Continuous deflecting coring method for realizing wire-line coring orientation

Abstract

The invention discloses a continuous deflecting coring method for realizing wire-line coring orientation, which relates to the technical field of drilling, and specifically comprises the following steps of: selecting a bent screw drill and a matched wire-line coring tool according to geological conditions and a designed drilling track, assembling and connecting the bent screw drill and the matched wire-line coring tool, and putting the bent screw drill and the matched wire-line coring tool into a drilling hole; in the drilling process, the hole bottom power drilling tool provides drilling power, a bent angle of the bent screw drilling tool enables a drilled hole to be inclined according to the design direction, and a rotor cavity of the hollow screw drilling tool allows an internal assembly and a core barrel to pass through. According to the continuous deflecting coring method for wire-line coring orientation, the high-precision directional drilling technology and the wire-line coring technology are organically combined, the problem of exploration of irregular deposited ore deposits and concealed ore deposits is solved, the precision and efficiency of geological exploration are improved, and by adopting the bent screw drill and the matched wire-line coring tool, the geological exploration efficiency is improved. Continuous directional drilling and continuous wire-line coring are carried out at the same time, the number of times of drill lifting is reduced, and the auxiliary time is shortened.

Description

Technical Field

[0001] The invention relates to the technical field of drilling, in particular to a continuous deflection coring method for realizing rope coring orientation. Background Art

[0002] High-precision directional drilling technology has reached a high level in oil drilling, utilization and development of soluble mineral resources, and rope coring technology has been used in my country for decades, and both are relatively mature application technologies. The organic combination of the two can solve the problems of mineral exploration and special engineering geological surveys such as irregular sedimentary deposits and concealed deposits;

[0003] At present, there are two common methods for directional drilling coring in China. One is the method of single-bend screw drill plus coring tube, and the other is the method of using hollow screw drill. Both of them cannot perform continuous rope coring along the directional drilling. The single-bend screw drill plus coring tube process can perform coring drilling while directional deflection, but it can only be cored by lifting the drill, and the rope coring process cannot be used, because the screw drill and the drilling measurement system block the upper and lower channels of the rope coring internal assembly, and as the hole depth increases, the auxiliary time is too long, and frequent lifting of the drill will lead to reduced work efficiency. In addition, because the core tube is added to the front end of the single-bend screw drill, As a result, its directional deflection effect is difficult to control, and the length of single-pass coring is short; the hollow screw drill improves the drilling efficiency through the composite drilling of the screw drill and the drill pipe column, but it does not have a built-in rope coring internal assembly. It also coring is carried out by lifting the drill, and the auxiliary time is also long. It is not used in the directional deflection section and does not have a directional deflection function. First, single-bend screw drill is not used, and second, because during the rope coring drilling, the drill pipe rotates at high speed, the generatrix of its tool face angle keeps changing, and the technical parameters of the drilling posture cannot be measured. In this regard, we propose a continuous deflection coring method to achieve rope coring orientation. Summary of the invention

[0004] In order to solve the above technical problems, a continuous deflection coring method for achieving rope coring orientation is provided. This technical solution solves the above problems.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0006] The continuous deflection coring method for realizing rope coring orientation specifically comprises the following steps:

[0007] According to the geological conditions and the designed drilling trajectory, select the bent screw drilling tool and the matching rope coring tool, assemble and connect them, and then lower them into the borehole;

[0008] During the drilling process, the bottom hole power drill provides drilling power, the bending angle of the bent screw drill makes the borehole inclined in the designed direction, and the rotor cavity of the hollow screw drill allows the internal assembly and core tube to pass through;

[0009] The measurement while drilling system monitors the drilling posture parameters in real time, and the drilling posture parameters include but are not limited to: well inclination angle, azimuth angle and tool face angle. The data transmission adopts mud pulse or electromagnetic wave mode, and the instrument types include magnetic inclinometer and gyro inclinometer.

[0010] When coring, the rope coring winch is used to lift the MWD system, rope internal assembly, and core tube through the cavity of the hollow screw drill bit. After obtaining the core, they are put back to continue drilling. The seat key method can always ensure the relative stability of the internal and external systems and avoid angular displacement affecting the drilling and coring accuracy.

[0011] Preferably, bottom hole power drilling tools are used for drilling, wherein the screw drill tool is a bent screw drill tool and a hollow screw drill tool, and its rotor has a cavity. The coring method is a rope coring method, and a measurement while drilling system is used to measure the drilling posture data. The seat key method is used to limit the mutual angular displacement of the internal and external systems to achieve inclination, orientation, side drilling and coring operations, and there is no need to lift the entire drill string when coring.

[0012] Preferably, the bending angle design of the bent screw drill meets the drilling trajectory control requirements, and the bending angle calculation formula is:

[0013] α=arctan(ΔD / L)

[0014] Where α is the bending angle, ΔD is the horizontal displacement increment of the borehole within a certain drilling length L;

[0015] The bending angle is determined according to the curvature radius R of the designed drilling trajectory. When R is known, α=57.3 / LR. By calculating the bending angle, the borehole is guided to drill along the predetermined trajectory to ensure the inclination accuracy.

[0016] Preferably, the rotor cavity size of the hollow screw drill is compatible with the outer diameter of the internal assembly and the core tube;

[0017] Assuming the outer diameter of the internal assembly and the core tube is d, and the inner diameter of the rotor cavity is D, it should satisfy:

[0018] Dd≥δ

[0019] Where δ is the safety gap, which is between 3-5mm.

[0020] Preferably, the measurement accuracy of the well inclination angle of the measurement while drilling system needs to reach ±0.1°, and the measurement accuracy of the azimuth angle needs to reach ±1°;

[0021] During the measurement process, the measurement system needs to be calibrated and maintained regularly, and compared with the adjacent borehole data with known precise drilling trajectories;

[0022] In view of the factors affecting the measurement accuracy, a magnetic shielding device is installed to reduce magnetic field interference, and a temperature sensor is used to monitor the temperature and perform data correction accordingly. The factors include but are not limited to: magnetic field interference and temperature changes in the borehole.

[0023] Preferably, the performance parameters of the rope coring winch need to be selected according to the actual drilling conditions:

[0024] Its lifting capacity must meet the requirements of safely lifting the internal assembly, core tube and measurement while drilling system under the conditions of drilling depth H and mud density ρ. The lifting force calculation formula is:

[0025] F=(m+ρgV)g

[0026] Where m is the total mass of the internal assembly, core tube, rock (ore) core and measurement while drilling system, V is the volume displaced in the mud, and g is the acceleration due to gravity;

[0027] When selecting a winch, the required lifting force should be estimated based on the designed drilling depth and the geological conditions encountered, and then a winch with a rated lifting force greater than the calculated value should be selected, and a certain safety factor should be reserved, which should be between 1.2-1.5.

[0028] Preferably, the drilling parameters of the bottom hole power drilling tool during drilling need to be optimized and adjusted according to geological conditions;

[0029] In soft formations, the speed is controlled at 80-120r / min and the drilling pressure is controlled at 2-4kN. In hard formations, the speed needs to be reduced to 40-60r / min, the drilling pressure is increased to 6-8kN, and impact drilling is used to improve drilling efficiency.

[0030] During the drilling process, sensors are used to collect drilling parameters in real time, including drilling speed, torque, and pump pressure, and transmit these data to the ground control system. Ground operators judge the drilling status based on data analysis and adjust the drilling parameters in time when the drilling speed drops abnormally, the torque is too large, or the pump pressure fluctuates abnormally.

[0031] Preferably, the performance index requirements of the mud in the borehole are:

[0032] The viscosity of the mud should be controlled at a funnel viscosity of 20-30s, the density should be controlled at 1.1-1.3g / cm3, and the water loss should be less than 15ml / 30min;

[0033] In the process of mud preparation, bentonite is selected as the main raw material, and additives are added according to actual needs. The additives include: viscosity enhancer and fluid loss reducer, which are stirred and mixed according to the proportion;

[0034] During the drilling process, the mud properties are checked regularly. If the mud viscosity is found to be beyond the predetermined range, it is adjusted by adding diluents or thickeners. If the density is abnormal, weighting materials or diluents are added. If the water loss is too large, a fluid loss reducer is added in time.

[0035] Preferably, the design parameters of the core tube in the coring process need to be based on the borehole diameter D c and geological conditions selection;

[0036] In soft formations, the length of the core tube L c 0.5D c -D c The material is seamless steel pipe with surface hardening treatment, and the cutting edge angle at the front end of the core tube is between 120°-150° to prevent core blockage;

[0037] In hard formations, the core tube length L c 0.3D c -0.5D c The material is seamless steel pipe and the surface is hardened. The front cutting edge angle is reduced to between 90° and 120°.

[0038] Preferably, the device parts include a spear fishing mechanism, a spring-loaded mechanism, a piston mechanism, a measuring mechanism, a keyway, a guide positioning mechanism, a guide slope, an in-place signaling mechanism, a suspension mechanism, a core blockage alarm mechanism, a single-action mechanism, an adjustment mechanism, a retaining spring, a retaining spring seat, an inner flat drill rod, a spring-loaded stopper, a spring-loaded chamber, a non-magnetic drill rod, a guide key, a positioning joint, a seat ring, a single-bend hollow screw and a drill bit.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The present invention proposes a continuous inclination coring method for rope coring and directional drilling, which organically combines high-precision directional drilling technology with rope coring technology, solves the exploration problems of irregular sedimentary deposits and concealed deposits, and improves the accuracy and efficiency of geological exploration. By adopting bent screw drill bits and matching rope coring tools, continuous directional drilling and continuous rope coring are achieved simultaneously. The inclination process is also the coring drilling process, which reduces the number of drill lifting times, reduces auxiliary time, and improves work efficiency. Drilling can be carried out according to the designed drilling trajectory to achieve the purposes of inclination, directional drilling, side drilling, and coring. There is no need to lift the entire drill rod column when coring, which further improves the drilling efficiency and coring quality. At the same time, the downhole measurement system monitors the drilling posture parameters in real time to ensure the precise control of the drilling trajectory and improve the accuracy of the exploration data. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a diagram of the method steps of the present invention;

[0042] Figure 2It is a schematic diagram of the internal assembly structure of the present invention;

[0043] Figure 3 It is a schematic diagram of the external assembly structure of the present invention. DETAILED DESCRIPTION

[0044] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0045] Reference Figure 1 As shown, the continuous deflection coring method for realizing rope coring orientation specifically comprises the following steps:

[0046] According to the geological conditions and the designed drilling trajectory, the bent screw drill and the matching rope coring tool are selected, assembled and connected, and then lowered into the borehole. According to different geological characteristics and drilling plans, the matching tools can be selected to ensure that the tools are perfectly matched with the working conditions, avoid various construction obstacles caused by improper tools, and enable the subsequent drilling and coring work to be carried out smoothly.

[0047] During the drilling process, the bottom hole power drill provides drilling power, the bend angle of the bent screw drill makes the borehole beveled in the designed direction, and the rotor cavity of the hollow screw drill allows the internal assembly and core tube to pass through. The stable power source is combined with the precise deflection function to ensure that the drilling strictly follows the designed trajectory and reduce errors. The hollow structure facilitates the passage of internal components, maintains the continuity of drilling and coring, and improves work efficiency.

[0048] The measurement while drilling system monitors the drilling posture parameters in real time, including but not limited to: well inclination, azimuth and tool face angle. Its data transmission adopts mud pulse or electromagnetic wave mode, and the instrument types include magnetic inclinometer and gyro inclinometer. It can control the drilling status in real time, detect deviations and make adjustments in time. A variety of data transmission methods and instrument types adapt to complex construction environments, ensure data accuracy, and provide strong support for construction quality.

[0049] When coring, the rope coring winch is used to lift the MWD system, rope internal assembly, and core tube through the cavity of the hollow screw drill. After obtaining the core, it is put back to continue drilling. The key method can always ensure the relative stability of the internal and external systems to avoid angular displacement affecting the drilling and coring accuracy. The coring operation is convenient and does not delay the construction progress. The key method maintains the stability of the system, effectively eliminates the interference of angular displacement, improves the coring and drilling accuracy, and obtains core samples with more research value.

[0050] The bottom hole power drill is used for drilling, in which the screw drill is a bent screw drill and a hollow screw drill. Its rotor has a cavity. The coring method is the rope coring method. The drilling posture data is measured by the measurement while drilling system, and the internal and external systems are limited to produce mutual angular displacement through the seat key method to achieve deflection, orientation, side drilling and coring operations, and there is no need to lift the entire drill string when coring. In this way, the bottom hole power drill provides stable drilling power. The bent screw drill achieves precise deflection, and the hollow structure facilitates rope coring. The measurement while drilling system grasps the drilling posture in real time and can be adjusted in time. The seat key method ensures system stability and improves operating accuracy. The drill string does not need to be lifted for coring, which greatly saves time and labor costs and improves work efficiency.

[0051] The bending angle design of the bent screw drill meets the drilling trajectory control requirements, and the bending angle calculation formula is:

[0052] α=arctan(ΔD / L)

[0053] Where α is the bending angle, ΔD is the horizontal displacement increment of the borehole within a certain drilling length L;

[0054] According to the designed radius of curvature R of the drilling trajectory, the size of the bend angle is determined. When R is known, α = 57.3 / LR. By calculating the bend angle, the drilling is guided to drill along the predetermined trajectory to ensure the accuracy of the inclination. The bend angle of the bent screw drill is calculated by a specific formula, and the size of the bend angle is accurately determined according to the radius of curvature of the drilling trajectory. This can guide the drilling of the hole strictly according to the predetermined trajectory, greatly improve the inclination accuracy, avoid drilling deviation caused by improper bend angles, ensure accurate and efficient drilling construction, and meet the high-precision requirements for drilling trajectories under complex geological conditions.

[0055] The rotor cavity size of the hollow screw drill is adapted to the outer diameter of the internal assembly and the core tube;

[0056] Assuming the outer diameter of the internal assembly and the core tube is d, and the inner diameter of the rotor cavity is D, it should satisfy:

[0057] Dd≥δ

[0058] Among them, δ is the safety gap, which is 3-5mm. The hollow screw drill rotor cavity size is accurately matched with the internal assembly and the outer diameter of the core tube. By setting the safety gap, it is ensured that the internal components can pass smoothly in the rotor cavity without getting stuck, ensuring the continuity of drilling and coring, and appropriate space is reserved to avoid wear caused by over-tight dimensions, extend the service life of the equipment, and improve the stability of operation.

[0059] The measurement accuracy of the well inclination of the measurement while drilling system must reach ±0.1°, and the measurement accuracy of the azimuth must reach ±1°;

[0060] During the measurement process, the measurement system needs to be calibrated and maintained regularly, and compared with the adjacent borehole data with known precise drilling trajectories;

[0061] In view of the factors that affect the measurement accuracy, a magnetic shielding device is installed to reduce magnetic field interference, and a temperature sensor is used to monitor the temperature and correct the data accordingly. The factors include but are not limited to: magnetic field interference and temperature changes in the borehole. High-precision measurement of well inclination and azimuth can accurately control the drilling status and detect trajectory deviations in time. Regular calibration and maintenance ensure that the measurement system is stable and reliable, and a variety of comparison methods are used to improve accuracy. Measures are taken to reduce magnetic field interference, correct temperature effects, ensure that the measurement data is true and valid, and provide an accurate basis for drilling operations.

[0062] The performance parameters of the rope coring winch need to be selected according to the actual drilling conditions;

[0063] Its lifting capacity must meet the requirements of safely lifting the internal assembly, core tube and measurement while drilling system under the conditions of drilling depth H and mud density ρ. The lifting force calculation formula is:

[0064] F=(m+ρgV)g

[0065] Where m is the total mass of the internal assembly, core tube, rock (ore) core and measurement while drilling system, V is the volume displaced in the mud, and g is the acceleration due to gravity;

[0066] When selecting a winch, the required lifting force should be estimated based on the designed depth of the borehole and the geological conditions encountered, and then a winch with a rated lifting force greater than the calculated value should be selected, and a certain safety factor should be reserved, with the safety factor between 1.2-1.5. Selecting a rope coring winch based on the actual drilling situation can meet different working conditions. Calculate the lifting force accurately according to the formula to ensure that the internal components can be lifted safely. Selecting a winch with a rated lifting force greater than the calculated value and a safety factor can not only meet the operational needs, but also respond to emergencies, avoid coring failures due to insufficient lifting force, and ensure the stable development of coring work.

[0067] The drilling parameters of the bottom hole power drilling tool during drilling need to be optimized and adjusted according to the geological conditions;

[0068] In soft formations, the speed is controlled at 80-120r / min and the drilling pressure is controlled at 2-4kN. In hard formations, the speed needs to be reduced to 40-60r / min, the drilling pressure is increased to 6-8kN, and impact drilling is used to improve drilling efficiency.

[0069] During the drilling process, sensors are required to collect drilling parameters in real time, including drilling speed, torque, and pump pressure, and transmit these data to the ground control system. Ground operators judge the drilling status based on data analysis. When the drilling speed is abnormally reduced, the torque is too large, or the pump pressure fluctuates abnormally, the drilling parameters are adjusted in time. Drilling parameters are optimized according to geological conditions, and different speeds, drilling pressures, and drilling methods are used for soft and hard formations to match the formation characteristics and improve drilling efficiency. Drilling parameters are collected and transmitted in real time. Operators can judge the drilling status based on the data, and can make timely adjustments when abnormalities occur, effectively avoiding equipment damage and drilling accidents, and ensuring smooth drilling work.

[0070] The performance index requirements of the mud in the borehole are:

[0071] The viscosity of the mud should be controlled at a funnel viscosity of 20-30s, the density should be controlled at 1.1-1.3g / cm3, and the water loss should be less than 15ml / 30min;

[0072] In the process of mud preparation, bentonite is selected as the main raw material, and additives are added according to actual needs. The additives include: viscosity enhancer and fluid loss reducer, which are stirred and mixed according to the proportion;

[0073] During the drilling process, the mud performance is regularly tested. If the mud viscosity is found to be beyond the predetermined range, it is adjusted by adding diluents or thickeners; if the density is abnormal, weighting materials or diluents are added; if the water loss is too large, a fluid loss reducer is added in time. Strictly controlling the mud performance indicators can stabilize the hole wall, carry rock cuttings, and cool and lubricate the drill bit. Bentonite is used in combination with additives to prepare mud to meet different drilling needs. Regular testing and adjustment as needed can ensure that the mud is always in the best condition, ensure smooth drilling, reduce accidents such as hole collapse and drill jamming, and improve drilling efficiency and safety.

[0074] The design parameters of the core tube in the coring process need to be based on the borehole diameter D c and geological conditions selection;

[0075] In soft formations, the length of the core tube L c 0.5D c -D c The material is seamless steel pipe with surface hardening treatment, and the cutting edge angle at the front end of the core tube is between 120°-150° to prevent core blockage;

[0076] In hard formations, the core tube length L c 0.3D c -0.5D cThe material is seamless steel pipe and surface hardened, and the front cutting edge angle is reduced to between 90°-120°. The core tube parameters are selected according to the borehole diameter and geological conditions. Core tubes of different lengths and cutting edge angles are used for soft and hard formations. Long tubes and large-angle cutting edges in soft formations prevent core clogging; short tubes and small-angle cutting edges in hard formations are easier to cut in. The surface-hardened seamless steel tube material is durable and can adapt to complex geology, ensuring the coring effect.

[0077] Reference Figure 2 and Figure 3 As shown, the device includes a spear fishing mechanism, a spring-loaded mechanism, a piston mechanism, a measuring mechanism, a keyway, a guide positioning mechanism, a guide slope, an in-place signaling mechanism, a suspension mechanism, a core blockage alarm mechanism, a single-action mechanism, an adjustment mechanism, a retaining spring, a retaining spring seat, an inner flat drill rod, a spring-loaded stopper, a spring-loaded chamber, a non-magnetic drill rod, a guide key, a positioning joint, a seat ring, a single-bend hollow screw and a drill bit.

[0078] The use process of the present invention is:

[0079] 1. Design drilling trajectory and coring based on previously known data.

[0080] 2. Drill the hole until it enters a relatively complete formation, insert the casing, and change the diameter.

[0081] 3. Assemble the drilling tools, including the internal assembly ( Figure 2 ) and external assembly ( Figure 3 The internal assembly includes a spearhead (1), a spring-loaded mechanism (2), a sealing piston mechanism (3), a measuring mechanism (4), a guiding and positioning mechanism (6), an in-place signaling mechanism (8), a suspension mechanism (9), a core blockage alarm mechanism (10), a single-action mechanism (11), an adjustment mechanism (12), and a core clamping mechanism. The external assembly includes an inner flat drill rod (15), a spring-loaded stopper (16), a spring-loaded chamber (17), a non-magnetic drill rod (18), a positioning joint (20), a single-bend hollow screw (22), and a drill bit (23), and the various components of the external assembly are connected by threaded fasteners.

[0082] 4. Reset the tool face angle of the single-bend hollow screw drill to zero on the surface, then lower the drill to the bottom of the hole and then lift it up 0.5m.

[0083] 5. Start the mud pump, start the screw drill, feed and pressurize for directional drilling and coring. The single-pass footage shall not exceed the length of the core tube. After stopping the footage, measure the drilling posture parameters.

[0084] 6. Use the rope coring winch to salvage the internal assembly and the core to the surface, remove the retaining ring seat and retaining ring, and take out the core; check and adjust the retaining ring, and reinstall it to the core tube.

[0085] 7. The internal assembly is put into the drill pipe column, and the water pump is started. The sealing piston mechanism (3) blocks the annular gap between the internal assembly and the inner flat drill pipe, and the internal assembly can be pushed to the bottom of the hole by high-pressure water; during the downward movement of the internal assembly, the guide key (19) located on the inner wall of the guide positioning joint (20) will inevitably contact the guide inclined surface (7), and slide into the key groove (5) under its guidance, so that the measuring mechanism (4) and the guide positioning mechanism (6) of the internal assembly and the positioning joint (20) and the single-bend screw drilling tool (22) of the external assembly maintain the same generatrix, and no angular displacement will occur. After the internal assembly reaches the specified position, the spring clamp (2) of the internal assembly enters the spring clamp chamber (17) and opens, and the spring clamp stopper (16) limits its upward movement, while the suspension ring (9) sits on the seat ring (20) and limits its downward movement. The above process ensures that the measuring mechanism (4) and the single-bend screw drilling tool (22) maintain the same tool surface, thereby ensuring the accuracy of the tool surface during each directional drilling.

[0086] 8. Compare the data measured in step 5 with the designed trajectory data. If the tool face angle needs to be adjusted, adjust the tool face angle to the correct position by rotating the drill string and drill to the bottom of the hole; if the tool face angle does not need to be adjusted, drill directly to the bottom of the hole.

[0087] 9. Repeat steps 5-8.

[0088] In summary, the advantages of the present invention are that continuous directional drilling and continuous rope coring can be carried out simultaneously, the deflection process is also the coring drilling process, drilling can be carried out according to the designed drilling trajectory, and the purposes of deflection, directional drilling, side drilling, coring, etc. can be achieved, and coring does not require the entire drill string to be lifted.

[0089] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A continuous deflection coring method for achieving directional coring with ropes, characterized in that: The specific steps include: According to the geological conditions and the designed drilling trajectory, select the bent screw drilling tool and the matching rope coring tool, assemble and connect them, and then lower them into the borehole; During the drilling process, the bottom hole power drill provides drilling power, the bending angle of the bent screw drill makes the borehole inclined in the designed direction, and the rotor cavity of the hollow screw drill allows the internal assembly and core tube to pass through; The measurement while drilling system monitors the drilling posture parameters in real time, and the drilling posture parameters include but are not limited to: well inclination angle, azimuth angle and tool face angle. The data transmission adopts mud pulse or electromagnetic wave mode, and the instrument types include magnetic inclinometer and gyro inclinometer. When coring, the rope coring winch is used to lift the MWD system, rope internal assembly, and core tube through the cavity of the hollow screw drill bit. After obtaining the core, they are put back to continue drilling. The seat key method always ensures that the internal and external systems are relatively stable to avoid angular displacement affecting the drilling and coring accuracy.

2. The continuous deflection coring method for achieving rope coring orientation according to claim 1 is characterized in that: Drilling is carried out using a bottom hole power drill, in which the screw drill is a bent screw drill and a hollow screw drill, and its rotor has a cavity. The coring method is a rope coring method, and the drilling posture data is measured using a measurement while drilling system. The seat key method is used to limit the mutual angular displacement of the internal and external systems to achieve inclination, orientation, side drilling and coring operations, and there is no need to lift the entire drill string when coring.

3. The continuous deflection coring method for achieving rope coring orientation according to claim 1 is characterized in that: The bending angle design of the bent screw drill meets the drilling trajectory control requirements, and the bending angle calculation formula is: α=arctan(ΔD / L) Where α is the bending angle, ΔD is the horizontal displacement increment of the borehole within a certain drilling length L; The bending angle is determined according to the curvature radius R of the designed drilling trajectory. When R is known, α=57.3 / LR. By calculating the bending angle, the borehole is guided to drill along the predetermined trajectory to ensure the inclination accuracy.

4. The continuous deflection coring method for achieving rope coring orientation according to claim 1 is characterized in that: The rotor cavity size of the hollow screw drill is adapted to the outer diameter of the internal assembly and the core tube; Assuming the outer diameter of the internal assembly and the core tube is d, and the inner diameter of the rotor cavity is D, it should satisfy: Dd≥δ Where δ is the safety gap, which is between 3-5mm.

5. The continuous deflection coring method for achieving rope coring orientation according to claim 1, characterized in that: The measurement accuracy of the well inclination of the measurement while drilling system must reach ±0.1°, and the measurement accuracy of the azimuth must reach ±1°; During the measurement process, the measurement system needs to be calibrated and maintained regularly, and compared with the adjacent borehole data with known precise drilling trajectories; In view of the factors affecting the measurement accuracy, a magnetic shielding device is installed to reduce magnetic field interference, and a temperature sensor is used to monitor the temperature and perform data correction accordingly. The factors include but are not limited to: magnetic field interference and temperature changes in the borehole.

6. The continuous deflection coring method for achieving rope coring orientation according to claim 1, characterized in that: The performance parameters of the rope coring winch need to be selected according to the actual drilling conditions; Its lifting capacity must meet the requirements of safely lifting the internal assembly, core tube and measurement while drilling system under the conditions of drilling depth H and mud density ρ. The lifting force calculation formula is: F=(m+ρgV)g Where m is the total mass of the internal assembly, core tube, rock (ore) core and measurement while drilling system, v is the volume displaced in the mud, and g is the acceleration due to gravity; When selecting a winch, the required lifting force should be estimated based on the designed drilling depth and the geological conditions encountered, and then a winch with a rated lifting force greater than the calculated value should be selected, and a certain safety factor should be reserved, which should be between 1.2-1.

5.

7. The continuous deflection coring method for achieving rope coring orientation according to claim 1, characterized in that: The drilling parameters of the bottom hole power drilling tool during drilling need to be optimized and adjusted according to the geological conditions; In soft formations, the speed is controlled at 80-120r / min and the drilling pressure is controlled at 2-4kN. In hard formations, the speed needs to be reduced to 40-60r / min and the drilling pressure increased to 6-8kN. During the drilling process, sensors are used to collect drilling parameters in real time, including drilling speed, torque, and pump pressure, and transmit these data to the ground control system. Ground operators judge the drilling status based on data analysis and adjust the drilling parameters in time when the drilling speed drops abnormally, the torque is too large, or the pump pressure fluctuates abnormally.

8. The continuous deflection coring method for achieving rope coring orientation according to claim 1, characterized in that: The performance index requirements of the mud in the drilling hole are: The viscosity of the mud should be controlled at a funnel viscosity of 20-30s, the density should be controlled at 1.1-1.3g / cm3, and the water loss should be less than 15ml / 30min; In the process of mud preparation, bentonite is selected as the main raw material, and additives are added according to actual needs. The additives include: viscosity enhancer and fluid loss reducer, which are stirred and mixed according to the proportion; During the drilling process, the mud properties are checked regularly. If the mud viscosity is found to be beyond the predetermined range, it is adjusted by adding diluents or thickeners. If the density is abnormal, weighting materials or diluents are added. If the water loss is too large, a fluid loss reducer is added in time.

9. The continuous deflection coring method for achieving rope coring orientation according to claim 1, characterized in that: The design parameters of the core tube in the coring process need to be based on the borehole diameter D c and geological conditions selection; In soft formations, the length of the core tube L c 0.5D c -D c The material is seamless steel pipe with surface hardening treatment, and the cutting edge angle at the front end of the core tube is between 120°-150° to prevent core blockage; In hard formations, the core tube length L c 0.3D c -0.5D c The material is seamless steel pipe and the surface is hardened. The front cutting edge angle is reduced to between 90° and 120°.

10. The continuous deflection coring method for achieving rope coring orientation according to claim 1, characterized in that: The device includes a spear fishing mechanism, a spring-loaded mechanism, a piston mechanism, a measuring mechanism, a keyway, a guide positioning mechanism, a guide slope, an in-place signaling mechanism, a suspension mechanism, a core blockage alarm mechanism, a single-action mechanism, an adjustment mechanism, a retaining spring, a retaining spring seat, an inner flat drill rod, a spring-loaded stopper, a spring-loaded chamber, a non-magnetic drill rod, a guide key, a positioning joint, a seat ring, a single-bend hollow screw and a drill bit.

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