Drilling system and method based on electric pulse rock breaking technology

Abstract

The invention discloses a well drilling system based on an electric pulse rock breaking technology. The well drilling system comprises a well mouth mechanism, a well drilling mechanism and an electric pulse mechanism. The wellhead mechanism comprises a derrick, a shaft, a blowout preventer and a drilling fluid group; the well drilling mechanism comprises a conductive drill rod and an electric pulse drill bit; the electric pulse mechanism comprises a high-voltage pulse power supply, a cable and a cable high-voltage connector; a lifting mechanism is arranged on the derrick and used for installing and lifting the conductive drill rod, the cable is connected to the electric pulse drill bit through the cable high-pressure connector and the conductive drill rod, and the conductive drill rod penetrates through a wellhead, enters a shaft and is connected to the shaft through a drilling fluid set to achieve well drilling. The invention further discloses a well drilling method. Downhole rocks are damaged through continuous discharge of the electrode drill bit, the drill bit and the drill rod do not need to rotate, the requirement for the performance of the drill rod is lowered, a well drilling system is simplified, the equipment cost can be effectively reduced, the electric pulse drill bit is simple in structure and convenient to manufacture, only the requirement for the electric conductivity of drilling fluid exists, and the influence on the environment is small.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas drilling, and in particular to a drilling system and method based on electric pulse rock breaking technology. Background Art

[0002] As the material basis for accelerating modernization, the demand for oil and natural gas has been rising year by year. To meet the global demand for oil and natural gas, it is necessary to improve the efficiency of exploration and development and reduce investment costs. The current mainstream drilling method still uses rotary drilling, that is, through the continuous rotation of the drill bit, the rock is damaged by scraping and shearing of the cutting teeth. This makes it inevitable that the drill bit will break and lose teeth; on the other hand, the rotary drilling method requires a power device to be configured on the ground or underground to ensure the continuous rotation of the drill bit, and the device is complicated; in addition, since the rotation of the drill bit is driven by the drill rod, the drill rod needs to withstand the torque generated by rock breaking. When encountering difficult-to-drill formations, stick-slip vibration and drill jamming are prone to occur.

[0003] Electric pulse rock breaking technology is a new drilling method that uses high-voltage electric pulses to damage rocks. It has the significant advantages of high rock breaking efficiency and low cost, and has been widely used in mining, rock excavation, mineral decomposition and other fields. Unlike rotary drilling methods, electric pulse drill bits do not need to rotate during the rock breaking process. It only needs to ensure that the drill bit is in contact with the rock surface without mechanical interaction, and relies on the continuous discharge of the drill bit to damage the rock. Therefore, the electric pulse drill bit has less wear, and the electric pulse rock breaking technology does not require ground or underground power devices, which can simplify the drilling system. These two aspects will greatly reduce drilling costs. In addition, the electric pulse drill bit has a simple structure, is easy to manufacture, and has low material costs. Summary of the invention

[0004] Based on the above background, the present invention provides a drilling system and method based on electric pulse rock breaking technology, which uses a high-voltage pulse power supply as an energy source, relies on the continuous discharge of the drill bit to damage the bottom rock of the well, and simplifies the ground and underground drilling systems, thereby realizing efficient, rapid and low-cost exploration and development of oil and gas resources.

[0005] In order to achieve the above object, the technical solution used in the present invention is: A drilling system based on electric pulse rock breaking technology, comprising a wellhead mechanism, a drilling mechanism, and an electric pulse mechanism; the wellhead mechanism comprises a derrick, a wellbore, a blowout preventer, and a drilling fluid group; the drilling mechanism comprises a conductive drill pipe and an electric pulse drill bit; the electric pulse mechanism comprises a high-voltage pulse power supply, a cable, and a cable high-voltage connector; a lifting mechanism is provided on the derrick for installing and lifting the conductive drill pipe, the cable is connected to the electric pulse drill bit via the cable high-voltage connector and the conductive drill pipe, the conductive drill pipe passes through the wellhead and enters the wellbore, and is connected to the wellbore via the drilling fluid group to realize drilling.

[0006] Furthermore, the wellbore includes a casing on the well wall and a blowout preventer and a sealing head at the wellhead, the drilling fluid group includes a large-size cuttings filter, a suction pump, a cyclone, a water pool, and a drilling fluid pump connected in sequence through a drilling fluid pipeline, the water pool is used to store drilling fluid, and the sealing head and the conductive drill pipe are also respectively connected to the drilling fluid pipeline to form a circulation path; The lifting mechanism includes a winch and a steel cable. A lifting platform is provided at the lower end of the steel cable. A pulley frame is provided on the derrick to support the cable to move up and down with the lifting platform. The pulley frame is composed of a sling, a pulley frame and a pulley.

[0007] Furthermore, the cable includes a high-voltage core and a grounding core; the high-voltage core and the grounding core are two independent lines, each wrapped with an insulating layer on the outside, the high-voltage core and the grounding core are wrapped with a braided layer and an outer insulating layer on the outside, and the inner side of the braided layer is filled with an insulating filler for supporting and fixing the high-voltage core and the grounding core.

[0008] Furthermore, the conductive drill pipe is composed of a drill pipe shell, a high-voltage male connector, a copper rod, a high-voltage female connector, an insulating layer, a grounding wire rod, and a drill pipe grounding head; the drill pipe shell is a cylindrical structure, the upper part of the drill pipe shell has an outer cone thread, the lower part has an inner cone thread, an axial through hole is provided inside as a high-voltage through hole of the shell, and a section of expansion hole is provided at both ends of the high-voltage through hole of the shell, respectively serving as an upper countersunk hole and a lower countersunk hole of the shell; at least one drilling fluid flow channel penetrating the drill pipe shell is provided on the outer side of the high-voltage through hole of the shell, and an expansion hole is opened at the bottom of the drilling fluid flow channel A flow channel annular groove is provided, a copper rod is installed in the high-pressure through hole of the shell, and a high-voltage male connector and a high-voltage female connector are installed at both ends of the copper rod respectively; a plurality of through holes axially penetrating the entire drill rod shell are provided on the shell shoulder outside the outer tapered thread of the shell as grounding wire through holes, and the bottom of the grounding wire through hole is a joint annular groove, and the joint annular groove is located in the outer end face of the inner tapered thread of the shell, a grounding wire rod is installed in the grounding wire through hole, a threaded hole is provided at one end of the grounding wire rod, and a drill rod grounding head is installed in the threaded hole, and the other end of the grounding wire rod is an outer tapered surface.

[0009] Furthermore, an insulating layer is provided in the high-voltage through hole of the shell to insulate the copper rod from the drill pipe shell. The high-voltage male connector and the high-voltage female connector are gyro-shaped structures. The size of the outer peripheral surface of the high-voltage male connector is larger than the bottom opening of the countersunk hole on the shell, and the size of the outer peripheral surface of the high-voltage female connector is larger than the top opening of the countersunk hole on the shell, thereby achieving the fixation of the copper rod, and an insulating layer is also provided on the contact surface between the high-voltage male connector and the high-voltage female connector and the drill pipe shell.

[0010] Furthermore, the electric pulse drill bit includes a drill bit high-voltage connector, a high-voltage electrode, an insulator, a grounding cone head, and a grounding electrode; the grounding cone head and the grounding electrode are both hollow structures and are connected up and down, an insulator is provided in the grounding cone head and the grounding electrode, an axial through hole is provided in the insulator, and the upper end of the through hole is an expansion section, a high-voltage electrode is fixed in the through hole, and a drill bit high-voltage connector installed in the expansion section of the through hole is provided in the upper section of the high-voltage electrode.

[0011] Furthermore, the upper part of the grounding cone head is a cone head outer cone thread, and the cone head shoulder is below the cone head outer cone thread; a convex head thread hole is opened on the cone head shoulder, and a grounding convex head is installed in the convex head thread hole; the bottom of the grounding cone head is opened with a plurality of cone head slots with square opening structures, and the inner cylindrical surface of the bottom is opened with a cone head inner slot, and a cone head square boss is provided; A cone head screw countersunk hole is provided on the cylindrical surface of the lower part of the grounding cone head for installing the cone head screw; the upper part of the grounding electrode is a grounding electrode protrusion, and the size of the grounding electrode protrusion is consistent with the cone head slot; the lower part of the grounding electrode is a grounding petal; a grounding electrode inner boss is provided on the inner cylindrical surface of the grounding electrode; a grounding electrode screw countersunk hole is provided on the cylindrical surface of the grounding electrode, and the grounding electrode screw countersunk hole passes through the grounding electrode inner boss, and the number of the grounding electrode screw countersunk holes is consistent with the grounding electrode inner boss; The upper part of the insulator is a frustum structure, the lower part of the frustum is an upper shoulder of the insulator, and below the upper shoulder of the insulator is a lower shoulder of the insulator; the upper shoulder of the insulator is provided with an upper slot of the insulator, which is consistent with the size of the square boss of the cone head, and the center of the upper slot of the insulator is provided with an upper threaded hole of the insulator; the lower shoulder of the insulator is provided with a lower slot of the insulator, the size of which is consistent with the inner boss of the grounding electrode; the center of the lower slot of the insulator is provided with a lower threaded hole of the insulator; the upper part of the insulator is provided with an insulator circular groove, and a high-voltage electrode hole is provided below the circular groove of the insulator, the circular groove of the insulator and the high-voltage electrode hole are coaxial with the insulator, and the shape of the high-voltage electrode hole is consistent with that of the high-voltage electrode; the bottom of the circular groove of the insulator is provided with a high-voltage joint threaded hole; the upper end face of the insulator is provided with a drilling fluid hole, and the drilling fluid hole runs through the entire insulator; the upper part of the high-voltage electrode is a cylinder, the lower part is a conical surface, and the lower end is a spherical surface, and the upper end face of the high-voltage electrode is provided with a threaded hole for fixing with the high-voltage joint of the drill bit.

[0012] Furthermore, the water tank, drilling fluid pump, drilling fluid pipeline, drilling fluid flow channel and flow channel annular groove of the drill pipe shell in the conductive drill pipe, and drilling fluid hole of the insulator in the electric pulse drill bit constitute an inner channel for drilling fluid circulation; the outer cylindrical surface of the electric pulse drill bit, the inner cylindrical surface of the casing, the blowout preventer, the sealing head, the large-size cuttings filter, the suction pump, the cyclone and the water tank constitute an outer channel for drilling fluid circulation.

[0013] A drilling method based on electric pulse rock breaking technology, using the above-mentioned drilling system based on electric pulse rock breaking technology, the specific steps are as follows: S1. Preparation work before drilling: fix the high-voltage pulse power supply, pulley frame, derrick, large-size cuttings filter, cyclone, drilling fluid pump, water pool, and suction pump on the ground, and ground the high-voltage pulse power supply as a whole; S2. Install the winch on the top platform of the derrick, then install the steel cable on the winch, connect the conductive drill pipe to the lifting platform, and install the cable high-voltage connector on the top of the conductive drill pipe. Connect the pulley frame to the derrick through the sling. Connect the head of the cable to the output end of the high-voltage pulse power supply, then pass the cable through the pulley frame, and connect the tail of the cable to the cable high-voltage connector. Connect the head and tail of the drilling fluid pipeline to the conductive drill pipe and the drilling fluid pump respectively; fix the blowout preventer to the wellhead, and install the sealing head on the top of the blowout preventer; finally, connect the electric pulse drill bit to the conductive drill pipe through the inner cone thread of the shell and the outer cone thread of the cone head.

[0014] S3. After the preparation work is completed, drilling begins. The drilling fluid pump is turned on, and the winch is ordered to lower the steel cable, so that the lifting platform drives the conductive drill pipe and the electric pulse drill bit to the bottom of the well. The high-voltage pulse power supply is turned on to start drilling and breaking rocks. The drilling fluid is sucked into the drilling fluid pump from the water pool, and then enters the conductive drill pipe through the drilling fluid pipeline, passes through the drilling fluid flow channel and the flow channel annular groove of the drill pipe shell in the conductive drill pipe, and the drilling fluid hole i of the insulator in the electric pulse drill bit to reach the bottom of the well; then the drilling fluid carries the returning cuttings through the outer cylindrical surface of the electric pulse drill bit, the inner cylindrical surface of the casing, the blowout preventer, the sealing head, the large-size cuttings filter, the suction pump, the cyclone, and finally flows back to the water pool to complete the drilling fluid circulation; S4. During the circulation of drilling fluid, large-sized cuttings in the returned cuttings are retained in the large-sized cuttings filter, and smaller-sized cuttings and mud are sucked into the cyclone by the suction pump; the cyclone separates the small-sized cuttings and mud from the drilling fluid; when the length of the steel cable is not enough to continue drilling, the winch retracts the steel cable so that the lifting platform drives the conductive drill rod and the electric pulse drill bit to rise, and a new conductive drill rod is added between the conductive drill rods. The process is the same as the traditional drill rod adding action, and then the above work is repeated until the drilling task is completed.

[0015] Furthermore, the high-voltage pulse power supply outputs direct current, the pulse rise time is less than 500ns, the output voltage is 100kV~400kV, and the discharge frequency is 1Hz~10Hz; the high-voltage pulse power supply is grounded as a whole; the conductivity of the drilling fluid is below 200 μs / cm The beneficial effects of the present invention are: 1. Compared with the existing drilling technology, the electric pulse drilling solution provided by the present invention does not require a rotating power device, and uses a high-voltage pulse power supply as an energy source, thereby simplifying the ground device; reducing the wear on the drill bit, thereby reducing the time and material loss caused by replacing the drill bit; and the structure designed by the present invention is more sophisticated, which can ensure the internal connection stability between each electric pulse device and each electric pulse device itself, and is easy to disassemble and assemble. It is also easy to replace and add or reduce components through lifting, thereby achieving an overall efficient drilling effect; 2. Based on the requirements of electric pulse drilling, the present invention only has the requirement of conductivity for the drilling fluid. The impact on the environment during the circulation of the drilling fluid is small, and it is easy to recycle in the later stage. It is not easy to cause damage and influence to the conductive drill pipe and other structures, thereby ensuring the drilling effect; 3. Compared with the existing electric pulse drilling technology, the electrode drill bit in the present invention adopts a segmented slot structure, which can effectively resist the circumferential vibration generated during the drilling process and ensure the stability of the structure; 4. The conductive drill rod of the present invention can effectively eliminate the hidden danger of electric shock and improve the safety during the drilling process; 5. The electrode drill bit of the present invention has a simple structure, is easy to manufacture, has low material cost, and is easier to install, use and maintain; at the same time, the mechanical properties requirements of the drill rod are lower than those of the traditional drilling method. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the drilling system; Figure 2 Schematic diagram of the internal cross-sectional structure of the cable; Figure 3-4 It is a schematic diagram of the conductive drill pipe structure; Figure 5-8 It is a schematic diagram of the conductive drill pipe housing structure; Figure 9-12 This is a schematic diagram of the electric pulse drill structure; Figure 13-16 It is a schematic diagram of the structure of the grounding cone; Figure 17-19 It is a schematic diagram of the structure of the grounding electrode; Figure 20-24 is a schematic diagram of the structure of an insulator; Figure 25-26 is a structural schematic diagram of a pulley frame; In the above figure: 1. high-voltage pulse power supply; 2. cable; 201. high-voltage core; 202. grounding wire; 203. outer insulation layer; 204. braided layer; 205. insulation layer; 206. insulation filler; 3. pulley frame; 301. sling; 302. pulley frame; 303. pulley; 4. winch; 5. derrick; 6. steel cable; 7. cable high-voltage connector; 8. lifting platform; 9. conductive drill pipe; 901. drill pipe shell; 901a. outer cone thread of shell; 901b. countersunk hole on shell; 901c. drilling fluid flow channel; 901d. grounding head countersunk hole; 901e. grounding wire through hole; 901f. flow channel annular groove; 901g. joint annular groove; 901h. inner cone thread of shell; 901i. Shell sink hole; 901j. Shell high-voltage through hole; 901k. Shell shoulder; 902. High-voltage male connector; 903. Copper rod; 904. High-voltage female connector; 905. Insulation layer; 906. Grounding rod; 907. Drill pipe grounding head; 10. Large-size cuttings filter; 11. Cyclone; 12. Drilling fluid pipeline; 13. Drilling fluid pump; 14. Water tank; 15. Drilling fluid; 16. Casing; 17. Electric pulse drill bit; 1701. Drill bit high-voltage connector; 1702. High-voltage connector screw; 1703. High-voltage electrode; 1704. Insulator; 1704a. Insulator upper shoulder; 1704b. Insulator lower shoulder; 1704c. Insulator upper slot; 1704d. Insulator upper threaded hole; 1704e. Insulator lower slot; 1704f. Insulator lower threaded hole; 1704g. Insulator circular slot; 1704h. High-voltage electrode hole; 1704i. Drilling fluid hole; 1704j. High-voltage joint threaded hole; 1705. Grounding cone head; 1705a. Cone head outer cone thread; 1705b. Cone head shoulder; 1705c. Protruding head threaded hole; 1705d. Cone head screw countersink; 1705e. Cone head slot; 1705f. Cone head inner slot; 1705g. Cone head square boss; 1706. Grounding electrode; 1706a. Grounding electrode protrusion; 1706b. Grounding electrode screw countersink; 1706c. Grounding petals; 1706d. Grounding electrode inner boss; 1707. Grounding protrusion; 1708. Cone head screw; 1709. Grounding screw; 18. Blowout preventer; 19. Sealing head; 20. Suction pump. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described below in conjunction with embodiments, but this does not limit the protection scope of the present invention.

[0019] like Figure 1-25As shown, a drilling system based on electric pulse rock breaking technology includes a high-voltage pulse power supply 1, a cable 2, a pulley frame 3, a winch 4, a derrick 5, a steel cable 6, a cable high-voltage connector 7, a lifting platform 8, a conductive drill pipe 9, a large-size cuttings filter 10, a cyclone 11, a drilling fluid pipeline 12, a drilling fluid pump 13, a water tank 14, drilling fluid 15, a casing 16, an electric pulse drill bit 17, a blowout preventer 18, a sealing head 19, and a suction pump 20. Figure 1 As shown; the head of the cable 2 is connected to the output end of the high-voltage pulse power supply 1, and then passes through the pulley frame 3, and the tail of the cable 2 is connected to the cable high-voltage connector 7; the cable high-voltage connector 7 is fixedly connected to the conductive drill rod 9; the conductive drill rod 9 is fixedly connected to the lifting platform 8, and the lifting platform 8 is fixedly connected to the steel cable 6, and the steel cable 6 is wound on the winch 4; the winch 4 is fixedly connected to the top platform of the derrick 5, and the bottom of the derrick 5 is fixed on the ground; the winch 4 realizes the retraction and extension of the steel cable 6 by rotating, thereby realizing the lifting platform 8 The drill pipe 9 and the electric pulse drill bit 17 are connected by threads to achieve lifting and lowering of the conductive drill pipe 9 and the electric pulse drill bit 17; the blowout preventer 18 is installed at the wellhead; the bottom of the sealing head 19 is connected to the top of the blowout preventer 18, and the top is connected to the platform in the middle of the derrick 5; the large-size rock cuttings filter 10 is connected to the sealing head 19 through a pipeline; the large-size rock cuttings filter 10 is connected to the suction pump 20 through a pipeline; the cyclone 11 is connected to the suction pump 20 through a pipeline.

[0020] The drilling fluid pipeline 12 is connected to the top of the conductive drill pipe 9 and the drilling fluid pump 13; the cable 2 is a coaxial cable, which is composed of a high-voltage core 201, a grounding core 202, an outer insulating layer 203, a braided layer 204, an insulating layer 205, and an insulating filler 206. Figure 2 Preferably, the high-voltage core 201 may be 20% thicker than the existing fiber core diameter used in the art to reduce power loss.

[0021] The pulley frame 3 is composed of a sling 301, a pulley frame 302, and a pulley 303, wherein Fig. 9 As shown, the sling 301 includes a plurality of slings 301 of equal length, which are evenly applied to the pulley frame 302. The pulleys 303 are in two rows, each row having the same number of pulleys. Figure 25-26 As shown, with such a design, the pulley frame 3 can allow the cable 2 to move and fix more evenly, dispersing the stress points to reduce the probability of damage.

[0022] like Figure 3-4As shown, the conductive drill rod 9 is composed of a drill rod housing 901, a high-voltage male connector 902, a copper rod 903, a high-voltage female connector 904, an insulating layer 905, a grounding wire rod 906, and a drill rod grounding head 907. The insulating layer 905 is bonded to the inner wall of the upper countersunk hole 901b, the lower countersunk hole 901i, and the high-voltage through hole 901j of the drill rod housing 901; the copper rod 903 is a cylinder with threaded holes at both ends, which is coaxial with the high-voltage through hole 901j of the housing, and the outer cylindrical surface of the copper rod 903 is in direct contact with the insulating layer 905; the upper part of the high-voltage male connector 902 is a truncated cone, the middle part is a boss, and the lower part is a threaded rod, and the high-voltage wire core is connected to the high-voltage male connector on the drill rod 9. 902; the upper part of the high-pressure female connector 904 is a threaded rod, the middle part is a boss, the lower part is a cylinder, the interior of the cylinder is a truncated cone cavity, and the truncated cone cavity is consistent with the truncated cone size of the upper part of the high-pressure male connector 902; the high-pressure male connector 902 and the high-pressure female connector 904 are fixedly connected to the copper rod 903 through threads, and the boss of the high-pressure male connector 902 and the boss of the high-pressure female connector 904 fix the axial position of the copper rod 903, the high-pressure male connector 902, and the high-pressure female connector 904; Figure 5-8 As shown, the drill rod housing 901 has an outer cone thread 901a on the upper part and an inner cone thread 901h on the lower part, and the outer cone thread 901a of the housing is consistent with the shape of the inner cone thread 901h; the drill rod housing 901 has a housing shoulder 901k below the outer cone thread 901a of the housing, and the housing shoulder 901k has a grounding head countersunk hole 901d for installing a drill rod grounding head 907, and the grounding wire is connected to the drill rod grounding head 907 on the drill rod 9; the grounding head countersunk hole of the drill rod housing 901 A grounding wire through hole 901e coaxial with 901d is provided below 901d for installing a grounding wire rod 906; the bottom of the grounding wire through hole 901e of the drill pipe housing 901 is a joint annular groove 901g; the drill pipe housing 901 is provided with 6 to 8 drilling fluid flow channels 901c, and a flow channel annular groove 901f is provided at the bottom of the drilling fluid flow channel 901c; a threaded hole is provided at one end of the grounding wire rod 906 for fixed connection with the drill pipe grounding head 907, and the other end of the grounding wire rod 906 is an outer cone.

[0023] like Figure 9-12 As shown, the electric pulse drill bit 17 is composed of a drill bit high-voltage connector 1701, a high-voltage connector screw 1702, a high-voltage electrode 1703, an insulator 1704, a grounding cone head 1705, a grounding electrode 1706, a grounding convex head 1707, a cone head screw 1708, and a grounding electrode screw 1709. Figure 13-16As shown, the upper part of the grounding cone head 1705 is a cone head outer cone thread 1705a, and the cone head shoulder 1705b is below the cone head outer cone thread 1705a; the cone head shoulder 1705b is provided with a convex head threaded hole 1705c that matches the grounding convex head 1707; the bottom of the grounding cone head 1705 is provided with a cone head groove 1705e, and the inner cylindrical surface of the bottom is provided with a cone head inner groove 1705f, and a cone head square boss 1705g; the cylindrical surface of the lower part of the grounding cone head 1705 is provided with a cone head screw countersunk hole 1705d for installing a cone head screw 1708; Figure 17-19 As shown, the upper part of the grounding electrode 1706 is a grounding electrode protrusion 1706a, and its size is consistent with the cone head slot 1705e. The cone head slot 1705e cooperates with the grounding electrode protrusion 1706a to increase the contact area between the two parts and enhance the grounding reliability; the lower part of the grounding electrode 1706 is a grounding petal 1706c; the inner cylindrical surface of the grounding electrode 1706 is provided with a grounding electrode inner boss 1706d, and the grounding electrode inner boss 1706d is inserted into the lower slot 1704e of the insulator to achieve positioning and enhance the reliability of the connection, and can resist the weak circumferential force generated during the drilling process; the cylindrical surface of the grounding electrode 1706 is provided with a grounding electrode screw countersunk hole 1706b, and the grounding electrode screw countersunk hole 1706b passes through the grounding electrode inner boss 1706d, and the number of the grounding electrode screw countersunk holes 1706b is consistent with the grounding electrode inner boss 1706d; as shown Figure 20-24As shown, the upper part of the insulator 1704 is a frustum structure, the lower part of the frustum is an upper shoulder 1704a of the insulator, and below the upper shoulder 1704a of the insulator is a lower shoulder 1704a of the insulator; the upper shoulder 1704a of the insulator is provided with an upper groove 1704c of the insulator, which is consistent with the size of the square boss 1705g of the cone head, and the center of the upper groove 1704c of the insulator is provided with an upper threaded hole 1704d of the insulator; the lower shoulder 1704a of the insulator is provided with a lower groove 1704e of the insulator, and the size is consistent with the inner boss 1706d of the grounding electrode; the center of the lower groove 1704e of the insulator is provided with a lower threaded hole 1704f of the insulator; the upper part of the insulator 1704 is provided with an insulator circular groove 1704g, and below the circular groove 1704g of the insulator is provided with a high-voltage electrode hole 1704d. 704h, the circular groove 1704g of the insulator and the high-voltage electrode hole 1704h are coaxial with the insulator 1704, and the shape of the high-voltage electrode hole 1704h is consistent with the high-voltage electrode 1703; a high-voltage connector threaded hole 1704j is provided at the bottom of the circular groove 1704g of the insulator; a drilling fluid hole 1704i is provided on the upper end face of the insulator 1704, and the drilling fluid hole 1704i runs through the entire insulator 1704; the upper part of the high-voltage electrode 1703 is a cylinder, the lower part is a conical surface, and the lower end part is a spherical surface, and a threaded hole is provided on the upper end face of the high-voltage electrode 1703 for fixing with the drill bit high-voltage connector 1701; such a design, through multi-positioned meshing fixation, can make the electric pulse drill bit 17 better fixed and connected together, and at the same time, the connection with the conductive drill rod 9 can be more stable.

[0024] According to the above structure, Figure 1 As shown, the water pool 14, the drilling fluid pump 13, the drilling fluid pipeline 12, the drilling fluid flow channel 901c and the flow channel annular groove 901f of the drill pipe shell 901 in the conductive drill pipe 9, and the drilling fluid hole 1704i of the insulator 1704 in the electric pulse drill bit 17 constitute the inner channel for drilling fluid circulation; the outer cylindrical surface of the electric pulse drill bit 17, the inner cylindrical surface of the casing 16, the blowout preventer 18, the sealing head 19, the large-size rock cuttings filter 10, the suction pump 20, the cyclone 11 and the water pool 14 constitute the outer channel for drilling fluid circulation. Such a design ensures that the entire drilling fluid 15 circulates smoothly, achieves stable conductive efficiency, and improves the effect of electric pulse drilling.

[0025] The drilling method based on the above-mentioned drilling system based on electric pulse rock breaking technology includes the following steps: 1. First, prepare for drilling. Fix the high-voltage pulse power supply 1, pulley frame 3, derrick 5, large-size cuttings filter 10, cyclone 11, drilling fluid pump 13, water tank 14, and suction pump 20 on the ground, and ground the high-voltage pulse power supply 1 as a whole; install the winch 4 on the top platform of the derrick 5, and then install the steel cable 6 on the winch 4; connect the conductive drill pipe 9 to the lifting platform 8, and install the cable high-voltage connector 7 on the top of the conductive drill pipe 9; fix the pulley frame through the sling 301. 3 is fixedly connected to the derrick 5; the head of the cable 2 is connected to the output end of the high-voltage pulse power supply 1, and then the cable 2 passes through the pulley frame 3, and the tail of the cable 2 is connected to the cable high-voltage connector 7; the head and tail of the drilling fluid pipeline 12 are respectively fixedly connected to the conductive drill pipe 9 and the drilling fluid pump 13; the blowout preventer 18 is fixed to the wellhead, and the sealing head 19 is installed on the top of the blowout preventer 18; finally, the electric pulse drill bit 17 is fixedly connected to the conductive drill pipe 9 through the inner cone thread 901h of the shell and the outer cone thread 1705a of the cone head; 2. After the above preparations are completed, start drilling; turn on the drilling fluid pump 13, let the winch 4 lower the steel cable 6, so that the lifting platform 8 drives the conductive drill pipe 9 and the electric pulse drill bit 17 to the bottom of the well, turn on the high-voltage pulse power supply 1 to start drilling and breaking rocks; the drilling fluid 15 is sucked into the drilling fluid pump 13 from the pool 14, and then enters the conductive drill pipe 9 through the drilling fluid pipeline 12, and passes through the drilling fluid flow channel 901c and the flow channel annular groove 901f of the drill pipe shell 901 in the conductive drill pipe 9, and the drilling fluid hole 1704i of the insulator 1704 in the electric pulse drill bit 17 to reach the bottom of the well; then the drilling fluid 15 is sucked into the drilling fluid pump 13 from the water pool 14, and then enters the conductive drill pipe 9 through the drilling fluid pipeline 12, and reaches the bottom of the well through the drilling fluid flow channel 901c and the flow channel annular groove 901f of the drill pipe shell 901 in the conductive drill pipe 9, and the drilling fluid hole 1704i of the insulator 1704 in the electric pulse drill bit 17; then The drilling fluid 15 carries the returning rock cuttings through the outer cylindrical surface of the electric pulse drill bit 17, the inner cylindrical surface of the casing 16, the blowout preventer 18, the sealing head 19, the large-size rock cutting filter 10, the suction pump 20, the cyclone 11, and finally flows back to the pool 14 to complete the drilling fluid circulation; when the lowering length of the steel cable 6 is not enough to continue drilling, the winch 4 is used to retract the steel cable 6 so that the lifting platform 8 drives the conductive drill rod 9 and the electric pulse drill bit 17 to rise, and a new conductive drill rod 9 is added between the conductive drill rods 9. The action of adding the conductive drill rod 9 is consistent with the existing drill rod adding method, and then the above work is repeated until the drilling task is completed.

[0026] In step 2, large-sized cuttings in the returned cuttings are retained in the large-sized cuttings filter 10, and small-sized cuttings and silt are sent to the cyclone 11 by the suction pump 20; the cyclone separates the small-sized cuttings and silt from the drilling fluid; the drilling fluid 15 that has completed the circulation separation can be put into use again to ensure the drilling efficiency.

[0027] Preferably, in the above steps, the high-voltage pulse power supply 1 outputs direct current, the pulse rise time is less than 500ns, the output voltage is 100kV~400kV, and the discharge frequency is 1Hz~10Hz; the high-voltage pulse power supply 1 is grounded as a whole; the material of the high-voltage wire core is copper, and the impedance is less than 50 Ω. The design of this parameter can effectively achieve a balance between rock breaking and energy consumption, is also more friendly to the material and durability of the equipment itself, and improves drilling efficiency.

[0028] Preferably, the conductivity of the drilling fluid 15 is below 200 μs / cm. Since electric pulse drilling is adopted, there is no need for cooling and the like. The function of the drilling fluid 15 is mainly to meet the conductivity requirement and to carry cuttings up the well. The use of this parameter is the best parameter range obtained in the current test and can meet the requirements of most well conditions.

[0029] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A drilling system based on electric pulse rock breaking technology, characterized in that: The invention comprises a wellhead mechanism, a drilling mechanism and an electric pulse mechanism; the wellhead mechanism comprises a derrick (5), a wellbore, a blowout preventer (18) and a drilling fluid group; the drilling mechanism comprises a conductive drill pipe and an electric pulse drill bit (17); the electric pulse mechanism comprises a high-voltage pulse power supply (1), a cable (2) and a cable high-voltage connector (7); a lifting mechanism is provided on the derrick (5) for installing and lifting the conductive drill pipe (9); the cable (2) is connected to the electric pulse drill bit (17) through the cable high-voltage connector (7) and the conductive drill pipe (9); the conductive drill pipe (9) passes through the wellhead and enters the wellbore, and is connected to the wellbore through the drilling fluid group to realize drilling.

2. A drilling system based on electric pulse rock breaking technology according to claim 1, characterized in that: The wellbore comprises a casing (16) on the wellbore wall and a blowout preventer (18) and a sealing head (19) at the wellhead. The drilling fluid assembly comprises a large-size cuttings filter (10), a suction pump (20), a cyclone (11), a water pool (14), and a drilling fluid pump (13) which are sequentially connected via a drilling fluid pipeline (12). The water pool (14) is used to store drilling fluid (15). The sealing head (19) and the conductive drill pipe (9) are also respectively connected to the drilling fluid pipeline (12) to form a circulation path. The lifting mechanism comprises a winch (4) and a steel cable (6); a lifting platform (8) is provided at the lower end of the steel cable (6); a pulley frame (3) is provided on the derrick (5) for supporting the cable (2) to move up and down with the lifting platform (8); the pulley frame (3) is composed of a sling (301), a pulley frame (302), and a pulley (303).

3. A drilling system based on electric pulse rock breaking technology according to claim 2, characterized in that: The cable (2) comprises a high-voltage core (201) and a grounding core (202); the high-voltage core (201) and the grounding core (202) are two independent lines, each of which is wrapped with an insulating layer (205) on the outside; a braided layer (204) and an outer insulating layer (203) are wrapped on the outside of the high-voltage core (201) and the grounding core (202); and an insulating filler (206) for supporting and fixing the high-voltage core (201) and the grounding core (202) is filled on the inside of the braided layer (204).

4. The drilling system based on electric pulse rock breaking technology according to claim 2 is characterized in that: The conductive drill rod (9) comprises a drill rod shell (901), a high-voltage male connector (902), a copper rod (903), a high-voltage female connector (904), an insulating layer (905), a grounding wire rod (906), and a drill rod grounding head (907); the drill rod shell (901) is a cylindrical structure; the upper portion of the drill rod shell (901) has a shell external tapered thread (901a), the lower portion has a shell internal tapered thread (901h), an axial through hole is provided inside as a shell high-voltage through hole (901j), and a section of reaming is provided at both ends of the shell high-voltage through hole (901j), respectively serving as a shell upper countersunk hole (901b) and a shell lower countersunk hole (901i); at least one drilling fluid flow channel (901c) penetrating the drill rod shell (901) is provided on the outer side of the shell high-voltage through hole (901j), and a reaming hole is provided at the bottom of the drilling fluid flow channel (901c). A flow channel annular groove (901f) is provided, a copper rod (903) is installed in the high-pressure through hole (901j) of the shell, and a high-voltage male connector (902) and a high-voltage female connector (904) are installed at both ends of the copper rod (903), respectively; a plurality of through holes axially penetrating the entire drill rod shell (901) are provided on the shell shoulder (901k) outside the shell external tapered thread (901a) as grounding wire through holes (901e), the bottom of the grounding wire through hole (901e) is a joint annular groove (901g), the joint annular groove (901g) is located on the shell internal tapered thread (901h), and in the outer end surface, a grounding wire rod (906) is installed in the grounding wire through hole (901e), a threaded hole is opened at one end of the grounding wire rod (906), and a drill rod grounding head (907) is installed in the threaded hole, and the other end of the grounding wire rod (906) is an outer tapered surface.

5. A drilling system based on electric pulse rock breaking technology according to claim 4, characterized in that: An insulating layer (905) is provided in the high-voltage through hole (901j) of the shell, and is used to insulate the copper rod (903) from the drill rod shell (901). The high-voltage male connector (902) and the high-voltage female connector (904) are gyro-shaped structures. The size of the outer peripheral surface of the high-voltage male connector (902) is larger than the bottom opening of the upper countersunk hole (901b) of the shell, and the size of the outer peripheral surface of the high-voltage female connector (904) is larger than the top opening of the lower countersunk hole (901i) of the shell, thereby achieving the fixation of the copper rod (903). An insulating layer (905) is also provided on the contact surface between the high-voltage male connector (902) and the high-voltage female connector (904) and the drill rod shell (901).

6. A drilling system based on electric pulse rock breaking technology according to claim 5, characterized in that: The electric pulse drill bit (17) comprises a drill bit high-voltage connector (1701), a high-voltage electrode (1703), an insulator (1704), a grounding cone head (1705), and a grounding electrode (1706); the grounding cone head (1705) and the grounding electrode (1706) are both hollow structures and are connected up and down; an insulator (1704) is provided inside the grounding cone head (1705) and the grounding electrode (1706); an axially penetrating through hole is provided inside the insulator (1704); the upper end of the through hole is an expanded hole section; a high-voltage electrode (1703) is fixed inside the through hole; and a drill bit high-voltage connector (1701) installed in the expanded hole section is provided on the upper section of the high-voltage electrode (1703).

7. A drilling system based on electric pulse rock breaking technology according to claim 6, characterized in that: The upper part of the grounding cone head (1705) is a cone head outer cone thread (1705a), and below the cone head outer cone thread (1705a) is a cone head shoulder (1705b); a convex head threaded hole (1705c) is formed on the cone head shoulder (1705b), and a grounding convex head (1707) is installed in the convex head threaded hole (1705c); the bottom of the grounding cone head (1705) is formed with a plurality of cone head slots (1705e) with square opening structures, and the inner cylindrical surface of the bottom is formed with a cone head inner slot (1705f), and a cone head square boss (1705g); The cylindrical surface at the bottom of the grounding cone head (1705) is provided with a cone head screw countersunk hole (1705d) for installing a cone head screw (1708); the upper part of the grounding electrode (1706) is a grounding electrode protrusion (1706a), and the size of the grounding electrode protrusion (1706a) is consistent with the cone head slot (1705e); the lower part of the grounding electrode (1706) is a grounding petal (1706c); the inner cylindrical surface of the grounding electrode (1706) is provided with a grounding electrode inner boss (1706d); the cylindrical surface of the grounding electrode (1706) is provided with a grounding electrode screw countersunk hole (1706b), the grounding electrode screw countersunk hole (1706b) penetrates the grounding electrode inner boss (1706d), and the number of the grounding electrode screw countersunk holes (1706b) is consistent with the number of the grounding electrode inner boss (1706d); The upper part of the insulator (1704) is a cone structure, the lower part of the cone is an upper shoulder (1704a) of the insulator, and below the upper shoulder (1704a) of the insulator is a lower shoulder (1704b) of the insulator; the upper shoulder (1704a) of the insulator is provided with an upper groove (1704c) of the insulator, which is consistent in size with the square boss (1705g) of the cone head, and an upper threaded hole (1704d) of the insulator is provided at the center of the upper groove (1704c); the lower shoulder (1704b) of the insulator is provided with a lower groove (1704e) of the insulator, which is consistent in size with the inner boss (1706d) of the grounding electrode; the lower groove (1704e) of the insulator is provided with a lower threaded hole (1704f) of the insulator; the upper part of the insulator (1704) is provided with an insulator circular groove (1704c) of the insulator, and the lower threaded hole (1704f) of the insulator is provided at the center of the lower groove (1704e); 04g), a high-voltage electrode hole (1704h) is opened below the circular groove (1704g) of the insulator, the circular groove (1704g) of the insulator and the high-voltage electrode hole (1704h) are coaxial with the insulator (1704), and the shape of the high-voltage electrode hole (1704h) is consistent with that of the high-voltage electrode (1703); a high-voltage joint threaded hole (1704j) is opened at the bottom of the circular groove (1704g) of the insulator; a drilling fluid hole (1704i) is opened on the upper end surface of the insulator (1704), and the drilling fluid hole (1704i) runs through the entire insulator (1704); the upper part of the high-voltage electrode (1703) is a cylinder, the lower part is a conical surface, and the lower end is a spherical surface, and the upper end surface of the high-voltage electrode (1703) is opened with a threaded hole for fixing with the drill bit high-voltage joint (1701).

8. The drilling system based on electric pulse rock breaking technology according to claim 7, characterized in that: The water pool (14), the drilling fluid pump (13), the drilling fluid pipeline (12), the drilling fluid flow channel (901c) and the flow channel annular groove (901f) of the drill rod housing (901) in the conductive drill rod (9), and the drilling fluid hole (1704i) of the insulator (1704) in the electric pulse drill bit (17) constitute an inner channel for drilling fluid circulation; the outer cylindrical surface of the electric pulse drill bit (17), the inner cylindrical surface of the casing (16), the blowout preventer (18), the sealing head (19), the large-size rock cuttings filter (10), the suction pump (20), the cyclone (11) and the water pool (14) constitute an outer channel for drilling fluid circulation.

9. A drilling method based on electric pulse rock breaking technology, characterized in that: The drilling system based on the electric pulse rock breaking technology as described in claims 1-8 is adopted, and the specific steps are as follows: S1. Preparation work before drilling: fix the high-voltage pulse power supply (1), the pulley frame (3), the derrick (5), the large-size cuttings filter (10), the cyclone (11), the drilling fluid pump (13), the water pool (14), and the suction pump (20) on the ground, and ground the high-voltage pulse power supply (1) as a whole; S2. Install the winch (4) on the top platform of the derrick (5), then install the steel cable (6) on the winch (4), connect the conductive drill rod (9) to the lifting platform (8), and install the cable high-voltage connector (7) on the top of the conductive drill rod (9). Connect the pulley frame (3) to the derrick (5) through the sling (301). Connect the head of the cable (2) to the output end of the high-voltage pulse power supply (1), then pass the cable (2) through the pulley frame (3), and connect the tail of the cable (2) to the cable high-voltage connector (7). The head and tail of the drilling fluid pipeline (12) are respectively connected to the conductive drill pipe (9) and the drilling fluid pump (13); the blowout preventer (18) is fixed to the wellhead, and a sealing head (19) is installed on the top of the blowout preventer (18); finally, the electric pulse drill bit (17) is connected to the conductive drill pipe (9) through the inner cone thread (901h) of the shell and the outer cone thread (1705a) of the cone head; S3. After the preparation work is completed, drilling begins. The drilling fluid pump (13) is turned on, and the winch (4) is caused to lower the steel cable (6), so that the lifting platform (8) drives the conductive drill pipe (9) and the electric pulse drill bit (17) to descend to the bottom of the well. The high-voltage pulse power supply (1) is turned on to start drilling and breaking rocks. The drilling fluid (15) is sucked into the drilling fluid pump (13) from the water pool (14), and then enters the conductive drill pipe (9) through the drilling fluid pipeline (12), and passes through the drill pipe housing (901) in the conductive drill pipe (9). The wellbore fluid flow channel (901c), the flow channel annular groove (901f), and the drilling fluid hole (1704i) of the insulator (1704) in the electric pulse drill bit (17) reach the bottom of the well; then the drilling fluid (15) carries the returning rock cuttings through the outer cylindrical surface of the electric pulse drill bit (17), the inner cylindrical surface of the casing (16), the blowout preventer (18), the sealing head (19), the large-size rock cutting filter (10), the suction pump (20), the cyclone (11), and finally flows back to the water pool (14), completing the drilling fluid circulation; S4. During the circulation of the drilling fluid, large-sized cuttings in the returned cuttings are retained in the large-sized cuttings filter (10), and smaller-sized cuttings and silt are sent to the cyclone (11) by the suction pump (20); the cyclone (11) separates the small-sized cuttings and silt from the drilling fluid (15); when the length of the steel cable (6) is not long enough to continue drilling, the winch (4) retracts the steel cable (6) so that the lifting platform (8) drives the conductive drill rod (9) and the electric pulse drill bit (17) to rise, and a new conductive drill rod (9) is added between the conductive drill rods (9), and then the above-mentioned work is repeated until the drilling task is completed.

10. The drilling method based on electric pulse rock breaking technology according to claim 9, characterized in that: The high-voltage pulse power supply (1) outputs direct current, the pulse rise time of which is less than 500 ns, the output voltage is 100 kV to 400 kV, and the discharge frequency is 1 Hz to 10 Hz; the high-voltage pulse power supply (1) is grounded as a whole; and the conductivity of the drilling fluid (15) is less than 200 μs / cm.

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