Distributed crack occurrence detection device and method suitable for directional drilling

Abstract

The invention discloses a distributed crack occurrence detection device and method suitable for directional drilling, a crack occurrence detection device is arranged in each measurement section in a drilling hole, and the crack occurrence detection devices between different measurement sections are connected through a drill rod; the crack occurrence detection device comprises an impression device and an eccentric gravity orientation device which are connected in series, and comprises the impression device, a first center through hole and a second center through hole, the eccentric gravity orienting device comprises a base body, a limiting device which is fixed in the base body and is close to one end of the impression device, an orienting eccentric disc which is rotatably fixed in the base body, a sliding piston which is limited between the limiting device and the orienting eccentric disc and can move, and a second central through hole of the limiting device, the orienting eccentric disc and the sliding piston; a lateral pressure channel is arranged between the limiting device and the sliding piston, the first center through hole is communicated, and the second center through hole is communicated with the lateral pressure channel. According to the method, time can be greatly saved, the drill lifting risk is reduced, and the efficiency of the directional drilling crack impression test is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of rock mechanics tests, and particularly relates to a distributed fracture attitude detection device and method applicable to directional drilling. Background Art

[0002] Directional drilling technology has been gradually and widely applied in drilling construction. In recent years, with the increasing hole depth and more complex penetrated formations, in-situ rock mass tests in the hole face major risk challenges. As an important part of in-situ tests in deep boreholes, the hydraulic fracturing method for in-situ stress measurement mainly includes two steps: First, a rock mass hydraulic fracturing test is carried out to form a pressure fracture on the hole wall of the measuring section, and stress value parameters can be obtained during this process; Second, an impression test is carried out on the attitude of the pressure fracture in the measuring section, and the attitude of the corresponding fracture plane can be obtained by combining the fracture traces left on the impression rubber cylinder with a directional device, and further the stress direction of the measuring point can be obtained. The hydraulic fracturing test generally can complete the full-hole measurement with one trip of the drill string, but the fracture attitude impression test generally can only obtain the data of one measuring section with one trip of the drill string. Therefore, it is necessary to carry out long-term and high-frequency trips of the drill string to complete all tests.

[0003] In view of the hole-forming characteristics of directional drilling, the hole inclination of the drill hole is generally in a small inclination or near-horizontal state, and the difficulty of the fracture attitude impression test is greater. On the one hand, in complex formations, horizontal drill holes are more likely to collapse and slough under their own weight, and the high-frequency trips of the drill string will greatly increase the risk of jamming the impression test equipment; on the other hand, during the process of taking out the tester from the deep hole, the long-term friction between the impression rubber cylinder and the hole wall easily causes the impression traces to wear and disappear. Therefore, it is necessary to develop a fracture attitude detection system applicable to directional drilling that can reduce the number of trips of the drill string during the impression test of directional drilling and can accurately measure the fracture direction. Summary of the Invention

[0004] An object of the present invention is to provide a distributed fracture attitude detection device applicable to directional drilling for the deficiencies of the prior art. The device can greatly save time, reduce the risk of pulling out the drill, and can accurately perform impression and orientation on the borehole fractures.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A distributed fracture attitude detection device applicable to directional drilling is provided with a fracture attitude detection device arranged at each measuring section in the drill hole, and the fracture attitude detection devices between different measuring sections are connected by drill pipes; the fracture attitude detection device includes an impression device and an eccentric gravity orientation device connected in series, wherein:

[0007] A impression device, which is used to retain the shape of cracks on the inner wall of a drill hole. One end of the impression device is connected to the first drill pipe section, and the other end is connected to an eccentric gravity orientation device. The impression device has a first central through hole, and the first central through hole is connected to a high-pressure water pump through a high-pressure hose;

[0008] An eccentric gravity orientation device, one end of which is connected to the impression device and the other end is connected to the second drill pipe section. The eccentric gravity orientation device includes a matrix with a cavity, a limiting device fixed at one end of the cavity of the matrix close to the impression device, an orientation eccentric disk rotatably arranged in the cavity close to the second drill pipe section, a positioning piston restricted between the limiting device and the orientation eccentric disk and slidable in the matrix, and a second central through hole penetrating the matrix axially. A lateral pressure channel is arranged between the limiting device and the positioning piston, and the first central through hole, the second central through hole and the lateral pressure channel are all communicated;

[0009] In the initial state, the positioning piston is located at one end of the cavity close to the limiting device. During operation, the high-pressure water pump continuously injects high-pressure water into the lateral pressure channel through the high-pressure hose, the first central through hole and the second central through hole. The positioning piston moves under the push of the high-pressure water until it moves to press against the orientation eccentric disk and locks it, and the angular condition of the orientation eccentric disk after being locked is obtained.

[0010] Further, the impression device includes an impression rubber cylinder, plugging joints sleeved at both ends of the impression rubber cylinder, and a wear-resistant strip layer sleeved on the plugging joints. One of the plugging joints at one end of the impression rubber cylinder is connected to the first drill pipe section, and the plugging joint at the other end is connected to the eccentric gravity orientation device. The outer diameter of the wear-resistant strip layer is larger than the outer diameter of the impression rubber cylinder.

[0011] Further, the matrix includes an orientation main body kit and a protection kit docked with the main body kit. After the orientation main body kit and the protection kit are docked, a cavity for accommodating the positioning piston, the central pipe and the orientation eccentric disk is formed inside, and a rear end interface for connecting the second drill pipe section is arranged at the end of the protection kit.

[0012] Further, the limiting device plugs the end side of the matrix close to the impression device. A plurality of protrusions are arranged on the end face of the limiting device close to the positioning piston. When the positioning piston slides towards the limiting device and presses against the protrusions on the limiting device, the lateral pressure channel is formed between the positioning piston and the end face of the limiting device.

[0013] Furthermore, at one end of the positioning main body kit away from the impression device, a T-shaped fixing block is sealed. A plurality of sliding holes parallel to its axial direction are penetrated through the fixing block. A positioning piston is slidably arranged in each sliding hole. And at one end of the positioning main body kit away from the limiting block, a first stepped surface which is matched with the shape of the fixing block and is closed is arranged. Correspondingly, a second stepped surface which is matched with the first stepped surface is arranged on the outer wall of the positioning piston, so that the positioning piston is limited and will not fall out of the base body.

[0014] Furthermore, the positioning piston includes a hollow piston base body, a limiting screw fixed in the piston base body, a spring connected to the limiting screw, a push rod connected to the spring and extending out of the piston base body, a disc fixed on the push rod, and a positioning pin arranged on the disc. When high-pressure water is continuously injected into the lateral pressure channel, the high-pressure water pushes the positioning piston to move towards the directional eccentric disc until the positioning pin pierces into the positioning eccentric disc to lock the positioning deflection disc.

[0015] Furthermore, the positioning piston further includes a limiting snap ring. Correspondingly, a limiting snap groove is arranged on the outer wall of the piston base body. The limiting snap groove is arranged such that when the positioning pin pierces into the positioning rubber disc to lock the positioning deflection disc, the limiting snap ring just snaps into the limiting snap groove.

[0016] Furthermore, the directional eccentric disc includes a disc, a positioning rubber disc fixed on the disc and corresponding to the positioning pin, and an eccentric lead block embedded and fixed on the edge of the disc. The disc is sleeved on the central tube through a bearing. The central tube is fixed in the axial direction of the base body. A scale and a pointing arrow convenient for reading the scale are arranged on the disc surface.

[0017] Another object of the present invention is to provide a method for detecting the fracture occurrence state by using the distributed fracture occurrence state detection device for directional drilling according to the above, including the following steps:

[0018] The first step is to determine the impression selection section and the corresponding depth of each measurement section. A set of fracture occurrence state detection devices is arranged in each measurement section. The fracture occurrence state detection devices between different measurement sections are connected by drill pipes.

[0019] The second step is to send the fracture occurrence state detection devices into the borehole through a drill pipe machine according to the depths of each section until all the fracture occurrence state detection devices correspond to their test depths one by one. And connect the first central through holes of all the fracture occurrence state detection devices in the borehole and the second central through holes of the eccentric gravity orientation devices to a high-pressure water pump through high-pressure hoses.

[0020] Step 3: In the initial state, i.e., when the positioning piston is on the side of the base close to the limiting device, start the high-pressure water pump to inject water and pressurize into the first central through-hole and the second central through-hole. A part of the high-pressure water enters the impression device, and the impression device absorbs water and expands to tightly adhere to the hole wall. The remaining high-pressure water enters the lateral pressure channel through the second central through-hole. The positioning piston moves under the push of the high-pressure water until it abuts against and locks the directional eccentric disc, thereby determining the angle of the directional disc. Continue to pressurize and maintain the pressure for a period of time to ensure that the shape of the hole wall crack remains on the impression device.

[0021] Step 4: Pull out the crack occurrence detection device in the borehole, remove the drill pipe and the high-pressure hose, and keep the impression device and the eccentric gravity orientation device of each measuring section in a connected state.

[0022] Step 5: Remove the base on the eccentric gravity orientation device, record the corresponding relationship between the trace direction of the crack remaining on the impression device and the angle change of the eccentric gravity orientation device, and then calculate the crack occurrence.

[0023] Further, the calculation of the crack occurrence includes calculating the crack dip and the crack dip angle; the calculation method includes:

[0024] (1) Coordinate system transformation formula

[0025] In the right-handed coordinate system, based on the A coordinate system (O-X 0 Y 0 Z 0 ), respectively rotate θ 0 , θ 0 , θ 0 around the X 1 , Y 2 , Z 3 axes in sequence according to the right-hand rule to obtain the B coordinate system (O-X 1 Y 1 Z 1 ). The coordinate system transformation matrices are respectively:

[0026]

[0027] Multiply the three matrices in the rotation order to obtain the rotation transformation formula of the coordinates of the spatial point P from the coordinate system A to the coordinate system B

[0028]

[0029] (2) Analysis of impression traces

[0030] There are three cases of impression traces: the crack direction is parallel to the borehole axis, the crack direction is oblique to the borehole axis, and the crack direction is orthogonal to the borehole axis. The three cases are uniformly divided based on the angle (β) between the crack plane and the borehole axis, that is: when β = 0°, the crack direction is parallel to the borehole axis; when β = 90°, the crack direction is perpendicular to the borehole axis; in other cases, the crack direction is oblique to the borehole axis.

[0031] (3) Coordinate system setting

[0032] Crack ellipse coordinate system: O-X 0 Y 0 Z 0 , X 0 points to the major axis of the crack ellipse, Y 0 points to the minor axis of the crack ellipse, Z 0 points to the normal direction of the crack ellipse plane;

[0033] Borehole coordinate system: O-X 1 Y 1 Z 1 , X 1 points along the borehole axis towards the hole mouth, Y 0 points horizontally to the right along the borehole radius, Z 0 points upwards along the borehole radius, see Figure 9 ;

[0034] Geodetic coordinate system: O-XYZ, X points north, Y points west, and Z points vertically upwards.

[0035] (4) Vector calculation of the crack plane in the geodetic coordinate system

[0036] ① Given: The crack normal vector in the crack ellipse coordinate system is Find the corresponding crack normal vector in the borehole coordinate system

[0037] First, rotate counterclockwise by θ 0 around the X 1 axis, at this time Y 0 coincides with Y 1 , where θ 1 = 90° - α, α ranges from 0 to 360°; then, rotate counterclockwise by θ 0 around the Y 2 axis, at this time X 0 coincides with X 1 , where θ 2 = -β, β = arcsin(r / l), where r is the borehole radius and l is half of the major axis of the crack ellipse. When α ∈ [0, 180°], r is positive; when α ∈ (180°, 360°), r is negative; after two rotations around the X 0 and Y 0 axes, Z 0Coincide with Z 1 Automatically coincide without rotating around the Z 0 axis;

[0038] Then: The fracture normal vector in the drilling coordinate system Substitute the corresponding rotation angles and vectors

[0039] ②, Given the fracture normal vector in the drilling coordinate system Find the corresponding fracture normal vector in the geodetic coordinates First, the Y 1 axis is in the horizontal plane and rotates counterclockwise around the Y 1 axis γ is the drilling inclination angle, positive for downward inclination. At this time, the X 1 Y 1 plane is in the horizontal plane and the Z 1 axis automatically coincides with the Z-axis and is vertically upward; then rotate counterclockwise around the Z 1 axis ω is the drilling azimuth angle. At this time, the drilling coordinate system is converted to the geodetic coordinate system; then:

[0040] The fracture normal vector in the geodetic coordinate system Substitute the corresponding rotation angles and vectors The fracture normal vector in the geodetic coordinate system is:

[0041]

[0042] Let the x, y, and z components in the vector be represented by e X 、e Y 、e Z respectively, then the fracture normal vector is abbreviated as:

[0043]

[0044] (5) Solve the attitude of the fracture plane. The attitude of the fracture plane includes the dip direction and dip angle in geology:

[0045] ① Dip direction calculation

[0046] The fracture dip direction is the azimuth angle of the projection of the normal vector on the horizontal plane. First, calculate the horizontal projection vector Then the fracture dip direction can be expressed as:

[0047] θ = -arctan(e Y / e X ) (7)

[0048] If e X > 0, the dip direction is θ; if eX < 0, the tendency is θ + 180°; if e X = 0 and e Y < 0, the tendency is 90°; if e X = 0 and e Y > 0, the tendency is 270°;

[0049] ② Dip angle calculation

[0050] The fracture dip angle is the angle between the normal vector and the vertical direction, and the fracture dip angle can be expressed as:

[0051]

[0052] where is the modulus of the normal vector.

[0053] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0054] (1) With the present invention, the fracture occurrence impression test for all-hole selected sections can be completed in one trip of the drill string, which can effectively reduce the test time and test risk; and by setting an eccentric gravity orientation device, the positioning piston is pushed by water pressure to move to lock the eccentric positioning disc, and the corresponding relationship between the scale on the disc and the trace direction of the impression rubber cylinder can be accurately measured, and this locking method is firm and easy to disassemble, convenient to operate and accurate in measurement; in addition, this eccentric gravity orientation device not only has a simple and reliable function of orienting the pressure fracture, but also the design of its central pressure channel provides a new idea for the modular impression test;

[0055] (2) With the present invention, the purposes of equipment connection, delivery and maintaining the stability of the borehole are achieved by means of wireline coring drill pipes, and no additional equipment needs to be added, which can reduce costs; and the self-protecting impression device can effectively protect the fracture imprints on the rubber cylinder. Brief description of the drawings

[0056] Figure 1 is a schematic diagram of the fracture occurrence impression system for directional drilling in an embodiment of the present invention;

[0057] Figure 2 is a longitudinal sectional structure schematic diagram of the impression device in an embodiment of the present invention;

[0058] Figure 3 is a longitudinal sectional structure schematic diagram of the eccentric gravity type orientation device in an embodiment of the present invention;

[0059] Figure 4 is a longitudinal sectional structure schematic diagram of the positioning piston in an embodiment of the present invention;

[0060] Figure 5It is a schematic structural diagram of the transverse section of the impression orientation device according to the embodiment of the present invention, (a) A-A', (b) B-B', (c) C-C';

[0061] Figure 6 It is a schematic longitudinal section structure diagram after the eccentric gravity orientation device according to the embodiment of the present invention is locked;

[0062] Figure 7 It is a schematic longitudinal section structure diagram after the eccentric gravity orientation device at the tail end in the borehole according to the embodiment of the present invention is locked;

[0063] Figure 8 It is a schematic diagram showing three trace distributions of impression rubber cylinder rubbing according to the embodiment of the present invention;

[0064] Figure 9 It is a display diagram of the relative relationship between the crack elliptic coordinate system and the borehole coordinate system according to the embodiment of the present invention. Detailed implementation manners

[0065] Next, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0066] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0067] Next, the present invention will be further described in conjunction with specific embodiments, but it is not a limitation of the present invention.

[0068] As Figure 1 shown, the embodiment of the present invention discloses a distributed crack occurrence detection device applicable to directional drilling. A crack occurrence detection device is arranged in each measurement section in the borehole, and the crack occurrence detection devices between different measurement sections are connected by a drill pipe 5. The crack occurrence detection device includes a series-connected impression device 4 and an eccentric gravity orientation device 3. Among them, see Figure 2, the impression device 4 includes a central flower tube 4-1, an impression rubber cylinder 4-6 sleeved on the central flower tube 4-1, and plugging joints 4-2 sleeved at both ends of the impression rubber cylinder 4-6. Among them, one plugging joint at one end of the plugging joint 4-2 is connected to the first section of drill pipe, and the plugging joint at the other end is connected to the eccentric gravity orientation device 3. In order to prevent the impression rubber cylinder 4-6 from rubbing against the borehole 1 and affecting the crack imprints on the impression rubber cylinder, a strip layer 4-3 with high wear resistance is welded on the plugging joint 4-2 and the protective steel rings 4-4 at both ends of the impression rubber cylinder 4-6. In addition, in order to protect the impression rubber cylinder 4-6, a protective ring 4-4 is also provided between the impression rubber cylinder 4-6 and the strip layer 4-3. In addition, a plurality of water outlet holes 4-5 are provided on the central flower tube 4-1, so that high-pressure water can flow from the water outlet holes 4-5 into the cavity between the impression rubber cylinder 4-6 and the central flower tube 4-1. A first central through hole can be formed inside the central flower tube 4-1. Among them, one end of the central flower tube 4-1 is connected to a high-pressure water pump 10 through a high-pressure hose 6. In order to facilitate monitoring the water pressure of the high-pressure water pump, the high-pressure hose 6 and the high-pressure water pump 10 are connected through a ground high-pressure pipe 9, and a pressure gauge 7 and a pressure relief valve 8 are provided on the ground high-pressure pipe 9.

[0069] See Figure 3 , the eccentric gravity orientation device 3 includes a matrix with a cavity, a limiting device fixed at one end close to the impression device 4 inside the cavity, an orientation eccentric disc rotatably arranged at one end close to the second section of drill pipe inside the cavity, a positioning piston 3-7 restricted between the limiting device and the orientation eccentric disc and slidable inside the cavity, and a second central through hole 3-16 penetrating the axis of the matrix. Among them, the matrix includes a hollow positioning main body kit 3-3 and a hollow protective kit 3-14 sleeved on the positioning main body kit 3-3. After the positioning main body kit 3-3 and the protective kit 3-14 are sleeved, the above-mentioned cavity for accommodating the limiting device, the sliding piston 3-7 and the orientation eccentric disc is formed inside. A front joint 3-1 for connecting the plugging joint 4-2 on the impression rubber cylinder 4-6 is provided at the end of the positioning main body kit 3-3, and a rear interface 3-15 for connecting the second section of drill pipe is provided at the end of the protective kit 3-14. For the eccentric gravity orientation device 3 located at the very end of the borehole, its end is closed with a cover 3-17 (see Figure 7 ).

[0070] In this embodiment, the limiting device is fixed at one end of the directional main body kit 3-3 near the stamp device 4. The limiting device includes a limiting block 3-5 that blocks one end of the stamp device 4 in the cavity, a plurality of screw holes that are arranged on the limiting block 3-5 and parallel to its axial direction, and a limiting screw 3-4 that is screwed into each screw hole, wherein the length of the limiting screw 3-4 in the directional main body kit 3-3 is greater than the length of the limiting block 3-5 so that a plurality of protrusions are formed on the end face of the limiting block 3-5 facing the sliding piston 3-7, so that even when the positioning piston 3-7 moves to the extreme position close to the limiting device, there is enough space between the positioning piston 3-7 and the end face of the limiting screw 3-4 to form a lateral pressure channel, ensuring that the high-pressure water flow entering from the lateral pressure channel 3-6 can easily push the positioning piston 3-7. A front end joint 3-2 is connected to the limiting block 3-5, and both the front end joint 3-2 and the limiting block 3-5 have axial holes in the axial direction, and the axial holes of the two are connected.

[0071] A T-shaped fixed block 3-18 is sealed at one end of the directional main body kit away from the stamp device 4. A plurality of sliding holes parallel to the axial direction are provided through the fixed block 3-18, and a positioning piston 3-7 is slidably provided in each sliding hole. The positioning piston 3-7 can move in the sliding hole of the fixed block 3-18. In order to prevent the positioning piston 3-7 from falling out of the base body and damaging the directional eccentric disk during movement, a first step surface that matches the shape of the fixed block 3-18 and is closed is provided at one end of the directional main body kit 3-3 close to the directional eccentric disk, and a second step surface that matches the first step surface is also provided on the outer surface of the positioning piston 3-7, so that the positioning piston 3-7 is limited so as not to fall out of the base body 3-3.

[0072] like Figure 4 As shown, the positioning piston 3-7 includes a hollow piston base 3-7.1, a limit screw 3-7.2 fixed in the piston base 3-7.1, a spring 3-7.4 connected to the limit screw 3-7.2, a push rod 3-7.6 connected to the spring 3-7.4 and extending out of the piston base 3-7.1, a fixed disk 3-7.7 fixed on the push rod 3-7.6, and a positioning pin 3-7.8 arranged on the fixed disk 3-7.7. Among them, the fixed disk 3-7.7 is made of rubber material, and the spring 3-7.4 and the fixed disk 3-7.7 both play a buffering role to prevent the rigid impact from damaging the directional eccentric disk. In order to prevent high-pressure water from leaking along the edge of the positioning piston 3-7 into the space where the directional eccentric disk is located, thereby affecting the movement of the positioning piston 3-7, a plurality of sealing rings 3-7.3 are mounted on the outer surface of the piston base 3-7.1. When high-pressure water is continuously injected into the lateral pressure channel 3-6, the high-pressure water pushes the positioning piston 3.7 to move toward the directional eccentric disc until the positioning pin 3-7.8 pierces the directional eccentric disc to lock it.

[0073] SeeFigure 5 , the directional eccentric disk includes a disk 3-10, a positioning rubber disk 3-9 fixed on the disk 3-10 and corresponding to the positioning pins 3-7.8, and an eccentric lead block 3-13 embedded and fixed on the edge of the disk 3-10. The disk 3-10 is sleeved on the central tube 3-12 through a bearing 3-11. Among them, the front-end joint 3-2, the limit block 3-5, the shaft holes of the fixed block 3-18 and the central tube 3-12 are connected to form the second central through-hole 3-16 of the eccentric gravity orientation device 3, and the second central through-hole 3-16 is communicated with the first central through-hole 4-1 and the high-pressure hose 6. In addition, a limit snap ring 3-8 is sleeved on the central tube 3-12. Correspondingly, a limit slot 3-7.5 is provided on the piston base 3-7.1. The limit slot 3-7.5 is set so that when the positioning pin 3-7.8 pierces into the positioning rubber disk 3-9 to lock the positioning deviation disk, the limit snap ring 3-8 just snaps into the limit slot 3-7.5. In order to facilitate reading the angle of the crack, scales and pointing arrows are engraved on the disk surface of the disk 3-10, and the arrow points to the center of gravity of the eccentric lead block 3-13 to ensure that the directional eccentric disk is affected by the eccentric gravity, and the arrow on the disk surface of the disk 3-10 always points directly below the cross-section of the drill hole.

[0074] The embodiment of the present invention also provides a method for detecting the occurrence of cracks by using the above-mentioned distributed crack occurrence detection device suitable for directional drilling, including the following steps:

[0075] The first step is to determine the impression selection section and the corresponding depth of each measurement section, and pre-match the crack occurrence detection device and the drill pipe length of each section; each measurement section crack occurrence detection device includes a self-protection impression device 4 ( Figure 2 ) and the eccentric gravity orientation device 3. The rear-end interface of the rear-end eccentric gravity orientation device 3 is closed, as Figure 7 shown, and the eccentric gravity orientation device 3 in the middle part is as Figure 3 shown;

[0076] The second step is to test the pressure-bearing capacity of the wireline core drill pipe 5. If its pressure-bearing capacity exceeds the maximum re-opening pressure of the cracks in each measurement section, the wireline core drill pipe 5 can be used as a pressure channel, and there is no need to connect the high-pressure hose 6 inside the drill pipe, which can effectively reduce the workload of pipeline installation; if the pressure-bearing capacity of the wireline core drill pipe 5 is less than the maximum re-opening pressure of the cracks in each measurement section, it is necessary to connect the high-pressure hose 6 inside the drill pipe to form an independent water pressure channel, as Figure 1 shown, which is suitable for ultra-deep directional drilling. The following are all the subsequent steps of this solution;

[0077] Step 3: Connect the crack attitude detection devices of each section to each other through drill pipes in sequence according to the depth of each section, and rely on the drilling rig to send them into the directional borehole 1. For ultra-deep directional boreholes, a high-pressure hose 6 needs to be connected synchronously until all impression devices 4 and their test depths correspond one by one. At this time, the first central through holes of all impression devices 4 in the borehole and the second central through hole 3-16 of the eccentric gravity orientation device 3 are interconnected through the high-pressure hose 6. The schematic state is as shown in Figure 1 shown;

[0078] Step 4: Connect the high-pressure water pump 10, the surface high-pressure pipe 9, the pressure gauge 7, and the pressure relief valve 8 outside the borehole, and connect the surface high-pressure pipe 9 to the high-pressure hose 6 in the borehole to complete the preparatory work. At this time, under the gravity of the eccentric lead block 3-13, the indicating arrow of the disc 3-10 remains downward, and the positioning piston 3-7 is in the initial position (i.e., in contact with the limit screw 3-4). The state is as shown in Figure 3 , Figure 4 and Figure 5 shown;

[0079] Step 5: Inject water into the high-pressure hose 6 through the high-pressure water pump 10 to pressurize. During the pressurization process, a small amount of pressurized water enters the cavity between the impression rubber cylinder 4-6 and the central flower pipe 4-1 through the water outlet hole 4-5 of the central flower pipe of the impression device 4, causing the impression rubber cylinder 4-6 to expand and tightly adhere to the hole wall. The remaining pressurized water enters the lateral pressure channel 3-6 through the second central through hole 3-16 of the eccentric gravity orientation device 3 and pushes the positioning piston 3-7 towards the eccentric positioning disc. Continue to inject water, and the positioning pin 3-7.8 on the positioning piston tightly adheres to and pierces into the positioning rubber disc 3-9, thereby locking the directional eccentric disc. The springs 3-7.4 in the piston matrix 3-7.1, the fixed disc 3-7.7 (made of rubber material), and the positioning rubber disc 3-9 all play a buffering role to prevent rigid impact from damaging the disc 3-10; the limit snap ring 3-8 is snapped into its limit groove 3-7.5 after the positioning piston 3-7 reaches the maximum stroke to limit the movement of the positioning piston 3-7 and ensure the locked state of the disc 3-10, as shown in Figure 6 and Figure 7 shown; Continue to pressurize to reach the maximum re-expansion pressure and maintain this pressure for a period of time to ensure that the impression rubber cylinder 4-6 expands and tightly adheres to the hole wall crack, so that the impression rubber cylinder can retain clear traces of the hole wall crack;

[0080] Step 6: Pull out the crack attitude detection device in the borehole through the traction of the drilling rig. During the extraction process, the hard alloy strip 4-3 attached to the self-protection impression device 4 can prevent the impression rubber cylinder 4-6 from directly rubbing against the borehole 1, serving the purpose of protecting the crack imprint on the impression rubber cylinder 4-6; synchronously remove the wireline coring drill pipe 5 and the high-pressure hose 6. The impression device 4 and the corresponding eccentric gravity orientation device 3 of each measurement section need to maintain the test connection state, and all the test devices in the borehole are taken out in sequence according to this requirement;

[0081] Step 7: Remove the protection kit 3-14 on the eccentric gravity orientation device 3 of each measurement section, observe and record the corresponding relationship between the crack trace direction remaining on the rubber layer of the impression rubber cylinder 4-6 and the scale on the disc 3-10;

[0082] Step 8: After the test is completed, restore the piston limit snap ring 3-8 and the positioning piston 3-7 to their initial states and perform equipment maintenance;

[0083] Step 9: Calculate the occurrence of cracks in each measurement section in the geodetic coordinate system. The calculation method is as follows:

[0084] (1) Coordinate system transformation formula

[0085] In the right-handed coordinate system, based on the A coordinate system (O-X 0 Y 0 Z 0 ), respectively, with X 0 , Y 0 , Z 0 axes as the axes, rotate θ 1 , θ 2 , θ 3 in turn in the right-hand rule to obtain the B coordinate system (O-X 1 Y 1 Z 1 ). The coordinate system transformation matrices are respectively

[0086]

[0087] Multiplying the three matrices in the rotation order, the rotation transformation formula for the coordinates of the spatial point P from the coordinate system A to the coordinate system B can be obtained:

[0088]

[0089] (2) Analysis of impression traces

[0090] The impression traces are divided into three cases: the crack direction is parallel to the borehole axis, the crack direction is oblique to the borehole axis, and the crack direction is orthogonal to the borehole axis, as shown in Figure 8 . In this embodiment, it is stipulated that looking from the hole mouth to the hole bottom, the borehole is horizontal to the right at 0°, and α is the corresponding angle of the orientation disc rotated counterclockwise by the crack trace or the vertex of the trace. As shown in Figure 9 , then the three cases in Figure 8 can be uniformly divided based on the included angle (β) between the crack plane and the borehole axis, that is: when β = 0°, the crack direction is parallel to the borehole axis; when β = 90°, the crack direction is perpendicular to the borehole axis; in other cases, the crack direction is oblique to the borehole axis;

[0091] (3) Coordinate system setting

[0092] Crack ellipse coordinate system: O-X 0Y 0 Z 0 ,X 0 points to the major axis of the fracture ellipse, Y 0 points to the minor axis of the fracture ellipse, Z 0 points to the normal direction of the fracture ellipse plane, see Figure 9 ;

[0093] Borehole coordinate system: O-X 1 Y 1 Z 1 ,X 1 points along the borehole axis towards the hole mouth, Y 0 points horizontally to the right along the borehole radius, Z 0 points upwards along the borehole radius, see Figure 9 ;

[0094] Geodetic coordinate system: O-XYZ, X points to N (due north), Y points to W (due west), and Z points vertically upwards.

[0095] (4) Vector calculation of the fracture plane in the geodetic coordinate system

[0096] ① Given: The fracture normal vector in the fracture ellipse coordinate system is Find the corresponding fracture normal vector in the borehole coordinate system

[0097] First, rotate counterclockwise by θ 0 around the X 1 axis. At this time, Y 0 coincides with Y 1 . Here, θ 1 = 90° - α (α ranges from 0 to 360°); then, rotate counterclockwise by θ 0 around the Y 2 axis. At this time, X 0 coincides with X 1 . Here, θ 2 = -β (β = arcsin(r / l), where r is the borehole radius and l is half of the major axis of the fracture ellipse. r is positive when α ∈ (0, 180°) and r is negative when α ∈ (180°, 360°), see Figure 9 ); After two rotations around the X 0 and Y 0 axes, Z 0 automatically coincides with Z 1 , and there is no need to rotate around the Z 0 axis.

[0098] Then: The fracture normal vector in the borehole coordinate system Substitute the corresponding rotation angles and vectors

[0099] ② Similarly, given the fracture normal vector in the drilling coordinate system Find the corresponding fracture normal vector in the geodetic coordinate system

[0100] First, the Y 1 axis is in the horizontal plane and rotates counterclockwise around the Y 1 axis by ( γ is the drilling inclination angle, positive for downward inclination), at this time the X 1 Y 1 plane is in the horizontal plane and the Z 1 axis automatically coincides with the Z axis (vertically upward); then rotate counterclockwise around the Z 1 axis by ( ω is the drilling azimuth angle), at this time the drilling coordinate system is converted to the geodetic coordinate system. Then:

[0101] The fracture normal vector in the geodetic coordinate system Substitute the corresponding rotation angles and vectors The fracture normal vector in the geodetic coordinate system is

[0102]

[0103] Let the x, y, and z axis coordinate components in the vector be replaced by e X , e Y , e Z respectively, then the fracture normal vector is abbreviated as

[0104]

[0105] (5) Solve the attitude of the fracture plane (i.e., strike and dip in geology)

[0106] ① Strike calculation

[0107] The fracture strike is the azimuth angle of the projection of the normal vector on the horizontal plane. First, calculate the horizontal projection vector Then the fracture strike can be expressed as:

[0108] θ = -arctan(e Y / e X ) (7)

[0109] If e X > 0, the strike is θ; if e X < 0, the strike is θ + 180°; if e X = 0 and e Y < 0, the strike is 90°; if e X = 0 and e Y > 0, the strike is 270°.

[0110] ② Dip angle calculation

[0111] The fracture dip angle is the angle between the normal vector and the vertical direction, so the fracture dip angle can be expressed as:

[0112]

[0113] Where is the modulus of the normal vector.

[0114] The present invention can greatly save time, reduce the risk of drill pipe lifting, thereby generating obvious economic benefits, improve the efficiency of the directional borehole fracture impression test, reduce the test cost, and the method has simple operation and low equipment requirements, which is convenient for large-scale popularization and application.

[0115] The above are only the preferred embodiments of the present invention, and do not limit the implementation manners and protection scope of the present invention. For those skilled in the art, it should be realized that all the equivalent replacements and obvious changes made by using the content of the specification of the present invention should be included in the protection scope of the present invention.

Claims

1. A distributed crack occurrence detection device suitable for directional drilling, characterized in that: A crack occurrence detection device is provided in each measuring section in the borehole, and the crack occurrence detection devices between different measuring sections are connected by a drill rod; the crack occurrence detection device comprises a stamp device and an eccentric gravity orientation device connected in series, wherein: A stamp device, which is used to retain the shape of the crack on the inner wall of the borehole, one end of the stamp device is connected to the first section of the drill rod, and the other end is connected to the eccentric gravity orientation device, the stamp device has a first central through hole, and the first central through hole is connected to the high-pressure water pump through a high-pressure hose; An eccentric gravity orientation device, one end of which is connected to the stamp device, and the other end of which is connected to the second section of the drill pipe, the eccentric gravity orientation device comprises a base body with a cavity, a limit device fixed in the base body cavity near one end of the stamp device, a directional eccentric disk rotatably arranged in the cavity near the second section of the drill pipe, a positioning piston limited between the limit device and the directional eccentric disk and slidable in the base body, and a second central through hole running through the axial direction of the base body, a lateral pressure channel is arranged between the limit device and the positioning piston, the first central through hole is connected, and the second central through hole and the lateral pressure channel are all connected; In the initial state, the positioning piston is located in the cavity at one end close to the limit device. When working, the high-pressure water pump continuously injects high-pressure water into the lateral pressure channel through the high-pressure hose, the first center through hole and the second center through hole. The positioning piston is pushed and moved by the high-pressure water until it moves to press against the directional eccentric disk and locks it, thereby obtaining the angle of the directional eccentric disk after being locked.

2. The distributed crack occurrence detection device suitable for directional drilling according to claim 1 is characterized in that: The stamping device includes a stamping rubber cylinder, a sealing joint sleeved on both ends of the stamping rubber cylinder, and a wear-resistant strip ring layer sleeved on the sealing joint, wherein the sealing joint at one end of the stamping rubber cylinder is connected to the first section of drill pipe, and the sealing joint at the other end is connected to the eccentric gravity orienting device, and the outer diameter of the wear-resistant strip ring layer is greater than the outer diameter of the stamping rubber cylinder.

3. The distributed crack occurrence detection device suitable for directional drilling according to claim 1 is characterized in that: The base includes a directional main body kit and a protection kit docked with the main body kit. After the directional main body kit is docked with the protection kit, a cavity for accommodating a positioning piston, a center tube and a directional eccentric disk is formed therein, and a rear end interface for connecting a second section of drill pipe is provided at the end of the protection kit.

4. The distributed crack occurrence detection device suitable for directional drilling according to claim 1 is characterized in that: The limiting device is sealed at the end side of the base body close to the stamp device, and a plurality of protrusions are arranged on the end face of the limiting device close to the positioning piston. When the positioning piston slides toward the limiting device until it presses against the protrusion on the limiting device, the lateral pressure channel is formed between the positioning piston and the end face of the limiting device.

5. The distributed crack occurrence detection device suitable for directional drilling according to claim 3 is characterized in that: A T-shaped fixing block is sealed at one end of the positioning main body kit away from the stamp device, and a plurality of sliding holes parallel to the axial direction are arranged through the fixing block. A positioning piston is slidably arranged in each sliding hole, and a first step surface that matches the shape of the fixing block and is closed is arranged at one end of the positioning main body kit away from the limiting block, and correspondingly, a second step surface that matches the first step surface is arranged on the outer wall of the positioning piston, so that the positioning piston is limited and does not fall out of the base.

6. The distributed fracture occurrence detection device suitable for directional drilling according to claim 1, characterized in that: The positioning piston includes a hollow piston base, a limit screw fixed in the piston base, a spring connected to the limit screw, a push rod connected to the spring and extending out of the piston base, a disc fixed on the push rod, and a positioning needle arranged on the disc. When high-pressure water is continuously injected into the lateral pressure channel, the high-pressure water pushes the positioning piston toward the directional eccentric disc until the positioning pin penetrates into the positioning eccentric disc to lock the positioning deflection disc.

7. The distributed fracture occurrence detection device suitable for directional drilling according to claim 6, characterized in that: The positioning piston also includes a limiting snap ring. Correspondingly, a limiting snap groove is provided on the outer wall of the piston base. The limiting snap groove is configured so that when the positioning needle penetrates into the positioning rubber disc to lock the positioning deflection disc, the limiting snap ring just fits into the limiting snap groove.

8. The distributed fracture occurrence detection device suitable for directional drilling according to claim 6, characterized in that: The directional eccentric disk includes a circular disk, a positioning rubber disk fixed on the circular disk and arranged corresponding to the positioning pin, and an eccentric lead block embedded in and fixed on the edge of the circular disk. The circular disk is mounted on a center tube through a bearing, and the center tube is fixed in the axial direction of the base. A scale and a directional arrow for convenient reading of the scale are arranged on the surface of the circular disk.

9. A method for detecting crack occurrence using a distributed crack occurrence detection device suitable for directional drilling according to any one of claims 1 to 8, characterized in that: The steps include: The first step is to determine the mold selection section and the corresponding depth of each measurement section, set up a set of crack occurrence detection devices in each measurement section, and connect the crack occurrence detection devices between different measurement sections through drill pipes; The second step is to send the crack occurrence detection device into the borehole through the drill rod machine according to the depth of each section until all the crack occurrence detection devices correspond to their test depths one by one, and connect the first central through hole of all the crack occurrence detection devices in the borehole and the second central through hole of the eccentric gravity orientation device to the high-pressure water pump through a high-pressure hose; The third step is that in the initial state, that is, the positioning piston is located on the side of the base body close to the limit device, the high-pressure water pump is started to inject water into the first central through hole and the second central through hole for pressurization, a part of the high-pressure water enters the stamp device, the stamp device absorbs water and swells and adheres to the hole wall, and the rest of the high-pressure water enters the lateral pressure channel through the second central through hole, the positioning piston moves under the push of the high-pressure water to press against the directional eccentric disk and lock it, thereby determining the angle of the directional disk, and the pressure is continued and maintained for a period of time to ensure that the shape of the crack on the hole wall is retained on the stamp device; The fourth step is to pull out the crack occurrence detection device in the borehole, remove the drill rod and high-pressure hose, and keep the impression device and eccentric gravity orientation device of each measuring section in a connected state; The fifth step is to remove the substrate on the eccentric gravity orientation device, record the corresponding relationship between the direction of the crack traces left on the impression device and the angle change of the eccentric gravity orientation device, and then calculate the crack occurrence.

10. The method for detecting crack occurrence by the distributed crack occurrence detection device suitable for directional drilling according to claim 9, characterized in that: Fracture occurrence calculation includes calculation of fracture inclination and fracture dip angle; The calculation method includes: (1) Coordinate system conversion formula In the right-hand coordinate system, based on the A coordinate system (O-X0Y0Z0), the X0, Y0, and Z0 axes are respectively rotated forward by θ1, θ2, and θ3 according to the right-hand rule to obtain the B coordinate system (O-X1Y1Z1). The coordinate system transformation matrices are: Multiply the three matrices in the rotation order to obtain the rotation transformation formula of the spatial point P coordinate from coordinate system A to coordinate system B (2) Analysis of impression marks There are three types of impression marks: the crack direction is parallel to the drilling axis, the crack direction is oblique to the drilling axis, and the crack direction is orthogonal to the drilling axis. The three types are uniformly divided based on the angle (β) between the crack plane and the drilling axis, that is, when β = 0°, the crack direction is parallel to the drilling axis, when β = 90°, the crack direction is perpendicular to the drilling axis, and in other cases, the crack direction is oblique to the drilling axis. (3) Coordinate system setting Crack ellipse coordinate system: O-X0Y0Z0, X0 points to the major axis of the crack ellipse, Y0 points to the minor axis of the crack ellipse, and Z0 points to the normal direction of the crack ellipse surface; Drilling coordinate system: O-X1Y1Z1, X1 points to the hole mouth along the center axis of the drill hole, Y0 points to the right horizontally along the radial direction of the drill hole, and Z0 points upward along the radial direction of the drill hole, see Figure 9; Geodetic coordinate system: O-XYZ, X points to due north, Y points to due west, and Z is vertically upward. (4) Calculation of the vector of the crack plane in the geodetic coordinate system ① Known: The crack normal vector in the crack ellipse coordinate system is Find the corresponding crack normal vector in the drilling coordinate system First, rotate θ1 counterclockwise with the X0 axis as the axis, at this time Y0 and Y1 coincide, where θ1 = 90°-α, α is 0-360°; then, rotate θ2 counterclockwise with the Y0 axis as the axis, at this time X0 and X1 coincide, where θ2 = -β, β = arcsin(r / l), where r is the drilling radius, l is 1 / 2 of the major axis of the crack ellipse, r is positive when α∈0,180°, and r is negative when α∈(180°,360°); after two rotations of the X0 and Y0 axes, Z0 and Z1 automatically coincide, and there is no need to rotate with the Z0 axis; Then: The crack normal vector in the drilling coordinate system is Substitute the corresponding rotation angle and vector ②, the crack normal vector in the known drilling coordinate system Find the corresponding crack normal vector in geodetic coordinates First, the Y1 axis is in the horizontal plane, and rotates counterclockwise around the Y1 axis. γ is the drilling inclination angle, downward inclination is positive, at this time, the X1Y1 plane is in the horizontal plane and the Z1 axis and the Z axis automatically coincide with each other, that is, vertically upward; then rotate counterclockwise with the Z1 axis as the axis ω is the borehole azimuth, and the borehole coordinate system is converted to the geodetic coordinate system; then: Crack normal vector in geodetic coordinate system Substitute the corresponding rotation angle and vector The crack normal vector in the geodetic coordinate system is: Let the x, y, and z components of the vector be e X 、e Y 、e Z Instead, the crack normal vector is abbreviated as: (5) Solution of fracture plane occurrence: ①Tendency calculation The crack inclination is the projection azimuth of the normal vector on the horizontal plane. First, calculate the horizontal projection vector The crack tendency can be expressed as: θ=-arctan(e Y / and X ) (7) If e X >0, the tendency is θ; if e X <0, the inclination is θ+180°; if e X = 0 and e Y <0, the inclination is 90°; if e X = 0 and e Y >0, the inclination is 270°; ② Inclination calculation The crack inclination is the angle between the normal vector and the vertical direction, so the crack inclination can be expressed as: in is the magnitude of the normal vector.

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