Sealed sampler for coal-bed gas well construction

Abstract

The utility model discloses a sealed sampler for coal-bed gas well construction, which comprises an outer barrel with an open lower end, a drilling hydraulic cylinder, a drilling hydraulic motor and a sampling pipe are sequentially arranged in the outer barrel from top to bottom, and the lower end of a telescopic rod of the drilling hydraulic cylinder is connected with the top of the drilling hydraulic motor. A power output shaft of the drilling hydraulic motor is in coaxial transmission connection with the upper end of the sampling pipe, and a detachable material guide sealing assembly is arranged in a lower port of the sampling pipe. The coal-bed gas well sampling device is scientific in principle, novel in structural design, rapid in sampling and high in sealing performance, enables a coal sample to keep good original ecology, is simple, convenient and rapid in sampling process, and provides reliable data support for coal-bed gas well drilling by testing the taken-out coal sample. The coal-bed gas sampling device is not only used for sampling a coal bed in a coal-bed gas well, but also used for sampling a coal sampling area of a coal mine.

Description

Technical Field

[0001] The utility model belongs to the technical field of mine gas prevention and control, and particularly relates to a sealed sampler for coalbed methane well construction. Background Art

[0002] Coalbed methane (CBM) drilling is a drilling project aimed at detecting the self-generated and self-retaining coalbed methane (also known as gas) found in underground coal seams. Coal seams in southern my country are often characterized by numerous, thin layers. This makes sampling while drilling CBM wells challenging. Even after sampling, poor sealing can affect the accuracy of test and analysis results. Therefore, there is a need to improve existing sampling devices and design a drilled coal sampler that provides an immediate and effective seal. Utility Model Content

[0003] In order to solve the deficiencies in the prior art, the utility model provides a sealed sampler for coalbed methane well construction, which has good sealing performance and improves the authenticity and reliability of coal sample test and analysis results.

[0004] To solve the above technical problems, the utility model adopts the following technical solutions: a sealed sampler for coalbed methane well construction, comprising an outer cylinder with an open lower end, wherein a drilling hydraulic cylinder, a drilling hydraulic motor and a sampling tube are sequentially arranged in the outer cylinder from top to bottom, the lower end of the telescopic rod of the drilling hydraulic cylinder is connected to the top of the drilling hydraulic motor, the power output shaft of the drilling hydraulic motor is coaxially connected to the upper end of the sampling tube, and a detachable material guide sealing assembly is provided inside the lower end of the sampling tube;

[0005] A number of annular retainers are evenly arranged on the middle and upper part of the outer circle of the sampling tube, and each annular retainer is provided with a number of balls that are in rolling connection with the inner wall of the outer cylinder;

[0006] A piston plate is slidingly provided on the upper part of the inner circle of the sampling tube, a one-way air valve is provided at the center of the piston plate, a straight hole that passes through the inside of the sampling tube is opened in the center of the drilling hydraulic motor, an L-shaped hole is provided inside the piston rod of the drilling hydraulic cylinder, the lower port of the L-shaped hole is connected to the upper port of the straight hole, the upper port of the L-shaped hole faces backward and is connected to a pipe joint that passes through the outer cylinder body, and a sealing cap is provided at the outer end of the pipe joint.

[0007] The detachable material guide sealing assembly includes a material guide cylinder coaxially assembled inside the lower port of the sampling tube. The inner circle of the material guide cylinder is composed of an upper cylindrical section, a middle conical section and a lower cylindrical section from top to bottom. The diameter of the upper cylindrical section is larger than the diameter of the lower cylindrical section. The middle conical section is a conical surface that is thicker at the top and thinner at the bottom. The diameter of the upper end of the middle conical section is equal to the diameter of the upper cylindrical section, and the diameter of the lower end of the middle conical section is equal to the diameter of the lower cylindrical section.

[0008] A disc is provided at the upper port of the upper cylindrical section, and a number of feeding holes are arranged evenly along the circumferential direction on the disc. A conical valve core is provided at the middle conical section, and the diameter of the upper end of the valve core is larger than the diameter of the lower port of the middle conical section and smaller than the diameter of the upper port of the middle conical section. A guide rod is vertically fixed at the center of the lower surface of the disc, and a guide hole with an upper end opening is provided at the center of the valve core. The lower part of the guide rod extends into the guide hole, and a compression spring is sleeved on the guide rod. The upper and lower ends of the compression spring are press-fitted with the lower surface of the disc and the upper end face of the valve core respectively. Under the action of the compression spring, the conical surface of the valve core is sealed with the conical surface of the middle conical section.

[0009] A flexible sheath which completely covers the compression spring is arranged between the lower surface of the disc and the upper surface of the valve core.

[0010] The guide cylinder and the sampling tube are connected as a whole by several radially arranged countersunk screws on the outer circle of the sampling tube. The lower end of the guide cylinder is connected to the lower end of the sampling tube. Several diamond bits are evenly arranged on the annular surface of the lower end of the sampling tube and the lower end of the guide cylinder.

[0011] By adopting the above technical solution, compared with the prior art, the present invention has the following technical effects:

[0012] 1) The drilling hydraulic cylinder and drilling hydraulic motor provide power for rotary drilling during the sampling process. The balls on the annular retainer roll on the inner wall of the sampling tube, playing a guiding role during the drilling process. The guide barrel is fixed to the inner circle of the sampling tube port by screws, which is convenient for installation and disassembly. The guide barrel is arranged from top to bottom as an upper cylindrical section, a middle conical section, and a lower cylindrical section. During the drilling sampling process, the extrusion force of the coal sample overcomes the elastic force of the compression spring, making it easier for the coal sample to enter the sampling tube. After the sampling is completed, the elastic force of the compression spring causes the valve core to quickly seal the guide barrel, thereby ensuring that the coal sample remains in its original state in the underground coal seam.

[0013] 2) The setting of the flexible sheath prevents the coal sample from contacting the compression spring and affecting the elasticity of the compression spring. At the same time, the flexible sheath can be flexibly deformed when the valve core slides up and down along the guide rod.

[0014] 3) The pipe joint, L-shaped hole, straight hole, and one-way air valve on the piston plate facilitate negative pressure vacuuming within the sampling tube, preventing the air in the temporary storage space after sampling from affecting the coal sample. At the same time, a positive pressure airflow channel is provided when removing the coal sample, driving the piston plate to move within the sampling tube to push the coal sample out of the tube.

[0015] In summary, the present invention has a scientific principle, novel structural design, rapid sampling, and strong sealing, which allows coal samples to remain in good original state. The sampling process is simple, convenient, and quick. By testing the extracted coal samples, reliable data support is provided for coalbed methane well drilling. The present invention is not only used for sampling coal seams in coalbed methane wells, but can also be used for sampling in areas where coal sampling is required in coal mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the axial structure of the present utility model;

[0017] Figure 2 yes Figure 1 Cross-sectional view at point A;

[0018] Figure 3 yes Figure 1 Cross-sectional view at point B. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0020] like Figure 1-Figure 3 As shown, the sealed sampler for coalbed methane well construction of the utility model includes an outer cylinder 6 with an open lower end, and a drilling hydraulic cylinder 7, a drilling hydraulic motor 8 and a sampling tube 9 are arranged in sequence from top to bottom in the outer cylinder 6. The lower end of the telescopic rod of the drilling hydraulic cylinder 7 is connected to the top of the drilling hydraulic motor 8, and the power output shaft of the drilling hydraulic motor 8 is coaxially connected to the upper end of the sampling tube 9. A detachable material guide sealing assembly is provided inside the lower end of the sampling tube 9.

[0021] A plurality of annular retainers 11 are evenly arranged on the middle and upper part of the outer circle of the sampling tube 9, and each annular retainer 11 is provided with a plurality of balls 12 that are rollingly connected to the inner wall of the outer cylinder 6;

[0022] A piston plate 13 is slidingly provided on the upper part of the inner circle of the sampling tube 9, and a one-way air valve 14 is provided at the center of the piston plate 13. A straight hole 15 (a hollow shaft hydraulic motor is used) is opened in the center of the drilling hydraulic motor 8 and is communicated with the inside of the sampling tube 9. An L-shaped hole 16 is provided inside the piston rod of the drilling hydraulic cylinder 7. The lower end of the L-shaped hole 16 is connected to the upper end of the straight hole 15. The upper end of the L-shaped hole 16 faces backward and is connected to a pipe joint passing through the outer cylinder 6. A sealing cap is provided at the outer end of the pipe joint.

[0023] The detachable material guide seal assembly includes a material guide cylinder 17 coaxially assembled inside the lower end of the sampling tube 9. The inner circle of the material guide cylinder 17 is composed of an upper cylindrical section 18, a middle conical section 19 and a lower cylindrical section 20 from top to bottom. The diameter of the upper cylindrical section 18 is larger than the diameter of the lower cylindrical section 20. The middle conical section 19 is a conical surface that is thicker at the top and thinner at the bottom. The diameter of the upper end of the middle conical section 19 is equal to the diameter of the upper cylindrical section 18, and the diameter of the lower end of the middle conical section 19 is equal to the diameter of the lower cylindrical section 20.

[0024] A disc 21 is provided at the upper end of the upper cylindrical section 18, and a plurality of feeding holes 22 are uniformly arranged along the circumferential direction are opened on the disc 21. A conical valve core 23 is provided on the middle conical section 19. The diameter of the upper end of the valve core 23 is larger than the diameter of the lower end of the middle conical section 19 and smaller than the diameter of the upper end of the middle conical section 19. A guide rod 24 is vertically fixed to the center of the lower surface of the disc 21. A guide hole 25 with an upper end opening is opened at the center of the valve core 23. The lower part of the guide rod 24 extends into the guide hole 25. A compression spring 26 is sleeved on the guide rod 24. The upper and lower ends of the compression spring 26 are respectively press-fitted with the lower surface of the disc 21 and the upper end surface of the valve core 23. Under the action of the compression spring 26, the conical surface of the valve core 23 is sealed with the conical surface of the middle conical section 19. A flexible sheath 27 is provided between the lower surface of the disc 21 and the upper surface of the valve core 23 to completely cover the compression spring 26.

[0025] The guide cylinder 17 and the sampling tube 9 are connected as a whole by several radially arranged countersunk screws 28 on the outer circle of the sampling tube 9. The lower end of the guide cylinder 17 extends out of the lower end of the sampling tube 9. Several diamond bits 29 are evenly arranged on the annular surface of the lower end of the sampling tube 9 and the lower end of the guide cylinder 17.

[0026] The outer cylinder 6 of the present invention is mounted on a support to maintain the stability of the support during sampling. The drilling hydraulic motor 8 and the drilling hydraulic cylinder 7 are connected to a hydraulic control device (a hydraulic station can be used) via oil pipes. The specific process of sampling using the present invention includes the following steps:

[0027] (1) First, vacuum the inside of the sampling tube 9. The specific process of vacuuming is as follows: first remove the sealing cap, then connect the outer end of the pipe joint to the exhaust pipe of the vacuum pump, start the vacuum pump, and vacuum the inside of the sampling tube 9 through the exhaust pipe, pipe joint, L-shaped hole 16, straight hole 15 and the one-way air valve 14 on the piston plate 13. When the vacuum pressure reaches 500-1000 Pa, turn off the vacuum pump, remove the exhaust pipe, and screw on the sealing cap.

[0028] (2) The lower end of the sampling tube 9 (which can change direction) is directed toward the coal body to be sampled, and the hydraulic motor 8 and the drilling hydraulic cylinder 7 are started. The drilling hydraulic motor 8 drives the sampling tube 9 and the detachable material guide sealing assembly to rotate at high speed. The drilling hydraulic cylinder 7 drives the hydraulic motor, the sampling tube 9 and the detachable material guide sealing assembly to move outward (to the lower end) along the outer cylinder 6. The balls 12 on the annular retainer 11 on the outer circle of the sampling tube 9 rotate at high speed and roll outward on the inner circle of the outer cylinder 6. The diamond bit 29 on the outer end of the sampling tube 9 and the material guide cylinder 17 drills perpendicularly to the inner wall of the wellbore. The coal sample entering the material guide cylinder 17 moves inward along the axial direction of the material guide cylinder 17. As the sampling tube 9 and the material guide cylinder 17 continue to drill, the coal sample entering the material guide cylinder 17 applies an inward push pressure to the lower end of the conical valve core 23. When the push pressure is greater than the elastic force of the spring, the valve core is driven. 23 compression spring 26, the valve core 23 moves inward along the guide rod 24, and the annular gap between the conical outer circle of the valve core 23 and the middle conical section 19 gradually increases. The coal sample enters the upper cylindrical section 18 through the annular gap, and then enters the sampling tube 9 through the evenly distributed feeding holes 22 on the disc 21. After the drilling hydraulic cylinder 7 is extended to the set limit, the drilling hydraulic cylinder 7 begins to retract. At this time, the coal sample inside the lower cylindrical section 20 no longer generates a top pressure on the lower end of the conical valve core 23. Under the action of the compression spring 26, the valve core 23 is driven to move outward along the guide rod 24, and the coal sample in the annular gap is squeezed into the lower cylindrical section 20. The annular gap gradually shrinks until the conical outer circle of the valve core 23 is pressed against the inner circle of the middle conical section 19, and the port of the sampling tube 9 is sealed. After the drilling hydraulic cylinder 7 is retracted to the shortest, the drilling hydraulic cylinder 7 and the drilling hydraulic motor 8 are closed to complete the sampling work.

[0029] The specific process of taking the coal sample out of the sampling tube 9 is as follows: first unscrew the sealing cap at the outer end of the pipe joint, connect the pipe joint to the air pump, then unscrew the screw 28 connecting the outer circle of the lower end of the sampling tube 9 with the guide cylinder 17, pull the guide cylinder 17, the disc 21 and the valve core 23 downward to remove the sampling tube 9, then immediately insert the lower end of the sampling tube 9 into the mouth of the coal sample tank, and seal the outer circle of the sampling tube 9 and the mouth of the coal sample tank with a flexible material, then start the air pump, and the high-pressure airflow generated by the air pump enters the sampling tube 9 through the pipe joint, the L-shaped hole 16 and the straight hole 15. Due to the one-way The air valve 14 can only be used to draw a vacuum outward. Therefore, the high-pressure airflow generated by the air pump pushes the piston plate 13 to slide downward in the sampling tube 9. The piston plate 13 pushes the coal sample in the sampling tube 9 and pushes the coal sample from the lower end of the sampling tube 9 into the coal sample tank. The tank cover of the coal sample tank is closed to complete the entire sampling work. The air pump is turned off and disconnected from the pipe joint. A long rod is used to push the piston into the interior of the sampling tube 9 for a distance. Finally, the material guide cylinder 17, disc 21 and valve core 23 are installed to the lower end of the sampling tube 9, and the screw 28 is tightened to fix the material guide cylinder 17 and the sampling tube 9 into a whole for the next sampling use.

[0030] The vacuum pump negative pressure vacuuming, the air pump positive pressure driving piston plate 13, and the control of the drilling hydraulic cylinder 7 and the drilling hydraulic motor 8 on and off through the hydraulic station involved in the present invention are all existing technologies, and the specific principles and contents will not be repeated here.

[0031] The above two embodiments do not impose any formal restrictions on the shape, material, structure, etc. of the utility model. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the utility model shall fall within the scope of protection of the technical solution of the utility model.

Claims

1. Sealed sampler for coalbed methane well construction, characterized by: It comprises an outer cylinder with an open lower end, in which a drilling hydraulic cylinder, a drilling hydraulic motor and a sampling tube are arranged in sequence from top to bottom. The lower end of the telescopic rod of the drilling hydraulic cylinder is connected to the top of the drilling hydraulic motor, the power output shaft of the drilling hydraulic motor is coaxially connected to the upper end of the sampling tube, and a detachable material guide sealing assembly is provided inside the lower end of the sampling tube. A number of annular retainers are evenly arranged on the middle and upper part of the outer circle of the sampling tube, and each annular retainer is provided with a number of balls that are in rolling connection with the inner wall of the outer cylinder; A piston plate is slidingly provided on the upper part of the inner circle of the sampling tube, a one-way air valve is provided at the center of the piston plate, a straight hole that passes through the inside of the sampling tube is opened in the center of the drilling hydraulic motor, an L-shaped hole is provided inside the piston rod of the drilling hydraulic cylinder, the lower port of the L-shaped hole is connected to the upper port of the straight hole, the upper port of the L-shaped hole faces backward and is connected to a pipe joint that passes through the outer cylinder body, and a sealing cap is provided at the outer end of the pipe joint.

2. The sealed sampler for coalbed methane well construction according to claim 1, characterized in that: The detachable material guide sealing assembly includes a material guide cylinder coaxially assembled inside the lower port of the sampling tube. The inner circle of the material guide cylinder is composed of an upper cylindrical section, a middle conical section and a lower cylindrical section from top to bottom. The diameter of the upper cylindrical section is larger than the diameter of the lower cylindrical section. The middle conical section is a conical surface that is thicker at the top and thinner at the bottom. The diameter of the upper end of the middle conical section is equal to the diameter of the upper cylindrical section, and the diameter of the lower end of the middle conical section is equal to the diameter of the lower cylindrical section. A disc is provided at the upper port of the upper cylindrical section, and a number of feeding holes are arranged evenly along the circumferential direction on the disc. A conical valve core is provided at the middle conical section, and the diameter of the upper end of the valve core is larger than the diameter of the lower port of the middle conical section and smaller than the diameter of the upper port of the middle conical section. A guide rod is vertically fixed at the center of the lower surface of the disc, and a guide hole with an upper end opening is provided at the center of the valve core. The lower part of the guide rod extends into the guide hole, and a compression spring is sleeved on the guide rod. The upper and lower ends of the compression spring are press-fitted with the lower surface of the disc and the upper end face of the valve core respectively. Under the action of the compression spring, the conical surface of the valve core is sealed with the conical surface of the middle conical section.

3. The sealed sampler for coalbed methane well construction according to claim 2, characterized in that: A flexible sheath which completely covers the compression spring is arranged between the lower surface of the disc and the upper surface of the valve core.

4. The sealed sampler for coalbed methane well construction according to claim 2 or 3, characterized in that: The guide cylinder and the sampling tube are connected as a whole through several radially arranged countersunk screws and the outer circle of the sampling tube. The lower end of the guide cylinder is connected to the lower end of the sampling tube. Several diamond bits are evenly arranged on the annular surface of the lower end of the sampling tube and the lower end of the guide cylinder.

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