19 (the closed state of the slit G at this time is the first closed state); then the simulated casing pipeline assembly is controlled to inject hydraulic oil into the pressure chamber assembly to inject hydraulic oil into the pressure chamber assembly, thereby applying pressure to the confining pressure liner 20 on the side of the core sample 19 in the pressure chamber assembly, and then uniformly applying confining pressure to the outer peripheral wall of the core sample 19 to close the slit G on the core sample 19 (the closed state of the slit G at this time is the first closed state); then the simulated casing pipeline assembly is controlled to inject hydraulic oil into the core sample 19. Drilling fluid is injected into the sample deep hole H of the core sample 19, and the pressure of the drilling fluid is uniformly increased. After the pressure of the drilling fluid increases to a first pressure, the pressure (i.e., the first pressure) exerted by the high-pressure drilling fluid on the wall of the sample deep hole H can open the slit G on the core sample 19, thereby allowing the drilling fluid to flow out of the slit G of the core sample 19. The controller obtains the first pressure of the drilling fluid at this time, which is the original loss pressure. After determining the original loss pressure, the controller stops the conveying functions of the confining pressure pipeline assembly and the simulated casing pipeline assembly. When the original leakage pressure and the leakage pressure after plugging are evaluated by the indoor evaluation device of the present embodiment, the slit insertion block 27 is inserted into the slit G, and then the combination of the core sample 19 and the slit insertion block 27 is placed in the accommodating cavity, and then the confining pressure pipeline assembly is controlled to inject hydraulic oil into the pressure chamber assembly, thereby applying pressure to the confining pressure liner 20 on the side of the core sample 19 in the pressure chamber assembly, and then achieving uniform application of confining pressure to the outer peripheral wall of the core sample 19 so that the pressure on the combination of the core sample 19 and the slit insertion block 27 is uniform. Slit G is closed (slit G is now in the second closed state). The simulated casing assembly is then controlled to inject drilling fluid into the deep sample hole H of the core sample 19, while uniformly increasing the drilling fluid pressure. After the drilling fluid pressure reaches the second pressure, the pressure exerted by the high-pressure drilling fluid on the walls of the deep sample hole H (i.e., the second pressure) opens the slit G in the core sample 19, allowing the drilling fluid to flow out of the slit G in the core sample 19. The controller then obtains the second pressure of the drilling fluid at this point, which is the post-plugging loss pressure. Furthermore, considering the difference between the original loss pressure and the post-plugging loss pressure, the indoor evaluation device needs to conduct experimental simulations on core samples 19 with different depths, different lithologies, and different interfaces, interlayers, and vugs, depending on actual needs. Multiple experimental simulations can be conducted on multiple core samples 19 as needed to further ensure the accuracy of the loss pressure array evaluation.

[0025] The indoor evaluation device for original loss pressure and loss pressure after plugging in this embodiment has a simple structure. By setting a pressure chamber component, a confining pressure pipeline component, a confining pressure liner 20, a simulated casing pipeline component and a controller, the original loss pressure of the core sample 19 can be evaluated. Adding a slit insert block 27 on the basis of the above components can also evaluate the loss pressure of the core sample 19 after plugging. It can ensure the evaluation accuracy of the loss pressure array and is simple and quick to operate, reducing the difficulty of evaluating the loss pressure array, which is conducive to improving the simulation effect of drilling fluid loss pressure measurement under different conditions.

[0026] Further, see Figures 7 to 14 In this embodiment, the core sample 19 can be of various types, such as any one of conventional cores, interface cores, fracture-type cores, and interlayer cores, so that the indoor evaluation device for the original loss pressure and the loss pressure after plugging can realize experimental simulation of cores with different depths of formation conditions, different lithologies, and different interfaces, different interlayers, and different hole conditions, that is, more formation parameters are introduced in the process of measuring the drilling fluid loss pressure, thereby improving the accuracy of the simulation experiment. Furthermore, it can be understood by those skilled in the art that the method of applying the confining pressure of the core sample 19 in this embodiment is not limited to the above-mentioned method of injecting hydraulic oil into the pressure chamber assembly through the confining pressure pipeline assembly, but can also be achieved by injecting water or other liquids. There are also many choices of drilling fluids, which can be emulsified drilling agents, water-based drilling agents, etc.

[0027] In one embodiment of the present application, the confined pressure pipeline assembly includes: A first pipeline 16, the first pipeline 16 is connected between the hydraulic oil source and the accommodating chamber; The first regulating member 25 is provided on the first pipeline 16 and is used to regulate the pressure of the hydraulic oil.

[0028] Specifically, if Figure 2As shown, the first pipeline 16 is connected to the confining pressure pipeline interface of the shell 22 (the confining pressure pipeline interface of the shell 22 is connected to the accommodating cavity). The first pipeline 16 introduces hydraulic oil from the hydraulic oil source into the accommodating cavity of the pressure chamber assembly. After the first adjusting member 25 adjusts the pressure of the hydraulic oil, the hydraulic oil will squeeze the confining pressure liner 20, thereby applying confining pressure to the outer wall of the core sample 19 until the slit G is closed. Among them, the first regulating member 25 can be a first high-pressure pump, the hydraulic oil source can be a hydraulic oil tank 26, and the confining pressure pipeline assembly also includes a confining pressure stabilization assembly 2, a valve 6, and a first pressure gauge 11, all of which are communicatively connected to the controller. The hydraulic oil is pressurized by the first high-pressure pump and enters the accommodating chamber through the first pipeline 16. The valve 6 is arranged on the first pipeline 16 and is used to control the on-off of the first pipeline 16. The first pressure gauge 11 is arranged on the first pipeline 16 and is used to detect and display the pressure of the hydraulic oil in the first pipeline 16. The confining pressure stabilization assembly 2 includes a hydraulic pipeline connected to the first pipeline 16, which is provided with multiple pressure control valves 6 (in this embodiment, multiple pressure control valves 6 are communicatively connected to the controller). The controller can adjust the actual pressure in the first pipeline 16 by adjusting the pressure control valves 6, and stabilize the above pressure. The above arrangement can further improve the accuracy of the simulation of the indoor evaluation device for the original leakage pressure and the leakage pressure after plugging, and facilitate the operation of the experimenter.

[0029] Furthermore, the confining pressure pipeline assembly also includes a first motor 23 and a first coupling 24. The first motor 23 is connected to the first adjusting member 25 through the first coupling 24. The suction port of the first adjusting member 25 is connected to the hydraulic oil tank 26, and the output port of the first adjusting member 25 is connected to the confining pressure stabilization assembly 2.

[0030] In one embodiment of the present application, the simulated casing pipeline assembly includes: The second pipeline 15 is connected between the drilling fluid source and the sample deep hole H; The second regulating member 4 is provided on the second pipeline 15 and is used to regulate the pressure of the drilling fluid.

[0031] Specifically, if Figure 2As shown, the second regulating member 4 can introduce drilling fluid from the drilling fluid source into the sample deep hole H of the core sample 19 via the second pipeline 15. After the second regulating member 4 increases the pressure of the drilling fluid to a certain level, the sufficiently high-pressure drilling fluid can open the slots G in the core sample 19, allowing the drilling fluid to flow out of the slots G in the core sample 19 to simulate drilling fluid loss. In this embodiment, the second regulating member 4 can be a second high-pressure pump, and the drilling fluid source can be a drilling fluid storage tank 5. The drilling fluid storage tank 5 can be filled with drilling fluid of different opening times to meet the conditions of different formation depths. The simulated casing pipeline assembly also includes a second pressure gauge 10, a third pressure gauge 9, and an on-off valve 7, all located downstream of the second regulating element 4 and in communication with the controller. These two pressure gauges are all mounted on a second pipeline 15, connected to the simulated casing pipeline assembly interface on the top plate 1 of the pressure chamber assembly. The third and second pressure gauges 9 and 10 are located upstream and downstream of the on-off valve 7, respectively. The third pressure gauge 9 detects and displays the pressure of the drilling fluid flowing through the third pressure gauge 9, while the second pressure gauge 10 detects and displays the pressure of the drilling fluid flowing through the second pressure gauge 10. After being pressurized by the second high-pressure pump, the drilling fluid enters the sample deep hole H of the core sample 19 through the third pressure gauge 9, the on-off valve 7, and the second pressure gauge 10. This configuration further improves the accuracy of the simulation of the original and post-plugging lost-flow pressures in the evaluation device within the chamber.

[0032] Furthermore, the simulated casing pipeline assembly also includes a second motor 3 and a second coupling 18. The second motor 3 is connected to the second adjusting member 4 through the second coupling 18. The inlet of the second adjusting member 4 is connected to the drilling fluid storage tank 5. The pressure of the drilling fluid in the second pipeline 15 is generated by the second motor 3 driving the second adjusting member 4. The speed of the second motor 3 is adjusted to continuously increase the pressure of the drilling fluid.

[0033] In one embodiment of the present application, Figures 1 to 6 As shown, the pressure chamber assembly includes a top plate 1, a bottom plate 21, a shell 22, a first sealing rubber ring and a second sealing rubber ring. The top plate 1 and the bottom plate 21 are spaced apart in the vertical direction. The shell 22 is arranged between the top plate 1 and the bottom plate 21 and the two ends of the shell 22 are detachably connected to the top plate 1 and the bottom plate 21 respectively. The top plate 1, the bottom plate 21 and the shell 22 are jointly enclosed to form a accommodating cavity. The first sealing rubber ring is arranged between the top plate 1 and the confining pressure liner 20 and is used to seal the gap between the top plate 1 and the confining pressure liner 20. The second sealing rubber ring is arranged between the bottom plate 21 and the confining pressure liner 20 and is used to seal the gap between the bottom plate 21 and the confining pressure liner 20.

[0034] Specifically, if Figure 1 and Figure 4As shown, a through hole with a diameter slightly larger than the full-diameter core sample 19 is provided at the center of the shell 22, and the confining pressure liner 20 is installed in the through hole by clearance fit. The full-diameter core sample 19 is installed in the confining pressure liner 20, and the top plate 1 and the bottom plate 21 are respectively installed on the upper and lower parts of the shell 22 by bolt connection; the diameter of the first sealing rubber ring is between the diameter of the simulated casing pipeline interface on the top plate 1 and the diameter of the full-diameter core sample 19, and the second sealing rubber ring is located between the lower part of the shell 22 and the upper part of the bottom plate 21 and has a diameter larger than the diameter of the through hole on the shell 22. The pressure chamber assembly is provided with a first connecting port a connected to the sample deep hole H, as well as a second connecting port b and a third connecting port c corresponding to the hollow cavity and the inner liner opening, respectively. Drilling fluid enters the sample deep hole H through the first connecting port a, thereby pressurizing the core sample 19 to open the slit G. Hydraulic oil enters the accommodating cavity through the second connecting port b and squeezes the confining pressure liner 20, thereby simulating the confining pressure of the core. After the pressure of the drilling fluid opens the slit G, the drilling fluid can flow out of the pressure chamber assembly through the slit G and the third connecting port c. With the above arrangement, the core sample 19 can be quickly replaced after the top plate 1 is disassembled, which is conducive to improving the experimental efficiency. The arrangement of the first sealing rubber ring and the second sealing rubber ring can also ensure that the sealing of the accommodating cavity of the pressure chamber assembly is not affected during multiple disassembly and assembly processes.

[0035] In one embodiment of the present application, the horizontal cross-section of the slitting insert block 27 is wedge-shaped.

[0036] Specifically, the size of the leakage pressure array is not only related to the form of the core sample 19 and the confining pressure of the core sample 19, but also affected by the opening of the slit G. In this embodiment, Figure 15 As shown, the slot insertion block 27 is inserted into the slot G and can adjust the slot G's opening. A scale indicating the slot G's opening (e.g., 2 mm, 3 mm, 4 mm, or 5 mm) is provided on the horizontal cross-section of the slot insertion block 27. After inserting the slot insertion block 27 into the slot G, the experimenter can quantitatively adjust the slot G's opening by adjusting the insertion depth of the slot insertion block 27 in the slot G (the insertion depth of the slot insertion block 27 in the slot G is proportional to the slot G's opening). This changes the slot G's opening and closes the slot G. The slot G's opening is aligned with a scale on the slot insertion block 27, thereby enabling measurement of the lost-flow pressure of the core sample 19 after plugging. Furthermore, the slot insertion block 27 can be made of an elastic material, such as rubber.

[0037] In one embodiment of the present application, Figure 1 and Figure 3As shown, the indoor evaluation device for the original lost leakage pressure and the lost leakage pressure after plugging also includes a third pipeline 17, an overflow pressure gauge 12, an overflow flow meter 13, a beaker 14 and a regulating valve 8 for controlling the on-off of the third pipeline 17. The third pipeline 17 is connected between the beaker 14 and the slit G. After the drilling fluid flows out of the slit G, it passes through the interface of the confining pressure liner 20 and flows into the beaker 14 through the third pipeline 17. The beaker 14 is used to collect the drilling fluid flowing out of the slit G; the overflow pressure gauge 12 and the flow meter are both installed on the third pipeline 17 and are used to respectively detect the pressure and flow in the third pipeline 17.

[0038] Another embodiment of the present application provides an indoor evaluation method for original leakage pressure and lost pressure after plugging. The indoor evaluation method for original leakage pressure and lost pressure after plugging is applicable to the indoor evaluation device for original leakage pressure and lost pressure after plugging in the above embodiment and includes the following steps: Step S101: controlling the confining pressure pipeline assembly to deliver hydraulic oil into the accommodating chamber to apply a first confining pressure to the core sample 19 and place the slit G in a first closed state; Step S102: controlling the simulated casing pipeline assembly to deliver drilling fluid with gradually increasing pressure to the sample deep hole H of the core sample 19; Step S103: Determine whether the drilling fluid flows out of the slot G; Step S104: obtaining a first pressure of the drilling fluid.

[0039] Specifically, the experimenter places the core sample 19 in the accommodating chamber (the confining pressure liner 20 is located outside the core sample 19), and ensures that the opening of the slit G of the core sample 19 is aligned with the outlet of the confining pressure liner 20. Then the shell 22 is controlled to start, and the shell 22 drives the first adjusting member 25 to rotate through the first coupling 24. The first adjusting member 25 pressurizes the hydraulic oil in the hydraulic oil tank 26 and maintains the pressure stable. Then the controller opens the valve 6 and adjusts the confining pressure stabilizing component 2 so that the pressure of the first pressure gauge 11 reaches the opening pressure. Conditions: Pressurized hydraulic oil is delivered from the first pipeline 16 to a portion of the accommodating cavity between the shell 22 and the confining pressure liner 20. The pressurized hydraulic oil uniformly applies pressure to the confining pressure liner 20 on the outer peripheral side of the core sample 19, thereby uniformly applying a first confining pressure to the outer peripheral wall of the core sample 19 to close the slit G on the core sample 19 (the closed state of the slit G is the first closed state at this time). The first confining pressure is the confining pressure to which the core sample 19 is subjected when the slit G on the core sample 19 is in the first closed state. Then the controller starts the second motor 3, and the second motor 3 drives the second adjusting member 4 to rotate through the second coupling 18. The second adjusting member 4 continuously pressurizes the drilling fluid in the drilling fluid storage tank 5, opens the opening and closing valve 7 and the regulating valve 8, and the pressurized drilling fluid is transported to the sample deep hole H of the core sample 19 through the second pipeline 15. When the drilling fluid pressure reaches a certain condition, the slit G on the core sample 19 is opened, and the drilling fluid flows out from the slit G and flows into the beaker 14 through the third pipeline 17. The overflow pressure gauge 12 measures the pressure of the drilling fluid in the third pipeline 17 and sends it to the controller. The pressure of the drilling fluid measured by the overflow pressure gauge 12 is the first pressure, that is, the original loss pressure.

[0040] Step S105: controlling the confining pressure pipeline assembly to stop delivering hydraulic oil into the accommodating cavity and controlling the simulated casing pipeline assembly to stop delivering drilling fluid into the sample deep hole H; Step S106: inserting the slit inserting block 27 into the slit G.

[0041] Specifically, after determining the first pressure, the controller stops the respective conveying functions of the confining pressure pipeline assembly and the simulated casing pipeline assembly. The experimenter inserts the slit insertion block 27 into the slit G (the experimenter inserts the slit insertion block 27 to an appropriate depth according to actual needs to make the opening of the slit G an appropriate opening), and then places the combination of the core sample 19 and the slit insertion block 27 in the accommodating cavity (the confining pressure liner 20 is located on the outside of the combination of the core sample 19 and the slit insertion block 27), and the opening of the slit G of the core sample 19 is aligned with the outlet of the confining pressure liner 20.

[0042] Step S107: controlling the confining pressure pipeline assembly to deliver hydraulic oil into the accommodating chamber to apply a second confining pressure to the core sample 19 and place the slit G in a second closed state; Step S108: controlling the simulated casing pipeline assembly to deliver drilling fluid to the sample deep hole H of the core sample 19 again; Step S109: Determine whether the drilling fluid flows out of the slot G again; Step S110: obtaining a second pressure of the drilling fluid; Step S111: determining a leakage pressure array according to the first pressure and the second pressure.

[0043] Specifically, the control housing 22 is started, and the housing 22 drives the first adjusting member 25 to rotate through the first coupling 24. The first adjusting member 25 pressurizes the hydraulic oil in the hydraulic oil tank 26 and maintains the pressure stable; then the controller opens the valve 6, and adjusts the confining pressure stabilization component 2 so that the pressure of the first pressure gauge 11 reaches the opening condition, and the pressurized hydraulic oil is transported by the first pipeline 16 to the partial accommodating cavity between the housing 22 and the confining pressure liner 20. The pressurized hydraulic oil uniformly applies pressure to the confining pressure liner 20 on the outer peripheral side of the core sample 19, thereby achieving uniform application of the second confining pressure on the outer peripheral wall of the core sample 19 to close the slit G on the core sample 19 (the closed state of the slit G at this time is the second closed state). The second confining pressure is the confining pressure to which the core sample 19 is subjected when the slit G on the core sample 19 is in the second closed state; Then the controller starts the second motor 3, and the second motor 3 drives the second adjusting member 4 to rotate through the second coupling 18. The second adjusting member 4 continuously pressurizes the drilling fluid in the drilling fluid storage tank 5, opens the opening and closing valve 7 and the regulating valve 8, and the pressurized drilling fluid is transported to the sample deep hole H of the core sample 19 through the second pipeline 15. When the drilling fluid pressure reaches a certain condition, the slit G on the core sample 19 is opened again, and the drilling fluid flows out of the slit G and flows into the beaker 14 through the third pipeline 17. The overflow pressure gauge 12 measures the pressure of the drilling fluid in the third pipeline 17 and sends it to the controller. The pressure of the drilling fluid measured by the overflow pressure gauge 12 is the second pressure, that is, the loss pressure after plugging. The controller determines that the original loss pressure and the loss pressure after plugging together constitute a loss pressure array.

[0044] Furthermore, the experimenter inserts the slot insertion block 27 into the slot G at different depths, and repeats steps S107 to S111 to obtain the leakage loss pressure after plugging at different slot G openings and draw a relationship diagram between the leakage loss pressure after plugging and the slot G opening.

[0045] In one embodiment of the present application, the indoor evaluation of the original leakage pressure and the leakage pressure after plugging further includes a first regulating member 25, and the indoor evaluation method of the original leakage pressure and the leakage pressure after plugging further includes: After controlling the confining pressure pipeline assembly to deliver hydraulic oil into the accommodating chamber, controlling the first regulating member 25 to regulate the pressure of the hydraulic oil to the first confining pressure, so that the slit G is in the first closed state; and After the confining pressure pipeline assembly is controlled to deliver hydraulic oil to the accommodating chamber again, the first regulating member 25 is controlled to regulate the pressure of the hydraulic oil to the second confining pressure, so that the slit G is in the second closed state.

[0046] Specifically, in step S101, the control housing 22 is started, and the housing 22 drives the first adjusting member 25 to rotate through the first coupling 24. The first adjusting member 25 pressurizes the hydraulic oil in the hydraulic oil tank 26 to a first confining pressure. When the hydraulic oil tank 26 outputs the hydraulic oil of the first confining pressure to the accommodating cavity, the slit G is placed in a first closed state. Similarly, in step S107, the control housing 22 is started, and the housing 22 drives the first adjusting member 25 to rotate through the first coupling 24. The first adjusting member 25 pressurizes the hydraulic oil in the hydraulic oil tank 26 until it reaches the second confining pressure. When the hydraulic oil tank 26 outputs the hydraulic oil of the second confining pressure to the accommodating cavity, the slit G can be placed in the second closed state.

[0047] In one embodiment of the present application, the second confining pressure is consistent with the first confining pressure, and the first confining pressure can be determined according to the following method:

[0048] (1) in, is a first preset wellbore stress; is a second preset wellbore stress; The third preset wellbore stress; is the preset well surface shear stress; is the preset wellbore radius; is the preset wellbore pressure; is the angle of the core sample 19 in the cylindrical coordinate system; is the distance between the core sample 19 and the origin in the cylindrical coordinate system; is the first confining pressure.

[0050] Specifically, in actual conditions, the confining pressure of the core is determined by the three-dimensional geostress in the principal stress space under underground conditions, the well inclination angle, the azimuth angle, the wellbore pressure, and the wellbore radius. However, in simulation experiments, it is necessary to convert the principal stress space coordinate system under underground simulation conditions into the wellbore coordinate system. That is to say, first, according to the three-dimensional geostress in the principal stress space coordinate system under the preset underground simulation conditions (i.e. 、 、 ), well inclination, azimuth and formula (2) to calculate the wellbore triaxial stress of core sample 19 in the wellbore coordinate system (i.e. 、 、 ) and well surface shear stress; Then, the first confining pressure of the core sample 19 in the cylindrical coordinate system is obtained by applying the wellbore triaxial stress, well surface shear stress, wellbore pressure, wellbore radius and formula (1).

[0051] Wherein, formula (2) is: (2) Furthermore, (3) in, is the first geostress of the three-dimensional geostress; is the second geostress of the three-dimensional geostress; is the third geostress of the three-dimensional geostress; is the well inclination angle; is the azimuth.

[0052] In one embodiment of the present application, determining in step S103 that the drilling fluid has flowed out of the slit G or determining in step S109 that the drilling fluid has flowed out of the slit G again includes: Obtain the flow rate value of the drilling fluid at the output end of the slot G; When the flow rate value reaches the preset overflow flow rate value, it is determined that the drilling fluid flows out from the slit G of the core sample 19 .

[0053] Specifically, if Figure 1 and Figure 3 As shown, in this embodiment, the preset overflow flow value is selected as zero, and an overflow flow meter 13 is set on the third pipeline 17. When the drilling fluid flows out from the slit G of the core sample 19, the overflow flow meter 13 will generate a reading and send the above reading result to the controller, and the controller can determine that drilling fluid has flowed out from the slit G of the core sample 19.

[0054] In another embodiment of the present application, determining in step S103 that the drilling fluid has flowed out of the slit G or determining in step S109 that the drilling fluid has flowed out of the slit G again includes: Obtain the pressure value of the drilling fluid at the output end of the slot G; When the pressure value reaches the preset overflow pressure value, it is determined that the drilling fluid flows out from the cut G of the core sample 19 .

[0055] Specifically, if Figure 1 and Figure 3 As shown, in this embodiment, the preset overflow pressure value is selected as zero, and an overflow pressure gauge 12 is set on the third pipeline 17. When the drilling fluid flows out of the slit G of the core sample 19, the overflow pressure gauge 12 generates a reading and sends the above reading result to the controller, and the controller can determine that drilling fluid has flowed out of the slit G of the core sample 19.

[0056] Furthermore, in actual operation, there is a certain time difference between confirming that the drilling fluid has flowed out of the slit G of the core sample 19 and recording the current drilling fluid pressure as the loss pressure. During this time difference, the second regulating member 4 is still increasing the drilling fluid pressure, so the pressure ultimately measured by the overflow pressure gauge 12 is typically greater than the actual loss pressure (i.e., the first pressure is typically greater than the actual original loss pressure, or the second pressure is typically greater than the actual post-plugging loss pressure). The greater the difference between the pressure measured by the overflow pressure gauge 12 and the actual loss pressure, the greater the flow rate and outflow pressure of the drilling fluid flowing out of the slit G. At this point, the readings of the overflow flow meter 13 and / or the overflow pressure gauge 12 can be used to determine whether the pressure measured by the overflow pressure gauge 12 is greater than the actual loss pressure, thereby correcting the loss pressure to further improve the accuracy of the indoor evaluation device for the original loss pressure and post-plugging loss pressure.

[0057] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0058] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0059] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

Claims

1. An indoor evaluation device for original leakage pressure and leakage pressure after plugging, characterized in that: The indoor evaluation device for the original leakage pressure and the leakage pressure after plugging includes: A pressure chamber assembly, wherein a receiving cavity for receiving a core sample (19) is formed in the pressure chamber assembly; a confining pressure pipeline assembly, wherein both ends of the confining pressure pipeline assembly are respectively connected to a hydraulic oil source and the accommodating chamber, and are used to transport hydraulic oil into the accommodating chamber; A confining pressure liner (20), arranged in the accommodating cavity and used to be sleeved on the outside of the core sample (19), and used to apply confining pressure to the core sample (19) through the hydraulic oil; A simulated casing pipeline assembly, wherein both ends of the simulated casing pipeline assembly are respectively connected to a drilling fluid source and a sample deep hole (H) of the core sample (19), and is used to transport drilling fluid to the sample deep hole (H); A slit insertion block (27) for being inserted into the slit (G); A controller is connected to the confining pressure pipeline assembly and the simulated casing pipeline assembly and is used to determine a leakage pressure array of the core sample (19), wherein the leakage pressure array includes an original leakage pressure and a leakage pressure after plugging.

2. The indoor evaluation device for original leakage pressure and leakage pressure after plugging according to claim 1 is characterized in that: The confined pressure pipeline assembly comprises: a first pipeline (16), the first pipeline (16) being connected between the hydraulic oil source and the accommodating chamber; A first regulating member (25) is provided on the first pipeline (16) and is used to regulate the pressure of the hydraulic oil.

3. The indoor evaluation device for original leakage pressure and leakage pressure after plugging according to claim 2 is characterized in that: The simulated casing pipeline assembly includes: a second pipeline (15), the second pipeline (15) being connected between the drilling fluid source and the sample deep hole (H); The second regulating member (4) is provided on the second pipeline (15) and is used to regulate the pressure of the drilling fluid.

4. The indoor evaluation device for original leakage pressure and leakage pressure after plugging according to claim 1 is characterized in that: The pressure chamber assembly comprises a top plate (1), a bottom plate (21), a shell (22), a first sealing rubber ring and a second sealing rubber ring. The top plate (1) and the bottom plate (21) are spaced apart in the vertical direction. The shell (22) is arranged between the top plate (1) and the bottom plate (21), and the two ends of the shell (22) are detachably connected to the top plate (1) and the bottom plate (21). The top plate (1), the bottom plate (21) and the shell (22) together enclose the accommodating cavity. The first sealing rubber ring is arranged between the top plate (1) and the confining pressure liner (20) and is used to seal the gap between the top plate (1) and the confining pressure liner (20). The second sealing rubber ring is arranged between the bottom plate (21) and the confining pressure liner (20) and is used to seal the gap between the bottom plate (21) and the confining pressure liner (20).

5. The indoor evaluation device for original leakage pressure and leakage pressure after plugging according to claim 1 is characterized in that: The horizontal cross-section of the slit insert block (27) is wedge-shaped.

6. A method for indoor evaluation of original leakage pressure and leakage pressure after plugging, characterized in that: The method for indoor evaluation of original leakage pressure and leakage pressure after plugging is applicable to the indoor evaluation device for original leakage pressure and leakage pressure after plugging according to any one of claims 1 to 5 and comprises: Controlling the confining pressure pipeline assembly to deliver hydraulic oil into the accommodating chamber to apply a first confining pressure to the core sample (19) and place the slit (G) in a first closed state; Controlling the simulated casing pipeline assembly to deliver drilling fluid with gradually increasing pressure to the sample deep hole (H) of the core sample (19); Determining that the drilling fluid flows out of the cut (G); obtaining a first pressure of the drilling fluid; Controlling the confining pressure pipeline assembly to stop delivering the hydraulic oil into the accommodating chamber and controlling the simulated casing pipeline assembly to stop delivering the drilling fluid to the sample deep hole (H); Inserting the slit insertion block (27) into the slit (G); Controlling the confining pressure pipeline assembly to deliver the hydraulic oil into the accommodating chamber to apply a second confining pressure to the core sample (19) and place the slit (G) in a second closed state; Controlling the simulated casing pipeline assembly to transport the drilling fluid to the sample deep hole (H) of the core sample (19) again; Determining that the drilling fluid flows out of the cut (G) again; obtaining a second pressure of the drilling fluid; The leak pressure array is determined based on the first pressure and the second pressure.

7. The indoor evaluation method for original leakage pressure and leakage pressure after plugging according to claim 6 is characterized in that: The indoor evaluation of the original leakage pressure and the leakage pressure after plugging further includes a first regulating member (25), and the indoor evaluation method of the original leakage pressure and the leakage pressure after plugging further includes: After controlling the confining pressure pipeline assembly to deliver the hydraulic oil to the accommodating chamber, controlling the first regulating member (25) to regulate the pressure of the hydraulic oil to a first confining pressure so that the slit (G) is in a first closed state; and After controlling the confining pressure pipeline assembly to deliver the hydraulic oil to the accommodating chamber again, controlling the first regulating member (25) to regulate the pressure of the hydraulic oil to a second confining pressure, so that the slit (G) is in a second closed state.

8. The indoor evaluation method for original leakage pressure and leakage pressure after plugging according to claim 6 is characterized in that: The first confining pressure is determined according to the following method: in, is a first preset wellbore stress; is a second preset wellbore stress; The third preset wellbore stress; is the preset well surface shear stress; is the preset wellbore radius; is the preset wellbore pressure; is the angle of the core sample (19) in the cylindrical coordinate system; is the distance between the core sample (19) and the origin in the cylindrical coordinate system; is the first confining pressure.

9. The indoor evaluation method for original leakage pressure and leakage pressure after plugging according to claim 6 is characterized in that: The determining that the drilling fluid flows out of the cutting slit (G) or determining that the drilling fluid flows out of the cutting slit (G) again includes: Obtaining a flow rate value of the drilling fluid at an output end of the slot (G); When the flow rate value reaches a preset overflow flow rate value, it is determined that the drilling fluid flows out of the cut (G) of the core sample (19).

10. The indoor evaluation method for original leakage pressure and leakage pressure after plugging according to claim 6 is characterized in that: The determining that the drilling fluid flows out of the cutting slit (G) or determining that the drilling fluid flows out of the cutting slit (G) again includes: Obtaining a pressure value of the drilling fluid at an output end of the slot (G); When the pressure value reaches a preset overflow pressure value, it is determined that the drilling fluid flows out of the cut (G) of the core sample (19).

Images