Fluid rock reaction device considering stress sensitivity and experimental method

Abstract

The embodiment of the invention provides a fluid rock reaction device considering stress sensitivity and an experimental method. The device comprises a reaction container, a core rubber sleeve and a plugging assembly, a fluid cavity for simulating fluid pressure and an annular pressure cavity for simulating formation stress are formed in the reaction container, and an annular pressure connector for communicating the annular pressure cavity with an external annular pressure pump, a test fluid connector communicated with the fluid cavity and a test fluid outlet are formed in the side wall of the reaction container; the rock core rubber sleeve is arranged in the annular pressure cavity and is used for accommodating a to-be-tested rock sample; the plugging assembly comprises a first plugging piece and a second plugging piece which are respectively sealed in an annular space between the rock core rubber sleeve and the annular pressure cavity and a second end face, deviating from the fluid cavity, of the rock sample to be tested. On the basis of stress sensitive factors, the fluid-rock action degree under different ground stress conditions, different temperatures and different fluid pressure conditions is researched, a fluid-rock action experiment is carried out on a real oil and gas natural rock sample, and guidance is provided for parameter optimization of an oil and gas reservoir fracturing process.

Description

Technical Field

[0001] The present application relates to the field of oil and gas storage technology, and in particular to a fluid rock reaction device and an experimental method taking stress sensitivity into consideration. Background Art

[0002] my country's unconventional oil and gas reservoirs are characterized by denseness, high crude oil viscosity, and poor fluidity. Using large-scale horizontal well volume fracturing technology to construct a fracture network with long-term conductivity can greatly reduce the flow resistance of crude oil, which is the key to achieving long-term stable production of unconventional oil and gas wells. A large number of studies have shown that the fluid-rock interaction caused by the fracturing fluid entering the formation has a significant impact on the effectiveness of the fracturing fractures. The impact of different fluid-rock interactions on the effectiveness of fractures is related to the efficient development of unconventional oil and gas.

[0003] However, traditional fluid-rock interaction experiments usually do not consider the influence of ground stress. Rocks are not subject to stress, and water-sensitive rocks are easily loosened and broken. Therefore, they do not conform to the actual situation of the reservoir. The experimental results are not accurate and have poor reliability, and cannot provide reliable data and support for conventional and unconventional oil and gas reserve and production increases. Summary of the invention

[0004] The embodiments of the present application provide a fluid-rock reaction device and experimental method that take stress sensitivity into consideration, which can accurately consider the interaction between fluid and reservoir rock under formation stress conditions, and can accurately simulate formation stress conditions and the interaction between fluid and reservoir rock, thereby providing reliable data and technical support for conventional and unconventional oil and gas reserve and production increases.

[0005] In a first aspect, an embodiment of the present application provides a fluid rock reaction device considering stress sensitivity, comprising:

[0006] A reaction container, wherein a fluid cavity and an annular pressure cavity are provided inside the reaction container, wherein the fluid cavity is used to simulate fluid pressure, and the annular pressure cavity is used to simulate formation stress, and an annular pressure interface, a test fluid interface and a test fluid outlet are provided on the side wall of the reaction container, wherein the test fluid interface is used to connect the fluid cavity with an external injection pump so that the injection pump injects fluid into the fluid cavity through the test fluid interface, and the annular pressure interface is used to connect the annular pressure cavity with an external annular pressure pump so that the annular pressure pump applies annular pressure to the annular pressure cavity through the annular pressure interface;

[0007] A core rubber sleeve, which is arranged in the annular pressure chamber and is used to accommodate the rock sample to be tested;

[0008] A plugging assembly, the plugging assembly includes a first plugging piece and a second plugging piece, the first plugging piece is used to seal the annular space between the core rubber sleeve and the annular pressure chamber, and to connect the first end face of the rock sample to be tested facing the fluid chamber to the fluid chamber, and the second plugging piece is used to seal the second end face of the rock sample to be tested away from the fluid chamber, so as to isolate the second end face of the rock sample to be tested from the external space of the core rubber sleeve.

[0009] In a possible implementation, it further includes a mounting frame for mounting the reaction container, the mounting frame is provided with two bearing seats, the bearing seats have built-in bearings, and the reaction container is rotatably mounted on the bearing seats via a rotating shaft and the bearings.

[0010] In a possible implementation, the reaction container includes a fluid reservoir and a holder, the fluid reservoir is provided with a plugging cavity and the fluid cavity in communication, and the holder is provided with a ring pressure cavity and a plugging component installation cavity in communication;

[0011] The reaction container also includes: a third sealing member, a fourth sealing member and at least two sealing members, wherein the third sealing member is arranged in the sealing cavity for sealing the sealing cavity and the middle space of the fluid cavity, the fourth sealing member is arranged on the second positioning step of the sealing component installation cavity for sealing the sealing component installation cavity, the annular pressure interface is arranged on the fourth sealing member, the test fluid interface and the test fluid outlet are arranged in the fluid reservoir, and the sealing member is arranged on the outer peripheral surface of the annular pressure cavity installation portion and the outer peripheral surface of the fourth sealing member.

[0012] In a possible implementation, a plug-in portion is provided on the outer peripheral surface of the front end of the fourth sealing member, and a plug-in fitting portion is provided inside the rear end of the core rubber sleeve, and the plug-in portion is used to be inserted into the inside of the plug-in fitting portion to axially limit the core rubber sleeve.

[0013] In a possible implementation manner, the front end surface of the plug-in portion is a tapered surface, and the plug-in fitting portion is provided with a tapered groove for matching the tapered surface.

[0014] In a possible embodiment, the interior of the reaction container is provided with a connecting wall for separating the fluid chamber and the front end annular pressure chamber, the connecting wall is provided with a conical sealing surface on one side of the front end cavity, and the front end of the core rubber sleeve is provided with a conical end surface adapted to the conical sealing surface.

[0015] In a possible implementation manner, the third sealing member includes a third core plug, a second pressure cap sleeved on the third core plug, and a sealing ring sealingly connecting the third core plug and the fluid reservoir.

[0016] In a possible embodiment, the fourth sealing member includes a socket for tightening the second sealing member, a plug removal rod inserted into the socket, a fourth sealing plug sleeved on the socket, a second pressure cap for locking the fourth sealing plug, and a third pressure cap for locking the plug removal rod.

[0017] In a possible implementation manner, the fluid reservoir is a fluid reservoir made of stainless and acid-resistant steel.

[0018] In a second aspect, an embodiment of the present application provides an experimental method, which is applied to any of the above-mentioned fluid rock reaction devices considering stress sensitivity, comprising the steps of:

[0019] Process the core into rock samples of preset specifications;

[0020] The rock sample is placed in a core rubber sleeve, and the core rubber sleeve containing the rock sample is placed in the annular pressure cavity of the reaction container, a second plugging member is installed in the core rubber sleeve, and a first plugging member is installed in the annular space between the sealing core rubber sleeve and the annular pressure cavity in the annular pressure cavity;

[0021] Connecting an annular pressure pump to an annular pressure interface, and applying annular pressure simulating formation stress to the annular pressure cavity through the annular pressure interface;

[0022] Connecting the injection pump to the test fluid interface, closing the test fluid outlet, and applying fluid pressure to the fluid cavity through the test fluid interface;

[0023] Place the reaction container in an oven, set the reaction temperature and reaction time, and perform fluid-rock reaction;

[0024] The reaction vessel is taken out of the oven, cooled, the test fluid outlet is opened, the ring pressure is unloaded, and the core is taken out;

[0025] Physical property tests are performed on the core and test fluid.

[0026] The fluid rock reaction device and experimental method considering stress sensitivity provided in the embodiment of the present application are provided by setting a reaction container, in which a fluid cavity and an annular pressure cavity are provided, and the fluid cavity is connected to an external injection pump through a test fluid interface, and the injection pump is used to inject a test fluid into the fluid cavity and apply fluid pressure, so that mineral composition testing, solution ion testing, rock mechanics testing and other tests can be carried out, and the degree of reaction to the rock under different fluid pressure conditions can be comprehensively analyzed. The annular pressure cavity is connected to an external annular pressure pump through an annular pressure interface, and annular pressure is applied to the annular pressure cavity by the annular pressure pump, so that formation stress can be simulated. By placing the reaction container in an oven and setting reaction parameters such as reaction temperature and reaction time, the degree of effect of the fluid on the rock under the reaction temperature and time conditions can be simulated.

[0027] The fluid-rock reaction device and experimental method considering stress sensitivity provided in the present application can study the degree of fluid-rock interaction under different ground stress conditions, different fluid pressure conditions, different types of fluids and different temperature conditions based on factors such as ground stress, fluid pressure, fluid type and temperature, and thus conduct fluid-rock interaction experiments considering factors such as formation stress, fluid pressure, temperature, etc. on real oil and gas natural rock samples, so as to obtain data on the influence of different types of fracturing fluids on reservoir rocks, judge the degree of influence of fracturing fluids on fracturing fracture surfaces, natural fractures or laminae, and provide guidance for parameter optimization of oil and gas reservoir fracturing technology. In addition, the present application has a simple structure and a compact layout. The entire experimental process is simple, efficient and easy to implement. It truly simulates the interaction environment between fracturing fluid and reservoir rock during on-site fracturing, and the test results are highly accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0029] Figure 1 A cross-sectional view of a fluid-rock reaction device considering stress sensitivity provided for a specific embodiment of the present application;

[0030] Figure 2 for Figure 1 A cross-sectional view of a fluid-rock reaction device considering stress sensitivity in an embodiment, with an external injection pump and an annular pressure pump;

[0031] Figure 3 Flowchart of the experimental methods provided for this application.

[0032] Description of reference numerals:

[0033] 10-reaction container; 20-core rubber sleeve; 30-plugging assembly; 40-injection pump; 50-annular pressure pump; 60-rock sample;

[0034] 11- fluid reservoir; 12- holder;

[0035] 101-fluid cavity; 102-ring pressure cavity; 103-ring pressure interface; 104-test fluid interface; 105-test fluid outlet; 106-connecting wall; 111-blocking cavity; 121-blocking assembly installation cavity; 201-plug-in mating part; 202-conical end face; 301-first blocking member; 302-second blocking member; 303-third blocking member; 304-fourth blocking member; 305-sealing member;

[0036] 1061-conical sealing surface; 1211-second positioning step; 2011-conical groove; 3031-third core plug; 3032-first pressure cap; 3033-sealing ring; 3041-plug-in part; 3042-conical surface; 3043-connecting sleeve; 3044-plug unloading rod; 3045-fourth sealing plug; 3046-second pressure cap; 3047-third pressure cap.

[0037] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0038] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0039] It should be noted that when a component is referred to as being "fixed on" or "disposed on" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right", "front", "rear" and similar expressions used in the specification of this application are for illustrative purposes only and do not represent the only implementation method.

[0040] In addition, 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. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0041] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first feature is directly in contact with the second feature, or the first feature and the second feature are in contact indirectly through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is smaller in level than the second feature.

[0042] Unless otherwise defined, all technical and scientific terms used in the specification of this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in the specification of this application includes any and all combinations of one or more related listed items.

[0043] Considering that existing fluid-rock interaction experiments usually do not consider the influence of factors such as geostress, fluid stress, fluid type, and temperature, they cannot truly simulate the fluid-rock reaction environment. Rocks are not subject to stress, and water-sensitive rocks are easily loosened and broken, which does not conform to the actual reservoir conditions, resulting in low experimental accuracy and poor reliability of experimental data.

[0044] This application is based on the limitations of traditional fluid-rock interaction experiments and the complexity of the environment in which natural oil and gas rocks are located, and taking into account the fact that the current fluid-rock reaction experiments do not consider influencing factors such as ground stress, fluid stress, fluid medium type, temperature, etc., and cannot simulate the actual situation of the reservoir, so the experimental accuracy is poor, the reliability is low, and the application scope is limited. Technical defects, a fluid-rock reaction device and experimental method considering stress sensitivity are proposed, which can carry out fluid-rock interaction experiments considering formation stress on real oil and gas natural rock samples, and compositely simulate fluid-rock interaction degree experiments under different ground stress conditions, different temperatures, different fluid types, and different fluid pressure conditions, so as to obtain the influence of different types of fracturing fluids on reservoir rocks, judge the degree of influence of fracturing fluids on fracturing fracture surfaces, natural fractures / laminae, etc., and provide data guidance and support for the optimization of conventional or unconventional oil and gas reservoir fracturing process parameters.

[0045] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0046] Please refer to Figure 1 and Figure 2. The embodiment of the present application provides a fluid rock reaction device considering stress sensitivity, which mainly includes: a reaction vessel 10, a core rubber sleeve 20 and a plugging assembly 30. Among them, a fluid cavity 101 and an annular pressure cavity 102 are provided inside the reaction vessel 10, and an annular pressure interface 103, a test fluid interface 104 and a test fluid outlet 105 are provided on the side wall of the reaction vessel 10. The annular pressure interface 103 is connected to the annular pressure cavity 102, and the test fluid interface 104 and the test fluid outlet 105 are both connected to the fluid cavity 101. The external injection pump 40 is connected to the fluid cavity 101 through the test fluid interface 104, so that the injection pump 40 injects fluid into the fluid cavity 101 through the test fluid interface 104, and the external annular pressure pump 50 is connected to the pressure cavity through the annular pressure interface 103, so as to ensure that the annular pressure pump 50 applies annular pressure to the annular pressure cavity 102 through the annular pressure interface 103.

[0047] The core rubber sleeve 20 is a sleeve body with two ends open and a closed periphery. The core rubber sleeve 20 is provided with an inner cavity. The shape and size of the inner cavity are set according to the shape and size of the rock sample to be tested. For example, when a cylindrical rock sample 60 is used, the inner cavity of the core rubber sleeve 20 is set to a circular cross section; when a strip rock sample 60 is used, the inner cavity of the core rubber sleeve 20 can be set to a square cross section or a rectangular cross section. Therefore, the shape and size of the core rubber sleeve 20 and the inner cavity therein are not limited herein, and it is sufficient to meet the installation of the rock sample 60.

[0048] The core rubber sleeve 20 is arranged in the annular pressure chamber 102 and is detachably installed in the cavity of the annular pressure chamber 102, and its two ends are sealed by the plugging assembly 30. The plugging assembly 30 includes a first plugging member 301 and a second plugging member 302. The first plugging member 301 seals the annular space between the core rubber sleeve 20 and the annular pressure chamber 102, and ensures that the first end face of the rock sample to be tested facing the fluid chamber 101 is connected to the fluid chamber 101. The second end face of the rock sample to be tested facing away from the fluid chamber 101 is sealed by the second plugging member 302, so that the second end face of the rock sample to be tested is isolated from the external space of the core rubber sleeve 20.

[0049] In other words, the two ends of the core rubber sleeve 20 are sealed by the first plugging member 301 and the second plugging member 302 respectively. Specifically, a connecting wall 106 is provided between the fluid chamber 101 and the annular pressure chamber 102, and the first plugging member 301 seals the outer end face of the core rubber sleeve 20 facing the fluid chamber 101 and the connecting wall 106, and under the condition that the fluid chamber 101 and the annular pressure chamber 102 are isolated and not connected, the end face of the rock sample to be tested inside the core rubber sleeve 20 is exposed to the fluid chamber 101, so that the test rock sample 60 contacts the test fluid, and because the rock sample 60 is a porous medium, it uses capillary force or relies on capillary force and power as a power source to achieve self-priming synchronous with the reaction.

[0050] The second plugging member 302 seals the inner cavity of the other end of the core rubber sleeve 20 to ensure that the test fluid completely enters the rock sample to be tested without leaking out, thereby ensuring that the test fluid reacts completely with the test rock sample 60 .

[0051] It should be noted that the fluid in this application may include gas and liquid, including but not limited to supercritical CO 2 , water, CO 2 Aqueous solution, hydrochloric acid, etc.

[0052] The fluid-rock reaction device considering stress sensitivity provided in the present application realizes the analysis of the degree of reaction between fluid and reservoir rock based on stress-sensitive conditions. Its working principle is as follows: by applying annular pressure to the annular pressure chamber 102 and injecting test fluid into the fluid chamber 101, a comprehensive simulation of fluid-rock interaction experiments under different formation stresses, different fluid pressures and different temperatures is realized, thereby significantly improving the experimental accuracy.

[0053] In order to meet the experimental requirements of different installation angles, a mounting frame can be set at the bottom of the reaction vessel 10. The frame mainly includes a base, a connecting frame and a placement table. The base is set on the experimental platform or the ground, and the reaction vessel 10 is placed on the placement table. The connecting frame is vertically connected between the base and the placement table to connect the placement table to the base. Two bearing seats are provided on the mounting frame. The two bearing seats are symmetrically arranged on the placement table. The bearing seats have built-in bearings. Rotating shafts are provided at both ends of the reaction vessel 10. The two rotating shafts are coaxially arranged. The ends of the rotating shafts extend into the bearings and are rotatably installed inside the bearing seats through the bearings.

[0054] The reaction container 10 is rotatably mounted on the bearing seat via a rotating shaft and a bearing, thereby achieving adjustment of the installation angle of the reaction container 10, and supporting the reaction container 10 to be placed horizontally, vertically, and at a certain inclination angle relative to the placement table.

[0055] When the reaction container 10 is placed vertically or obliquely, the rock sample 60 inside the reaction container 10 is arranged vertically, and the capillary force and gravity are used as pumping power, so that the test fluid quickly enters the rock sample 60, the penetration force is greater, the fluid loss can be reduced, and the reaction efficiency can be improved. Among them, when the reaction container 10 is placed vertically and the fluid cavity 101 is facing upward, the penetration force is the largest, the fluid loss is the smallest, and the reaction efficiency is the highest.

[0056] It can be understood that in this embodiment, the reaction container 10 can be rotatably installed, and its placement angle can be adjusted arbitrarily according to experimental needs.

[0057] Furthermore, the reaction vessel 10 adopts a split structure, including a fluid storage device 11 and a clamp 12. The fluid storage device 11 is provided with a sealing cavity 111 and a fluid cavity 101, and the two cavities are connected. The clamp 12 is provided with an annular pressure cavity 102 and a sealing component installation cavity 121, and the two are connected. The sealing cavity 111, the fluid cavity 101, the annular pressure cavity 102 and the sealing component installation cavity 121 are coaxially arranged and connected from one end of the reaction container 10 to the other end.

[0058] The reaction vessel 10 further includes: a third blocking member 303, a fourth blocking member 304 and at least two sealing members 305. The third blocking member 303 is arranged in the blocking cavity 111, and the blocking cavity 111 and the middle space of the fluid cavity 101 are blocked by the third blocking member 303. The inner wall of the blocking component installation cavity 121 is provided with a second positioning step 1211. The fourth blocking member 304 is arranged in the blocking component installation cavity 121, and is positioned and installed by the second positioning step 1211. The fourth blocking member 304 is used to seal the blocking component installation cavity 121 inside the clamp 12. In addition, the sealing member 305 is arranged on the outer peripheral surface of the mounting portion of the annular pressure cavity 102 and the outer peripheral surface of the fourth blocking member 304. With such an arrangement, the fluid cavity 101 and the annular pressure cavity 102 form a closed space isolated from the outside of the reaction device. The test fluid interface 104 and the test fluid outlet 105 are arranged in the fluid reservoir 11. The test fluid interface 104 is connected to an external injection pump 40, and the fluid enters the fluid chamber 101, and enters the pores of the rock sample 60 from the middle space of the fluid chamber 101, and gradually enters the rock sample 60 while reacting with the rock sample 60. The external annular pressure pump 50 is connected through the annular pressure interface 103 to simulate different formation stresses.

[0059] In this application, the annular pressure chamber 102 is used to simulate the formation stress, and any value of the ground stress in the range of 0 to 80 MPa can be simulated. The fluid chamber 101 is used to simulate the fluid pressure, and any value of the fluid pressure in the range of 0 to 60 MPa can be simulated, and relevant fluid-rock interaction experiments can be carried out.

[0060] In a specific embodiment, a plug-in portion 3041 may be provided on the fourth plugging member 304, and the plug-in portion 3041 is provided on the front peripheral surface of the fourth plugging member 304, and correspondingly, a plug-in fitting portion 201 is provided inside the rear end of the core rubber sleeve 20. During assembly, the plug-in portion 3041 is inserted into the plug-in fitting portion 201, and axial positioning is performed through the matching surfaces of the two, thereby realizing axial limitation of the core rubber sleeve 20.

[0061] In order to improve the sealing performance between the fourth sealing piece 304 and the core rubber sleeve 20, the front end face of the plug-in portion 3041 is a conical surface 3042, and a conical groove 2011 is provided inside the plug-in fitting portion 201. The conical groove 2011 and the conical surface 3042 are plugged and matched with each other, and the contact area is increased by the contact inclined surface, thereby ensuring the sealing effect of the connecting end of the core rubber sleeve 20 and the fourth sealing piece 304.

[0062] Since the reaction vessel 10 is provided with a connecting wall 106 inside, the fluid chamber 101 and the front annular pressure chamber 102 are separated by the connecting wall 106, and the core rubber sleeve 20 is positioned. In order to improve the sealing performance between the core rubber sleeve 20 and the connecting wall 106, a conical sealing surface 1061 is provided on the side of the connecting wall 106 located at the front cavity, and a conical end surface 202 is provided on the front end surface of the core rubber sleeve 20, and the conical end surface 202 is adapted to the conical sealing surface 1061 of the connecting wall 106, and the two form a conical sealing surface 1061 to improve the sealing effect between the core rubber sleeve 20 and the connecting wall 106.

[0063] Specifically, the third sealing member 303 includes a third core plug 3031 , a first pressure cap 3032 mounted on the third core plug 3031 , and a sealing ring 3033 sealingly connecting the third core plug 3031 and the fluid reservoir 11 .

[0064] Specifically, the fourth sealing member 304 includes a socket 3043 for tightening the second sealing member 302, a plug removal rod 3044 inserted into the socket 3043, a fourth sealing plug 3045 sleeved on the socket 3043, a second pressure cap 3046 for locking the fourth sealing plug 3045, and a third pressure cap 3047 for locking the plug removal rod 3044.

[0065] In order to prevent the test fluid from corroding the fluid chamber 101 inside the reaction device during the reaction between the fluid and the rock, thereby causing the fluid chamber 101 to lose its sealing property, the material of the fluid chamber 101 is preferably, but not limited to, stainless acid-resistant steel. It should be noted that the specific materials of the fluid storage 11 and its internal fluid chamber 101 can be varied and are not limited herein.

[0066] The sealing ring 3033 in the present application can be but is not limited to a sealing ring made of fluororubber. Since fluororubber material has excellent high temperature resistance and chemical corrosion resistance, it can ensure that fluororubber maintains stable sealing performance under extreme conditions and extend the service life of the sealing ring 3033.

[0067] In summary, the stress-sensitive fluid-rock reaction device provided in the present application can comprehensively consider factors such as ground stress, fluid pressure, fluid medium type, temperature, etc., simulate the interaction environment between fracturing fluid and reservoir rock during on-site fracturing, and conduct fluid-rock interaction experiments on rocks. The entire experimental process is simple, fast, efficient, highly reliable, accurate in testing, and easy to implement.

[0068] refer to Figure 3 The present application also provides an experimental method, which is applied to the above-mentioned fluid-rock reaction device considering stress sensitivity, and includes the following steps:

[0069] Step S1: Processing the rock sample into a rock sample of preset specifications;

[0070] Step S2: loading the rock sample into the core rubber sleeve, and loading the core rubber sleeve containing the rock sample into the annular pressure cavity of the reaction vessel, installing the second plugging member in the core rubber sleeve, and installing the first plugging member in the annular space between the sealed core rubber sleeve and the annular pressure cavity in the annular pressure cavity;

[0071] Step S3: connecting the annular pressure pump to the annular pressure interface to apply annular pressure to the annular pressure cavity to simulate formation stress;

[0072] Step S4: Connect the injection pump to the test fluid interface, close the test fluid outlet, and apply fluid pressure to the fluid cavity through the injection pump;

[0073] Step S5: placing the reaction container into an oven, setting the reaction temperature and reaction time, and performing fluid-rock reaction;

[0074] Step S6: taking the reaction container out of the oven, cooling it, opening the outlet of the test fluid, unloading the ring pressure, and taking out the core;

[0075] Step S7: Perform physical property tests on the core and the test fluid.

[0076] The core in the present application can be an irregular oil and gas reservoir rock sample in the oil and gas reservoir. In step S1, the irregular oil and gas reservoir rock sample is processed into a regular core that meets the specifications of the core bin of the water-rock reaction device as a rock sample to be tested. The shape of the test rock sample can be but is not limited to a cylinder, for example, it can be a strip or irregular shape.

[0077] In step S2, after the rock sample is inserted into the core rubber sleeve, the core rubber sleeve containing the rock sample is placed in the annular pressure chamber, and plugging pieces are placed on the left and right sides of the core rubber sleeve. The plugging pieces may be sealing plugs.

[0078] In step S3, a hydraulic pump is connected to the annular pressure interface to apply annular pressure to simulate formation stress.

[0079] In step S4, the test fluid is connected to the test fluid inlet, the test fluid outlet is closed, and fluid pressure is applied by the injection pump.

[0080] In step S5, the reaction container is placed in an oven to set the reaction temperature and reaction time. After the reaction time is reached, the reaction container is taken out of the oven, and after cooling, the test fluid outlet is opened, the ring pressure is unloaded, and the rock sample is taken out.

[0081] In step S6, a series of physical property tests are performed on the rock sample and the test fluid, thereby analyzing the degree of fluid-rock reaction.

[0082] The following simulated ground stress is 50MPa, the fluid pressure is 30MPa, and the test fluid is CO 2 Taking aqueous solution and reaction time of 24 hours as an example, the above experimental method is explained, and the specific steps are as follows:

[0083] Step S1: Processing the irregular oil and gas reservoir rock sample 60 into a regular cylindrical rock core that meets the specifications of the core bin of the water-rock reaction device: that is, the rock sample 60 has a diameter of 2.5 cm and a length of 5 cm;

[0084] Step S2: insert the rock sample to be tested into the core rubber sleeve 20 and place it into the annular pressure chamber 102, and seal the first plugging member 301 and the second plugging member 302 at the left and right ends of the core rubber sleeve 20;

[0085] Step S3: Connect the hydraulic pressure to the ring pressure interface 103 to apply ring pressure to 50 MPa to simulate formation stress;

[0086] Step S4: Add the test fluid CO 2 The aqueous solution is connected to the test fluid inlet, and the test fluid outlet 105 is closed, and the fluid pressure is applied to 30 MPa through the injection pump 40;

[0087] Step S5, step S6: put the reaction container 10 into the oven and set the reaction temperature. After the reaction time reaches 24 hours, open the test fluid outlet 105 to unload the fluid pressure; open the ring pressure interface 103 to unload the ring pressure and take out the rock sample 60;

[0088] Step S7: Perform a series of physical property tests on the rock sample 60 and the test fluid, including but not limited to mineral composition test, solution ion test, rock mechanics test, etc., to analyze the degree of fluid-rock reaction.

[0089] Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary technical means in the art not disclosed by the present invention, are not limited to the precise structure described above and shown in the drawings, and may be modified and changed in various ways without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A fluid-rock reaction device considering stress sensitivity, characterized in that: include: A reaction container (10), wherein a fluid cavity (101) and an annular pressure cavity (102) are provided inside the reaction container (10), wherein the fluid cavity (101) is used to simulate fluid pressure, and the annular pressure cavity (102) is used to simulate formation stress, and an annular pressure interface (103), a test fluid interface (104) and a test fluid outlet (105) are provided on the side wall of the reaction container (10), wherein the test fluid interface (104) is used to connect the fluid cavity (101) with an external injection pump (40) so that the injection pump (40) injects fluid into the fluid cavity (101) through the test fluid interface (104), and the annular pressure interface (103) is used to connect the annular pressure cavity (102) with an external annular pressure pump (50) so that the annular pressure pump (50) applies annular pressure to the annular pressure cavity (102) through the annular pressure interface (103); A core rubber sleeve (20), the core rubber sleeve (20) being arranged in the annular pressure chamber (102) and being used to accommodate a rock sample to be tested; A plugging assembly (30), the plugging assembly (30) comprising a first plugging member (301) and a second plugging member (302), the first plugging member (301) being used to seal the annular space between the core rubber sleeve (20) and the annular pressure chamber (102), and to connect the first end face of the rock sample to be tested facing the fluid chamber (101) to the fluid chamber (101), and the second plugging member (302) being used to seal the second end face of the rock sample to be tested facing away from the fluid chamber (101), so as to isolate the second end face of the rock sample to be tested from the external space of the core rubber sleeve (20).

2. The stress-sensitive fluid-rock reaction device according to claim 1 is characterized in that: It also includes a mounting frame for mounting the reaction container (10), wherein the mounting frame is provided with two bearing seats, the bearing seats have built-in bearings, and the reaction container (10) is rotatably mounted on the bearing seats via a rotating shaft and the bearings.

3. The stress-sensitive fluid-rock reaction device according to claim 1 is characterized in that: The reaction container (10) comprises a fluid storage container (11) and a holder (12); the fluid storage container (11) is provided with a plugging cavity (111) and the fluid cavity (101) which are connected to each other; the holder (12) is provided with a ring pressure cavity (102) and a plugging component installation cavity (121) which are connected to each other; The reaction container (10) further comprises: a third blocking member (303), a fourth blocking member (304) and at least two sealing members (305), wherein the third blocking member (303) is arranged in the blocking cavity (111) and is used to block the blocking cavity (111) and the middle space of the fluid cavity (101); the fourth blocking member (304) is arranged on the second positioning step (1211) of the blocking component installation cavity (121) and is used to block the blocking component installation cavity (121); the annular pressure interface (103) is arranged on the fourth blocking member (304); the test fluid interface (104) and the test fluid outlet (105) are arranged in the fluid reservoir (11); and the sealing member (305) is arranged on the outer peripheral surface of the mounting portion of the annular pressure cavity (102) and the outer peripheral surface of the fourth blocking member (304).

4. The stress-sensitive fluid-rock reaction device according to claim 3 is characterized in that: The front end outer peripheral surface of the fourth blocking member (304) is provided with an inserting portion (3041), and the rear end of the core rubber sleeve (20) is provided with an inserting fitting portion (201), and the inserting portion (3041) is used to be inserted into the inside of the inserting fitting portion (201) to axially limit the core rubber sleeve (20).

5. The stress-sensitive fluid-rock reaction device according to claim 4 is characterized in that: The front end surface of the plug-in portion (3041) is a conical surface (3042), and the plug-in fitting portion (201) is provided with a conical groove (2011) for matching the conical surface (3042).

6. The stress-sensitive fluid-rock reaction device according to any one of claims 1 to 5, characterized in that: The reaction container (10) is provided with a connecting wall (106) for separating the fluid chamber (101) and the front annular pressure chamber (102), the connecting wall (106) is provided with a conical sealing surface (1061) on one side of the front chamber, and the front end of the core rubber sleeve (20) is provided with a conical end surface (202) adapted to the conical sealing surface (1061).

7. The stress-sensitive fluid-rock reaction device according to claim 3 is characterized in that: The third sealing member (303) comprises a third core plug (3031), a first pressure cap (3032) mounted on the third core plug (3031), and a sealing ring (3033) sealingly connecting the third core plug (3031) and the fluid reservoir (11).

8. The stress-sensitive fluid-rock reaction device according to any one of claims 3 to 5, characterized in that: The fourth sealing member (304) includes a sleeve (3043) for tightening the second sealing member (302), a plug removal rod (3044) inserted into the sleeve (3043), a fourth sealing plug (3045) sleeved on the sleeve (3043), a second pressure cap (3046) for locking the fourth sealing plug (3045), and a third pressure cap (3047) for locking the plug removal rod (3044).

9. The stress-sensitive fluid-rock reaction device according to any one of claims 3 to 5, characterized in that: The fluid storage container (11) is a fluid storage container made of stainless and acid-resistant steel.

10. An experimental method, applied to the stress-sensitive fluid-rock reaction device as described in any one of claims 1 to 9, characterized in that: Includes steps: Process the core into rock samples of preset specifications; The rock sample is placed in a core rubber sleeve, and the core rubber sleeve containing the rock sample is placed in the annular pressure cavity of the reaction container, a second plugging member is installed in the core rubber sleeve, and a first plugging member is installed in the annular space between the sealing core rubber sleeve and the annular pressure cavity in the annular pressure cavity; Connecting an annular pressure pump to an annular pressure interface, and applying annular pressure simulating formation stress to the annular pressure cavity through the annular pressure interface; Connecting the injection pump to the test fluid interface, closing the test fluid outlet, and applying fluid pressure to the fluid cavity through the test fluid interface; Place the reaction container in an oven, set the reaction temperature and reaction time, and perform fluid-rock reaction; The reaction vessel is taken out of the oven, cooled, the test fluid outlet is opened, the ring pressure is unloaded, and the core is taken out; Physical property tests are performed on the core and test fluid.

Images