Deep formation rock drillability testing device and testing method based on scratch test

Abstract

The present invention discloses a deep formation rock drillability test device and test method based on a scratch test, including a central control base and a reactor arranged on the central control base; a rotating clamping mechanism is arranged at both ends of the reactor; the interior of the reactor is hollow and the two ends are open, and the two ends of the reactor are threadedly connected with end covers; a resistance heating wire is installed at the bottom of the reactor cavity for heating the air in the reactor; a carving mechanism and a confining pressure regulating system are arranged in the reactor; the confining pressure regulating system is used to carry the rock sample and apply confining pressure to the rock sample, and the carving mechanism is used to scratch the surface of the rock sample. The present invention establishes the change of rock drillability curve along different angles in space through experiments, establishes continuous data of drillability in space concept, and provides a deep formation environment with high temperature and high surrounding rock, so that the test results are more accurate; and the test process causes little damage to the rock, the test cost is low, and the test time is short.

Description

Technical Field

[0001] The invention relates to the technical field of rock performance testing, and in particular to a deep formation rock drillability testing device and a testing method based on a scratch test. Background Art

[0002] Drilling is an important means of geotechnical engineering investigation, and is of great significance for the identification of geotechnical parameters such as stratum properties, structure, and groundwater development. Rock drillability is an important parameter for evaluating the difficulty of rock crushing during drilling, and has important applications in deep geotechnical engineering investigation, unconventional natural gas engineering, underground waste disposal, and deep geothermal resource development.

[0003] There are four main methods for traditional rock drillability:

[0004] (1) Use the physical and mechanical properties of rocks to evaluate the drillability of rocks: that is, use appropriate measuring instruments indoors to measure one or several mechanical properties that can reflect the essence of broken rocks as rock drillability indicators. (2) Use micro-drilling speed to evaluate the drillability of rocks: that is, use micro-equipment and tools to conduct simulation tests indoors, and use micro-drilling speed to reflect the comprehensive indicators of certain drilling conditions and technologies. (3) Use actual drilling speed to evaluate the drillability of rocks: It reflects the combined influence of multiple factors such as different formations, rocks, and technical processes, and can only be evaluated by data during the actual drilling process. (4) Use crushing specific work to evaluate the drillability of rocks: that is, use the volume of broken rocks per unit time to calculate the corresponding drilling speed.

[0005] However, for deep formation drilling, it has the characteristics of high drilling, sampling, and completion costs, long construction period, and complex underground environment. In the process of indoor testing using natural samples, the samples will be damaged, and the testing cost is high; non-destructive testing (such as Leeb hardness testing, etc.) has certain errors and cannot accurately characterize the drillability of rocks under deep formations. In addition, deep formations often have the characteristics of high temperature and high confining pressure. Existing drillability testing equipment cannot perform tests in simulated deep underground environments, especially at corresponding temperatures and pressures. Therefore, there is an urgent need for a rock drillability testing device and method that is low-cost, time-saving, highly continuous, and can meet the deep formation environment. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a deep formation rock drillability testing device and testing method based on a scratch test. Through testing at different angles, drillability curves in different directions are obtained, the error caused by the measurement can be corrected, the change of the rock drillability curve at different angles in space is established, continuous data of drillability in space is established, and a deep formation environment with high temperature and high surrounding rock is provided, so that the test results are more accurate; and the damage to the rock is small, the test cost is low, and the test time is short.

[0007] In order to achieve the above-mentioned object, the present invention provides a deep formation rock drillability testing device based on a scratch test, comprising a central control base and a reaction kettle arranged on the central control base;

[0008] The two ends of the reactor are provided with a rotating clamping mechanism for clamping and fixing the rock sample; the interior of the reactor is hollow and the end surface facing the rotating clamping mechanism is open, and the two ends of the reactor are threadedly connected with end covers that can close their own openings;

[0009] A resistance heating wire is installed at the bottom of the inner cavity of the reactor to heat the air in the reactor; a carving mechanism and a confining pressure regulating system are arranged in the reactor;

[0010] The confining pressure regulating system is used to carry the rock sample and apply confining pressure to the rock sample, and the carving knife mechanism is used to scratch the surface of the rock sample.

[0011] Further, the rotating clamping mechanism comprises a clamping link, a rotating handle, an angle plate, a sliding rod and an adjusting screw, one end of the clamping link is fixedly connected to the rotating handle, and the other end is penetrated through the center of the end cover, the clamping link and the end cover can slide relative to each other, and one end of the clamping link penetrated through the end cover abuts against the end surface of the rock sample;

[0012] A sliding groove is provided on the top surface of the central control base, and the adjusting screw is rotatably installed in the sliding groove. A nut block is fixed to one end of the sliding rod, and the nut block is slidably connected to the sliding groove. The adjusting screw is penetrated into the nut block and is threadedly connected to the nut block. The end of the sliding rod away from the nut block is fixedly connected to the angle disk, and the angle disk is sleeved on the clamping connecting rod, and the inner ring of the angle disk is embedded in the clamping connecting rod, so that the axial positions of the two are relatively fixed; a pointer is fixed to the outer peripheral surface of the clamping connecting rod, and the pointer fits against the outer wall of the angle disk.

[0013] Furthermore, the clamping link is passed through the center of the angle disk and is rotatably connected to the angle disk. A fastener is provided between the angle disk and the clamping link, and the angle disk and the clamping link can be locked and fixed by the fastener.

[0014] Furthermore, the confining pressure regulation system includes a confining pressure loading bin, which is coaxial with the reactor, is hollow inside and has openings at both axial ends, and has an axial slot for feeding the knife on the outer peripheral side of the confining pressure loading bin close to the engraving mechanism, a support rod is installed on the bottom surface of the confining pressure loading bin, and the support rod is fixed to the inner wall of the reactor to provide support for the confining pressure loading bin and the rock sample therein; the inner wall of the confining pressure loading bin is provided with a confining pressure sensing optical fiber to monitor the confining pressure changes in real time.

[0015] Furthermore, the engraving mechanism is located at the top of the confining pressure regulating system, and the engraving mechanism includes a bracket, an engraving driver and an engraving knife. The bracket is fixed to the inner wall of the reactor, the engraving driver is installed on the bracket, and the engraving knife is installed at the output end of the engraving driver. A force sensor and a displacement sensor are installed on the engraving knife, which are respectively used to detect the resistance size encountered by the engraving knife during engraving and the position of the engraving knife.

[0016] Furthermore, a control system and a data collection and recording system are installed in the central control base. The data collection and recording system is electrically connected to the temperature sensor, the force sensor, the displacement sensor and the confining pressure sensing optical fiber, and is used to collect and record the temperature, confining pressure and force and displacement data of the engraving knife in the reactor;

[0017] The control system is electrically connected to the carving knife mechanism, the resistance heating wire and the confining pressure regulating system, and can control the displacement of the carving knife and adjust the temperature and confining pressure values ​​required for the test.

[0018] The present invention also discloses a method for testing the deep formation rock drillability testing device based on a scratch test, and adopts the deep formation rock drillability testing device based on a scratch test; the deep bottom rock drillability testing method specifically comprises the following steps:

[0019] S1: Put the rock sample into the confining pressure loading chamber, adjust the position of the rotating clamping mechanism by the adjusting screw, make the clamping connecting rod tightly contact the end surface of the rock sample, and fix the rock sample; then tighten the end caps and install them at both ends of the reactor;

[0020] S2: Rotate the clamping link by rotating the handle so that the pointer points to 0° on the angle plate; then lock and fix the angle plate and the clamping link by the fastener;

[0021] S3: adjusting the temperature and confining pressure required for the test through the control system, and controlling the carving knife mechanism to move the carving knife to the origin to prepare for cutting;

[0022] S4: After adjusting the position of the carving knife, start cutting at a constant depth and speed; wherein the cutting speed is between 0.1 mm / s and 5 mm / s; the depth of the scratch is greater than the particle size of the rock sample; at the same time, the data collection and recording system monitors and records the force and displacement of the carving knife;

[0023] S5: When the displacement data of the carving knife no longer changes, the carving knife is returned to the origin through the control system;

[0024] S6: Loosen the fastener, rotate the clamping link by rotating the handle, so that the pointer on the angle disk deflects 45°; then tighten the fastener to lock and fix the angle disk and the clamping link again;

[0025] S7: repeat the above steps S2-S6 until the rock sample rotates one circle, and then obtain the change trend of rock drillability in 8 directions;

[0026] S8: Take a portion of the rock from the rock sample, use a PDC drill bit to perform a micro-drilling test, record the drilling time and take the average value; and calculate the specific energy of the rock sample and the rock drillability grade of the micro-drilling test;

[0027] S9: convert the eight drillability data of the scratch test and obtain the specific energy of the rock in the scratch test;

[0028] S10: combining the data of the micro-drilling test obtained in step S8 with the data of the scratch test obtained in step S9, to obtain a linear relationship between the specific energy of the rock sample in the scratch test and the specific energy of the rock sample in the micro-drilling test;

[0029] S11: According to the linear relationship between the specific energies of the two test rock samples obtained in step S10, the rock drillability grade determined by the scratch test is obtained.

[0030] Beneficial effects of the present invention:

[0031] The present invention constructs a basically non-destructive rock drillability testing method. Through testing at different angles, drillability curves in different directions are obtained, which can not only correct the error caused by the measurement, but also establish the changes of the rock drillability curves at different angles in space, and establish continuous data of drillability in spatial concept, so as to make the results richer; under this testing method, the rock drillability in different directions along the formation can be obtained, avoiding the problem of discontinuous drillability measurement caused by the anisotropy of the rock in the prior art; and there is no specific requirement for the length of the rock, with the advantages of low cost and short testing time; and a high-temperature and high-pressure deep environment device is provided for the test, so that the test results are closer to the site; in addition, by comparing multiple curves, the anisotropy of the rock sample at different angles can be analyzed, microcracks / cracks can be identified, and the foundation for intelligent perception of drilling is laid. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0033] Figure 2 It is a partial cross-sectional view of the present invention for reflecting the structure inside the reactor.

[0034] Figure 3 It is a partial structural diagram of the present invention for embodying the rotary clamping mechanism.

[0035] Figure 4 It is a structural diagram of a fastener embodying the present invention.

[0036] Figure 5 It is a microscopic angle diagram of the engraving knife during its advancement in the present invention.

[0037] In the figure: 1. Reactor; 11. End cover; 12. Engraving mechanism; 121. Bracket; 122. Engraving drive; 123. Engraving; 124. Force sensor; 125. Displacement sensor; 126. Temperature sensor; 13. Confining pressure adjustment system; 131. Confining pressure loading bin; 132. Support rod; 2. Central control base; 21. Control system; 22. Data collection and recording system; 23. Slide; 3. Rotary clamping mechanism; 31. Clamping link; 32. Rotating handle; 33. Angle plate; 34. Sliding rod; 35. Adjusting screw; 36. Nut block; 37. Fastener; 371. Lower hoop; 372. Upper hoop; 373. Fastening bolt. DETAILED DESCRIPTION

[0038] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0039] The invention discloses a deep formation rock drillability testing device based on a scratch test.

[0040] Reference Figure 1 and Figure 2 A deep formation rock drillability testing device based on a scratch test comprises a central control base 2 and a reactor 1 arranged on the central control base 2; a rotating clamping mechanism 3 for clamping and fixing a rock sample is arranged at both ends of the reactor 1; the interior of the reactor 1 is hollow and the end face facing the rotating clamping mechanism 3 is open, and end covers 11 for closing the openings are threadedly connected at both ends of the reactor 1; a carving mechanism 12 and a confining pressure regulating system 13 are arranged in the reactor 1; a resistance heating wire is installed at the bottom of the inner cavity of the reactor 1 for heating the air in the reactor 1, and a temperature sensor 126 is installed on the bracket 121 of the carving mechanism 12 for detecting the temperature in the reactor 1;

[0041] Reference Figure 3 The rotating clamping mechanism 3 includes a clamping link 31, a rotating handle 32, an angle plate 33, a sliding rod 34 and an adjusting screw 35. One end of the clamping link 31 is fixedly connected to the rotating handle 32, and the other end is penetrated through the center of the end cover 11. The clamping link 31 and the end cover 11 can slide relative to each other, and one end of the clamping link 31 penetrates through the end cover 11 and abuts against the end surface of the rock sample.

[0042] A slide groove 23 is provided on the top surface of the central control base 2, and the adjusting screw 35 is rotatably installed in the slide groove 23. A nut block 36 is fixed at one end of the sliding rod 34, and the nut block 36 is slidably connected in the slide groove 23. The adjusting screw 35 is penetrated in the nut block 36 and is threadedly connected to the nut block 36. The end of the sliding rod 34 away from the nut block 36 is fixedly connected to the angle disk 33. The angle disk 33 is sleeved on the clamping link 31, and the inner ring of the angle disk 33 is embedded in the clamping link 31, so that the axial positions of the two are relatively fixed; a pointer is fixed on the outer peripheral surface of the clamping link 31, and the pointer fits the outer wall of the angle disk 33.

[0043] Reference Figure 3 and Figure 4 The angle disc 33 is rotationally connected to the clamping link 31, and a fastener 37 is provided between the angle disc 33 and the clamping link 31. The fastener 37 can be used to lock and fix the angle disc 33 and the clamping link 31. The fastener 37 includes a lower hoop piece 371, an upper hoop piece 372 and two fastening bolts 373 connected to the two ends of the lower hoop piece 371 and the upper hoop piece 372. The lower hoop piece 371 is fixed on the angle disc 33, and the lower hoop piece 371 is in contact with the bottom of the outer peripheral surface of the clamping link 31. The upper hoop piece 372 is connected to the lower hoop piece 371 by the fastening bolt 373. By tightening the nut on the fastening bolt 373, the upper hoop piece 372 can be made to hold the clamping link 31 tightly, so that the angle disc 33 and the clamping link 31 are relatively fixed.

[0044] By rotating the rotating handle 32, the clamping link 31 is driven to rotate synchronously, and the end face of the clamping link 31 abuts against the rock sample, which can drive the rock sample to rotate, and the rotation angle of the rock sample is synchronously displayed on the angle disk 33, and then the sample is fixed and rotated at a certain angle, and the displacement and force on the carving knife 123 are recorded, so that the rock drillability at different angles can be obtained, and a continuous curve of the rock drillability along this direction can be drawn, and a change curve of the rock drillability in space can be obtained.

[0045] Reference Figure 2The confining pressure regulating system 13 includes a confining pressure loading chamber 131, which is coaxial with the reactor 1. The confining pressure loading chamber 131 is hollow inside and its two axial ends are open. When conducting a deep formation rock drillability test, the rock sample is placed in the confining pressure loading chamber. A support rod 132 is installed on the bottom surface of the confining pressure loading chamber 131. The support rod 132 is fixed to the inner wall of the reactor 1 to provide support for the confining pressure loading chamber 131 and the rock sample therein. In some embodiments, the height of the support rod 132 is adjustable, and then the position of the confining pressure loading chamber 131 can be adjusted to better adapt to the test requirements of rock samples of different diameters and ensure that the axis of the rock sample is the same as the axis of the reactor 1. The inner wall of the confining pressure loading chamber 131 is provided with a confining pressure sensing optical fiber to monitor the confining pressure changes in real time. The confining pressure loading method of the confining pressure loading chamber 131 can be pneumatic or hydraulic, such as the loading methods disclosed in the existing patents with publication numbers CN103267804B, CN101231226A and CN110441157A, etc., which are not described in detail in this embodiment.

[0046] Reference Figure 2 ,and Figure 5 The carving mechanism 12 is located at the top of the confining pressure regulating system 13, and the confining pressure loading chamber 131 is provided with a slot for cutting along its own axial direction near the outer peripheral side of the carving mechanism 12. The carving mechanism 12 includes a bracket 121, a carving knife driving member 122 and a carving knife 123. The bracket 121 is fixed to the inner wall of the reactor 1, and the carving knife driving member 122 is installed on the bracket 121. The carving knife driving member 122 can adopt a driving member such as a hydraulic cylinder, a cylinder, an electric push rod or a motor plus a screw. In this embodiment, the carving knife driving member 122 adopts an electric push rod; the carving knife 123 is installed at the output end of the carving knife driving member 122, and the carving knife 123 is in contact with the rock sample through the slot of the confining pressure loading chamber 131, and a force sensor 124 and a displacement sensor 125 are installed on the carving knife 123, which are respectively used to detect the size of the resistance encountered by the carving knife 123 during notching and the position of the carving knife 123. A position sensor is provided in the clamping link 31 at the front end, and the position sensor is located in one end of the clamping link 31 close to the rock sample. The position sensor is connected to the control system 21 and is responsible for positioning the origin of the carving knife 123 .

[0047] A control system 21 and a data collection and recording system 22 are installed in the central control base 2. The data collection and recording system 22 is electrically connected to the temperature sensor 126, the force sensor 124, the displacement sensor 125 and the confining pressure sensing optical fiber, and is used to collect and record the temperature in the reactor 1, the force and displacement of the engraving knife 123, the confining pressure and other data and display them on the central control base 2; the control system 21 is connected to the engraving knife mechanism 12, and is responsible for controlling the active displacement of the engraving knife 123, including starting, retracting, advancing, etc., and is connected to the position sensing element, and can control the engraving knife 123 to return to the same vertical plane as the position sensing element; the control system 21 is connected to the resistance heating wire and the confining pressure adjustment system 13, and can adjust the temperature and confining pressure required for the test.

[0048] The present invention also discloses a method for testing a deep formation rock drillability testing device based on a scratch test, which specifically comprises the following steps:

[0049] S1: Put the rock sample into the confining pressure loading chamber 131, adjust the position of the rotating clamping mechanism 3 by adjusting the screw 35, so that the clamping connecting rod 31 is tightly pressed against the end surface of the rock sample to fix the rock sample; then tighten the end cover 11 and install it on both ends of the reactor 1;

[0050] S2: Then, the clamping link 31 is rotated by rotating the handle 32 so that the pointer points to 0° on the angle plate 33; and the angle plate 33 and the clamping link 31 are locked and fixed by the fastener 37;

[0051] S3: adjusting the temperature and confining pressure required for the test through the control system 21, and controlling the carving knife mechanism 12 to move the carving knife 123 to the origin to prepare for cutting;

[0052] S4: After adjusting the position of the carving knife 123, start feeding at a constant depth and speed; wherein the feeding speed is between 0.1 mm / s and 5 mm / s; the depth of the scratch is greater than the particle size of the rock sample to ensure that the measured properties are the properties of the rock aggregate, rather than the properties of a specific mineral composition;

[0053] At the same time, the data collection and recording system monitors and records the force and displacement of the engraving knife; and decomposes the total force F acting on the engraving knife into the tangential force F along the scratching direction. S and the normal force F perpendicular to the scratch surface N ;

[0054] S5: When the displacement data no longer changes, the engraving knife returns to the origin through the control system;

[0055] S6: Loosen the fastener 37, rotate the clamping link 31 by rotating the handle 32, so that the pointer on the angle disk 33 deflects the set angle; in this embodiment, rotate the clamping link 31 to deflect the pointer 45° clockwise; then tighten the fastener 37 to lock the angle disk 33 and the clamping link 31; in addition, it should be noted that the same angle must be maintained during the rotation process to avoid measurement errors caused by torque on the rock.

[0056] S7: Repeat the above steps S2-S6 until the sample rotates one circle, and then obtain the change trend of rock drillability in 8 directions;

[0057] S8: Take a part of the rock from the rock sample and use a PDC drill bit to conduct a micro-drilling test, maintain the drilling speed at 55r / min, the drilling depth at 3mm, record the drilling time and take the average value; and calculate the specific energy of the rock sample and the rock drillability grade;

[0058] The formulas for the specific energy of rock samples and the rock drillability grade calculated by the micro-drilling experiment are as follows:

[0059]

[0060] Where ε1 is the specific energy of the rock sample calculated by the micro-drilling test, in MPa; μ k is the ratio of the tangential force and normal force of the PDC drill bit on the rock, which is only related to the back rake angle of the drill bit and is a constant; F P is the weight of the PDC drill bit, in N; t is the average drilling time of the micro-drilling test, in s; r is the radius of the PDC drill bit, in mm; K d The drillability grade of a rock determined for microdrilling tests.

[0061] S9: The 8 drillability data of the scratch test are converted to a certain extent. During the process of the carving knife moving, the following formula is established:

[0062] F S =ε2A (3);

[0063]

[0064] A = wd (5);

[0065]

[0066] Among them, F S 、F N are the tangential force and normal force acting on the chisel, in N; ε2 is the specific energy of the rock in the scratch test, in MPa; A is the cross-sectional area of ​​the scratch made by the chisel, in mm 2 ; F N and FS The ratio is a constant; w is the width of the chisel, in mm; d is the depth of the chisel into the rock, in mm; α is the back tilt angle of the chisel, in °; ψ is the interface friction angle, in °;

[0067] By combining the above formulas (3)-(6), the specific energy of the rock in the scratch test can be calculated.

[0068] S10: Comparing the data of the scratch test and the micro-drilling test, there is a certain linear relationship, namely:

[0069] ε1=aε2+b (7);

[0070] Among them, a and b are dimensionless constants, which are only related to the stratum and can be approximately considered to remain unchanged in a continuous stratum. By comparing the results of the two tests, their values ​​can be determined.

[0071] S11: Combining the above formulas (1), (2) and (7), we can obtain the discriminant formula for determining the rock drillability grade using the scratch test:

[0072]

[0073] where K' d The rock drillability is determined by the scratch test. Then, by plotting the drillability-knife displacement graph, the continuous change of rock drillability in different directions and angles can be obtained.

[0074] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for testing the drillability of deep formation rocks based on a scratch test, characterized in that: A deep formation rock drillability testing device based on a scratch test is used; the drillability testing device comprises a central control base (2) and a reaction kettle (1) arranged on the central control base (2); Rotating clamping mechanisms (3) for clamping and fixing rock samples are arranged at both ends of the reactor (1); the reactor (1) is hollow inside and has an opening facing the end surface of the rotating clamping mechanism (3); and end covers (11) for closing the openings are threadedly connected to the openings at both ends of the reactor (1); A resistance heating wire is installed at the bottom of the inner cavity of the reactor (1) for heating the air in the reactor (1); a carving mechanism (12) and a confining pressure regulating system (13) are arranged in the reactor (1); The confining pressure regulating system (13) is used to carry the rock sample and apply confining pressure to the rock sample, and the carving knife mechanism (12) is used to scratch the surface of the rock sample; The rotating clamping mechanism (3) comprises a clamping link (31), a rotating handle (32), an angle plate (33), a sliding rod (34) and an adjusting screw (35); one end of the clamping link (31) is fixedly connected to the rotating handle (32), and the other end is inserted through the center of the end cover (11); the clamping link (31) and the end cover (11) slide relative to each other, and one end of the clamping link (31) that penetrates the end cover (11) abuts against the end surface of the rock sample; A slide groove (23) is provided on the top surface of the central control base (2), and the adjusting screw (35) is rotatably installed in the slide groove (23). A nut block (36) is fixed to one end of the sliding rod (34), and the nut block (36) is slidably connected to the slide groove (23). The adjusting screw (35) is inserted into the nut block (36) and is threadedly connected to the nut block (36). One end of the sliding rod (34) away from the nut block (36) is fixedly connected to the angle plate (33), and the angle plate (33) is sleeved on the clamping connecting rod (31), and the inner ring of the angle plate (33) is embedded in the clamping connecting rod (31), so that the axial positions of the two are relatively fixed; a pointer is fixed to the outer peripheral surface of the clamping connecting rod (31), and the pointer is attached to the outer wall of the angle plate (33); The confining pressure regulating system (13) comprises a confining pressure loading chamber (131), the confining pressure loading chamber (131) is coaxial with the reactor (1), the confining pressure loading chamber (131) is hollow inside and its two axial ends are open, the outer peripheral side of the confining pressure loading chamber (131) close to the engraving knife mechanism (12) is provided with a slot for knife feeding along its own axial direction, the bottom surface of the confining pressure loading chamber (131) is installed with a support rod (132), the support rod (132) is fixed to the inner wall of the reactor (1) to provide support for the confining pressure loading chamber (131) and the rock sample therein; the inner wall of the confining pressure loading chamber (131) is provided with a confining pressure sensing optical fiber to monitor the confining pressure change in real time; The deep bottom rock drillability test method specifically includes the following steps: S1: Place the rock sample into the confining pressure loading chamber (131), adjust the position of the rotating clamping mechanism (3) by adjusting the screw (35), so that the clamping connecting rod (31) is tightly pressed against the end surface of the rock sample to fix the rock sample; then tighten the end cover (11) and install it on both ends of the reactor (1); S2: The clamping link (31) is rotated by rotating the handle (32) so that the pointer points to 0° on the angle plate (33); and the angle plate (33) and the clamping link (31) are locked and fixed by the fastener (37); S3: adjusting the temperature and confining pressure required for the test through the control system (21) in the central control base (2), and controlling the carving mechanism (12) so that the carving knife (123) of the carving mechanism (12) moves to the origin to prepare for cutting; S4: After adjusting the position of the carving knife (123), the cutting is started at a constant depth and speed; wherein the cutting speed is between 0.1 mm / s and 5 mm / s; the depth of the scratch is greater than the particle size of the rock sample; at the same time, the data collection and recording system (22) in the central control base (2) monitors and records the force and displacement of the carving knife (123); S5: When the displacement data of the engraving knife (123) no longer changes, the engraving knife (123) is returned to the origin through the control system (21) in the central control base (2); S6: Loosen the fastener (37), rotate the clamping link (31) by rotating the handle (32), and deflect the pointer on the angle plate (33) by 45°; then tighten the fastener (37) to lock and fix the angle plate (33) and the clamping link (31) again; S7: repeat the above steps S3-S6 until the rock sample rotates one circle, and then obtain the change trend of rock drillability in 8 directions; S8: Take a portion of the rock from the rock sample, use a PDC drill bit to perform a micro-drilling test, record the drilling time and take the average value; and calculate the specific energy of the rock sample and the rock drillability grade of the micro-drilling test; The formulas for the specific energy of rock samples and the rock drillability grade calculated by the micro-drilling experiment are as follows: ； ； in, The specific energy of the rock sample calculated for the microdrilling test, in MPa; It is the ratio of the tangential force and normal force of the PDC drill bit on the rock, which is only related to the back rake angle of the drill bit and is a constant; is the weight of the PDC drill bit, in N; is the average drilling time of the micro-drilling test, in seconds; r is the radius of the PDC drill bit, in mm; rock drillability grade determined for microdrilling tests; S9: convert the eight drillability data of the scratch test and obtain the specific energy of the rock in the scratch test; As the carving knife moves, the following formula holds true: ； ； ； ； in, , They are the tangential force and normal force acting on the engraving knife, in N; is the specific energy of rock in the scratch test, in MPa; is the cross-sectional area of ​​the scratch made by the engraving knife, in units of ; for and The ratio of is a constant; w is the width of the chisel, in mm; d is the depth of the chisel into the rock, in mm; is the back tilt angle of the engraving tool, unit: °; is the interface friction angle, unit: °; By combining the above formulas, the specific energy of the rock in the scratch test is obtained; S10: combining the data of the micro-drilling test obtained in step S8 with the data of the scratch test obtained in step S9, to obtain a linear relationship between the specific energy of the rock sample in the scratch test and the specific energy of the rock sample in the micro-drilling test; ； Where a and b are dimensionless constants, which are only related to the stratum and are approximately considered to remain unchanged in a continuous stratum. Their values ​​are determined by comparing the results of the two tests. S11: according to the linear relationship between the specific energies of the two test rock samples obtained in step S10, the rock drillability grade determined by the scratch test is obtained; The discriminant formula for rock drillability grade is: ； in, rock drillability determined for scratch tests; Then, by drawing an image of drillability-knife displacement, the continuous change of rock drillability in different directions and angles can be obtained.

2. A method for testing the drillability of deep formation rocks based on a scratch test according to claim 1, characterized in that: The clamping link (31) is inserted through the center of the angle plate (33) and is rotatably connected to the angle plate (33). A fastener (37) is provided between the angle plate (33) and the clamping link (31), and the angle plate (33) and the clamping link (31) are locked and fixed by the fastener (37).

3. A method for testing the drillability of deep formation rocks based on a scratch test according to claim 2, characterized in that: The engraving mechanism (12) is located at the top of the confining pressure regulating system (13), and comprises a bracket (121), an engraving driver (122) and an engraving knife (123). The bracket (121) is fixed to the inner wall of the reaction kettle (1), the engraving driver (122) is installed on the bracket (121), and the engraving knife (123) is installed at the output end of the engraving driver (122). A force sensor (124) and a displacement sensor (125) are installed on the engraving knife (123), which are used to detect the resistance of the engraving knife (123) when engraving and the position of the engraving knife (123), respectively.

4. A method for testing the drillability of deep formation rocks based on a scratch test according to claim 3, characterized in that: The central control base (2) is equipped with a control system (21) and a data collection and recording system (22). The data collection and recording system (22) is electrically connected to a temperature sensor (126), a force sensor (124), a displacement sensor (125) and a confining pressure sensing optical fiber, and is used to collect and record the temperature and confining pressure in the reactor (1) and the force and displacement data of the engraving knife (123); The control system (21) is electrically connected to the engraving knife mechanism (12), the resistance heating wire and the confining pressure adjustment system (13), and controls the displacement of the engraving knife (123) and adjusts the temperature and confining pressure values ​​required for the test.

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