CN109469479B

CN109469479B - Hydraulic fracturing ground stress measurement system and method

Info

Publication number: CN109469479B
Application number: CN201811457167.5A
Authority: CN
Inventors: 杨景贺; 司林坡; 高富强; 娄金福; 吕华文; 林健; 王晓卿; 李建忠; 刘晓敏; 杨磊; 原贵阳; 武龙云
Original assignee: Tiandi Science and Technology Co Ltd
Current assignee: Tiandi Science and Technology Co Ltd
Priority date: 2018-11-30
Filing date: 2018-11-30
Publication date: 2023-07-14
Anticipated expiration: 2038-11-30
Also published as: CN109469479A

Abstract

The invention relates to the field of geomechanical engineering, and provides a hydraulic fracturing ground stress measuring system which comprises a packer, a packing water injection pipeline and a fracturing water injection pipeline, wherein an upper packer and a lower packer are sealed with the wall surface of a test hole to form two sections of packing sections, a fracturing test section is formed between the upper packer and the lower packer, a packer core pipe and a packer hole sealing water injection pipe are arranged on the packer, the hydraulic fracturing ground stress measuring system further comprises a regulating and controlling connecting device, the regulating and controlling connecting device is connected with the upper packer, and the packer hole sealing water injection pipe and the external environment are regulated by the on-off of the regulating and controlling connecting device. The invention discloses a hydraulic fracturing ground stress measurement method which comprises a test process, a packer pressure relief process and a packer control pipeline pressure relief process. The invention provides a packer for solving the problems of hole sealing pressure relief and automatic hole sealing recovery of a packer; testing water injection pressure at the measuring point; the drilling construction cost of the ground stress measurement is reduced, the remote control can be realized, and the hydraulic fracturing ground stress measurement system and method are suitable for small-bore deep holes.

Description

Hydraulic fracturing ground stress measurement system and method

Technical Field

The invention relates to the field of geomechanical engineering, in particular to a hydraulic fracturing ground stress measuring system and method.

Background

The ground stress is natural stress which exists in the crust and is not disturbed by engineering, is an internal stress effect generated by crust materials due to the reasons of geologic structure movement and the like in long geologic years, and is a collective name of the crust stress. In general, the ground stress at each point in the crust increases with increasing depth from the earth's surface, and the gradient of the ground stress throughout the depth varies due to the different construction locations and geographic locations. Ground stress is the fundamental force causing deformation and destruction of mining, hydropower, civil construction, railways, highways, military and other various underground or open-air rock and soil excavation and slope engineering, and all deformation, such as wrinkles, breaks and the like, occurring throughout the crust are also the result of the ground stress.

The magnitude and the direction of the ground stress are closely related to the stability of underground engineering, and accurately measuring the ground stress is a necessary premise for determining the mechanical property of engineering geotechnical and analyzing the stability of surrounding rock so as to realize geotechnical engineering excavation design and decision scientization. The ground stress state is known to have important significance for earthquake prediction, regional crust stability evaluation, oil field oil well stability, nuclear waste storage, rock burst, coal and gas outburst, earth dynamics research and the like. The earth stress measurement is carried out, the earth crust stress state is ascertained, the engineering construction of various rock masses can be served, and important scientific basis can be provided for earth dynamics research, fracture activity research and geological disaster early warning research. The ground stress measurement is one of important contents of geomechanical research, and is widely applied to the fields of engineering construction, geological disaster early warning, fracture activity research and the like.

At present, the ground stress measuring method is more, and comprises a direct measuring method such as a hydraulic fracturing method, an acoustic emission method, a borehole collapse method and the like, and an indirect measuring method such as a core stress relief method, a strain recovery method and the like. The hydraulic fracturing ground stress measuring method is used for in-situ measurement in the rock mass, and directly measures the stress state in the rock mass under the condition that related rock mechanical parameters are not required to be acquired, and has the advantages of small disturbance to the stress field of the original rock structure, simple equipment, convenient operation, strong representativeness of measured values, good adaptability and the like, is widely applied to the ground stress measurement of various geotechnical engineering, and is particularly widely used in the ground stress measurement of deep rock mass engineering.

The existing hydraulic fracturing ground stress testing device refers to the patent document with the authority of CN2643300Y, and still has the defects of low testing precision, certain limitation of testing conditions and the like in consideration of construction difficulty, engineering cost and testing system requirements.

Disclosure of Invention

First, the technical problem to be solved

The present invention aims to solve at least one of the following technical problems in the prior art or related art:

(1) The packer cannot be decompressed and retracted under the action of hydrostatic pressure, and the test system is difficult to recover, so that huge engineering waste is caused.

(2) The radial space occupation size is large, the leakage is easy, the space condition for installing the water injection pressure test recorder is not provided near the test point, the distance between the test instrument and the actual test point is long, the pressure difference is large, the system is long, and the test precision is low.

(3) The fracturing process lacks the effective monitoring to the packer hole sealing state, easily causes the misjudgement to the condition that the packer seepage can not normally fracture, causes due test data to lack.

The purpose of the invention is that: the problem of hole sealing pressure relief and automatic hole sealing recovery of a packer is solved; the earth stress measurement can be performed on a borehole of any formation condition; the water injection pressure is tested at the measuring point, so that the accuracy of the test data is improved; the hydraulic fracturing crustal stress measuring system and method can meet the crustal stress measuring requirement of small-aperture drilling with phi 60 mm-phi 75mm, reduce the drilling construction cost of crustal stress measurement, can be remotely controlled, and are suitable for small-aperture deep holes.

(II) technical scheme

In order to solve the technical problems, the invention provides a hydraulic fracturing ground stress measuring system, which comprises a packer, a sealing water injection pipeline and a fracturing water injection pipeline, wherein the packer comprises an upper packer and a lower packer, the upper packer and the lower packer are sealed with the wall surface of a test hole to form two sections of sealing sections, a fracturing test section is formed between the upper packer and the lower packer, a packer core pipe and a packer hole sealing water injection pipeline are arranged on the packer, the sealing water injection pipeline supplies pressure fluid to the packer hole sealing water injection pipeline, the pressure fluid in the packer hole sealing water injection pipeline enables the packer to bulge and form a sealing section with the test hole, the fracturing water injection pipeline supplies pressure fluid to the packer core pipe, the pressure fluid in the packer core pipe flows into the fracturing test section, the hydraulic fracturing ground stress measuring system further comprises a regulating and connecting device, the regulating and connecting device is connected with the upper packer, and the packer hole sealing water injection pipeline and the external environment are regulated by the regulating and controlling the on-off of the regulating and connecting device.

Preferably, the device further comprises a packer control pipeline, pressure fluid in the packer control pipeline presses the regulating and controlling connecting device, a pressure relief assembly is arranged in the regulating and controlling connecting device, the pressure relief assembly bears pressure change to act, and the on-off of the packer hole sealing water injection pipe and the external environment is regulated.

In any of the above schemes, it is preferable that the regulation and control connecting device is provided with a fracturing water injection pipe interface, a hole sealing water injection pipe interface and a packer control water injection pipe interface, one end of the fracturing water injection pipe interface is connected with the packer core pipe, the other end of the fracturing water injection pipe interface is connected with the packer hole sealing water injection pipe, the other end of the hole sealing water injection pipe interface is connected with the packer water injection pipe, the packer control water injection pipe interface is connected with the packer control pipe, and the on-off of the hole sealing water injection pipe and the external environment is regulated.

In any of the above schemes, it is preferable that a pressure release water guiding hole is arranged between the packer control water injection pipe interface and the hole sealing water injection pipe interface, a pressure release component is connected to the packer control water injection pipe interface, a plurality of packer water draining holes are formed in the regulating and controlling connecting device, and the pressure release component regulates the on-off of the pressure release water guiding hole and the packer water draining holes.

In any of the above schemes, preferably, the pressure release assembly comprises a pressure release valve needle, a sealing body, a reset valve core, a reset spring and a pressure regulating screw plug, the pressure release valve needle bears the fluid pressure in the interface of the packer control water injection pipe, the pressure release valve needle is abutted to the sealing body, the sealing body moves to enable the packer water release hole to be communicated with or disconnected from the pressure release water guide hole, and the pressure regulating screw plug is screwed to regulate the preset pressing force of the reset spring.

In any of the above aspects, it is preferable that the sealing body has a spherical structure, and the sealing body has a polyester ball.

In any of the above embodiments, it is preferable that the return spring is provided as a plurality of disc springs.

In any of the above schemes, it is preferable that the fracturing water injection pipeline, the packing water injection pipeline and the packer control pipeline are connected with water injection pipeline joints.

In any of the above schemes, preferably, the water injection pipeline joint comprises a joint body, a limit slide plate, a locking screw and an anti-drop screw, wherein the joint body is used for connecting two adjacent sections of the fracturing water injection pipeline, a positioning groove is formed in the joint body, the sealing water injection pipeline and the packer control pipeline are arranged in the positioning groove, the limit slide plate is arranged on the upper cover of the positioning groove, the locking screw and the anti-drop screw are detachably connected on the joint body, and the locking screw is locked and fixed on the limit slide plate.

In any of the above schemes, it is preferable that a limit baffle is arranged on the water injection pipeline connector, a butt joint connector is arranged on the sealing and isolating water injection pipeline and/or the packer control pipeline, and the limit baffle is clamped with the connector body and the butt joint connector.

In any of the above schemes, it is preferable that the packer water injection pipeline, the fracturing water injection pipeline and the packer control pipeline are connected with pressure measuring assemblies.

In any of the above schemes, preferably, the packing water injection pipeline is connected with a second water injection pressure tester, and the fracturing water injection pipeline is connected with a third water injection pressure tester.

In any of the above schemes, preferably, the regulation connection device is connected with a first water injection pressure tester.

In any of the above schemes, preferably, the first water injection pressure tester is communicated with a fracturing water injection pipe interface on the regulation and control connecting device.

In any of the above schemes, it is preferable that the packing water injection pipeline, the fracturing water injection pipeline and the packer control pipeline are all connected to the water injection assembly, and stop valves are arranged between the packing water injection pipeline, the fracturing water injection pipeline and the packer control pipeline and the water injection assembly.

In any of the above schemes, preferably, a pressure relief device is connected to the control pipeline of the packer.

The invention also provides a hydraulic fracturing ground stress measuring method,

the method comprises the steps that in the testing process, a water injection assembly injects pressure fluid into a packing water injection pipeline, the pressure fluid is injected into a packer through a water injection pipeline joint and a regulating and controlling connecting device, so that an upper packer and a lower packer are simultaneously inflated and abutted on the inner wall of a testing hole to form an upper packing section and a lower packing section, a closed fracturing testing section is formed between the upper packing section and the lower packing section, and the packer is in a hole sealing and pressure maintaining state;

the water injection assembly injects pressure fluid into the fracturing water injection pipeline, the pressure fluid flows into the fracturing test section along the water injection piece through the water injection pipeline joint, the regulating and controlling connecting device and penetrates through the upper packer, the pressure fluid is continuously injected until the fracturing process is completed, and the water injection assembly stops injecting the pressure fluid into the fracturing water injection pipeline;

the packer pressure relief process comprises the steps that a water injection assembly injects pressure fluid into a packer control pipeline, the pressure fluid is injected into a regulating and controlling connecting device through a water injection pipeline joint, the pressure in a packer control water injection pipe interface of the regulating and controlling connecting device reaches the opening pressure of the pressure relief assembly, the sealing water injection pipe interface in the regulating and controlling connecting device is communicated with a packer water discharge hole through a pressure relief water guide hole, the pressure fluid in the packer flows out, and the packer is depressurized; the packer control pipeline enters a pressure maintaining state until the packer is completely depressurized and retracted;

The pressure of the packer control pipeline is reduced to hydrostatic pressure, the pressure relief assembly is automatically reset, a channel of the pressure relief water guide hole of the packer water discharge hole and the hole sealing water injection pipe is closed, the hole sealing water injection pipe is sealed, and the system is restored to a testing state.

(III) beneficial effects

Compared with the prior art, the invention has the following advantages:

(1) The regulating and controlling connecting device with a special structure is directly connected with the packer to control the hole sealing and pressure relief of the packer, the pressure relief assembly uses the belleville springs as regulating and controlling reset force application elements to adjust the superposition quantity of each group of springs and the tightness degree of the pressure regulating screw plugs, the opening pressure regulation of the control system is simply and conveniently realized, and the adaptability of the control system is obviously improved; the reset valve core is matched with the elastic spherical sealing body, so that the sealing reliability is improved, and the manufacturing cost is reduced;

(2) A regulation and control connecting device with control and measurement functions is used for forming a measurement and control integrated structure, and a first water injection pressure tester is installed close to a measuring point to realize direct measurement record of real data of the position of the measuring point;

(3) The three water injection pipeline systems are arranged in a hole sealing, fracturing and controlling way, and are independently connected with a ground high-pressure water injection pump, so that the pressure change of the hole sealing system and the fracturing system is monitored on the ground at the same time, and the situation of fracturing test failure and the like caused by hole sealing leakage can be conveniently identified;

(4) The radial dimension of all parts in the system after being assembled is limited within the diameter phi 56mm, so that the small-aperture test requirement is met, the system is particularly suitable for a drilling test process with small aperture and large depth from top to bottom in engineering construction, and the water injection pipeline joint is utilized to restrict all pipeline systems, so that the problem of winding of a hose in a drilling hole is solved;

(5) The fracturing water injection pipeline is used for fracturing water injection, simultaneously has the functions of a lowering and recycling test system, uses the high-strength thick-wall seamless steel tube, has high bearing capacity and meets the requirements of the kilometer deep hole ground stress test.

The system and the method for measuring the hydraulic fracturing ground stress provided by the invention are further described with reference to the following drawings.

Drawings

FIG. 1 is a schematic diagram of the overall structure of a hydraulic fracturing crustal stress measuring system of the present invention;

FIG. 2 is a schematic cross-sectional structural view of a packer unit of the hydraulic fracturing crustal stress measurement system of the present invention;

FIG. 3 is a schematic diagram of the connection structure of a packer of the hydraulic fracturing crustal stress measuring system of the present invention;

FIG. 4 is a schematic diagram of the overall structure of a control connection device of the hydraulic fracturing crustal stress measuring system of the present invention;

FIG. 5 is a schematic diagram of the left-hand structure of FIG. 4 of the hydraulic fracturing crustal stress measuring system of the present invention;

FIG. 6 is a schematic diagram of the right-hand view of FIG. 4 illustrating a hydraulic fracturing crustal stress measurement system of the present invention;

FIG. 7 is a schematic diagram of the structure of A-A in FIG. 4 of the hydraulic fracturing crustal stress measuring system of the present invention;

FIG. 8 is a schematic diagram of the structure of B-B in FIG. 7 of the hydraulic fracturing crustal stress measuring system of the present invention;

FIG. 9 is a schematic diagram of the structure of C-C in FIG. 8 of the hydraulic fracturing crustal stress measuring system of the present invention;

FIG. 10 is a schematic diagram of the structure of D-D in FIG. 8 of the hydraulic fracturing crustal stress measuring system of the present invention;

FIG. 11 is a schematic diagram of the structure of E-E in FIG. 10 of the hydraulic fracturing crustal stress measuring system of the present invention;

FIG. 12 is a schematic view of the hydraulic fracturing crustal stress measuring system of the present invention showing an enlarged partial structure of I in FIG. 10;

FIG. 13 is a schematic diagram of an assembly structure of a water injection pipeline joint of the hydraulic fracturing crustal stress measuring system of the present invention;

FIG. 14 is a schematic side view of the hydraulic fracturing crustal stress measurement system of FIG. 13 of the present invention;

FIG. 15 is a schematic top view of the hydraulic fracturing crustal stress measurement system of the present invention in the state of FIG. 13;

FIG. 16 is a schematic cross-sectional structural view of the connector body of the water injection line connector of FIG. 13 of the hydraulic fracturing crustal stress measurement system of the present invention;

FIG. 17 is a schematic cross-sectional structural view of the joint body F-F of FIG. 16 of the hydraulic fracturing crustal stress measuring system of the present invention;

FIG. 18 is a schematic view of a limit stop of the water injection line connector of FIG. 13 of the hydraulic fracturing crustal stress measurement system of the present invention;

FIG. 19 is a schematic view of a partially cut-away structure of the connection of a packer, a regulatory connection device and a water injection pipeline joint of the hydraulic fracturing crustal stress measurement system of the present invention;

FIG. 20 is a schematic top view of the hydraulic fracturing crustal stress measuring system of FIG. 19 of the present invention.

In the figure, 1, a packer; 101. a packer core tube; 102. sealing the water injection pipe by a packer; 103. a locking ring; 104. packer rubber; 106. sealing the hole water injection pipe plug; 107. plugging a core pipe; 108. fracturing the water injection pipe joint;

2. a water injection member;

3. regulating and controlling a connecting device; 301. fracturing a water injection pipe interface; 302. hole sealing water injection pipe interfaces; 303. the packer controls the water injection pipe interface; 304. a packer drainage hole; 305. water injection pressure test water guide measuring hole; 306. a pressure relief water guide hole; 307. a pressure relief valve needle; 308. a sealing body; 309. resetting the valve core; 310. a return spring; 311. pressure regulating screw plug;

4. a water injection pipeline joint; 401. a joint body; 402. a limit baffle; 403. a limit sliding plate; 404. a locking screw; 405. an anti-drop screw;

5. a test well;

7. A pressure measurement assembly; 701. a first water injection pressure tester; 702. a second water injection pressure tester; 703. a third water injection pressure tester;

8. a pressure relief device; 9. a stop valve; 10. a water injection assembly; 11. sealing and isolating the water injection pipeline; 12. fracturing a water injection pipeline; 13. the packer controls the pipeline.

Detailed Description

The following describes in further detail the embodiments of the present invention with reference to the drawings and examples. The following examples are illustrative of the invention and are not intended to limit the scope of the invention.

The hydraulic fracturing ground stress measuring method is that two ends of a section of drilling hole are sealed by a packer in the drilling hole to form a section of sealing space, high-pressure water is injected into the sealing section of the drilling hole, and the ground stress magnitude is determined through the expansion of a hole wall rock mass. The hydraulic fracturing ground stress measuring system consists of a packer, a test hole, a water injection pipeline, a water injection pressure test recorder, a high-pressure water injection pump and the like.

In the hydraulic fracturing ground stress testing process, the construction difficulty, engineering cost and testing system requirements are considered, the diameter of a drilling hole for testing is small, the testable hole diameter comprises phi 75mm, phi 91mm, phi 110mm and phi 130mm, and the diameter of the drilling hole limits the radial dimension of the fracturing system. The invention provides a hydraulic fracturing ground stress measuring system capable of being remotely controlled, which is particularly suitable for the ground stress testing process of a small-aperture and large-depth drilling hole.

Referring to fig. 1-20, this embodiment provides a hydraulic fracturing ground stress measurement system, including a packer 1, a packing water injection pipeline 11 and a fracturing water injection pipeline 12, the packer 1 includes an upper packer and a lower packer, the upper packer and the lower packer are sealed with the wall surface of a test hole 5 to form two sections of packing sections, a fracturing test section is formed between the upper packer and the lower packer, a packer core pipe 101 and a packer hole sealing water injection pipe 102 are arranged on the packer 1, the packing water injection pipeline 11 supplies pressure fluid to the packer hole sealing water injection pipe 102, the pressure fluid in the packer hole sealing water injection pipe 102 causes the packer 1 to bulge and form a packing section with the test hole 5 in a sealing manner, the fracturing water injection pipeline 12 supplies pressure fluid to the packer core pipe 101, the pressure fluid in the packer core pipe 101 flows into the fracturing test section, the hydraulic fracturing ground stress measurement system further includes a regulating and connecting device 3, the regulating and connecting device 3 connects the upper packer, and the packer hole sealing water injection pipe 102 is regulated with the external environment by regulating and controlling the on-off of the connecting device 3.

In order to reduce the mutual interference between the sealing pipeline and the fracturing pipeline, the sealing water injection pipeline 11 and the fracturing water injection pipeline 12 which are mutually independent are arranged, so that the independence between the packer core pipe 101 and the packer hole sealing water injection pipe 102 is improved, and the influence of any pipeline leakage or pipeline fault on the system test is reduced.

The pressure fluid in the packer hole sealing water injection pipe 102 can be directly discharged through the regulating and controlling connecting device 3, the regulating and controlling connecting device 3 is connected with the upper packer, after the fracturing test is completed, the pressure fluid in the packer directly leaks into the test hole 5 through the regulating and controlling connecting device 3, the pressure release height of the packer hole sealing water injection pipe 102 is obviously reduced, the problem that the pressure release is carried out after the pressure is required to flow back to the ground through a pipeline in the prior art is solved, and the reliability of the pressure release of the packer is ensured.

The system further comprises a packer control pipeline 13, pressure fluid in the packer control pipeline 13 presses the regulating and controlling connecting device 3, a pressure relief component is arranged in the regulating and controlling connecting device 3, and the pressure relief component bears pressure change to act so as to regulate the on-off of the packer hole sealing water injection pipe 102 and the external environment.

The system is a measuring system with three independent pipeline system structures for hole sealing, fracturing and pressure relief control and same drilling multi-pipeline arrangement.

The packer control line 13 is used to pressurize the pressure relief assembly within the regulatory linkage 3 to regulate the condition of the pressure relief assembly within the regulatory linkage 3. Normally, the pressure release assembly closes a water release hole of the packer, and a hole sealing water injection pipeline is in a sealing state; during pressure relief, the pressure relief assembly is opened, and pressure fluid in the packer hole sealing water injection pipe 102 flows out along the regulating and controlling connecting device 3 to relieve pressure. The opening power of the pressure relief assembly is the fluid pressure in the packer control pipeline 13, and the opening pressure required by the pressure relief assembly can be adjusted at any time.

The packer 1 is provided with a packer core pipe 101 and a packer hole sealing water injection pipe 102, the packer 1 is connected with a regulating and controlling connecting device 3, the regulating and controlling connecting device 3 is provided with a fracturing water injection pipe interface 301, a hole sealing water injection pipe interface 302 and a packer control water injection pipe interface 303, the fracturing water injection pipe interface 301 is connected with the packer core pipe 101, the hole sealing water injection pipe interface 302 is connected with the packer hole sealing water injection pipe 102, the packer control water injection pipe interface 303 is connected with a packer control pipeline, and the on-off of the hole sealing water injection pipe interface 302 and the external environment is regulated.

Specifically, as shown in fig. 1-3, 19 and 20, the packer 1 of the present embodiment adopts the packer 1 of the existing structure, the packer 1 includes two, that is, an upper packer and a lower packer, the upper packer and the lower packer have the same structure, the upper packer and the lower packer are respectively attached to and sealed with the inner wall of the test hole 5 to form a packing section, and a drilling part between the upper packer and the lower packer forms a fracturing test section.

The packer 1 is connected with a regulating and controlling connecting device 3, and the pressure fluid of the packing section and the fracturing test section of the packer 1 is independently supplied and monitored by setting the regulating and controlling connecting device 3. And be equipped with packer control water injection pipe interface 303 on the regulation and control connecting device 3, the pressure fluid in the packer hole sealing water injection pipe 102 can be followed the direct discharge of pressure release passageway, has solved in the current structure and needs backward flow to ground discharge and lead to the packer to retract inefficiency, retract effectually, easily block in test hole 5 scheduling problem.

The pressure fluid flows in 3 paths in the regulating and controlling connecting device 3, namely fracturing fluid provided for the packer core tube 101, sealing fluid provided for the packer sealing water injection tube 102 and packer decompression control fluid provided for the packer control water injection tube interface 303, and the fluids of the three paths are mutually independent; the pressure measuring assemblies 7 can be arranged on the flow paths of the pressure fluid of the sealing and isolating water injection pipeline 11 and the fracturing water injection pipeline 12 so as to independently monitor the state of the pressure fluid on each path and improve the accuracy of the test process; the packer control pipeline 13 can be provided with a pressure measuring assembly 7, so that remote monitoring of three paths is realized. Furthermore, the regulating and controlling connecting device 3 has compact structure and small radial size, and is suitable for the testing process of small-aperture drilling.

Furthermore, the regulating and controlling connecting device 3 is connected with a fracturing water injection pipeline 12, a packing water injection pipeline 11 and a packer control pipeline 13, and three independent pipelines independently supply pressure fluid to three paths of the regulating and controlling connecting device 3. Specifically, a fracturing water injection pipeline 12 is connected to a fracturing water injection pipe connector 301, a sealing water injection pipeline 11 is connected to a sealing water injection pipe connector 302, and a packer control pipeline 13 is connected to a packer control water injection pipe connector 303.

In practical application, the fracturing water injection pipeline 12, the packing water injection pipeline 11 and the packer control pipeline 13 are all deep to a test position along the ground, the length of the pipeline can reach hundreds to thousands of meters, and the pipelines are connected in a sectional butt joint mode, so that the production and the transportation of the whole system are facilitated.

The fracturing water injection pipeline 12 is used as a main pipeline, a high-strength seamless steel pipe with strong bearing capacity is adopted, the sealing and isolating water injection pipeline 11 and the packer control pipeline 13 are made of high-pressure rubber pipes with smaller diameters, and when the extending length of the sealing and isolating water injection pipeline 11 and the packer control pipeline 13 is large, the winding problem is easy to occur. In order to solve the problem of intertwining between the pipelines, a water injection pipeline joint 4 with a limiting function is designed at the butt joint part of the pipelines, and the water injection pipeline joint 4 positions a fracturing water injection pipeline 12, a packing water injection pipeline 11 and a packer control pipeline 13 to prevent the pipelines from being intertwined.

Specifically, the high-strength seamless steel pipe with the outer diameter phi of 25mm and the wall thickness of 7.5mm is used for manufacturing the fixed-length pipeline by the fracturing water injection pipeline 12, and the fixed-length pipeline is also used as a bearing and conveying function of a system, has the bearing capacity of 22 tons and meets the total weight requirement of the bearing test system for connecting 1.5 km; the packer water injection pipeline 11 and the packer control pipeline 13 use high-pressure rubber pipes with the diameter phi of 12mm, so that the overall radial dimension is reduced.

The fracturing water injection pipe connector 301 on the regulating and controlling connecting device 3 is connected with the packer core pipe 101 through the fracturing water injection pipe connector 108, and the connecting structure is simple.

Remote monitoring of a system

As shown in fig. 1, 4 and 19-20, the packing water injection pipeline 11 and the fracturing water injection pipeline 12 are connected with a pressure measuring assembly 7, and the pressure measuring assembly 7 comprises a first water injection pressure tester 701, a second water injection pressure tester 702 and a third water injection pressure tester 703; specifically, the sealing and isolating water injection pipeline 11 is connected with a second water injection pressure tester 702, and the fracturing water injection pipeline 12 is connected with a third water injection pressure tester 703. The second water injection pressure tester 702 and the third water injection pressure tester 703 are respectively arranged at the inlet ends of two pipelines on the ground, and the two water injection pressure testers respectively monitor the injection pressure of the packing water injection pipeline 11 and the fracturing water injection pipeline 12.

During pressure relief, the second water injection pressure tester 702 on the packing water injection pipeline 11 and the third water injection pressure tester 703 on the fracturing water injection pipeline 12 can quickly reduce the displayed system pressure, and can directly reflect the working state of the packer control pipeline 13. The packer control pipeline 13 can also be provided with a water injection pressure tester, so that the pressure of the pressure relief process control pipeline system is monitored, multiple monitoring is realized, and the monitoring on the testing process and the pressure relief process is more perfect.

The fracturing water injection pipe connector 301 of the regulating and controlling connecting device 3 is connected with a first water injection pressure tester 701, the fracturing water injection pipe connector 301 is provided with a water injection pressure test water guide measuring hole 305, the first water injection pressure tester 701 tests the pressure of pressure fluid in the water injection pressure test water guide measuring hole 305, and monitoring of the pressure fluid in the fracturing water injection pipe connector 301 is achieved. The first water injection pressure tester 701 cooperates with the third water injection pressure tester 703 to perform multiple monitoring of the fracturing water injection line 12 so as to find problems in the fracturing water injection line 12 in time. The first water injection pressure tester 701, the second water injection pressure tester 702 and the third water injection pressure tester 703 are all devices with recording functions. The water injection pressure test water guide hole 305 is set to be a branch connected to the fracturing water injection pipe interface 301, and is used for connecting the first water injection pressure tester 701, so as to ensure the test accuracy.

The packer water injection pipeline 11, the fracturing water injection pipeline 12 and the packer control pipeline 13 are all connected to the water injection assembly 10, a stop valve 9 is arranged between the packer water injection pipeline 11, the fracturing water injection pipeline 12 and the packer control pipeline 13 and the water injection assembly 10, and the packer control pipeline 13 is connected with the pressure relief device 8.

The water injection assembly 10 is provided with a high-pressure pump, the high-pressure pump supplies pressure fluid into the water injection pipeline, the pressure fluid is preferably high-pressure water, and the high-pressure pump is provided with a high-pressure water pump; the high-pressure pump is connected with a packing water injection pipeline 11, a fracturing water injection pipeline 12 and a packer control pipeline 13, and the three pipelines are all provided with stop valves 9 so as to regulate and control the on-off of the high-pressure pump and the pipeline. The pressure relief device 8 on the packer control line 13 is set as a pressure relief valve to regulate the pressure relief process.

Wherein, the regulation and control components such as the first water injection pressure tester 701, the second water injection pressure tester 702, the third water injection pressure tester 703, the pressure release valve, the stop valve 9 and the like can be remotely regulated so as to perform centralized operation and monitoring on the system.

A preferred embodiment of the packer construction

As shown in fig. 2 and 3, the packer 1 comprises an inflatable high-strength packer rubber cylinder 104, a packer core tube 101, a packer hole sealing water injection tube 102, a locking ring 103 and the like. The packer rubber barrel 104 of each packer penetrates through a packer core tube 101 for fracturing water injection, two ends of the packer rubber barrel 104 are buckled on the packer core tube 101 by using locking rings 103, and the packer core tube 101 and the packer rubber barrel 104 are mutually sealed at the positions of the locking rings 103 at the two ends, so that mutual independence of a packing section and a fracturing test section is ensured. The packer sealing water injection pipe 102 is installed at the two ends of the packer rubber barrel 104, the packer sealing water injection pipe 102 penetrates through the locking ring 103, and the packer sealing water injection pipe 102 is communicated with a gap between the inner cavity of the packer rubber barrel 104 and the outer wall of the packer core pipe 101, so that the process of filling pressure fluid into the packer rubber barrel 104 is realized.

The packer hole sealing water injection pipes 102 of the upper packer and the lower packer are mutually butted, and the packer hole sealing water injection pipe 102 injects water into the packer rubber 104 so as to cause the packer rubber 104 to bulge and be in sealing contact with the test hole 5; the packer core tubes 101 of the two packers are mutually butted through the water injection piece 2, the water injection piece 2 is a hollow pipe joint, a radial water guide hole is formed in the middle of the water injection piece 2, the water injection piece 2 conducts the packer core tubes 101 with the outside, pressure fluid is filled into a fracturing test section, and a fracturing test process is implemented.

The packer hole sealing water injection pipe 102 and the packer core pipe 101 of the lower packer are required to be sealed through a plugging structure, the packer hole sealing water injection pipe 102 is connected with a hole sealing water injection pipe plug 106, and the packer core pipe 101 is connected with a core pipe plug 107.

A preferred embodiment of the regulatory connection means 3

Referring to fig. 3-12, the system solves the problems of packer sealing and pressure release control by using the regulation and control connecting device 3, and simultaneously sets the installation position of the first water injection pressure tester 701 by using the regulation and control connecting device 3, so as to realize direct measurement of the water injection pressure in the fracturing process at the measuring point position.

Regulating and controlling the pipeline path in the connecting device 3: one end of the fracturing water injection pipe interface 301 is connected with the fracturing water injection pipeline 12, the other end of the fracturing water injection pipe interface is connected with the packer core pipe 101, one end of the hole sealing water injection pipe interface 302 is connected with the packing water injection pipeline 11, the other end of the hole sealing water injection pipe interface is connected with the packer hole sealing water injection pipe 102, the packer control water injection pipe interface 303 is connected with the packer control pipeline 13, and the pressure relief valve needle is arranged in the packer control water injection pipe interface and used for controlling the on-off of the packing water injection pipeline 12 and the outside.

The fracturing water injection pipe connector 301 is communicated with a water injection pressure test water guide measuring hole 305, and the first water injection pressure tester 701 is used for measuring the fluid pressure in the water injection pressure test water guide measuring hole 305 and measuring the fluid pressure in the packer core pipe 101.

Referring to fig. 10-12, the packer controls the on-off adjustment structure of the water injection pipe interface 303 to the hole sealing water injection pipe interface 302:

a pressure relief water guide hole 306 is arranged between the packer control water injection pipe interface 303 and the hole sealing water injection pipe interface 302, the pressure relief assembly is connected inside the packer control water injection pipe interface 303, a packer water discharge hole 304 is formed in the regulating and controlling connecting device 3, and the pressure relief assembly regulates the on-off of the pressure relief water guide hole 306 and the packer water discharge hole 304.

The hole sealing water injection pipe interface 302, the pressure relief water guide hole 306 and the packer water discharge hole 304 are communicated to form a pressure relief channel, pressure fluid in the packer hole sealing water injection pipe 102 flows out through the pressure relief channel, and pressure relief power of the pressure relief channel is used for controlling the pressure of the fluid introduced by the water injection pipe interface 303. The fluid pressure of the water injection pipe interface 303 is controlled to enable the pressure relief water guide hole 306 and the packer water discharge hole 304 to be communicated, and pressure fluid in the packer sealing water injection pipe 102 can be directly discharged to finish packer pressure relief.

Further, the pressure relief assembly comprises a pressure relief valve needle 307, a sealing body 308, a reset valve core 309, a reset spring 310 and a pressure regulating screw plug 311, wherein the pressure relief valve needle 307 bears the fluid pressure in the packer control water injection pipe interface 303, the pressure relief valve needle 307 is abutted against the sealing body 308, and the pressure relief valve needle 307 pushes the sealing body 308 to move so that the packer water drain hole 304 is communicated with or disconnected from the pressure relief water guide hole 306.

The sealing body 308 is of a spherical structure, and the sealing body 308 is of a polyester ball; the return springs 310 are provided as a plurality of belleville springs.

The pressure release water guide hole 306 is arranged between the cavity where the sealing body 308 is arranged and the packer sealing water injection pipe 102, the packer water discharge hole 304 is arranged between the pressure release valve needle 307 and the sealing body 308, and the packer water discharge hole 304 is communicated with the radial outer wall of the shell of the regulation and control connecting device 3 so as to facilitate the outflow of fluid. The number of the packer water discharge holes 304 is distributed in the radial direction of the shell of the regulating and controlling connecting device 3, so that quick pressure relief is ensured.

The casing of regulation and control connecting device 3 is established to irregular tubular structure, hole sealing water injection pipe interface 302 and fracturing water injection pipe interface 301 are the pipeline that link up the casing both ends, packer control water injection pipe interface 303 also establishes the pipeline structure in the casing, each part of pressure release subassembly is all connected in packer control water injection pipe interface 303, pressure release water guide hole 306 is the pipeline that is used for the intercommunication hole sealing water injection pipe interface 302 and the cavity that sealing body 308 is located that inclines to set up in the casing, packer drain hole 304 is the pipeline at the radial distribution of casing with packer control water injection pipe interface 303 intercommunication. The sealing body 308 is disposed in the pipeline of the packer control water injection pipe interface 303, and the sealing body 308 is used for isolating or communicating the pressure relief water guide hole 306 with the packer water drain hole 304.

The pipeline extension path of the fracturing water injection pipe interface 301 is provided with a U-shaped concave section for adapting to the installation of the first water injection pressure tester 701, a groove-shaped structure is formed on the shell at the U-shaped concave position of the fracturing water injection pipe interface 301, the first water injection pressure tester 701 is installed in the groove-shaped structure, and the protruding size of the first water injection pressure tester 701 relative to the shell is reduced.

The packer control water injection pipe interface 303 and the hole sealing water injection pipe interface 302 are arranged in the radial direction of the fracturing water injection pipe interface 301, and the packer control water injection pipe interface 303 and the hole sealing water injection pipe interface 302 form an included angle of 90 degrees relative to the center of the fracturing water injection pipe interface 301, so that the structure installation requirement is met, and the radial structure size is effectively controlled.

The rear end of the mounting hole of the pressure release valve needle 307 is the connecting end of the packer control water injection pipe connector 303 and the packer control pipeline 13, pressure fluid in the packer control pipeline 13 presses the pressure release valve needle 307, the pressure release valve needle 307 is pushed to move, the pressure release valve needle 307 pushes the sealing body 308 to move, the return spring 310 compresses, the pressure release water guide hole 306 is communicated with the packer water discharge hole 304, and the pressure release water discharge process is completed. After the packer rubber 104 is retracted, the packer control pipeline 13 is depressurized; the elastic restoring force of the restoring spring 310 pushes the restoring valve core 309 and the sealing body 308, the sealing body 308 compresses the end face of the packer control water injection pipe interface 303, so that the mounting hole of the pressure release valve needle 307 is automatically closed, the pressure release water guide hole 306 is separated from the packer water discharge hole 304, namely, a pressure release channel is separated, the system automatically restores to a sealing test state, and remote control of the test system in the drilling is realized.

The pressure of the test process control system always keeps the hydrostatic pressure effect of the test depth, and the drilling depth of the ground stress measurement at different places is greatly changed from tens of meters to thousands of meters, so that the hydrostatic pressure is greatly changed. On one hand, the pressure relief system is required to be sealed under hydrostatic pressure when the drilling is at the maximum test depth, and on the other hand, the pressure of the control system during pressure relief is not required to be too high, so that the reliability of the system is ensured.

The degree of tightening of the pressure regulating screw 311 is adjusted to change the initial deformation force of the return spring 310. When the pressure fluid pushes the pressure release valve needle 307 to release pressure, the thrust of the pressure release valve needle 307 pushing the sealing body 308 is larger than the preset pressing force of the pressure regulating screw plug 311 to the return spring 310, the return spring 310 compresses, and the sealing body 308 and the return valve core 309 simultaneously slide to one side of the pressure regulating screw plug 311 to complete pressure release.

The pressure regulating screw plug 311 is used for regulating the preset pressing force of the return spring 310, when the tightness degree of the pressure regulating screw plug 311 changes, the pressing force of the return spring 310 is different, and the pressure relief force (pressure relief control system pressure) required by the pressure relief valve needle 307 to jack the sealing body 308 is different. The pressure release assembly is usually kept in a sealed state to meet the test requirement, namely, the sealing body 308 is pressed on the orifice of the pressure release valve needle 307, and the water release channel is kept sealed; during pressure relief, under the action of pressure fluid of the packer control pipeline 13, the pressure relief valve needle 307 pushes the sealing body 308 to move, the sealing is released, the pressure relief channel is opened, and the packer automatically relieves pressure.

System pressurization measurement and depressurization process

After the ground stress measuring system is assembled, when the control system of the packer 1 is in a stop (hydrostatic pressure) state, the measuring system is in a test state, and the hole sealing and fracturing test processes can be directly completed; when the control system of the packer 1 is started to release pressure, the hole sealing system is completely released, and the pressure of the water provided by the high-pressure water injection pump and the hydrostatic pressure formed by the depth of the measuring point are included, so that the packer rubber 104 is ensured to retract smoothly to the original size, and the measuring system is freely lifted in the borehole; after the pressure relief of the packer 1 is completed and the pressure relief of the control system is carried out on the ground, the measurement system should automatically recover to a sealing test state.

And in the hole sealing and fracturing process after hole sealing, the pressure relief action of the regulating and controlling connecting device 3 does not occur, and the hole sealing system and the fracturing system keep a sealing state. The first water injection pressure tester 701 installed on the regulation and control connection device 3 tests and records the pressure of the fracturing whole-process pressure fluid of the drilling test section.

After the fracturing test is finished, high-pressure water entering through the packer control water injection pipe interface 303 pushes the pressure release valve needle 307 to move forwards, the pressure release valve needle 307 pushes the spherical sealing body 308, the spherical sealing body 308 is separated from the mounting hole of the pressure release valve needle 307 to form a gap, water stored in the inner cavity of the packer rubber cylinder 104 and the packing water injection pipeline 11 enters the cavity where the spherical sealing body 308 is located through the pressure release water guide hole 306 and then enters the packer water release hole 304 through the front end of the mounting hole of the pressure release valve needle 307, so that the whole sealing system is decompressed, and the packer rubber cylinder 104 is retracted smoothly under the action of deformation force.

The system uses water pressure as power and performs remote opening control on the pressure relief assembly on the ground. In order to ensure the reliability of the control system, the control system is not provided with a pressure relief mechanism in the packing water injection pipeline 11, so that when the control system is not started, the pressure relief valve needle 307 is still subjected to the hydrostatic pressure of the system generated from the measuring point to the ground. When the hydraulic fracturing ground stress measurement is carried out, the measurement system is fed into the drilling hole once, then the multipoint test is continuously completed, the measurement system is required to be smoothly decompressed, and meanwhile, the system can automatically recover to a sealing test state after decompression, namely: after the ground closes the stop valve 9 on the control system and opens the pressure relief device 8 to relieve pressure, the spherical sealing body 308 should push the pressure relief valve needle 307 reversely, so that the spherical sealing body 308 compresses the mounting hole of the pressure relief valve needle 307 again and keeps the sealing state. After the packer is depressurized, the return power for the control system is provided by an internal return spring 310 of the depressurization assembly.

The hydrostatic pressure formed at the formation survey point locations at different depths is different. The greater the drilling test depth, the higher the hydrostatic pressure, and the maximum hydrostatic pressure of the control system and the maximum required restoring force are measured at the maximum drilling depth measuring point of the measuring system. The control system provides a restoring force to the spherical seal body 308 that meets the sealing requirements of the deepest point.

According to the characteristics of hydrostatic pressure change measured by the hydraulic fracturing ground stress, in the pressure relief control system of the packer, the reset spring 310 is preferably a disc spring with the outer diameter phi of 10mm, and is assembled and installed according to the maximum test depth of a drilling hole. Changing the number of combinations of return springs 310 in each set can smoothly change the magnitude of the return force of the control system, and in particular, the greater the number of belleville springs in each set, the greater the return force provided under certain deformation conditions. By adjusting the tightening degree of the pressure adjusting screw plug 311, the initial pressing force of the return spring 310 can be changed, and thus the control system pressure required by the pressure release valve needle 307 to push the sealing body 308 open can be changed.

The reset seal of the control system adopts a combined structure of the reset valve core 309 and the spherical sealing body 308, the reset valve core 309 positions and guides the disc-shaped reset spring 310, meanwhile, the acting force of the reset spring 310 is transmitted to push the sealing body 308, the spherical rolling action of the spherical sealing body 308 is utilized to automatically center the sealing body 308 with the mounting hole of the pressure release valve needle 307, meanwhile, the spherical sealing body 308 uses a polyester ball with higher strength and better elasticity, the adaptability of the sealing body 308 to the machining shape of an orifice is improved, and the machining precision requirement is reduced while the sealing effect is ensured.

A preferred embodiment of the water injection line connection 4

In order to realize the measurement of the small aperture, the structure which restricts the radial dimension of the measurement system is the largest structure which occupies the radial space of the test system except the radial dimension of the packer and the regulating and controlling connecting device 3. The water injection pipeline joint 4 in the test system is provided with a constraint mechanism for sealing the water injection pipeline 11 and the packer control pipeline 13 while being connected with the fracturing water injection pipeline 12, so that the overall radial size of the system is reduced, and winding of a hose during lifting in a drill hole is avoided.

The fracturing water injection pipeline 12 is used as a main pipeline, the fracturing water injection pipeline 12 is a high-strength seamless steel pipe, and the packing water injection pipeline 11 and the packer control pipeline 13 use small-diameter high-pressure rubber pipes so as to reduce the radial size. The water injection pipeline joint 4 is provided with a plurality of pipelines which extend to the testing position along the ground at intervals so as to ensure the butt joint between the pipelines and prevent the pipelines from intertwining.

As shown in fig. 3-18, the water injection pipeline connector 4 comprises a connector body 401, a limit sliding plate 403, a locking screw 404 and an anti-drop screw 405, wherein the connector body 401 is used for connecting two adjacent sections of fracturing water injection pipelines 12, a positioning groove is formed in the connector body 401, the packing water injection pipeline 11 and the packer control pipeline 13 are arranged in the positioning groove, the limit sliding plate 403 is covered on the positioning groove, the locking screw 404 and the anti-drop screw 405 are detachably connected to the connector body 401, and the locking screw 404 locks and fixes the limit sliding plate 403. The shape of the positioning groove is matched with the shapes of the packing water injection pipeline 11 and the packer control pipeline 13, and the packing water injection pipeline 11 and the packer control pipeline 13 are arranged in the positioning groove.

When the water injection pipeline joint 4 is connected, the joint body 401 is connected with the fracturing water injection pipeline 12, the joint body 401 is of a tubular structure, threaded holes are formed in the joint body 401, the threaded holes are symmetrically formed in two ends of the joint body 401, threaded sections are arranged at the end parts of the fracturing water injection pipeline 12, sealing rings are sleeved on the end parts of the fracturing water injection pipeline 12, the two-section fracturing water injection pipeline 12 is in butt joint in the joint body 401, the joint body 401 is sealed with the fracturing water injection pipeline 12 through threaded connection and sealing rings, and the butt joint mode is simple, good in sealing effect and high in structural strength. The limiting slide plate 403, the locking screw 404 and the anti-falling screw 405 are matched to position the high-pressure rubber pipes of the packing water injection pipeline 11 and the packer control pipeline 13. Locking screw 404 sets up in the bilateral symmetry of the joint body 401, and limit slide 403 is established to fall trapezoidal structure, and the terminal surface of limit slide 403's tip compresses tightly and seals water injection pipeline 11 and packer control pipeline 13, and locking screw 404 runs through limit slide 403, and locking screw 404 is fixed limit slide 403 locking on the joint body 401, and the tip butt anticreep screw 405 of limit slide 403. The limiting slide plate 403 is provided with a counter bore and a through hole which are communicated with each other, and the locking screw 404 can be slidably adjusted in the counter bore and the through hole.

The limiting slide plate 403 is used for compressing the end surfaces of the packing water injection pipeline 11 and the packer control pipeline 13, and can extend to the direction of the pipeline to be an arc-shaped curved surface, so that the fixing stability of the limiting slide plate 403 to the pipeline is ensured.

Positioning process of the packing water injection pipeline 11 and the packer control pipeline 13: screwing the anti-drop screw 405 into the threaded hole, loosening the locking screw 404 to take down the limiting slide plate 403, then clamping the pipe fittings of the sealing and isolating water injection pipeline 11 and the packer control pipeline 13 into the positioning groove of the joint body 401, sleeving the limiting slide plate 403 into the locking screw 404 from the end of the through hole, sliding the limiting slide plate 403 to the end of the counter bore, screwing the locking screw 404, withdrawing the anti-drop screw 405 by 3-5mm, positioning the limiting slide plate 403 on the joint body 401 by the anti-drop screw 405, and completing connection.

With the structure, the joint body 401 directly clamps and positions the packing water injection pipeline 11 and the packer control pipeline 13 under the condition that no pipe fitting is butted in the length direction of the packing water injection pipeline 11 or the packer control pipeline 13, so that the pipelines are prevented from being intertwined.

Another preferred embodiment of the water injection line connection 4

As shown in fig. 3 to 18, the water injection line joint 4 of the present embodiment includes all the features of the water injection line joint 4, and differs from the embodiment of the water injection line joint 4 in that:

The water injection pipeline joint 4 is also provided with a limit baffle 402, the sealing and isolating water injection pipeline 11 and/or the packer control pipeline 13 is provided with a butt joint, and the limit baffle 402 is clamped with the joint body 401 and the butt joint.

The limit baffle 402 is a strip-shaped plate provided with a U-shaped notch, the shape of the U-shaped notch is matched with the pipeline shapes of the packing water injection pipeline 11 and the packer control pipeline 13, and the packing water injection pipeline 11 and the packer control pipeline 13 are clamped in the U-shaped notch. The limit baffle 402 is arranged between the boss of the joint body 401 and the butt joint on the pipeline, and the limit baffle 402 limits the butt joint of the pipeline and prevents the pipeline from rotating axially.

Positioning process of the packing water injection pipeline 11 and the packer control pipeline 13: screwing the anti-drop screw 405 into the threaded hole, loosening the locking screw 404 to take down the limit slide plate 403, putting the limit baffle 402 into the positioning groove of the joint body 401, putting the seal water injection pipeline 11 and the packer control pipeline 13 into the limit baffle 402, sleeving the limit slide plate 403 into the locking screw 404 from the end of the through hole, sliding the limit slide plate 403 to the end of the counter bore, tightening the locking screw 404, withdrawing the anti-drop screw 405 by 3-5mm, positioning the limit slide plate 403 on the joint body 401 by the anti-drop screw 405, and completing connection.

The structure of this embodiment is applicable to the position where the packing water injection pipeline 11 or the packer control pipeline 13 is butt-jointed with two sections of pipe fittings on the water injection pipeline joint 4, and the limiting baffle 402 is used for limiting the axial direction of the pipe fittings, preventing the pipe fittings from loosening or winding, and improving the running stability of the system.

The water injection pipeline joint 4 structure described in the above two embodiments can be designed into two components with different structures, and can be integrated on one water injection pipeline joint 4, wherein one pipeline is in a pipeline butt joint position, and the other pipeline is in a through pipe fitting structure without butt joint.

The invention relates to a hydraulic fracturing ground stress measuring method which comprises the following steps,

firstly, assembling a measurement system, wherein a regulating and controlling connecting device 3 is connected to a packer, a water injection pipeline joint 4 is connected to the regulating and controlling connecting device 3, a sealing and isolating water injection pipeline 11, a fracturing water injection pipeline 12 and a packer control pipeline 13 are connected to the water injection pipeline joint 4, and the sealing and isolating water injection pipeline 11, the fracturing water injection pipeline 12 and the packer control pipeline 13 are connected to a water injection assembly 10;

step two, in the test process, the water injection assembly 10 injects pressure fluid into the packing water injection pipeline 11, the pressure fluid is injected into the packer through the water injection pipeline joint 4 and the regulating and controlling connecting device 3, so that the packer bulges and abuts against the inner wall of the test hole 5 to form a packing section, a closed fracturing test section is formed between two adjacent packing sections, and the packer is in a hole sealing and pressure maintaining state;

The water injection assembly 10 injects pressure fluid into the fracturing water injection pipeline 12, the pressure fluid flows into the fracturing test section along the water injection piece 2 through the water injection pipeline joint 4, the regulating and controlling connecting device 3 and penetrates through the upper packer, the pressure fluid is continuously injected until the fracturing process is completed, and the water injection assembly 10 stops injecting the pressure fluid into the fracturing water injection pipeline 12;

step three, in the pressure relief process of the packer, the water injection assembly 10 injects pressure fluid into the packer control pipeline 13, the pressure fluid is injected into the regulating and controlling connecting device 3 through the water injection pipeline joint 4, the pressure of the packer control water injection pipeline joint 303 in the regulating and controlling connecting device 3 reaches the opening pressure of the pressure relief assembly in the packer control connecting device, and the packer control pipeline 13 enters a pressure maintaining state; the hole sealing water injection pipe interface 302 in the regulating and controlling connecting device 3 is communicated with the packer water draining hole 304 through the pressure releasing water guiding hole 306, and the pressure fluid in the packer flows out; until the packer is retracted, the packer control pipeline 13 stops maintaining the pressure;

and step four, in the pressure relief process of the packer control pipeline 13, starting the pressure relief device 8 on the packer control pipeline 13 until the pressure of the packer control pipeline 13 is reduced to the hydrostatic pressure, and resetting the pressure relief assembly.

Specifically, the on-site assembly connection test system is used for measuring, after the packer is assembled, the regulation and control connecting device 3 and the pressure measuring assembly 7 are sequentially connected and installed, and the water injection pipeline joint 4 is utilized to gradually lengthen the packer water injection pipeline 11, the fracturing water injection pipeline 12 and the packer control pipeline 13 until the packer is lowered to a test layer. After the sealing and isolating water injection pipeline 11 and the fracturing water injection pipeline 12 are connected to the ground, the pressure measuring assembly 7, the stop valve 9 and the communicated high-pressure water injection pump are respectively installed. After the packer control line 13 is connected to the surface, the pressure relief device 8 and the shut-off valve 9 are installed and then connected to the high pressure water injection pump.

And in the measurement process, after the system connection is completed, a high-pressure water injection pump is started, the packing water injection pipeline 11 is opened, high-pressure water enters the inner cavities of the packer rubber barrels 104 at the two ends of the packer through the packing water injection pipeline 11 and the regulating and controlling connecting device 3, and the drilling packing of the fracturing test section is completed. And after the hole sealing is finished, closing the sealing water injection pipeline 11 to enable the hole sealing system to be in a sealing and pressure maintaining state.

And then the fracturing water injection pipeline 12 is opened, high-pressure water enters the packer core pipe 101 through the fracturing water injection pipeline 12 and the regulating and controlling connecting device 3, and the high-pressure water flows into the water injection piece 2 from the packer core pipe 101 and is injected into the fracturing test section, and the fracturing process is finished by continuous water injection.

After the fracturing test is finished, the fracturing water injection pipeline 12 is closed, the packer control pipeline 13 is opened, high-pressure water enters the regulating and controlling connecting device 3 through the packer control pipeline 13, when the water pressure reaches the set opening pressure of the pressure relief assembly, the high-pressure water stored in the inner cavity of the packer rubber cylinder 104 and in the packing water injection pipeline 11 is discharged into a drill hole through the packer water discharge hole 304 of the regulating and controlling connecting device 3, the packer is depressurized and automatically retracted, and meanwhile, the water stored in the fracturing test section in the fracturing process is discharged into the drill hole.

After the pressure relief of the packer is retracted, the packer control pipeline 13 and the high-pressure water injection pump are closed, the pressure relief device 8 of the packer control pipeline 13 is opened, the system pressure of the packer control pipeline 13 is reduced to hydrostatic pressure, the pressure relief assembly inside the regulating and controlling connecting device 3 is automatically reset, the pressure relief channel of the packer is closed, and the system is restored to a test state.

And (3) sending the packer to a test point at the next layer in the drill hole, repeating the test process until the test of all the test points of the drill hole is finished, and recovering the test system after pressure relief.

The second water injection pressure tester 702 and the third water injection pressure tester 703 which are respectively installed on the ground are utilized to seal the water injection pipeline 11 and the fracturing water injection pipeline 12, and meanwhile, the water pressure changes of the hole sealing system and the fracturing system in the test process are monitored, the abnormal situation of the fracturing process in the test section is analyzed, and the hole sealing leakage and the rock stratum breaking situation are identified.

As can be seen from the above embodiments,

(1) The regulating and controlling connecting device 3 with a special structure is directly connected with the packer to control the hole sealing and pressure relief of the packer, the pressure relief assembly uses the belleville springs as regulating and resetting force application elements to adjust the superposition quantity of each group of springs to match the tightening degree of the pressure regulating screw plugs, the opening pressure adjustment of the control system is simply and conveniently realized, and the adaptability of the control system is obviously improved; the reset valve core 309 is matched with the elastic spherical sealing body 308, so that the sealing reliability is improved, and the manufacturing cost is reduced;

(2) A regulation and control connecting device 3 with control and measurement functions is used for forming a measurement and control integrated structure, and a first water injection pressure tester 701 is installed close to a measuring point, so that direct measurement and recording of real data of the position of the measuring point are realized;

(4) The radial dimension of all parts in the system after being assembled is limited within the diameter phi 56mm, so that the small-aperture test requirement is met, all pipeline systems are restrained by using the water injection pipeline joint 4, and the problem of winding of the hose in a drilled hole is solved;

(5) The test system is particularly suitable for testing the drilling holes with small ground aperture and large depth, and in engineering construction, the construction cost can be effectively reduced by reducing the drilling hole aperture, but the existing ground stress test system can not meet the test requirement of drilling holes with the diameter smaller than 70 mm;

(6) The fracturing water injection pipeline 12 is used for fracturing water injection, plays a role of a lowering and recycling test system, and is high in bearing capacity and meets the requirements of a kilometer deep hole ground stress test by using a high-strength thick-wall seamless steel tube.

In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood as appropriate by those of ordinary skill in the art.

Furthermore, in the description of the present invention, unless otherwise indicated, the meaning of "a plurality", "a plurality of groups" is two or more.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.

Claims

1. The hydraulic fracturing ground stress measurement system is characterized by comprising an upper packer and a lower packer, wherein the upper packer and the lower packer are sealed with the wall surface of a test hole to form two sections of packing sections, a fracturing test section is formed between the upper packer and the lower packer, a packer core pipe and a packer hole sealing water injection pipe are arranged on the packer, the packing water injection pipe is used for supplying pressure fluid to the packer hole sealing water injection pipe, the pressure fluid in the packer hole sealing water injection pipe enables the packer to bulge and form a packing section with the test hole in a sealing mode, the fracturing water injection pipe is used for supplying pressure fluid to the packer core pipe, the pressure fluid in the packer core pipe flows into the fracturing test section, the hydraulic fracturing ground stress measurement system further comprises a regulating and controlling connecting device, the packer hole sealing water injection pipe is connected with the upper packer, and the external environment is regulated by the regulating and controlling connecting device;

The pressure release assembly is arranged in the regulation and control connecting device and is used for bearing pressure change to act so as to adjust the on-off of the packer hole sealing water injection pipe and the external environment;

the device comprises a regulating and controlling connecting device, a pressure control device and a pressure control device, wherein the regulating and controlling connecting device is provided with a fracturing water injection pipe interface, a hole sealing water injection pipe interface and a packer control water injection pipe interface, one end of the fracturing water injection pipe interface is connected with a packer core pipe, the other end of the fracturing water injection pipe interface is connected with a fracturing water injection pipe, one end of the hole sealing water injection pipe interface is connected with the packer sealing water injection pipe, the other end of the hole sealing water injection pipe interface is connected with the packer control pipe, the on-off of the hole sealing water injection pipe interface and the external environment is regulated, and the regulating and controlling connecting device is connected with a first water injection pressure tester which is communicated with the fracturing water injection pipe interface on the regulating and controlling connecting device;

a pressure relief water guide hole is formed between the packer control water injection pipe interface and the hole sealing water injection pipe interface, the packer control water injection pipe interface is connected with the pressure relief assembly, a plurality of packer water discharge holes are formed in the regulating and controlling connecting device, and the pressure relief assembly regulates the on-off of the pressure relief water guide hole and the packer water discharge holes;

The pressure relief assembly comprises a pressure relief valve needle, a sealing body, a reset valve core, a reset spring and a pressure regulating screw plug, wherein the pressure relief valve needle bears the fluid pressure in a packer control water injection pipe interface, the pressure relief valve needle is abutted to the sealing body, the sealing body moves to enable a packer water discharge hole to be communicated with or disconnected from a pressure relief water guide hole, the pressure regulating screw plug is screwed to adjust the preset pressing force of the reset spring, the sealing body is of an elastic spherical structure, and the reset spring is arranged into a plurality of belleville springs.

2. The hydraulic fracturing ground stress measurement system of claim 1, wherein said sealing body is provided as a polyester ball.

3. The hydraulic fracturing crustal stress measurement system of claim 1 or 2, wherein a water injection pipeline joint is connected to said fracturing water injection pipeline, said packing water injection pipeline and said packer control pipeline.

4. The hydraulic fracturing ground stress measurement system of claim 3, wherein the water injection pipeline joint comprises a joint body, a limiting slide plate, a locking screw and an anti-drop screw, wherein the joint body is used for connecting two adjacent sections of the fracturing water injection pipeline, a positioning groove is formed in the joint body, the sealing water injection pipeline and the packer control pipeline are arranged in the positioning groove, the limiting slide plate is covered on the positioning groove, the locking screw and the anti-drop screw are detachably connected on the joint body, and the locking screw is used for locking and fixing the limiting slide plate.

5. The hydraulic fracturing crustal stress measurement system of claim 4, wherein a limit baffle is arranged on the water injection pipeline joint, a butt joint is arranged on the packer water injection pipeline and/or the packer control pipeline, and the limit baffle is clamped with the joint body and the butt joint.

6. The hydraulic fracturing crustal stress measurement system of claim 5, wherein said packing water injection pipeline and fracturing water injection pipeline are connected with a pressure measuring assembly, said packing water injection pipeline is connected with a second water injection pressure tester, and said fracturing water injection pipeline is connected with a third water injection pressure tester; the packer is characterized in that the packer water injection pipeline, the fracturing water injection pipeline and the packer control pipeline are all connected to the water injection assembly, a stop valve is arranged between the packer water injection pipeline, the fracturing water injection pipeline and the packer control pipeline and the water injection assembly, and the packer control pipeline is connected with a pressure relief device.

7. A method of measuring hydraulic fracture crustal stress, characterized in that it is based on the hydraulic fracture crustal stress measuring system according to any one of claims 1 to 6, comprising:

the pressure of the packer control pipeline is relieved, a pressure relief device on the packer control pipeline is opened until the pressure of the packer control pipeline is reduced to hydrostatic pressure, and the pressure relief assembly is automatically reset; and closing the channels of the packer water discharge hole and the pressure relief water guide hole, sealing the hole sealing water injection pipeline, and recovering the system to a test state.