Unstable deep drilling while drilling type geostress testing device and testing method

Abstract

The application discloses an unstable deep borehole while-drilling type ground stress testing device and testing method, which comprises a pressurized water injection device, a high-pressure drill rod in communication with the pressurized water injection device, a rope core drill rod sleeved outside the high-pressure drill rod, a channel switching valve comprising a valve body, a water inlet arranged on the valve body, a first water outlet channel in selective communication with the water inlet, and a second water outlet channel, wherein the other end of the high-pressure drill rod is in communication with the water inlet, one end of the rope core drill rod is fixedly connected with the valve body, and the other end is fixed to the ground during the test, and the testing device comprises, in sequence, an upper packer, a center fracturing section, and a lower packer, the first water outlet channel is in communication with the upper packer and the lower packer in sequence, and the second water outlet channel is in communication with the center fracturing section; and a geological drill bit is used to remove obstacles when passing through unstable strata. The application not only can prevent the backflow of sewage in the borehole into the channel switching valve and the inner cavity of the packer, but also can pass through the unstable deep borehole to perform stress testing.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of rock mass mechanics test, and particularly relates to an unstable deep borehole while-drilling type geostress testing device and testing method. BACKGROUND

[0002] At present, the hydraulic fracturing method is the most commonly used method for testing the geostress characteristics in a borehole, which is simple and efficient. In the process of testing the geostress of deep underground engineering, unstable boreholes are inevitably encountered, such as crossing through a broken zone or a soft rock area. The surrounding rock of the broken zone borehole is unstable and prone to falling or local hole collapse, and the surrounding rock of the soft rock area borehole is prone to large deformation to cause the hole diameter to be reduced. These instabilities of the borehole will cause the geostress testing device to be unable to pass through, and the required test data cannot be obtained. Secondly, before the formation of the unstable borehole, in order to enhance the self-stability of the hole wall, materials such as mud and plant glue are usually added during drilling to protect the wall, resulting in muddy and viscous water in the hole. When the ordinary geostress device is lowered, the sewage in the hole often flows back to the passage conversion valve and the inner cavity of the packer through the water outlet, thereby causing the blockage of some small-diameter pipelines and resulting in test failure. Finally, according to the current drilling technology, the deep borehole is usually drilled by using a rope core drill rod which is slightly smaller than the hole diameter. Such a thin-walled drill rod cannot withstand high pressure and cannot meet the requirements of deep hole geostress testing. It needs to be replaced by a small-diameter thick-walled high-pressure resistant drill rod, but such a drill rod does not have the function of hole protection. In view of the above situation, it is urgent to develop a device system and method which can reliably and efficiently test the geostress in an unstable deep borehole. SUMMARY

[0003] One object of the present application is to provide an unstable deep borehole while-drilling type geostress testing device, which can not only prevent the sewage in the borehole from flowing back to the passage conversion valve and the inner cavity of the packer, but also can pass through the unstable deep borehole to test the geostress.

[0004] To solve the above technical problems, the present application adopts the following technical scheme:

[0005] An unstable deep borehole while-drilling type geostress testing device comprises:

[0006] A pressurized water injection device is used for water injection and pressurization during the test, and the pressurized water injection device is connected with a data acquisition device, and the data acquisition device is used for acquiring pressure data of the test process;

[0007] A high-pressure drill rod is in communication with the pressurized water injection device at one end, and the high-pressure drill rod is connected with a winch device, and the winch device is used for lifting or lowering the high-pressure drill rod;

[0008] A rope core drill rod is sleeved outside the high-pressure drill rod;

[0009] The channel conversion valve comprises a valve body, a water inlet arranged on the valve body, a first water outlet channel in selective communication with the water inlet, and a second water outlet channel, wherein the other end of the high-pressure drill rod is in communication with the water inlet, one end of the wire-line coring drill rod is fixedly connected with the valve body, and the other end thereof is fixed to the ground during testing;

[0010] The testing device comprises an upper packer, a central fracturing section, and a lower packer connected in sequence, wherein the first water outlet channel is in communication with the upper packer and the lower packer in sequence, and the second water outlet channel is in communication with the central fracturing section, when the high-pressure drill rod is lowered, the high-pressure drill rod is in communication with the water inlet of the valve body, the first water outlet channel, the upper packer, and the lower packer in sequence, and when the high-pressure drill rod is lifted, the high-pressure drill rod is in communication with the water inlet of the valve body, the second water outlet channel, and the central fracturing section in sequence.

[0011] The geological drill bit is arranged at the bottom end of the lower packer and is used for removing obstacles and crossing unstable strata.

[0012] Further, the pressurized water injection device comprises a high-pressure water pump, a high-pressure water pipe connected with the high-pressure water pump at one end, and a pressure relief valve arranged on the high-pressure water pipe, and the other end of the high-pressure water pipe is connected with the high-pressure drill rod through a pipe joint.

[0013] Further, a pressure sensor is arranged on the high-pressure water pipe, and the pressure sensor is connected with the data acquisition device, and the pressure sensor is used for collecting the water flow pressure in the high-pressure water pipe and transmitting the water flow pressure to the data acquisition device.

[0014] Further, the channel conversion valve further comprises a first water inlet hole arranged in the axial direction of the valve body, a second water inlet hole connected with the first water inlet hole, a push-pull pipe movably arranged in the inner wall of the first water inlet hole, a blocking plug arranged on the upper packer and used for blocking or opening the end of the push-pull pipe close to the upper packer during the movement of the push-pull pipe, the end of the push-pull pipe away from the upper packer extends into the high-pressure drill rod and is in communication with the high-pressure drill rod, the end port of the push-pull pipe away from the upper packer is the water inlet, the end of the push-pull pipe close to the upper packer extends into the second water inlet hole, a third water inlet hole is further arranged on the side wall of the valve body, and a first through hole is correspondingly arranged on the side wall of the push-pull pipe, when the push-pull pipe moves downward to block the end of the push-pull pipe close to the upper packer by the blocking plug, the first water inlet hole, the first through hole, and the third water inlet hole are in communication to form the first water outlet channel, a second through hole in communication with the central fracturing section is arranged on the side wall of the blocking plug, when the push-pull pipe moves upward to separate the end of the push-pull pipe close to the upper packer from the blocking plug, the first water inlet hole, the second water inlet hole, and the second through hole are in communication to form the second water outlet channel.

[0015] Further, the inner diameter of the first water inlet hole is smaller than that of the second water inlet hole, a stop ring is arranged on the outer wall of the end of the push-pull tube close to the upper packer, the outer diameter of the stop ring is equivalent to the inner diameter of the second water inlet hole, and when the push-pull tube moves up and down in the first water inlet hole, the stop ring on the push-pull tube moves up and down along the inner wall of the second water inlet hole.

[0016] Further, axial through holes are arranged on the upper packer, the center fracturing section and the lower packer, and the axial through holes of the three are sequentially communicated, the blocking plug is in U shape, the opening end of the blocking plug is connected with the center through hole of the upper packer in correspondence, so that the third through hole is sequentially communicated with the axial through holes of the upper packer and the center fracturing section, and the third through hole for water injection of the geostress test section is arranged on the axial through hole wall of the center fracturing section.

[0017] Further, the outer diameter of the blocking plug is equivalent to the inner diameter of the push-pull tube, so that the blocking plug can just block the push-pull tube.

[0018] Further, the upper packer and the lower packer each have an inner cavity, and a communication hole for communicating the inner cavities of the upper packer and the lower packer is arranged on the center fracturing section.

[0019] Further, the drilling machine is also included, when the test device connected with the high-pressure drill rod meets an obstacle, the rotary power head of the drilling machine is connected with the rope coring drill rod, the rotary power head works to drive the rope coring drill rod to rotate and drive the geological drill bit to rotate through the test device to pass through the obstacle.

[0020] The application also provides a test method of the unstable deep borehole while drilling geostress test device, comprising the following steps:

[0021] Step 1, assemble the rope coring drill rod and the high-pressure drill rod in sequence, lower the test device connected with the drill rod to a specified depth in the borehole through the winch device, and rotate downward to remove obstacles and cross unstable strata during the lowering process;

[0022] Step 2, fix the rope coring drill rod on the ground after reaching the specified depth, connect the high-pressure drill rod with the pressurized water injection device, and connect the high-pressure drill rod with the winch device, under the action of gravity, the high-pressure drill rod moves downward relative to the channel switching valve, the high-pressure drill rod sequentially communicates with the upper and lower packers through the first water outlet passage, at this time, the second water outlet passage is in a closed state, and the sewage in the hole cannot enter the channel switching valve through the center fracturing section.

[0023] Step 3, open the pressurized water injection device and gradually pressurize to a predetermined pressure, the high-pressure water flow sequentially enters the upper and lower packers through the high-pressure drill rod and the first water outlet passage of the channel switching valve, under the action of water and pressure, the upper and lower packers expand and tightly adhere to the borehole wall, and the sealed space formed between the upper and lower packers is the test section.

[0024] Step 4, the high-pressure drill pipe is lifted relative to the upper packer by the hoisting device until it cannot be lifted, at this time, the high-pressure drill pipe is connected with the water inlet and the second water outlet passage of the channel conversion valve, the high-pressure water flows through the pressurized water injection device, the high-pressure drill pipe, the water inlet and the second water outlet passage of the channel conversion valve and the central fracturing section into the test section, the pressurized water injection device continues to inject water until the hydraulic fracture of the test section rock mass is generated, and the water pressure fracturing stress parameters in the working process are collected by using the data acquisition device;

[0025] Step 5, after the data acquisition is completed, the pressurized water injection device is stopped and depressurized, the high-pressure drill pipe is lowered until it cannot be lowered, the water inlet of the channel conversion valve is connected with the first water outlet passage, at this time, the pressure water in the upper and lower packers flows out along the first water outlet passage of the channel conversion valve, the drill pipe, the upper and lower packers shrink and separate from the hole wall, and return to the initial state, that is, the water pressure fracturing stress test of the section is completed, and the above process is repeated to realize the geostress test of the next selected section.

[0026] Compared with the prior art, the beneficial effects of the present application are: the test device of the present application is designed based on the drilling method and the wall protection of the wireline coring drill pipe and the high-pressure resistance characteristics of the thick-walled high-pressure drill pipe, when encountering unstable strata (such as fault zones, soft rock strata, etc.), the geological drill bit can pass through the unstable geological layer, has good passability and pipe blockage prevention ability, this method is not only suitable for vertical holes, but also suitable for horizontal holes or inclined holes, the high-pressure drill pipe is arranged in the wireline coring drill pipe, which reduces the influence of high stress of deep borehole on the drill pipe, and also ensures the applicability of the high-pressure drill pipe in high geostress environment; the present application solves the problem of geostress test of unstable deep borehole, thereby obvious economic benefits can be generated, the method is easy to operate, the device structure is simple and practical, the manufacturing cost is low, and the method is convenient for large-scale popularization and application; in addition, the present application can also ensure that the sewage in the borehole cannot enter the channel conversion valve to block the pipeline in the channel conversion valve, thereby greatly ensuring the success rate of the test. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a structure schematic view of the unstable deep borehole while drilling type geostress test device of the embodiment of the present application

[0028] Figure 2 It is the first state of the channel conversion valve connected during the test of the embodiment of the present application;

[0029] Figure 3 It is the second state of the channel conversion valve connected during the test of the embodiment of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of the present application.

[0031] It should be noted that the experimental methods in the following embodiments are all conventional methods, and the reagents and materials are all commercially available unless otherwise specified. In the description of the present application, the terms "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only used for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0032] The present application will be further described below with reference to specific embodiments, but not as a limitation on the present application.

[0033] As Figure 1The embodiment of the present application discloses an unstable deep borehole drilling type geostress testing device, which comprises a pressurized water injection device, a winch device, a rope core drill rod 12, a high-pressure drill rod 13, a channel conversion valve 17, an upper packer 18, a center fracturing section 19, a lower packer 20 and a geological drill bit 21. The pressurized water injection device comprises a high-pressure water pump 1, a high-pressure water pipe 6 connected with the high-pressure water pump, a pressure sensor 3 arranged on the high-pressure water pipe 6, a pressure gauge 4 and a pressure relief valve 5. In order to facilitate the collection of stress data, a data acquisition device 2 for collecting the data of the pressure sensor 3 in real time is further arranged. One end of the rope core drill rod 12 is rigidly connected with the outer diameter of the channel conversion valve 17, and the other end of the rope core drill rod 12 is stretched out of the borehole in the test and is fixed at the orifice of the borehole by a drill rod holder 14. One end of the high-pressure drill rod 13 is connected with the high-pressure water pipe 6 through a pipe joint 7, and the other end of the high-pressure drill rod 13 is connected with the channel conversion valve 17. In order to facilitate the lifting or lowering of the high-pressure drill rod 13 in the test process, the upper end of the pipe joint 7 is further connected with the winch device. The winch system comprises a power unit 10, a lifting rope wound on a winch rotating shaft 11, a fixed pulley through which the lifting rope is wound and a lifting basket 8 connected with the pipe joint 7. In the test, the winch device works, the pipe joint 7 is lifted through the lifting basket 8 to lift the high-pressure drill rod 13. The channel conversion valve 17 comprises a valve body, a water inlet arranged on the valve body and a first water outlet passage and a second water outlet passage selectively communicated with the water inlet. In the test, the high-pressure drill rod 13 is lowered relative to the upper packer 18, the water inlet is communicated with the first water outlet passage; the high-pressure drill rod 13 is lifted relative to the upper packer 18, the water inlet is communicated with the second water outlet passage.

[0034] In the embodiment, the channel switching valve further comprises a first water inlet hole 17-5 arranged axially along the valve body, a second water inlet hole 17-6 connected with the first water inlet hole 17-5, a push-pull tube 17-1 movably arranged on the inner wall of the first water inlet hole 17-5, and a blocking plug 17-4 arranged on the upper packer 18 and capable of blocking or opening the end of the push-pull tube 17-1 close to the upper packer 18 during the movement of the push-pull tube 17-1. In order to facilitate the switching between the first water outlet channel and the second water outlet channel, the inner diameter of the first water inlet hole 17-5 is arranged to be smaller than the inner diameter of the second water inlet hole 17-6, and a stop ring 17-7 is arranged on the outer wall of the end of the push-pull tube 17-1 close to the upper packer 18 to make the push-pull tube 17-1 in T shape, and the outer diameter of the stop ring 17-7 is equivalent to the inner diameter of the second water inlet hole 17-6. The end of the push-pull tube 17-1 away from the upper packer 18 extends into the high-pressure drill pipe 13 and communicates with the high-pressure drill pipe 13, and the end of the push-pull tube 17-1 close to the upper packer 18 extends into the second water inlet hole 17-6 and the stop ring 17-7 on the outer wall thereof is in contact connection with the inner wall of the second water inlet hole 17-6, and during the lifting or lowering of the high-pressure drill pipe 13, the stop ring of the push-pull tube 17-1 moves up and down along the inner wall of the second water inlet hole 17-6. The blocking plug 17-4 is in U shape, the open end thereof is fixed on the upper packer 18 and communicates with the central fracturing section 19, the closed end of the blocking plug 17-4 is equivalent to the inner diameter of the push-pull tube 17-1 for blocking the end of the push-pull tube 17-1 close to the upper packer 17-4, and a second through hole 17-8 is further arranged on the side wall of the blocking plug 17-4. In addition, a plurality of third water inlet holes 17-3 are arranged on the side wall of the valve body, and a plurality of first through holes 17-2 corresponding to the plurality of third water inlet holes 17-3 are arranged on the side wall of the push-pull tube 17-1, when the push-pull tube 17-1 moves downward to block the end of the push-pull tube 17-1 close to the upper packer 18 by the blocking plug 17-4, the first water inlet hole 17-5, the first through hole 17-2 and the third water inlet hole 17-3 are connected to form the first water outlet channel, and when the push-pull tube 17-1 moves upward to separate the end of the push-pull tube 17-1 close to the upper packer 18 from the blocking plug 17-4, the first water inlet hole 17-5, the second water inlet hole 17-6 and the second through hole 17-8 are connected to form the second water outlet channel. In order to ensure that the first water outlet channel and the second water outlet channel are not connected, a sealing ring is arranged on the inner wall of the first water inlet hole 17-5 and the inner wall of the end of the push-pull tube close to the upper packer, and the sealing ring on the inner wall of the first water inlet hole 17-5 is arranged above and below the third water inlet hole respectively.

[0035] The axial through holes of the upper packer 18, the central fracturing section 19 and the lower packer 20 are sequentially communicated, and the axial through hole 20-3 of the lower packer 20 is closed at the bottom end. The open end of the blocking plug 17-4 is fixedly connected with the axial through hole of the upper packer 18, so that the second through hole 17-8 of the blocking plug 17-4 is communicated with the axial through hole 18-3 of the upper packer 18. The upper and lower packers each have a water flow passage and an inner cavity communicated with the water flow passage. In addition, the side wall of the central fracturing section 19 is provided with a communication hole 19-1 for communicating the inner cavities of the upper packer 18 and the lower packer 20, one end of the communication hole 19-1 is communicated with the water flow passage 18-1 of the upper packer 18, and the other end is communicated with the water flow passage 20-1 of the lower packer 20. When the water inlet is communicated with the first water outlet passage, the water flow in the high-pressure drill pipe enters the water flow passage 18-1 of the upper packer 18, the inner cavity of the upper packer, the communication hole 19-1, the water flow passage 20-1 of the lower packer 20 and the inner cavity of the lower packer 20 in sequence through the first water outlet passage. The side wall of the axial through hole of the central fracturing section 19 is also provided with a third through hole 19-2 for supplying water to the test section. When the water inlet is communicated with the second water outlet passage, the water flow in the high-pressure drill pipe enters the test section through the third through hole 19-2 in sequence through the second water outlet passage, the axial through hole of the upper packer and the axial through hole of the central fracturing section. In order to facilitate the entire device to clear the obstacles and cross the unstable stratum, a geological drill bit 21 is arranged at the bottom end of the lower packer 20, and the geological drill bit 21 is rigidly connected with the lower packer 20. When the drill hole encounters a fractured rock mass 15 or a weak stratum 16, the device cannot be normally lowered due to the influence of falling blocks, collapse and necking. At this time, the rotating power head 9 of the drilling machine is connected to the wireline coring drill pipe 12 and drives the geological drill bit 21 to rotate to clear the obstacles until the entire hole collecting device crosses the unstable stratum to the specified test depth.

[0036] Figure 2 The first state of the channel switching valve in communication during the test is shown. At this time, the high-pressure drill pipe 13 is communicated with the push-pull pipe 17-1 of the channel switching valve, the push-pull pipe 17-1 is in the pushed-in state, the lower end outlet is blocked by the upper end of the blocking plug 17-4, and the water path can only pass through the first through hole 17-2 of the side wall of the push-pull pipe 17-1, the third water outlet hole 17-3 on the side wall of the valve body, the water flow passage 18-1 of the upper packer, and then enter the inner cavity 18-2 of the upper packer, and then enter the inner cavity 20-2 of the lower packer through the communication hole 19-1 of the central fracturing section 19 and the water flow passage 20-1 connected therewith. The lower end of the lower packer 20 is closed and rigidly connected with the geological drill bit 21. When the surface is pressurized, the area between the upper and lower packers in the first state forms a test section.

[0037] Figure 3The second state of the channel switching valve connected during the test is shown. In this state, the push-pull tube 17-1 is in the stretched state, the first through hole 17-2 on the side wall of the push-pull tube 17-1 is separated from the third water outlet hole 17-3 on the side wall of the channel switching valve 17 so that the two are not connected. The lower end outlet of the push-pull tube 17-1 is separated from the blocking plug 17-4, and the outlet at the lower end of the push-pull tube 17-1 is opened. At this time, the first water inlet hole 17-5 and the second water inlet hole 17-6 are connected through the push-pull tube 17-1, that is, the second water outlet passage of the channel switching valve 17 is connected, and the first water inlet hole 17-5, the second water inlet hole 17-6, the second through hole 17-8 on the blocking plug 17-4, the axial through hole 18-3 of the upper packer 18 and the axial through hole of the central fracturing section 19 are sequentially connected. During the test, the high-pressure water flow enters the axial through hole of the central fracturing section from this section of the passage, and then enters the isolated test section from the third through hole 19-2 on the wall of the axial through hole of the central fracturing section 19.

[0038] The embodiment of the present application also provides a test method suitable for the unstable deep borehole hydraulic fracturing in-situ stress testing device, which comprises the following steps:

[0039] Step 1, assemble the channel switching valve 17, the upper packer 18, the central fracturing section 19, the lower packer 20 and the geological drill bit 21 on the ground, start the power unit 10, and place the assembled in-hole collecting device into the borehole through the lifting basket 8 of the hoisting device and fix it at the orifice by relying on the drill rod holder 14; the first high-pressure drill rod 13 is connected to the upper end of the push-pull tube 17-1 of the channel switching valve, and the first wireline coring drill rod 12 is connected to the outer diameter of the channel switching valve 17; thereafter, sequentially connect the wireline coring drill rod 12 and the high-pressure drill rod 13 and move the in-hole collecting device to the selected depth; during the process, when the fractured rock mass 15 or the soft formation 16 is encountered in the borehole, the device cannot be normally lowered due to the influence of rock falling, collapse and necking, at this time, the rotary power head 9 of the drilling machine is connected to the wireline coring drill rod 12 and rotates the geological drill bit 21 to remove the obstacles until the entire in-hole collecting device crosses the unstable formation and reaches the specified test depth; at the same time, during the drilling process, the high-pressure drill rod 13 moves downward relative to the upper packer under the action of gravity, and the channel switching valve connection in the borehole is always in the first state, as shown in Figure 2 , that is, the push-pull tube 17-1 is in the pushed-in state, the blocking plug 17-4 closes the lower end of the push-pull tube 17-1, and at this time, the axial through hole of the central fracturing section 19 is not connected with the second water inlet hole 17-6 and the first water inlet hole 17-5 of the channel switching valve, which ensures that the sewage in the borehole cannot enter the pipeline in the channel switching valve 17 through the third through hole 19-2 during drilling;

[0040] Step 2, after reaching the specified depth, the rope core drill pipe 12 is fixed with the drill pipe holder 14 on the ground; the ground pressurized water injection device is connected on the ground, and the data acquisition device can be connected to the high-pressure drill pipe 13 through the pipe variable diameter connector 7 to collect information in the hole; the high-pressure water pump 1 on the ground is pressurized to pump high-pressure fluid into the push-pull pipe 17-1 of the channel conversion valve through the high-pressure drill pipe 13; because the lower end outlet of the push-pull pipe is blocked by the upper end blockage 17-4, the high-pressure fluid passes through the first through hole 17-2 on the side wall of the push-pull pipe 17-1, the third water outlet hole 17-3 on the valve body, the water flow passage 18-1 of the upper packer, and then enters the inner cavity 18-2 of the upper packer, and then passes through the communication hole 19-1 of the central fracturing section 19 and the water flow passage 20-1 of the lower packer 20 connected thereto to enter the inner cavity 20-2 of the lower packer; continue to pressurize until the upper and lower packer rubber plugs are inflated and tightly attached to the hole wall, forming a closed test section between the upper and lower packers;

[0041] Step 3, open the winch system to pull the pipe variable diameter connector 7 and the high-pressure drill pipe 13 through the lifting basket 8 to pull the push-pull pipe 17-1 upward to a stable state; because the upper and lower packer rubber plugs are tightly attached to the hole wall, the frictional resistance and the weight of the drill pipe can prevent the hole device from moving with the lifting; at this time, the channel conversion valve connection in the drill hole is in the second state, as shown in Figure 3 , the first through hole 17-2 on the side wall of the push-pull pipe 17-1 is separated from the third water inlet hole 17-3 of the channel conversion valve 17, and the lower end outlet of the push-pull pipe 17-1 is separated from the blockage 17-4, so that the lower end of the push-pull pipe 17-1 is opened, thereby connecting the second water outlet passage of the channel conversion valve; during the pressurized collection process, the pumped high-pressure fluid can pass through the push-pull pipe 17-1 and the second water inlet hole of the channel conversion valve through the high-pressure drill pipe 13, and then pass through the second through hole 17-8 on the blockage 17-4 to enter the axial through hole of the central fracturing section 19 and the upper packer 18, and then pass through the third through hole 19-2 on the axial through hole pipe wall of the central fracturing section 19 to enter the isolated test section; continue to pressurize until the rock mass in the test section produces water pressure induced cracks; according to the test principle of the water pressure induced cracking method, the required pressure parameters are collected;

[0042] Step 4, after the data collection is completed, the high-pressure water pump 1 is closed and the pressure relief valve 5 is opened; the winch device is operated to lower the high-pressure drill pipe 13 through the lifting basket 8 to move the push-pull pipe 17-1 downward to be blocked by the blockage 17-4, and the channel conversion valve returns to the first state; at this time, the high-pressure water in the inner cavities of the upper and lower packers will flow back to the ground through the third water inlet hole 17-3, the push-pull pipe 17-1, the high-pressure drill pipe 13, the high-pressure water pipe 6, and the pressure relief valve 5 until the upper and lower packers are contracted to be separated from the drill hole.

[0043] Step 5, operate the winch device to reach the next measurement section position by increasing or decreasing the drill pipe, and repeat the above process to achieve rapid and continuous testing of the next measurement section.

[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the protection scope of the present invention.

Claims

1. An unstable deep borehole while-drilling geostress testing device, characterized in that, The application relates to a test device for testing the strength of a wellbore wall, which comprises the following parts: a pressurized water injection device for pressurized water injection during the test, which is connected with a data acquisition device for collecting pressure data of the test process; a high-pressure drill rod, one end of which is communicated with the pressurized water injection device, and the high-pressure drill rod is connected with a winch device for lifting or lowering the high-pressure drill rod; a rope core drill rod, which is sleeved outside the high-pressure drill rod; a channel switching valve, which comprises a valve body, a water inlet arranged on the valve body, a first water outlet channel selectively communicated with the water inlet, and a second water outlet channel, wherein the other end of the high-pressure drill rod is communicated with the water inlet, and one end of the rope core drill rod is fixedly connected with the valve body, and the other end of the rope core drill rod is fixed to the ground during the test; a test device, which comprises an upper packer, a central fracturing section, and a lower packer connected in sequence, wherein the first water outlet channel is communicated with the upper packer and the lower packer in sequence, and the second water outlet channel is communicated with the central fracturing section, when the high-pressure drill rod is lowered, the high-pressure drill rod is communicated with the water inlet of the valve body, the first water outlet channel, the upper packer, and the lower packer in sequence, and when the high-pressure drill rod is lifted, the high-pressure drill rod is communicated with the water inlet of the valve body, the second water outlet channel, and the central fracturing section in sequence; a geological drill bit arranged at the bottom end of the lower packer, which is used for removing obstacles and crossing unstable strata; wherein the channel switching valve further comprises a first water inlet hole arranged in the axial direction of the valve body, a second water inlet hole connected with the first water inlet hole, a push-pull tube movably arranged on the inner wall of the first water inlet hole, a blocking plug arranged on the upper packer and used for blocking or opening the end of the push-pull tube close to the upper packer during the movement of the push-pull tube, the end of the push-pull tube away from the upper packer is inserted into the high-pressure drill rod and communicated with the high-pressure drill rod, the port of the end of the push-pull tube away from the upper packer is the water inlet, the end of the push-pull tube close to the upper packer is inserted into the second water inlet hole, a third water inlet hole is further arranged on the side wall of the valve body, and a first through hole is correspondingly arranged on the side wall of the push-pull tube, when the push-pull tube is moved downwards to block the end of the push-pull tube close to the upper packer by the blocking plug, the first water inlet hole, the first through hole, and the third water inlet hole are communicated to form the first water outlet channel; a second through hole communicated with the central fracturing section is arranged on the side wall of the blocking plug, when the push-pull tube is moved upwards to separate the end of the push-pull tube close to the upper packer from the blocking plug, the first water inlet hole, the second water inlet hole, and the second through hole are communicated to form the second water outlet channel; axial through holes are arranged on the upper packer, the central fracturing section, and the lower packer, and the axial through holes of the three parts are communicated in sequence, the blocking plug is in the shape of U, the open end of the blocking plug is connected with the central through hole of the upper packer to make the third through hole communicated with the axial through holes of the upper packer and the central fracturing section in sequence, and a third through hole for water injection of a ground stress test section is arranged on the hole wall of the axial through hole of the central fracturing section.

2. The unstable deep borehole while-drilling geostress testing device according to claim 1, characterized in that, The pressurized water injection device comprises a high-pressure water pump, a high-pressure water pipe connected with the high-pressure water pump at one end, and a pressure relief valve arranged on the high-pressure water pipe, and the other end of the high-pressure water pipe is connected with the high-pressure drill rod through a pipe joint.

3. The unstable deep borehole while-drilling geostress testing device according to claim 2, characterized in that, The pressure sensor is arranged on the high-pressure water pipe and connected with the data acquisition device, and is used for collecting the water flow pressure in the high-pressure water pipe and transmitting the water flow pressure to the data acquisition device.

4. The unstable deep borehole, drill-sty stress testing device of claim 1, wherein, The inner diameter of the first water inlet hole is smaller than that of the second water inlet hole, a stop ring is arranged on the outer wall of the end of the push-pull pipe close to the upper packer, and the outer diameter of the stop ring is equivalent to the inner diameter of the second water inlet hole, so that the stop ring on the push-pull pipe moves up and down along the inner wall of the second water inlet hole when the push-pull pipe moves up and down in the first water inlet hole.

5. The unstable deep borehole, drill-sty stress testing device of claim 1, wherein, The outer diameter of the plugging plug is equivalent to the inner diameter of the push-pull pipe, so that the plugging plug can just plug the push-pull pipe.

6. The unstable deep borehole, drill-sty stress testing device of claim 1, wherein, The upper packer and the lower packer each have an inner cavity, and a communication hole for communicating the inner cavities of the upper packer and the lower packer is arranged on the central fracturing section.

7. The unstable deep borehole, drill-sty stress testing device of claim 1, wherein, The drilling machine is connected with the rope coring drill pipe when the test device connected with the drill pipe encounters an obstacle during lowering, the rotary power head of the drilling machine is connected with the rope coring drill pipe, the rotary power head works to drive the rope coring drill pipe to rotate and drive the geological drill bit to rotate through the test device to pass through the obstacle.

8. A method of testing the unstable deep borehole while drilling geostress testing device according to any one of claims 1-7, characterized in that, The method comprises the following steps: Step 1: sequentially assemble the rope coring drill pipe and the high-pressure drill pipe, lower the test device connected with the drill pipe to a specified depth in the borehole through the winch device, and rotate downward to drive the geological drill bit to remove the obstacle and cross the unstable stratum during the lowering process; Step 2: fix the rope coring drill pipe on the ground after reaching the specified depth, connect the high-pressure drill pipe with the pressurized water injection device, and connect the high-pressure drill pipe with the winch device, under the action of gravity, the high-pressure drill pipe moves downward relative to the passage conversion valve, the high-pressure drill pipe sequentially communicates with the upper and lower packers through the first water outlet passage, at this time, the second water outlet passage is in a closed state, and the sewage in the borehole cannot enter the passage conversion valve through the central fracturing section; Step 3: open the pressurized water injection device and gradually pressurize to a predetermined pressure, the high-pressure water flow sequentially enters the upper and lower packers through the high-pressure drill pipe and the first water outlet passage of the passage conversion valve, under the action of water and pressure, the upper and lower packers expand and tightly adhere to the borehole wall, and a sealed space formed between the upper and lower packers is the test section; Step 4: lift the high-pressure drill pipe relative to the upper packer through the winch device until it cannot be lifted, at this time, the high-pressure drill pipe is connected with the water inlet of the passage conversion valve and the second water outlet passage, the high-pressure water flow enters the test section through the pressurized water injection device, the high-pressure drill pipe, the water inlet of the passage conversion valve, the second water outlet passage and the central fracturing section, the pressurized water injection device continuously pressurizes and injects water until the test section rock mass produces hydraulic fracturing cracks, and the water pressure fracturing stress parameters in the working process are collected by using the data acquisition device; Step 5: after the data acquisition is completed, stop the pressurized water injection device and perform pressure relief, lower the high-pressure drill pipe until it cannot be lowered, connect the water inlet of the passage conversion valve with the first water outlet passage, at this time, the pressure water in the upper and lower packers flows out along the first water outlet passage of the passage conversion valve and the drill pipe, the upper and lower packers shrink and separate from the borehole wall, and return to the initial state, that is, the water pressure fracturing geostress value and direction of this section are tested, and the above process is repeated to realize the geostress test of the next selected section.

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