Synchronous / asynchronous fracturing physical simulation system for layering of thin-medium thickness superposed reservoir

Abstract

The invention discloses a layered synchronous / asynchronous fracturing physical simulation system for thin-medium-thick stacked reservoirs. The layered synchronous / asynchronous fracturing physical simulation system comprises a host, a loading system, a pumping system, an acoustic emission crack monitoring system and a stress loading and data acquisition system control platform, the main machine comprises a main machine frame and a displacement supporting frame, and the loading system is arranged in the main machine and comprises a normal loading part and a confining pressure loading experiment box. The method solves the problems that in the prior art, in the multi-thin coal seam combination / separate layer fracturing process, the crack initiation expansion position is unknown, and the competition expansion and extension rule between the seams is unknown.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic fracturing, and in particular to a physical simulation system for synchronous / asynchronous fracturing of thin-medium-thick superimposed reservoir layers. Background Art

[0002] At present, the physical simulation equipment for coalbed methane development in China is mainly concentrated in physical simulation devices or physical simulation systems such as multi-field coupling, gas-liquid two-phase flow, seepage, displacement, hydraulic fracturing, fracturing fluid return, production, combined production, drainage, and development effect evaluation. From the perspective of indoor research, researchers are more inclined to study the stress state of coal rock and the flow law of coalbed methane under multi-field coupling conditions; for engineering research, scholars prefer research that provides services for engineering construction, such as optimizing hydraulic fracturing construction technology, hydraulic fracture initiation and extension laws, and drainage and gas production laws of multiple coal seams / single coal seams. However, the coalbed methane resources in the eastern Yunnan and western Guizhou regions are characterized by "one weak, two abundant, three high, and four major", namely, one weak: weak water content; two abundant: many types of gas-controlling structures and many coal seams; three high: high coalbed methane content, high resource abundance, high reservoir pressure and ground stress; four major: large coalbed methane resources, large coal grade changes, large coal seam permeability changes, and large vertical changes in geological conditions. In view of the above-mentioned geological conditions and construction difficulties, how to optimize the transformation methods of multiple and thin coal reservoirs is of great significance to improving coalbed methane recovery rate and achieving cost reduction and efficiency improvement.

[0003] Hydraulic fracturing technology is a highly commercialized process in the development of low-permeability oil reservoirs in my country and is one of the commonly used means of unconventional natural gas extraction in my country. With the development of hydraulic fracturing technology, fracturing construction methods such as multi-stage hydraulic fracturing, segmented multi-cluster fracturing, and spiral perforation have been proposed one after another. These methods have greatly enhanced the transformation effect of the reservoir, but due to the limitations of reservoir physical properties and the understanding of the expansion mechanism of hydraulic fractures, on-site fracturing construction still relies on experience. Regarding the study of the hydraulic fracture expansion mechanism, scholars in the industry mainly focus on the interaction between hydraulic fractures and geological discontinuities such as natural fractures, or qualitatively describe the impact of various factors on the results of hydraulic fracturing. There are few studies on the fracture initiation position of multi-coal seam combined fracturing, the extension law of fractures, and the interference mechanism of hydraulic fractures between composite coal seams. Therefore, for the geological status quo of the southern multi-coal seam area where the coal seams are mostly more than 30 coal seams and the thickness of the coal seams varies greatly, conducting physical simulation tests of multi- and thin-stacked reservoir combined fracturing is of great significance to further deepen the understanding of the interference of fractures in adjacent coal seams and reveal the influence of the interlayer interaction of multiple and thin coal seams on the transformation effect of coal body and the initiation and extension law of fracture network. Summary of the invention

[0004] The embodiment of the present invention provides a thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system, which is used to solve the problems of unclear crack initiation and expansion positions and unclear laws of competitive expansion and extension between fractures in the process of combined / stratified fracturing of multiple thin coal seams in the prior art.

[0005] The present invention aims to provide a thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system, comprising a host, a loading system, a pumping system, an acoustic emission fracture monitoring system and a stress loading and data acquisition system control platform; the host comprises a host frame and a displacement support frame;

[0006] The loading system is arranged in the mainframe, and includes a normal loading component and a confining pressure loading test box. The normal loading component performs normal displacement to realize normal loading of the specimen. The confining pressure loading test box includes a specimen installation cavity for placing the specimen, a loading hydraulic cylinder for providing pressure to the specimen, and a confining pressure static loading device connected to the loading hydraulic cylinder and loading the specimen. The confining pressure loading test box is divided into multiple layers, each layer corresponds to a different rock layer of the specimen, and the confining pressure static loading device pressurizes the six layers of the specimen respectively to realize synchronous loading of different layers.

[0007] The pumping system includes a fracturing fluid tank connected to the test piece and a pumping system for providing pressure to the fracturing fluid tank;

[0008] The acoustic emission crack monitoring system comprises an acoustic emission joint arranged on the outer wall of the confining pressure loading test box, an acoustic emission probe arranged on the inner wall of the specimen installation cavity, and an acoustic emission instrument for controlling the acoustic emission;

[0009] The stress loading and data acquisition system control platform is connected to the loading system and the pumping system.

[0010] Furthermore, the normal loading component is arranged on the top of the main frame.

[0011] Furthermore, the normal loading component includes a normal loading cylinder, a normal displacement sensor disposed at the bottom of the normal loading cylinder, and a normal loading plate disposed at the bottom of the normal loading cylinder and connected to the normal displacement sensor.

[0012] Furthermore, a retractable normal cylinder extension joint is also provided on the upper portion of the normal loading cylinder.

[0013] Furthermore, there are four confining pressure static loading devices, corresponding to the four sides of the specimen respectively. The width of the confining pressure static loading device is the same as the side length of the specimen installation cavity connected to it, forming multiple layers matching the specimen. A loading hydraulic cylinder is arranged inside the outer frame running through the confining pressure loading test box, and each layer of confining pressure static loading device corresponds to a different loading hydraulic cylinder.

[0014] Furthermore, displacement sensors are arranged on the outer walls of the confining pressure loading test box.

[0015] Furthermore, the main machine includes a displacement support frame for supporting and pushing the confining pressure loading test box to translate, and the displacement support frame includes a support base, a translation bracket arranged on the support base, and a confining pressure flap support plate slidably arranged on the translation bracket.

[0016] Furthermore, the main frame is an annular frame, the normal loading component is arranged at the top of the annular frame of the main frame, one end of the translation bracket is arranged on the upper part of the support base, and the other end is supported on the bottom of the annular frame of the main frame.

[0017] Furthermore, the fracturing fluid tank is a gas cylinder or a liquid tank.

[0018] Furthermore, a gas control valve is provided on the gas pipeline between the gas cylinder and the test piece, and a water pressure control valve is provided on the liquid pipeline between the liquid tank and the test piece.

[0019] Furthermore, a fracturing sealing plate is provided on the upper part of the specimen, a fracturing liquid inlet pipe is provided inside the fracturing sealing plate, one end of the fracturing liquid inlet pipe is connected to the fracturing liquid tank, and the other end passes through the fracturing sealing plate and is inserted into the mouth of the simulated fracturing wellbore.

[0020] Furthermore, a fracturing sealing sleeve is provided at the mouth of the simulated fracturing wellbore, and the fracturing liquid inlet pipe passes through the fracturing sealing sleeve.

[0021] Furthermore, an acoustic emission amplifier is connected between the acoustic emission instrument and the acoustic emission connector via an acoustic emission connecting wire, and the acoustic emission connector is wirelessly connected to an acoustic emission acquisition system.

[0022] Furthermore, a lifting device is also provided on the top of the main machine.

[0023] Furthermore, a lifting cylinder is arranged inside the bottom of the main frame, a normal loading plate is arranged on the upper part of the lifting cylinder, and the normal loading plate protrudes from the main frame.

[0024] Compared with the prior art, the beneficial technical effects of the present invention are:

[0025] The present invention can simulate hydraulic fracturing of rock layers at different burial depths by improving the structure of the confining pressure loading test box, and can also realize synchronous loading or asynchronous loading of different rock layer distributions in hydraulic fracturing tests of multiple thin coal seams.

[0026] The thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system of the present invention can simulate uniaxial compression tests of rock specimens of different sizes.

[0027] The thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system of the present invention can monitor the generation, expansion and connectivity of hydraulic fracturing cracks in real time, and analyze the fracturing mode and expansion law of multiple thin rock layers under different rock formation conditions.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0030] Attached Figure 1 The figure is a schematic diagram of the working process of a physical simulation system for synchronous / asynchronous fracturing of thin-medium-thick superimposed reservoirs.

[0031] Attached Figure 2 It is a structural schematic diagram of a thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system of the present invention.

[0032] Attached Figure 3 It is a schematic diagram of the structure of the main machine in a thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system of the present invention, a cross-sectional view in the AA direction, and a top view.

[0033] Attached Figure 4 This is an internal structural diagram of a normal loading component in a thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system of the present invention.

[0034] Attached Figure 5 It is a top view of a confining pressure loading test box in a thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system of the present invention.

[0035] Attached Figure 6 For the present invention Figure 5 Stereoscopic image of the confining pressure loading test box after the section in the middle BB direction.

[0036] Attached Figure 7 For the present invention Figure 5 Stereoscopic image of the confining pressure loading test box after the mid-CC section.

[0037] Attached Figure 8 For the present invention Figure 5 Cross-sectional view along the DD direction.

[0038] Attached Fig. 9 For the present invention Figure 8 Cross-section along the EE direction.

[0039] In the attached drawings, 1 is the host; 2 is the loading system; 3 is the pumping system; 3a is the gas cylinder; 3b is the gas control valve; 3c is the gas pipeline; 3d is the water pressure control valve; 3e is the liquid pipeline; 3f is the liquid tank; 3g is the booster pump; 3h is the fracturing liquid tank; 3i is the pumping system; 3j is the first wire; 3k is the second wire; 4 is the acoustic emission crack monitoring system; 4a is the acoustic emission acquisition system; 4b is the acoustic emission instrument; 4c is the acoustic emission amplifier; 4d is the acoustic emission probe; 4e is the acoustic emission connecting wire; 4f is the acoustic emission connector; 5 is the stress loading and data acquisition system control platform; 5a is the data acquisition unit; 5b is the stress loading control unit; 5c is the fracturing fluid control unit; 6 is the fracturing wellbore; 6a is the fracturing liquid inlet pipe; 6b is the fracturing sealing sleeve; 6c is the fracturing sealing plate; 7 is the host frame; 8 is the specimen; 8a is the rock mass 1st layer; 8b is the second layer of rock mass; 8c is the third layer of rock mass; 8d is the fourth layer of rock mass; 8e is the fifth layer of rock mass; 8f is the sixth layer of rock mass; 9 is the confining pressure loading test box; 9a is the first layer of confining pressure loading layer; 9b is the second layer of confining pressure loading layer; 9c is the third layer of confining pressure loading layer; 9d is the fourth layer of confining pressure loading layer; 9e is the fifth layer of confining pressure loading layer; 9f is the sixth layer of confining pressure loading layer; 10 is the supporting base; 11 is the translation bracket; 12 is the confining pressure flap supporting plate; 13 is the normal loading component; 13a is the normal loading plate; 13b is the normal displacement sensor; 13c is the normal loading cylinder; 13d is the normal cylinder extension joint; 14 is the lifting cylinder; 15 is the normal bearing plate; 16 is the confining pressure static loading device; 17 is the hoisting device; 18 is the loading pressure head; 19 is the loading hydraulic cylinder; 20 is the inner wall of the specimen installation cavity. DETAILED DESCRIPTION

[0040] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0041] See also Figure 1-Figure 9 , a thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system, comprising a host 1, a loading system 2, a pumping system 3, an acoustic emission fracture monitoring system 4 and a stress loading and data acquisition system control platform 5; the host 1 comprises a host frame 7 and a displacement support frame;

[0042] The loading system 2 is arranged in the main machine 1, including a normal loading component 13 and a confining pressure loading test box 9. The normal loading component 13 performs normal displacement to realize normal loading of the specimen 8. The confining pressure loading test box 9 includes a specimen installation cavity for placing the specimen 8, a loading hydraulic cylinder 19 for providing pressure to the specimen 8, and a confining pressure static loading device 16 connected to the loading hydraulic cylinder 19 and loading the specimen 8; the confining pressure loading test box 9 is divided into multiple layers, each layer corresponds to a different rock layer of the specimen 8, and the confining pressure static loading device 16 pressurizes the six layers of the specimen 8 respectively to realize synchronous loading of different layers; the specimen 8 is normally pressurized by the normal loading component 13, and the specimen 8 is circumferentially pressurized by the confining pressure loading test box 9.

[0043] The pumping system 3 includes a fracturing fluid tank 3f connected to the test piece 8 and a pumping system 3i for providing pressure to the fracturing fluid tank 3f. The pumping system 3 is connected to the test piece 8 and injects fluid into the test piece 8 to achieve the purpose of fracturing.

[0044] The acoustic emission crack monitoring system 4 includes an acoustic emission joint 4f arranged on the outer wall of the confining pressure loading test box 9, an acoustic emission probe 4d on the inner wall 20 of the specimen installation cavity, and an acoustic emission instrument 4b for controlling the acoustic emission;

[0045] The stress loading and data acquisition system control platform 5 is connected to the loading system 2 and the pumping system 3 .

[0046] See also Figure 1-Figure 4 , the normal loading component 13 is arranged at the top of the main frame 7. The normal loading component 13 includes a normal loading cylinder 13c, a normal displacement sensor 13b arranged at the bottom of the normal loading cylinder 13c, and a normal loading plate 13a arranged at the bottom of the normal loading cylinder 13c and connected to the normal displacement sensor 13b. A retractable normal cylinder extension joint 13d is also arranged on the upper part of the normal loading cylinder 13c. The normal loading component 13 cooperates with the lifting cylinder 14 to perform normal pressurization on the specimen 8. When the size of the specimen 8 is changed, the normal cylinder extension joint 13d is used to move the normal loading cylinder 13c normally to ensure that the normal loading plate 13a is in contact with the specimen 8.

[0047] There are four confining pressure static loading devices 16, corresponding to the four sides of the specimen 8 respectively. The width of the confining pressure static loading device 16 is the same as the side length of the mounting cavity of the specimen 8 connected thereto, forming multiple layers matching the specimen 8. Loading hydraulic cylinders 19 are arranged inside the outer frame of the confining pressure loading test box 9, and each layer of the confining pressure static loading device 16 corresponds to a different loading hydraulic cylinder 19. A loading pressure head 18 for fixing the confining pressure static loading device 16 is arranged on the top of the confining pressure static loading device 16. When conducting a hydraulic fracturing simulation test, the loading hydraulic cylinders 19 corresponding to each layer of the specimen 8 work separately, and the pressure of each loading hydraulic cylinder 19 can be controlled by the stress loading and data acquisition system control platform 5, so as to achieve different pressures on each layer of the specimen 8 and asynchronous loading of different rock layers. After changing the size of the specimen 8, a steel plate can be added inside the confining pressure static loading device 16 to reduce the inner diameter of the specimen mounting cavity, thereby meeting the hydraulic fracturing simulation test of rock samples of various sizes.

[0048] Displacement sensors are arranged on the outer walls of the confining pressure loading test box 9 .

[0049] In order to facilitate the placement and handling of the test piece 8 and the convenience of work, the mainframe 1 includes a displacement support frame for supporting and pushing the translation of the confining pressure loading test box 9, and the displacement support frame includes a support base 10, a translation support 11 arranged on the support base 10, and a confining pressure flap support plate 12 slidably arranged on the translation support 11. When placing and taking the test piece 8, the confining pressure loading test box 9 arranged on the confining pressure flap support plate 12 is slid on the translation support 11 and moved out of the mainframe 1; after the placement and taking is completed, the confining pressure flap support plate 12 is moved on the translation support 11 again until it reaches a fixed position corresponding to the normal loading component 13 in the mainframe 1.

[0050] The main frame 7 is an annular frame, the normal loading component 13 is arranged at the top of the annular frame of the main frame 7, one end of the translation bracket 11 is arranged on the upper part of the support base 10, and the other end is supported at the bottom of the annular frame of the main frame 7. During the test, the loading system 2 is arranged in the annular frame to facilitate the fixation and operation of the position.

[0051] The fracturing fluid tank 3f is a gas cylinder 3a or a liquid tank 3f.

[0052] A gas control valve 3b is provided on the gas pipeline 3c between the gas cylinder 3a and the test piece 8, and a water pressure control valve 3d is provided on the liquid pipeline 3e between the liquid tank 3f and the test piece 8. When gas fracturing is required, the gas control valve 3b is opened and the water pressure control valve 3d is closed; when liquid fracturing is required, the water pressure control valve 3d is opened and the gas control valve 3b is closed. In a preferred embodiment, a booster pump 3g is provided in the liquid tank.

[0053] See also Figure 1A pump pressure system 3i is provided inside the stress loading and data acquisition system control platform 5. The pump pressure system 3i controls the operation of the fracturing fluid tank 3f through the first wire 3j, and feeds back the pressure, flow rate and other conditions of the fracturing fluid tank 3f to the pump pressure system 3i through the second wire 3k. The pump pressure system 3i realizes the switch control of the fracturing fluid tank 3f and the control of the pressure and flow rate.

[0054] A fracturing sealing plate 6c is provided on the upper part of the test piece 8, and a fracturing liquid inlet pipe 6a is provided inside the fracturing sealing plate 6c. One end of the fracturing liquid inlet pipe 6a is connected to the fracturing liquid tank 3f, and the other end passes through the fracturing sealing plate 6c and is inserted into the mouth of the simulated fracturing wellbore 6.

[0055] A fracturing sealing sleeve 6b is provided at the mouth of the simulated fracturing wellbore 6, and the fracturing liquid inlet pipe 6a passes through the fracturing sealing sleeve 6b.

[0056] An acoustic emission amplifier 4c is also connected between the acoustic emission instrument 4b and the acoustic emission connector 4f via an acoustic emission connecting wire 4e, and the acoustic emission connector 4f is wirelessly connected to an acoustic emission acquisition system 4a.

[0057] A hoisting device 17 is also provided on the top of the main machine 1 .

[0058] A lifting cylinder 14 is arranged in the bottom of the main frame 7 , and a normal loading plate 13 a is arranged on the upper part of the lifting cylinder 14 . The normal loading plate 13 a protrudes from the main frame 7 .

[0059] The stress loading and data acquisition system control platform 5 includes a data acquisition unit 5a, a stress loading control unit 5b and a fracturing fluid control unit 5c. The data acquisition unit 5a is used to collect data such as pressure and flow during the fracturing test. The stress loading control unit 5b is connected to the loading system 2 to control the operation of the loading system 2; the fracturing fluid control unit 5c is connected to the pumping system 3 to control the switching of the water pressure control valve 3b and the gas control valve 3b in the pumping system 3, and the switching of the pumping system 3i and the booster pump 3g.

[0060] The working process of the thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system of the present invention is as follows:

[0061] The sizes of rock specimens 8 commonly used in hydraulic fracturing simulation tests are mainly the following: 150mm×150mm×150mm, 200mm×200mm×600mm, 300mm×300mm×300mm. The internal space of the specimen installation cavity can be changed by adding or removing steel plates to adapt to hydraulic fracturing simulation tests of rock formations of various sizes.

[0062] See also Fig. 9In the embodiment of the present invention, a commonly used 200mm×200mm×600mm rock layer specimen 8 is used as an example for operation. There are six layers in total. The first layer 8a of the rock mass is a mudstone reservoir, the second layer 8b of the rock mass is a coal reservoir, the third layer 8c of the rock mass is a mudstone reservoir, the fourth layer 8d of the rock mass is a limestone reservoir, the fifth layer 8e of the rock mass is a coal reservoir, and the sixth layer 8f of the rock mass is a mudstone reservoir. The thicknesses are 100mm, 150mm, 50mm, 50mm, 100mm, and 150mm, respectively. After the rock mass specimen 8 is manufactured, a fracturing wellbore 6 is simulated by drilling in the middle of the rock mass. The confining pressure static loading device 16 also forms six layers according to the rock mass specimen 8.

[0063] First, the stress loading and data acquisition system control platform 5 controls the confining pressure flap support plate 12 to drive the confining pressure loading test box 9 to move horizontally on the translation bracket 11 to the outside of the main machine 1, and the hoisting device 17 is used to hoist the specimen 8 into the specimen installation cavity, and then it is moved to the fixed position of the main machine 1 through the translation bracket 11. The fracturing sealing plate 6c is replaced on the fracturing wellbore 6, and the fracturing sealing sleeve 6b seals the fracturing wellbore 6; the stress loading and data acquisition system control platform 5 controls the lifting cylinder 14 to move up and down to adjust the height of the confining pressure loading test box 9, so that the normal loading plate 13a contacts the specimen 8 and applies a normal force. Turn on the acoustic emission crack monitoring system 4, and control the loading hydraulic cylinder 19 and the confining pressure static loading device 16 through the stress loading and data acquisition system control platform 5 to pressurize the specimen 8 with confining pressure.

[0064] The pressure is preset in advance in the stress loading and data acquisition system control platform 5. The confining pressure loading is divided into the first layer 9a with a pressure of 3MPa, the second layer 9b with a pressure of 4MPa, the third layer 9c with a pressure of 5MPa, the fourth layer 9d with a pressure of 6MPa, the fifth layer 9e with a pressure of 7MPa, and the sixth layer 9f with a pressure of 8MPa.

[0065] After the confining pressure and the normal pressure are both stable, the gas control valve 3b / water pressure control valve 3d is opened through the stress loading and data acquisition system control platform 5, and the fracturing fluid is injected into the rock specimen 8 to start hydraulic fracturing. The acoustic emission is recorded through the acoustic emission crack monitoring system 4, and the time, confining pressure, normal pressure, fluid pressure, fluid flow, etc. are recorded through the stress loading and data acquisition system control platform 5. Until fluid flows out from the lower part of the confining pressure loading test box 9, the fracturing is completed, and the gas control valve 3b / water pressure control valve 3d is closed to release the pressure, and a fracturing test is completed.

[0066] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0067] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0068] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A physical simulation system for synchronous / asynchronous fracturing of thin-medium-thick superimposed reservoirs, characterized by: It includes a host, a loading system, a pumping system, an acoustic emission crack monitoring system and a stress loading and data acquisition system control platform; the host includes a host frame and a displacement support frame; The loading system is arranged in the mainframe, and includes a normal loading component and a confining pressure loading test box. The normal loading component performs normal displacement to realize normal loading of the specimen. The confining pressure loading test box includes a specimen installation cavity for placing the specimen, a loading hydraulic cylinder for providing pressure to the specimen, and a confining pressure static loading device connected to the loading hydraulic cylinder and loading the specimen. The confining pressure loading test box is divided into multiple layers, each layer corresponds to a different rock layer of the specimen, and the confining pressure static loading device pressurizes the six layers of the specimen respectively to realize synchronous loading of different layers. The pumping system includes a fracturing fluid tank connected to the test piece and a pumping system for providing pressure to the fracturing fluid tank; The acoustic emission crack monitoring system comprises an acoustic emission joint arranged on the outer wall of the confining pressure loading test box, an acoustic emission probe arranged on the inner wall of the specimen installation cavity, and an acoustic emission instrument for controlling the acoustic emission; The stress loading and data acquisition system control platform is connected to the loading system and the pumping system.

2. A thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system as claimed in claim 1, characterized in that: The normal loading component comprises a normal loading cylinder, a normal displacement sensor arranged at the bottom of the normal loading cylinder, and a normal loading plate arranged at the bottom of the normal loading cylinder and connected to the normal displacement sensor.

3. A thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system as claimed in claim 1, characterized in that: There are four confining pressure static loading devices, which correspond to the four sides of the specimen respectively. The width of the confining pressure static loading device is the same as the side length of the specimen installation cavity connected to it, forming multiple layers matching the specimen. A loading hydraulic cylinder is arranged inside the outer frame that runs through the confining pressure loading test box, and each layer of confining pressure static loading device corresponds to a different loading hydraulic cylinder.

4. A thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system as claimed in claim 1, characterized in that: The main machine includes a displacement support frame for supporting and pushing the confining pressure loading test box to translate, and the displacement support frame includes a support base, a translation bracket arranged on the support base, and a confining pressure flap support plate slidably arranged on the translation bracket.

5. A physical simulation system for synchronous / asynchronous fracturing of thin-medium-thick superimposed reservoirs as claimed in claim 4, characterized in that: The main frame is an annular frame, the normal loading component is arranged at the top of the annular frame of the main frame, one end of the translation bracket is arranged on the upper part of the support base, and the other end is supported at the bottom of the annular frame of the main frame.

6. A thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system as claimed in claim 1, characterized in that: The fracturing fluid tank is a gas cylinder or a liquid tank.

7. A physical simulation system for synchronous / asynchronous fracturing of thin-medium-thick superimposed reservoirs as claimed in claim 6, characterized in that: A gas control valve is provided on the gas pipeline between the gas cylinder and the test piece, and a water pressure control valve is provided on the liquid pipeline between the liquid tank and the test piece.

8. A physical simulation system for synchronous / asynchronous fracturing of thin-medium-thick superimposed reservoirs as claimed in claim 7, characterized in that: A fracturing sealing plate is arranged on the upper part of the test piece, a fracturing liquid inlet pipe is arranged inside the fracturing sealing plate, one end of the fracturing liquid inlet pipe is connected to the fracturing liquid tank, and the other end passes through the fracturing sealing plate and is inserted into the mouth of the simulated fracturing wellbore.

9. A thin-medium-thick superimposed reservoir stratified synchronous / asynchronous fracturing physical simulation system as claimed in claim 1, characterized in that: An acoustic emission amplifier is also connected between the acoustic emission instrument and the acoustic emission connector via an acoustic emission connecting wire, and the acoustic emission connector is wirelessly connected to an acoustic emission acquisition system.

10. A physical simulation system for synchronous / asynchronous fracturing of thin-medium-thick superimposed reservoirs according to claim 1, characterized in that: A lifting cylinder is arranged in the bottom of the main frame, and a normal loading plate is arranged on the upper part of the lifting cylinder, and the normal loading plate protrudes from the main frame.

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