Small diameter hydraulic fracturing test packer

Abstract

The application provides a small-diameter hydraulic fracturing test packer, and belongs to the technical field of in-situ stress measurement. The small-diameter hydraulic fracturing test packer comprises an upper packer, a lower packer and a flower pipe; a seat sealing passage and a fracturing passage are axially arranged in a double-circuit coaxial installation rod connector; a plug is connected to one end of the lower packer; the flower pipe is axially provided with a seat sealing butt joint passage and a fracturing butt joint passage, the seat sealing butt joint passage is communicated with the seat sealing passage, the fracturing butt joint passage is communicated with the fracturing passage, and the surface of the flower pipe is provided with a fracturing water outlet hole communicated with the fracturing butt joint passage. The structure is simple, and the assembly is convenient; the five components, i.e., the double-circuit coaxial installation rod connector, the upper packer, the flower pipe with the water outlet hole, the lower packer and the plug, can realize the sealing of a test section for in-situ stress measurement of water pressure fracturing in a small-diameter borehole and the fracturing operation of high-pressure fluid.

Description

Technical Field

[0001] This application relates to the field of in-situ stress measurement, and more specifically, to a small-diameter hydraulic fracturing test packer. Background Technology

[0002] Currently, the hydraulic fracturing (HF) method for in-situ stress measurement is one of the most important geostress measurement technologies. Geostress, as one of the most important physical properties of the solid Earth's crust, is crucial basic data indispensable for the construction of major national infrastructure projects and the exploration and development of key deep mineral resources and energy materials. Among all geostress measurement methods, hydraulic fracturing testing technology, with its three major characteristics and advantages—unrestricted test depth, no need for rock mechanics parameters in theoretical calculations, and relatively stable test results—has become the most direct and effective method for determining rock mass geostress, widely used in tunnels, mines, energy development, and other fields.

[0003] M.K. Hubbert and D.W. Williams believed that the in-situ stress deep underground is both vertical and horizontal, emphasizing that the two horizontal principal stresses are not necessarily equal and are independent of the vertical stress, rather than being under hydrostatic pressure. These theoretical understandings and elasticity models remain the foundation for our understanding of hydraulic fracturing today (Hubbert and Williams, 1957; Kirsch, 1898). Haimson and Fairhurst (1967) pointed out that the fractures generated on the wellbore are related to the following three factors: ① crustal stress, ② the differential stress between the hydraulic fracturing fluid pressure and the pore water pressure, and ③ the radial flow rate of rock mass seepage. B.C. Haimson and C. Fairhurst extended the pore elasticity theory to confined boreholes and extended the elastic model of M.K. Hubbert and D.W. Williams to consider the effect of fluid seepage, thus perfecting the basic theory of hydraulic fracturing stress testing. In the early 1970s, American scholars B.C. Haimson and C. Fairhurst, among others, developed the theory of in-situ hydraulic fracturing stress measurement, along with corresponding measurement techniques and procedures, based on hydraulic fracturing enhancement technology in the petroleum industry. Their work laid a solid foundation for the development of the HF method, which has since remained a research hotspot. In 1970, a research group led by H.S. Schonfeldt and C. Fairhurst conducted the first truly meaningful engineering practice of hydraulic fracturing stress measurement in shallow boreholes (including vertical and horizontal boreholes) in an underground granite mass in Minnesota, experimentally verifying the feasibility of hydraulic fracturing as an in-situ measurement method (Schonfeldt and Fairhurst, 1972). In 1971, a branch of the U.S. Geological Survey financially supported hydraulic fracturing stress measurement in the Rangyy oil field in Colorado, marking the earliest "deep-hole hydraulic fracturing stress measurement" work and paving the way for the widespread acceptance of this method. Thus, the dominant position of hydraulic fracturing in the field of geostress testing, especially in deep geostress testing, was established. my country's hydraulic fracturing geostress measurement began in the early 1980s, introduced from the United States through international cooperation by the Institute of Crustal Stress, China Earthquake Administration. In October 1980, my country's first in-situ hydraulic fracturing stress measurement was successfully conducted in Yi County, Baoding City, Hebei Province (Li Fangquan et al., 1980). Subsequently, Chen Qunce et al. addressed the problems existing in the three-dimensional hydraulic fracturing geostress measurement method by conducting nonlinear research on the processing of hydraulic fracturing stress measurement data from multiple intersecting boreholes, and proposed a new theoretical model based on the minimum principal stress failure criterion.From 1992 to 1996, the representative work on hydraulic fracturing in-situ stress testing technology in my country was the Sino-Japanese cooperation project between the Institute of Crustal Stress of the China Earthquake Administration and the Central Research Institute of Electric Power of Japan. This project achieved the miniaturization and portability of the testing equipment, which laid a solid foundation for the widespread application of hydraulic fracturing in-situ stress testing methods in my country.

[0004] Hydraulic fracturing in-situ stress measurement equipment is currently mainly divided into five categories: (1) heavy-duty cable-type hydraulic fracturing in-situ stress measurement equipment, represented by the Swiss MESY-SOLEXPERTS equipment; (2) lightweight cable-type hydraulic fracturing in-situ stress measurement equipment, mainly represented by the shallow hole testing equipment manufactured by Japan's OYO Corporation and the shallow hole testing equipment manufactured by Australia's CSIRO organization; (3) heavy-duty cable-type integrated testing equipment, represented by the new type of hydraulic fracturing testing equipment that combines hydraulic fracturing testing with other geophysical logging equipment, manufactured by Professor Cornet of France and Professor Thiercelin of the United States; (4) deep well master-daughter hole high-precision testing equipment, represented by the BABHY testing equipment manufactured by Tohoku University of Japan; (5) detachable and lightweight hydraulic fracturing testing equipment, represented by the drill pipe type hydraulic fracturing in-situ stress measurement equipment widely used in China.

[0005] The widely used measurement system in China consists of six parts: a pressure fluid control system, a high-pressure water pump, a power system, a data recording system, a jumper packer, and a high-pressure fluid delivery system. This measurement system is further divided into two types: one for shallow holes up to 100m deep, where drill pipe and high-pressure hoses are used to supply water to the packer and fracturing section respectively to achieve fracturing. The other type of equipment is for deep holes over 100m deep, where a switching valve supplies pressurized fluid to the fracturing section and the packer separately. The test system diagram is shown below. Figure 7 , Figure 8 As shown;

[0006] The existing technical solutions described above have the following drawbacks: For small-diameter hydraulic fracturing testing systems, the drill rods, high-pressure hoses, and other equipment used in conventional hydraulic fracturing in-situ stress testing are too large in diameter, making it impossible to install the high-pressure liquid and testing equipment in the predetermined location using the original technical methods. Furthermore, there has been limited in-depth research both domestically and internationally on the design and development of hydraulic fracturing in-situ stress testing systems with diameters less than 36mm. Utility Model Content

[0007] To overcome the above shortcomings, this application provides a small-diameter hydraulic fracturing test packer, which aims to improve the problem that it is impossible to install high-pressure liquid and test equipment in the predetermined position using the original technical approach.

[0008] This application provides a small-diameter hydraulic fracturing test packer, including an upper packer, a lower packer, and a perforated tube;

[0009] One end of the upper packer is connected to a dual-circuit coaxial mounting rod connector, which has an axially opened seat sealing channel and a fracturing channel; one end of the lower packer is connected to a plug.

[0010] One end of the perforated tube is connected to the upper packer, and the other end of the perforated tube is connected to the lower packer. The perforated tube has a seat seal connection channel and a fracturing connection channel along the axial direction. The seat seal connection channel is connected to the seat seal channel, and the fracturing connection channel is connected to the fracturing channel. A fracturing water outlet hole is opened on the surface of the perforated tube and is connected to the fracturing connection channel.

[0011] In a preferred embodiment of the present invention, the upper packer includes an upper connecting section, an expansion sealing section, and a lower connecting section. The upper connecting section and the lower connecting section are disposed at both ends of the expansion sealing section, and a steel sheet is embedded in the expansion sealing section.

[0012] In a preferred embodiment of this utility model, the upper packer has inner holes at both ends, and the two inner holes have internal threads. The two ends of the dual-circuit coaxial mounting rod connector have external threads, and the end of the dual-circuit coaxial mounting rod connector is connected to the end of the upper packer by threads.

[0013] In a preferred embodiment of this utility model, the upper packer, the lower packer, and the perforated tube are coaxially arranged, and the upper packer and the lower packer have the same composition and structure.

[0014] In a preferred embodiment of this utility model, one end of the plug is provided with an external thread that is threaded to the lower packer, and both ends of the perforated tube are provided with external threads that are threaded to the upper packer and the lower packer, respectively.

[0015] In a preferred embodiment of this utility model, multiple sealing channels are provided, the fracturing channel is coaxially arranged with the dual-circuit coaxial mounting rod connector, one end of the dual-circuit coaxial mounting rod connector is provided with a packer water inlet and a fracturing end water inlet, the packer water inlet is connected to the sealing channel, and the fracturing end water inlet is connected to the fracturing channel.

[0016] In a preferred embodiment of this utility model, a sealing groove A is provided on the outer surface of the dual-circuit coaxial mounting rod connector, and an O-ring A is snapped into the sealing groove A. A sealing groove B is provided on the inner wall of the fracturing channel, and an O-ring B is snapped into the sealing groove B.

[0017] In a preferred embodiment of this utility model, a stainless steel tube is provided through the shaft of the plug, one end of the stainless steel tube is fixedly connected to the plug, and the other end of the stainless steel tube extends and is connected to the dual-circuit coaxial mounting rod connector.

[0018] In a preferred embodiment of this utility model, the outer surface of the plug is provided with anti-slip texture, and the outer surface of the plug is provided with a sealing groove C, and an O-ring C is engaged in the sealing groove C.

[0019] In a preferred embodiment of this utility model, a sealing groove D is formed on the surface of the perforated tube, and an O-ring D is snapped into the sealing groove D. There are two sealing grooves D, which are formed at the end of the external thread on the surface of the perforated tube. A sealing groove E is formed on the inner wall of the fracturing docking channel port, and an O-ring E is snapped into the sealing groove E. The fracturing water outlet is set between the two O-rings D, and there are multiple fracturing water outlets.

[0020] Beneficial effects:

[0021] 1. A small-diameter bridging packer was invented to conduct in-situ stress testing of small-diameter hydraulic fracturing. The packer meets the requirements of an external dimension of Φ30±1mm and a pressure resistance of 40MPa, while the sealing measures also meet the 40MPa pressure resistance requirement. The structure is simple and easy to assemble. It consists of five components: a dual-circuit coaxial mounting rod connector, an upper packer, a perforated pipe with water jets, a lower packer, and a plug. These components enable sealing of the test section for in-situ stress measurement of hydraulic fracturing in small-diameter boreholes and facilitate high-pressure fluid fracturing operations.

[0022] 2. The design includes a connector that mates with the dual-loop coaxial mounting rod. The two types of water inlets on the dual-loop coaxial mounting rod connector of this packer supply water to the packer and the fracturing section respectively. Water pressure fracturing tests are conducted on the sealing section through the spray holes of the connector between the upper and lower packers. Simultaneously, the pressure values ​​of the fracturing section and the packer are monitored, which facilitates the acquisition of high-quality stress measurement data and enables in-situ stress measurement of water pressure fracturing in Φ30mm small-diameter geological exploration boreholes.

[0023] 3. The small-diameter hydraulic fracturing in-situ stress testing system is characterized by its lightweight equipment and low requirements for testing pressurization equipment. It can use a manual pump or a two-phase electric high-pressure oil pump for pressurization. In practice, the small-diameter testing equipment has low requirements for intact rock mass. Compared with large-diameter boreholes, under the same working conditions, small-diameter boreholes can generate more than twice the amount of test data. Moreover, the drilling cost decreases as the borehole diameter decreases, which can greatly reduce the cost of in-situ stress testing and shorten the testing time. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a three-dimensional structural diagram of the small-diameter hydraulic fracturing test packer provided in the embodiments of this application;

[0026] Figure 2 A cross-sectional structural diagram provided for an embodiment of this application;

[0027] Figure 3 A schematic diagram of the upper packer structure provided for an embodiment of this application;

[0028] Figure 4 A schematic diagram of the flower tube structure provided for an embodiment of this application;

[0029] Figure 5 A schematic diagram of the dual-circuit coaxial mounting rod connector structure provided for an embodiment of this application;

[0030] Figure 6 A schematic diagram of the plug structure provided for an embodiment of this application;

[0031] Figure 7 A schematic diagram of a dual-loop testing system composed of a hydraulic fracturing in-situ stress measurement device provided in the embodiments of this application;

[0032] Figure 8 A schematic diagram of a single-loop test system consisting of a water pressure-induced in-situ stress measurement device provided in this application embodiment.

[0033] In the diagram: 100, upper packer; 110, upper connecting section; 120, expansion sealing section; 121, steel sheet; 130, lower connecting section; 200, dual-circuit coaxial mounting rod connector; 201, O-ring A; 202, O-ring B; 210, seated seal channel; 211, packer inlet; 220, fracturing channel; 221, fracturing end inlet; 300, lower packer; 400, plug; 401, O-ring C; 410, stainless steel pipe; 500, perforated pipe; 501, O-ring D; 502, O-ring E; 510, seated seal docking channel; 520, fracturing docking channel; 530, fracturing outlet. Detailed Implementation

[0034] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0035] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0036] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0037] Please see Figures 1-6 This utility model provides a small-diameter hydraulic fracturing test packer, including an upper packer 100, a lower packer 300, and a perforated tube 500;

[0038] One end of the upper packer 100 is connected to a dual-loop coaxial mounting rod connector 200, which has an axially formed sealing channel 210 and a fracturing channel 220. One end of the lower packer 300 is connected to a plug 400. Using existing technology, a dual-loop structure with a sealing channel 210 and a fracturing channel 220 is employed. High-pressure fluid is supplied to the fracturing section and the packer sealing section via two separate loops within the packer. A cross-connected packer for a small-diameter hydraulic fracturing test device is designed and manufactured. In a dual-loop structure, a dual-loop mounting rod is typically used to connect to the packer. Compared to the previous dual-core parallel mounting rod, dual-loop coaxial mounting rods are now more commonly used to better adapt to borehole diameters. Therefore, when designing the packer, a connector that mates with the dual-loop coaxial mounting rod must be designed.

[0039] One end of the perforated tube 500 is connected to the upper packer 100, and the other end of the perforated tube 500 is connected to the lower packer 300. The perforated tube 500 has a seat sealing connection channel 510 and a fracturing connection channel 520 along the axial direction. The seat sealing connection channel 510 is connected to the seat sealing channel 210, and the fracturing connection channel 520 is connected to the fracturing channel 220. A fracturing water outlet hole 530 connected to the fracturing connection channel 520 is opened on the surface of the perforated tube 500.

[0040] In a specific embodiment of this utility model, the upper packer 100 includes an upper connecting section 110, an expansion sealing section 120, and a lower connecting section 130. The upper connecting section 110 and the lower connecting section 130 are disposed at both ends of the expansion sealing section 120, and a steel sheet 121 is embedded in the expansion sealing section 120.

[0041] In a specific embodiment of this utility model, the upper packer 100 has inner holes at both ends, and the two inner holes have internal threads. The dual-circuit coaxial mounting rod connector 200 has external threads at both ends, and the end of the dual-circuit coaxial mounting rod connector 200 is connected to the end of the upper packer 100 by threads.

[0042] The dual-circuit coaxial mounting rod connector 200 is made of 304 stainless steel, and its two ends are threaded to connect the dual-circuit coaxial mounting rod and the upper packer 100, respectively. The mechanical structure of the dual-circuit coaxial mounting rod connector 200... Figure 5 As shown. From Figure 5 It can be seen that the right end of the dual-circuit coaxial mounting rod connector 200 is connected to the dual-channel coaxial mounting rod. The small hole connects to the inner tube and serves as the water inlet of the fracturing section, while the large hole connects to the joint of the mounting rod. Multiple sealing holes in the connector serve as packer water inlets 211. The fracturing section water inlet is connected to the fracturing channel 220 of the hollow fracturing section inside the upper packer 100, and the packer water inlet 211 is connected to the sealing channel inside the rubber sleeve of the upper packer 100.

[0043] In a specific embodiment of this utility model, the upper packer 100, the lower packer 300, and the perforated tube 500 are coaxially arranged, and the upper packer 100 and the lower packer 300 have the same composition and structure.

[0044] During the measurement of in-situ stress induced by hydraulic fracturing, such as Figures 2-5As shown, high-pressure fluid enters the fracturing section inlet and packer inlet 211 through two channels inside the dual-circuit coaxial mounting rod. One channel enters the fracturing channel (the inner cavity of the stainless steel tube 410 of the plug 400) within the packer via the fracturing section inlet and the internal pipe of the connector. The other channel enters the sealing channel inside the packer's rubber sleeve (the gap between the rubber sleeve and the steel pipe) through the packer inlet 211 and multiple fine holes inside the connector, causing the rubber sleeve in the middle of the packer to expand and seal the borehole wall. O-rings are also fitted at the grooves connecting the dual-circuit mounting rod connector to the inner tube and to the packer connector, respectively, to achieve a seal at the threaded connection end face.

[0045] The upper packer 100 and lower packer 300 in the bridging packer are of the same model. Both are expansion packer sleeves, with a Φ31mm specification for in-situ stress measurement in small-diameter hydraulic fracturing. Both packers withstand pressures up to 40MPa and temperatures up to 130℃. Both ends of the packers have connecting threads for easy connection to other parts of the packer. The middle part of the packer is the expansion sealing section 120, which contains a steel sheet 121 to enhance its strength. During in-situ stress measurement in hydraulic fracturing, high-pressure liquid enters the expansion sealing section 120 through the sealing channel, expands it, and adheres it to the borehole wall. The two packers together achieve the required seal at the test end.

[0046] In a specific embodiment of this utility model, one end of the plug 400 is provided with an external thread that is threaded to the lower packer 300, and both ends of the perforated tube 500 are respectively provided with external threads that are threaded to the upper packer 100 and the lower packer 300.

[0047] The perforated tube 500 has two channels: a setting and connection channel 510 and a fracturing connection channel 520. The fracturing connection channel 520 passes through a stainless steel pipe 410, which is welded to the bottom of the plug 400. The perforated tube 500 has three nozzles connected to the fracturing connection channel 520 for ejecting high-pressure fluid during hydraulic fracturing. The setting and connection channel 510 connects to the inside of the packer rubber sleeve, bridging the rubber sleeves of the upper packer 100 and the lower packer 300. This allows for the expansion of the rubber sleeve by the high-pressure fluid during hydraulic fracturing, sealing the test section of the borehole wall. Furthermore, the perforated tube 500 has O-rings at the connection grooves of the upper and lower packers 300 to achieve a seal at the threaded connection end face.

[0048] In a specific embodiment of this utility model, the sealing channel 210 is provided in multiple ways, the fracturing channel 220 is coaxially arranged with the dual-circuit coaxial mounting rod connector 200, and one end of the dual-circuit coaxial mounting rod connector 200 is provided with a packer water inlet 211 and a fracturing end water inlet 221. The packer water inlet 211 is connected to the sealing channel 210, and the fracturing end water inlet 221 is connected to the fracturing channel 220.

[0049] In a specific embodiment of this utility model, a sealing groove A is provided on the outer surface of the dual-circuit coaxial mounting rod connector 200, and an O-ring A201 is snapped into the sealing groove A. A sealing groove B is provided on the inner wall of the fracturing channel 220, and an O-ring B202 is snapped into the sealing groove B.

[0050] In a specific embodiment of this utility model, a stainless steel tube 410 is axially inserted through the plug 400, and one end of the stainless steel tube 410 is fixedly connected to the plug 400. The other end of the stainless steel tube 410 extends and is connected to the dual-circuit coaxial mounting rod connector 200.

[0051] In a specific embodiment of this utility model, the outer surface of the plug 400 is provided with anti-slip texture, and the outer surface of the plug 400 is provided with a sealing groove C, and an O-ring C401 is snapped into the sealing groove C.

[0052] The plug 400 is located at the bottom of the bridging packer. It is made of 304 stainless steel, with threads at the front end connecting to the lower packer 300. The rear end has cross-knurled surfaces to increase friction for tightening. Its mechanical structure diagram is shown below. Figure 6 As shown, a stainless steel tube 410 is welded to the center of the plug and fits into its inner hole. The inner cavity of the stainless steel tube 410 serves as a fracturing channel. One end of the stainless steel tube 410 is welded to the bottom of the plug 400, and the other end is connected to the dual-channel coaxial mounting rod connector, which is pressure-resistant and leak-proof. Furthermore, an O-ring rubber seal C401 is fitted into the groove of the plug 400 to achieve a threaded connection end face seal.

[0053] In a specific embodiment of this utility model, a sealing groove D is formed on the surface of the perforated tube 500, and an O-ring D501 is snapped into the sealing groove D. There are two sealing grooves D, which are formed at the end of the external thread on the surface of the perforated tube 500. A sealing groove E is formed on the inner wall of the port of the fracturing docking channel 520, and an O-ring E502 is snapped into the sealing groove E. The fracturing water outlet 530 is arranged between the two O-rings D501, and there are multiple fracturing water outlets 530.

[0054] A dual-circuit coaxial mounting rod connector 200 is used, with threads at both ends, connecting the dual-circuit coaxial mounting rod and the upper packer 100 respectively. One end of the dual-circuit coaxial mounting rod connector 200 connects to the dual-channel coaxial mounting rod, with a small hole connecting to the inner tube. The inner cavity of the inner tube serves as the water inlet for the fracturing section, connecting to the fracturing channel of the hollow fracturing section inside the upper packer 100 through an internal pipe. The large hole connects to the connector of the mounting rod, and one end has a sealing small hole serving as the packer water inlet 211. The corresponding through hole of the mounting rod connector serves as... The upper packer 100 and the lower packer 300 are both threaded at both ends. The middle part of the packer is the expansion sealing section 120, which contains steel plates 121 to enhance its strength. During the in-situ stress test caused by water pressure fracturing, the high-pressure fluid enters the expansion sealing section 120 through the dual-circuit coaxial mounting rod and the corresponding connector, expands it, and makes it fit against the borehole wall. The upper and lower packers achieve the sealing requirements of the test end. The perforated tube 500 has threads at both ends to connect the upper and lower packers. The central hole of the perforated tube 500 serves as a fracturing channel and passes through a stainless steel tube 410. Another hole serves as a sealing channel, connecting the rubber sleeves of the upper packer 100 and the lower packer 300 to achieve bridging. The perforated tube 500 has three water nozzles on its side that connect to the fracturing channel, used for fracturing operations where high-pressure liquid is sprayed outward during water-induced fracturing. The plug 400 with steel pipe is located at the bottom of the bridging packer. One end is threaded and connected to the lower packer 300. A stainless steel tube 410 is welded to the middle and attached to its inner hole, with the inner cavity of the stainless steel tube 410 serving as a fracturing channel. The surface is inlaid with cross knurling to increase friction. The bottom of the plug 400 is welded to one end of the stainless steel tube 410.

[0055] To ensure a tight seal, the entire packer has sealing grooves and sealing rings at several locations. O-rings are used at the grooves where the dual-circuit mounting rod connector connects to the inner tube and to the packer, at the grooves where the perforated tube 500 connects to the two packers, and at the grooves where the plug 400 connects to the lower packer 300, to achieve a seal at the threaded connection end faces.

[0056] The working principle of this small-diameter hydraulic fracturing test packer is as follows: During use, when the mounting rod is connected to the entire packer assembly and placed at the target test depth, a high-pressure water pump on the ground first delivers high-pressure liquid to the sealing channel between the inner and outer pipes of the mounting rod. This liquid then enters the sealing channel cavity formed by the steel pipe of the upper packer 100 and the plug 400 through multiple sealing holes in the dual-circuit coaxial mounting rod connector 200. From this cavity, it flows along the sealing channel of the perforated pipe 500 into the sealing channel cavity formed by the lower packer 300 and the steel pipe. After this process, the upper packer 100 and the lower packer 300 expand under water pressure and adhere tightly to the borehole wall. This process individually seals and isolates the borehole test section between the upper and lower packers.

[0057] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

Claims

1. A small-diameter hydraulic fracturing test packer, characterized in that, include The upper packer (100) has a dual-circuit coaxial mounting rod connector (200) connected to one end. The dual-circuit coaxial mounting rod connector (200) has an axially opened seat sealing channel (210) and fracturing channel (220). A lower packer (300), one end of which is connected to a plug (400); A perforated tube (500) is provided, one end of which is connected to the upper packer (100), and the other end of which is connected to the lower packer (300). The perforated tube (500) is provided with a seat sealing connection channel (510) and a fracturing connection channel (520) along the axial direction. The seat sealing connection channel (510) is connected to the seat sealing channel (210), and the fracturing connection channel (520) is connected to the fracturing channel (220). A fracturing water outlet hole (530) is provided on the surface of the perforated tube (500) and is connected to the fracturing connection channel (520).

2. The small-diameter hydraulic fracturing test packer according to claim 1, characterized in that, The upper packer (100) includes an upper connecting section (110), an expansion sealing section (120), and a lower connecting section (130). The upper connecting section (110) and the lower connecting section (130) are disposed at both ends of the expansion sealing section (120), and a steel sheet (121) is embedded in the expansion sealing section (120).

3. A small-diameter hydraulic fracturing test packer according to claim 2, characterized in that, The upper packer (100) has inner holes at both ends, and the two inner holes have internal threads. The two ends of the dual-circuit coaxial mounting rod connector (200) have external threads, and the end of the dual-circuit coaxial mounting rod connector (200) is connected to the end of the upper packer (100) by threads.

4. A small-diameter hydraulic fracturing test packer according to claim 3, characterized in that, The upper packer (100), lower packer (300), and perforated tube (500) are coaxially arranged, and the upper packer (100) and the lower packer (300) have the same composition and structure.

5. A small-diameter hydraulic fracturing test packer according to claim 1, characterized in that, One end of the plug (400) is provided with an external thread that is threaded to the lower packer (300), and both ends of the perforated tube (500) are provided with external threads that are threaded to the upper packer (100) and the lower packer (300), respectively.

6. A small-diameter hydraulic fracturing test packer according to claim 1, characterized in that, Multiple sealing channels (210) are provided. The fracturing channel (220) is coaxially arranged with the dual-circuit coaxial mounting rod connector (200). One end of the dual-circuit coaxial mounting rod connector (200) is provided with a packer water inlet (211) and a fracturing end water inlet (221). The packer water inlet (211) is connected to the sealing channel (210), and the fracturing end water inlet (221) is connected to the fracturing channel (220).

7. A small-diameter hydraulic fracturing test packer according to claim 1, characterized in that, The outer surface of the dual-circuit coaxial mounting rod connector (200) is provided with a sealing groove A, and an O-ring A (201) is snapped into the sealing groove A. The inner wall of the fracturing channel (220) is provided with a sealing groove B, and an O-ring B (202) is snapped into the sealing groove B.

8. A small-diameter hydraulic fracturing test packer according to claim 1, characterized in that, A stainless steel tube (410) is axially inserted through the plug (400). The end of the stainless steel tube (410) is fixedly connected to the plug (400), and the other end of the stainless steel tube (410) extends to connect to the dual-circuit coaxial mounting rod connector (200).

9. A small-diameter hydraulic fracturing test packer according to claim 1, characterized in that, The plug (400) has anti-slip texture on its outer surface and a sealing groove C on its outer surface. An O-ring C (401) is engaged in the sealing groove C.

10. A small-diameter hydraulic fracturing test packer according to claim 1, characterized in that, The surface of the perforated tube (500) is provided with a sealing groove D, and an O-ring D (501) is snapped into the sealing groove D. There are two sealing grooves D. The sealing groove D is located at the end of the external thread on the surface of the perforated tube (500). The inner wall of the port of the fracturing docking channel (520) is provided with a sealing groove E, and an O-ring E (502) is snapped into the sealing groove E. The fracturing water outlet (530) is located between the two O-rings D (501). There are multiple fracturing water outlets (530).

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