Drilling system and method based on electrical pulse rock breaking technology

Abstract

The application discloses a drilling system based on rock breaking technology of electric pulse, which comprises a wellhead mechanism, a drilling mechanism and an electric pulse mechanism; the wellhead mechanism comprises a derrick, a well shaft, a blowout preventer and a drilling fluid group; the 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; the derrick is provided with a lifting mechanism for installing and lifting the conductive drill rod; the cable is connected to the electric pulse drill bit through the cable high-voltage connector and the conductive drill rod; the conductive drill rod penetrates the wellhead and enters the well shaft, and is connected to the well shaft through the drilling fluid group to realize drilling. The drilling method thereof is also disclosed. The rock at the bottom of the well is damaged by the continuous discharge of the electrode drill bit, the drill bit and the drill rod do not need to rotate, the performance requirement of the drill rod is reduced, the drilling system is simplified, the equipment cost is effectively reduced, the electric pulse drill bit is simple in structure and convenient to manufacture, only the conductivity of the drilling fluid is required, and the influence on the environment is small.

Description

TECHNICAL FIELD

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

[0002] As the material basis for accelerating modernization, the demand for oil and gas is increasing year by year. In order to meet the global demand for oil and gas, it is necessary to improve the efficiency of exploration and development and reduce the cost of investment. The current mainstream drilling method still uses rotary drilling method, that is, through the continuous rotation of the drill bit, relying on the scraping and shearing of the cutting teeth to cause damage to the rock. This makes the phenomenon of drill bit tooth collapse and tooth loss inevitable; on the other hand, rotary drilling method needs to configure a power device on the ground or downhole to ensure the continuous rotation of the drill bit, and the device is complex; in addition, since the rotation of the drill bit is driven by the drill pipe, the drill pipe needs to bear the torque generated by rock breaking, and when difficult strata are encountered, stick-slip vibration, sticking and other phenomena are prone to occur.

[0003] Electric pulse rock breaking technology is a new drilling method that uses high-voltage electric pulse to cause damage to the rock, has the 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 method, electric pulse drill bit does not need to rotate during rock breaking, 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 cause damage to the rock. Therefore, the wear of the electric pulse drill bit is small, and the electric pulse rock breaking technology does not need a power device on the ground or downhole, which can simplify the drilling system, and these two aspects will greatly reduce the drilling cost. In addition, the electric pulse drill bit has a simple structure, is easy to manufacture and has a low material cost. SUMMARY

[0004] Based on the above background, the present application 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 cause damage to the bottom hole rock, and simplifies the ground and downhole drilling system, realizes efficient, fast and low-cost exploration and development of oil and gas resources.

[0005] In order to achieve the above purpose, the technical scheme of the present application is as follows:

[0006] 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 set; 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, an electric cable and a cable high-voltage connector; the derrick is provided with a lifting mechanism for installing and lifting the conductive drill pipe, the electric cable is connected to the electric pulse drill bit through the cable high-voltage connector and the conductive drill pipe, the conductive drill pipe passes through the wellhead and enters the wellbore, and the drilling fluid set is connected to the wellbore to realize drilling.

[0007] Further, the wellbore comprises a casing on the well wall and a blowout preventer and a sealing head of the wellhead, the drilling fluid set comprises a large-size cuttings filter, a suction pump, a cyclone, a pool and a drilling fluid pump connected in sequence through a drilling fluid pipeline, the pool is used for storing drilling fluid, and the sealing head and the conductive drill pipe are also connected with the drilling fluid pipeline respectively to form a circulation path.

[0008] The lifting mechanism comprises a winch and a steel cable, a lifting platform is arranged at the lower end of the steel cable, and a pulley frame is arranged 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.

[0009] Further, the cable comprises a high-voltage core and a grounding core; the high-voltage core and the grounding core are two independent lines, and are respectively wrapped with an insulation layer one; a braided layer and an outer surface insulation layer are wrapped outside the high-voltage core and the grounding core, and an insulation filler for supporting and fixing the high-voltage core and the grounding core is filled in the inner side of the braided layer.

[0010] Further, the conductive drill pipe is composed of a drill pipe shell, a high-voltage male connector, a copper bar, a high-voltage female connector, an insulation layer two, 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 a shell outer taper thread, the lower part has a shell inner taper thread, an axial through hole is arranged in the inside as a shell high-voltage through hole, and a hole expansion is arranged at both ends of the shell high-voltage through hole as a shell upper counterbore and a shell lower counterbore respectively; at least one drilling fluid flow channel penetrating through the drill pipe shell is arranged outside the shell high-voltage through hole, a hole expansion flow channel annular groove is opened at the bottom of the drilling fluid flow channel, the copper bar is installed in the shell high-voltage through hole, and a high-voltage male connector and a high-voltage female connector are respectively installed at both ends of the copper bar; a plurality of through holes penetrating through the entire drill pipe shell as grounding wire through holes are arranged on the shoulder of the shell outer taper thread, the bottom of the grounding wire through hole is a connector annular groove, the connector annular groove is located in the shell inner taper thread, and the end face outside is arranged with a grounding wire rod installed in the grounding wire through hole, a threaded hole is opened at one end of the grounding wire rod, and a drill pipe grounding head is installed in the threaded hole, and the other end of the grounding wire rod is an outer taper face.

[0011] Further, an insulation layer is arranged in the shell high-voltage through hole to insulate the copper bar from the drill pipe shell, the high-voltage male connector and the high-voltage female connector are in a gyroscopic structure, the size of the outer circumferential surface of the high-voltage male connector is greater than the bottom opening of the shell upper counterbore, and the size of the outer circumferential surface of the high-voltage female connector is greater than the top opening of the shell lower counterbore, so as to fix the copper bar, and an insulation layer is also arranged on the contact surface of the high-voltage male connector and the high-voltage female connector with the drill pipe shell.

[0012] Further, the electric pulse drill bit comprises a drill bit high pressure connector, a high pressure electrode, an insulator, a grounding cone, and a grounding electrode; the grounding cone and the grounding electrode are hollow structures and are connected in sequence, the insulator is arranged in the grounding cone and the grounding electrode, an axial through hole is arranged in the insulator, the upper end of the through hole is an expanded hole section, the high pressure electrode is fixed in the through hole, and the drill bit high pressure connector is arranged in the expanded hole section of the through hole.

[0013] Further, the upper part of the grounding cone is a cone outer taper thread, the lower part of the cone outer taper thread is a cone shoulder, a convex thread hole is arranged on the cone shoulder, a grounding convex head is arranged in the convex thread hole, a plurality of square opening structure cone clamping grooves are arranged on the bottom of the grounding cone, a cone inner clamping groove is arranged on the inner cylindrical surface of the bottom, and a cone square boss is arranged on the bottom;

[0014] the cylindrical surface of the lower part of the grounding cone is provided with a cone screw counterbore for mounting a cone screw, the upper part of the grounding electrode is a grounding electrode protrusion, the size of the grounding electrode protrusion is consistent with the cone clamping groove, the lower part of the grounding electrode is a grounding petal, the inner cylindrical surface of the grounding electrode is provided with a grounding electrode inner boss, the cylindrical surface of the grounding electrode is provided with a grounding electrode screw counterbore, the grounding electrode screw counterbore penetrates the grounding electrode inner boss, the number of the grounding electrode screw counterbores is consistent with the number of the grounding electrode inner bosses;

[0015] the upper part of the insulator is a conical structure, the lower part of the conical structure is an insulator upper shoulder, the lower part of the insulator upper shoulder is an insulator lower shoulder, the insulator upper shoulder is provided with an insulator upper clamping groove, the size of the insulator upper clamping groove is consistent with the size of the cone square boss, the center of the insulator upper clamping groove is provided with an insulator upper thread hole, the insulator lower shoulder is provided with an insulator lower clamping groove, the size of the insulator lower clamping groove is consistent with the size of the grounding electrode inner boss, the center of the insulator lower clamping groove is provided with an insulator lower thread hole, the upper part of the insulator is provided with an insulator circular groove, the lower part of the insulator circular groove is provided with a high pressure electrode hole, the insulator circular groove, the high pressure electrode hole and the insulator are coaxial, the shape of the high pressure electrode hole is consistent with the shape of the high pressure electrode, the bottom of the insulator circular groove is provided with a high pressure connector thread hole, the upper end surface of the insulator is provided with a drilling fluid hole, the drilling fluid hole penetrates the entire insulator, the upper part of the high pressure electrode is a cylinder, the lower part of the high pressure electrode is a conical surface, the lower end of the high pressure electrode is a spherical surface, the upper end surface of the high pressure electrode is provided with a thread hole for fixedly connecting with the drill bit high pressure connector.

[0016] Further, the drilling fluid circulation inner channel is formed by the drilling fluid flow channel of the drill pipe shell in the conductive drill pipe, the flow channel annular groove of the drilling fluid flow channel ring, and the drilling fluid hole of the insulator in the electric pulse drill bit; the drilling fluid circulation outer channel is formed by 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 rock debris filter, the suction pump, the cyclone, and the water pool.

[0017] A drilling method based on the electric pulse rock breaking technology, adopting the drilling system based on the electric pulse rock breaking technology, and the specific steps are as follows:

[0018] S1, before drilling, fixing the high-voltage pulse power supply, the pulley frame, the derrick, the large-size rock debris filter, the cyclone, the drilling fluid pump, the pool and the suction pump on the ground, and grounding the high-voltage pulse power supply as a whole;

[0019] S2, installing the winch on the top platform of the derrick, then installing the steel cable on the winch, fixing the conductive drill rod with the lifting platform, and installing the cable high-voltage connector on the top end of the conductive drill rod. Through the sling, the pulley frame is fixed with the derrick. The head of the cable is connected with the output end of the high-voltage pulse power supply, then the cable passes through the pulley frame, and the tail of the cable is connected with the cable high-voltage connector. The head and tail of the drilling fluid pipeline are fixed with the conductive drill rod and the drilling fluid pump respectively; the blowout preventer is fixed on the wellhead, and the sealing head is installed on the top of the blowout preventer; finally, the electric pulse drill bit is fixed with the conductive drill rod through the inner cone thread of the shell and the outer cone thread of the cone head.

[0020] S3, after the preparation work is completed, drilling is started, the drilling fluid pump is opened, the winch is lowered, the lifting platform drives the conductive drill rod and the electric pulse drill bit to descend to the bottom of the well, the high-voltage pulse power supply is started to drill and break rocks, the drilling fluid is sucked into the drilling fluid pump from the pool, then enters the conductive drill rod through the drilling fluid pipeline, and reaches the bottom of the well through the drilling fluid flow channel of the drill rod shell in the conductive drill rod, the annular groove of the flow channel and the drilling fluid hole i of the insulator in the electric pulse drill bit; then the drilling fluid carries the upward rock debris to pass 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 rock debris filter, the suction pump, the cyclone, and finally flows back to the pool, completing the drilling fluid circulation;

[0021] S4, during the drilling fluid circulation process, the large-size rock debris in the upward rock debris is left in the large-size rock debris filter, and the small-size rock debris and the sand are pumped into the cyclone by the suction pump; the cyclone separates the small-size rock debris and the sand from the drilling fluid; when the length of the steel cable is insufficient for continuous drilling, the winch is recovered to make the lifting platform drive the conductive drill rod and the electric pulse drill bit to ascend, and new conductive drill rods are added between the conductive drill rods, the process is the same as the traditional drill rod adding action, then the above work is repeated until the drilling task is completed.

[0022] Further, the high-voltage pulse power supply outputs direct current, the pulse rising edge time is less than 500 ns, the output voltage is 100 kV~400 kV, and the discharge frequency is 1 Hz~10 Hz; the high-voltage pulse power supply is grounded as a whole; and the conductivity of the drilling fluid is below 200 μs / cm.

[0023] The beneficial effects of the present application are:

[0024] 1. The electric pulse drilling scheme provided by the present application, compared with the existing drilling technology, does not need a rotating power device, uses a high-voltage pulse power supply as an energy source, simplifies the ground device, reduces the wear of the drill bit, thereby reducing the time and material loss caused by replacing the drill bit, and the structure of the present application is more exquisite, can ensure the stability of the internal connection between each electric pulse device and each electric pulse device itself, is convenient to disassemble and assemble, is convenient to replace and increase or decrease parts through lifting, and thus realizes the overall efficient drilling effect.

[0025] 2. Based on the requirements of electric pulse drilling, the present application only has a requirement for the conductivity of the drilling fluid, has a small influence on the environment during the circulation of the drilling fluid, is convenient to use in the later circulation, is not easy to cause damage and influence to the conductive drill pipe and other structures, and thus ensures the drilling effect.

[0026] 3. Compared with the existing electric pulse drilling technical scheme, the electrode drill bit in the present application adopts a segmented clamping groove structure, which can effectively resist the circumferential vibration generated during drilling to ensure the stability of the structure.

[0027] 4. The conductive drill pipe in the present application can effectively eliminate the electric shock hidden danger and improve the safety in the drilling process.

[0028] 5. The electrode drill bit in the present application has a simple structure, is convenient to manufacture, has a low material cost, is more easy to install, use and maintain, and at the same time, has a lower requirement for the mechanical properties of the drill pipe than the traditional drilling method. BRIEF DESCRIPTION OF DRAWINGS

[0029] The present application will be further described in detail below in combination with the drawings.

[0030] Figure 1 is a schematic diagram of a drilling system;

[0031] Figure 2 is a schematic diagram of the internal cross-sectional structure of a cable;

[0032] Figures 3-4 is a schematic diagram of the structure of a conductive drill pipe;

[0033] Figures 5-8 is a schematic diagram of the structure of a conductive drill pipe shell;

[0034] Figures 9-12 is a schematic diagram of the structure of an electric pulse drill bit;

[0035] Figures 13-16 is a schematic diagram of the structure of a grounding cone;

[0036] Figures 17-19 is a schematic diagram of the structure of a grounding electrode;

[0037] Figures 20-24 is a schematic diagram of the structure of an insulator;

[0038] Figures 25-26 Structure diagram of pulley frame;

[0039] In the above figures: 1. High-voltage pulse power supply; 2. Cable; 201. High-voltage core; 202. Ground wire; 203. Outer insulating layer; 204. Braided layer; 205. Insulating layer one; 206. Insulating filler; 3. Pulley frame; 301. Hoist rope; 302. Pulley frame; 303. Pulley; 4. Winch; 5. Derrick; 6. Cable; 7. Cable high-voltage connector; 8. Elevating platform; 9. Conductive drill pipe; 901. Drill pipe shell; 901a. Shell outer taper thread; 901b. Shell upper counterbore; 901c. Drilling fluid flow channel; 901d. Ground head counterbore; 901e. Ground wire through hole; 901f. Flow channel annular groove; 901g. Connector annular groove; 901h. Shell inner taper thread; 901i. Shell lower counterbore; 901j. Shell high-voltage through hole; 901k. Shell shoulder; 902. High-voltage male connector; 903. Copper rod; 904. High-voltage female connector; 905. Insulating layer two; 906. Ground rod; 907. Drill pipe grounding head; 10. Large-size rock debris 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 clamping groove; 1704d. Insulator upper threaded hole; 1704e. Insulator lower clamping groove; 1704f. Insulator lower threaded hole; 1704g. Insulator circular groove; 1704h. High-voltage electrode hole; 1704i. Drilling fluid hole; 1704j. High-voltage connector threaded hole; 1705. Ground cone head; 1705a. Cone head outer taper thread; 1705b. Cone head shoulder; 1705c. Convex head threaded hole; 1705d. Cone head screw counterbore; 1705e. Cone head clamping groove; 1705f. Cone head inner clamping groove; 1705g. Cone head square boss; 1706. Ground electrode; 1706a. Ground electrode protrusion; 1706b. Ground electrode screw counterbore; 1706c. Ground petal; 1706d. Ground electrode inner boss; 1707. Ground convex head; 1708. Cone head screw; 1709. Ground electrode screw; 18. Blowout preventer; 19. Sealing head; 20. Suction pump. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described below in conjunction with examples, but is not a limitation to the scope of protection of the present application.

[0041] As shown in Figures 1-25 , a drilling system based on electric pulse rock breaking technology, comprising 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 joint 7, a lifting platform 8, a conductive drill pipe 9, a large-size rock debris filter 10, a cyclone 11, a drilling fluid pipeline 12, a drilling fluid pump 13, a pool 14, drilling fluid 15, a casing 16, an electric pulse drill bit 17, a blowout preventer 18, a sealing head 19, a suction pump 20, as shown in Figure 1 ; the head of the cable 2 is connected with 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 with the cable high-voltage joint 7; the cable high-voltage joint 7 is fixedly connected with the conductive drill pipe 9; the conductive drill pipe 9 is fixedly connected with the lifting platform 8, and the lifting platform 8 is fixedly connected with the steel cable 6, which is wound on the winch 4; the winch 4 is fixedly connected with the top platform of the derrick 5, and the bottom of the derrick 5 is fixed on the ground; the winch 4 realizes the winding and unwinding of the steel cable 6 by rotating, so as to realize the lifting and lowering of the lifting platform 8; the drill pipe 9 is fixedly connected with the electric pulse drill bit 17 by thread, so as to realize the lifting and lowering of the conductive drill pipe 9 and the electric pulse drill bit 17; the blowout preventer 18 is installed at the well mouth; the sealing head 19 is fixedly connected with the top end of the blowout preventer 18 and the platform in the middle of the derrick 5; the large-size rock debris filter 10 is connected with the sealing head 19 through a pipeline; the large-size rock debris filter 10 is connected with the suction pump 20 through a pipeline; the cyclone 11 is connected with the suction pump 20 through a pipeline.

[0042] The drilling fluid pipeline 12 is connected with the top of the conductive drill pipe 9 and the drilling fluid pump 13; the cable 2 is a coaxial line, which is composed of a high-voltage wire core 201, a grounding wire core 202, an outer surface insulating layer 203, a braided layer 204, an insulating layer 205 and an insulating filler 206, as shown in Figure 2 . Preferably, the high-voltage wire core 201 can adopt a size of more than 20% thicker than the existing fiber core diameter used in the field, so as to reduce power loss.

[0043] The pulley frame 3 is composed of a sling 301, a pulley frame 302 and a pulley 303, wherein, as shown in Figure 9 , the sling 301 includes a plurality of equal-length slings 301, which are uniformly applied to the pulley frame 302; the pulley 303 has a structure of two rows of pulleys arranged above and below, and each row has the same number of pulleys, as shown in Figures 25-26 . In this way, the pulley frame 3 can make the cable 2 move and fix more uniformly, and disperse the stress points to reduce the damage probability.

[0044] As shown in Figures 3-4As shown, the conductive drill pipe 9 is composed of a drill pipe shell 901, a high pressure male joint 902, a copper rod 903, a high pressure female joint 904, an insulation layer two 905, a grounding wire rod 906, and a drill pipe grounding head 907. The insulation layer two 905 is bonded to the inner walls of the shell upper counterbore 901b, the shell lower counterbore 901i, and the shell high pressure through hole 901j of the drill pipe shell 901. The copper rod 903 is a cylinder with threaded holes at both ends, coaxial with the shell high pressure through hole 901j, and the outer cylindrical surface of the copper rod 903 directly contacts the insulation layer two 905. The upper part of the high pressure male joint 902 is a circular truncated cone, the middle part is a boss, and the lower part is a threaded rod. The high pressure core is connected to the high pressure male joint 902 on the drill pipe 9. The upper part of the high pressure female joint 904 is a threaded rod, the middle part is a boss, and the lower part is a cylinder. The inside of the cylinder is a circular truncated cone cavity, which is the same size as the circular truncated cone of the upper part of the high pressure male joint 902. The high pressure male joint 902 and the high pressure female joint 904 are fixedly connected to the copper rod 903 through threads. The boss of the high pressure male joint 902 and the boss of the high pressure female joint 904 fix the axial positions of the copper rod 903, the high pressure male joint 902, and the high pressure female joint 904. As shown, Figures 5-8 As shown, the drill pipe shell 901 has a shell outer tapered thread 901a at the upper part and a shell inner tapered thread 901h at the lower part. The shape of the shell outer tapered thread 901a is consistent with that of the shell inner tapered thread 901h. The drill pipe shell 901 has a shell shoulder 901k below the shell outer tapered thread 901a, and the shell shoulder 901k has a grounding head counterbore 901d for installing the drill pipe grounding head 907. The grounding wire is connected to the drill pipe grounding head 907 on the drill pipe 9. The drill pipe shell 901 has a grounding wire through hole 901e coaxial with the grounding head counterbore 901d below, for installing the grounding wire rod 906. The bottom of the grounding wire through hole 901e of the drill pipe shell 901 is a joint annular groove 901g. The drill pipe shell 901 has 6-8 drilling fluid flow channels 901c, and the bottom of each drilling fluid flow channel 901c has a flow channel annular groove 901f. One end of the grounding wire rod 906 has a threaded hole for fixedly connecting with the drill pipe grounding head 907, and the other end of the grounding wire rod 906 is an outer tapered surface.

[0045] As shown, Figures 9-12 The electric pulse drill bit 17 is composed of a drill bit high pressure joint 1701, a high pressure joint screw 1702, a high pressure electrode 1703, an insulator 1704, a grounding cone head 1705, a grounding electrode 1706, a grounding boss 1707, a cone head screw 1708, and a grounding electrode screw 1709. As shown, Figures 13-16As shown, the upper part of the grounding cone head 1705 is the cone head outer taper thread 1705a, and the lower part of the cone head outer taper thread 1705a is the cone head shoulder 1705b; the cone head shoulder 1705b is provided with a protrusion thread hole 1705c matched with the grounding protrusion 1707; the bottom of the grounding cone head 1705 is provided with a cone head clamping groove 1705e, and the inner cylindrical surface of the bottom is provided with a cone head inner clamping groove 1705f, and there is 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 counterbore 1705d for installing the cone head screw 1708; as shown Figures 17-19 As shown, the upper part of the grounding electrode 1706 is the grounding electrode protrusion 1706a, which is consistent in size with the cone head clamping groove 1705e, and the cone head clamping groove 1705e is matched 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 the grounding petal 1706c; the inner cylindrical surface of the grounding electrode 1706 is provided with the grounding electrode inner boss 1706d, which is inserted into the insulator lower clamping groove 1704e to realize positioning and enhance the reliability of the connection, and can resist the weak circumferential force generated during drilling; the cylindrical surface of the grounding electrode 1706 is provided with the grounding electrode screw counterbore 1706b, which penetrates the grounding electrode inner boss 1706d, and the number of the grounding electrode screw counterbore 1706b is consistent with that of the grounding electrode inner boss 1706d; as shown Figures 20-24As shown, the upper part of the insulator 1704 is a frustum structure, the lower part of the frustum is an insulator upper shoulder 1704a, and the lower part of the insulator upper shoulder 1704a is an insulator lower shoulder 1704a; the insulator upper shoulder 1704a is provided with an insulator upper clamping groove 1704c, which is consistent in size with the square protrusion 1705g of the cone head, and the center of the insulator upper clamping groove 1704c is provided with an insulator upper threaded hole 1704d; the insulator lower shoulder 1704a is provided with an insulator lower clamping groove 1704e, which is consistent in size with the inner protrusion 1706d of the grounding electrode; the center of the insulator lower clamping groove 1704e is provided with an insulator lower threaded hole 1704f; the upper part of the insulator 1704 is provided with an insulator circular groove 1704g, and the lower part of the insulator circular groove 1704g is provided with a high-voltage electrode hole 1704h, the insulator circular groove 1704g, the high-voltage electrode hole 1704h and the insulator 1704 are coaxial, and the high-voltage electrode hole 1704h is consistent in shape with the high-voltage electrode 1703; the bottom of the insulator circular groove 1704g is provided with a high-voltage connector threaded hole 1704j; the upper end surface of the insulator 1704 is provided with a drilling fluid hole 1704i, which penetrates 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 provided with a threaded hole for fixed connection with the drill bit high-voltage connector 1701; such design can better fix and connect the electric pulse drill bit 17 together, and can also make the connection with the conductive drill pipe 9 more stable through the engagement and fixation of multiple positions.

[0046] According to the above structure, as Figure 1 As shown, the drilling fluid flow channel 901c and the flow channel annular groove 901f of the drill pipe shell 901 of the conductive drill pipe 9, the drilling fluid hole 1704i of the insulator 1704 of the electric pulse drill bit 17, 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 debris filter 10, the suction pump 20, the cyclone 11 and the water tank 14 constitute the inner passage of the drilling fluid circulation; the outer passage of the drilling fluid circulation is composed of the electric pulse drill bit 17, the casing 16, the blowout preventer 18, the sealing head 19, the large-size rock debris filter 10, the suction pump 20, the cyclone 11 and the water tank 14; such design ensures smooth circulation of the entire drilling fluid 15, realizes stable conductivity efficiency, and improves the effect of electric pulse drilling.

[0047] Based on the above-mentioned drilling method of the drilling system based on the electric pulse rock breaking technology, the method comprises the following steps:

[0048] 1、First, the preparation work before drilling, the high-voltage pulse power 1, pulley frame 3, derrick 5, large size rock debris filter 10, cyclone 11, drilling fluid pump 13, pool 14, suction pump 20 fixed on the ground, and the high-voltage pulse power 1 grounding; winch 4 is installed on the top platform of derrick 5, then the steel cable 6 is installed on the winch 4; the conductive drill pipe 9 is connected with the lifting platform 8, and the cable high-voltage connector 7 is installed on the top of the conductive drill pipe 9; through the sling 301, the pulley frame 3 is connected with the derrick 5; the head of the cable 2 is connected with the output end of the high-voltage pulse power 1, then the cable 2 passes through the pulley frame 3, and the tail of the cable 2 is connected with the cable high-voltage connector 7; the head and tail of the drilling fluid pipeline 12 are respectively connected with the conductive drill pipe 9 and the drilling fluid pump 13; the blowout preventer 18 is fixed on the well mouth, and the sealing head 19 is installed on the top of the blowout preventer 18; finally, the electric pulse drill bit 17 is connected with the conductive drill pipe 9 through the shell inner taper thread 901h and the taper head outer taper thread 1705a;

[0049] 2、After the above preparation work is completed, the drilling work is started; the drilling fluid pump 13 is opened, the winch 4 is lowered, the steel cable 6 is lowered, 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 1 is opened to start drilling and rock breaking; the drilling fluid 15 is sucked into the drilling fluid pump 13 from the pool 14, then enters the conductive drill pipe 9 through the drilling fluid pipeline 12, passes through the drilling fluid flow channel 901c of the drill pipe shell 901 and the flow channel annular groove 901f 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 carries the upward rock debris to pass through the electric pulse drill bit 17, the casing 16, the blowout preventer 18, the sealing head 19, the large size rock debris filter 10, the suction pump 20 and the cyclone 11, and finally flows back to the pool 14 to complete the drilling fluid circulation; when the length of the steel cable 6 is insufficient to continue drilling, the winch 4 is recovered to make the lifting platform 8 drive the conductive drill pipe 9 and the electric pulse drill bit 17 to rise, new conductive drill pipes 9 are added between the conductive drill pipes 9, the action of adding the conductive drill pipe 9 is consistent with the existing method of adding the drill pipe, then the above work is repeated until the drilling task is completed.

[0050] In step 2, the large size rock debris in the upward rock debris is left in the large size rock debris filter 10, and the small size rock debris and silt are sent into the cyclone 11 by the suction pump 20; the cyclone separates the small size rock debris and silt from the drilling fluid; the drilling fluid 15 which completes the circulation and separation can be used again to ensure the drilling efficiency.

[0051] Preferably, in the above steps, the high-voltage pulse power supply 1 outputs direct current, the pulse rising edge 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. With the design of the above parameters, the balance of rock breaking and energy consumption can be effectively realized, the material and durability of the device itself are relatively friendly, and the drilling efficiency is improved.

[0052] Preferably, the conductivity of the drilling fluid 15 is below 200 μs / cm. Since the electric pulse drilling is adopted, the cooling and other treatments are not required, the function of the drilling fluid 15 is mainly to meet the conductivity requirement and to realize the purpose of carrying the rock debris to the well, and the above parameter is the best parameter range obtained in the current test, which can meet the requirement of most well conditions.

[0053] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the technical solution of the present application, and the equivalent embodiments with equivalent changes are equivalent to the above embodiments. Any simple modification, equivalent change and modification made on the basis of the technical essence of the present application to the above embodiments are still within the scope of the technical solution of the present application.

Claims

1. A drilling system based on electrical pulse rock breaking technology, characterized in that, The application relates to a drilling device with an electric pulse mechanism, which comprises a wellhead mechanism, a drilling mechanism and the electric pulse mechanism; the wellhead mechanism comprises a derrick (5), a well shaft, a blowout preventer (18) and a drilling fluid set; the drilling mechanism comprises a conductive drill rod 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); the derrick (5) is provided with a lifting mechanism for installing and lifting the conductive drill rod (9); the cable (2) is connected to the electric pulse drill bit (17) through the cable high-voltage connector (7) and the conductive drill rod (9); the conductive drill rod (9) penetrates the wellhead and enters the well shaft and is connected to the well shaft through the drilling fluid set to realize drilling; 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 in sequence; the insulator (1704) is arranged in the grounding cone head (1705) and the grounding electrode (1706); an axial through hole is arranged in the insulator (1704); the upper end of the through hole is an expanded hole section; the high-voltage electrode (1703) is fixed in the through hole; the drill bit high-voltage connector (1701) is arranged in the expanded hole section of the through hole and is arranged on the upper section of the high-voltage electrode (1703); The upper part of the grounding cone head (1705) is a cone head outer taper thread (1705a); the lower part of the cone head outer taper thread (1705a) is a cone head shoulder (1705b); the cone head shoulder (1705b) is provided with a stud thread hole (1705c); the grounding stud (1707) is arranged in the stud thread hole (1705c); the bottom of the grounding cone head (1705) is provided with a plurality of square opening structure cone head clamping grooves (1705e); the bottom inner cylindrical surface is provided with a cone head inner clamping groove (1705f); and the bottom is provided with a cone head square protrusion (1705g); The cylindrical surface of the lower part of the grounding cone head (1705) is provided with a cone head screw counterbore (1705d) for arranging the cone head screw (1708); the upper part of the grounding electrode (1706) is a grounding electrode protrusion (1706a); the size of the grounding electrode protrusion (1706a) is consistent with that of the cone head clamping groove (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 protrusion (1706d); the cylindrical surface of the grounding electrode (1706) is provided with a grounding electrode screw counterbore (1706b); the grounding electrode screw counterbore (1706b) penetrates the grounding electrode inner protrusion (1706d); the number of the grounding electrode screw counterbores (1706b) is consistent with that of the grounding electrode inner protrusion (1706d). The upper part of the insulator (1704) is a conical structure, the lower part of the conical structure is an insulator upper shoulder (1704a), and the lower part of the insulator upper shoulder (1704a) is an insulator lower shoulder (1704b); the insulator upper shoulder (1704a) is provided with an insulator upper clamping groove (1704c) with a size consistent with that of the square convex column (1705g) of the conical head, and the center of the insulator upper clamping groove (1704c) is provided with an insulator upper threaded hole (1704d); the insulator lower shoulder (1704b) is provided with an insulator lower clamping groove (1704e) with a size consistent with that of the inner convex column (1706d) of the grounding electrode; the center of the insulator lower clamping groove (1704e) is provided with an insulator lower threaded hole (1704f); the upper part of the insulator (1704) is provided with an insulator circular groove (1704g), the lower part of the insulator circular groove (1704g) is provided with a high-voltage electrode hole (1704h), the insulator circular groove (1704g), the high-voltage electrode hole (1704h) and the insulator (1704) are coaxial, the high-voltage electrode hole (1704h) has a shape consistent with that of the high-voltage electrode (1703); the bottom of the insulator circular groove (1704g) is provided with a high-voltage connector threaded hole (1704j); the upper end surface of the insulator (1704) is provided with a drilling fluid hole (1704i), and the drilling fluid hole (1704i) penetrates 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; the upper end surface of the high-voltage electrode (1703) is provided with a threaded hole for fixed connection with the drill bit high-voltage connector (1701).

2. The drilling system based on electrical pulse rock breaking technology according to claim 1, characterized in that, The wellbore comprises a casing (16) on the well wall and a blowout preventer (18) and a sealing head (19) at the wellhead, and the drilling fluid set comprises a large-size rock debris filter (10), a suction pump (20), a cyclone (11), a pool (14), a drilling fluid pump (13) connected in sequence through a drilling fluid pipeline (12), the pool (14) is used for storing drilling fluid (15), and the sealing head (19) and the conductive drill rod (9) are also connected with the drilling fluid pipeline (12) respectively to form a circulation path. The lifting mechanism comprises a winch (4) and a steel cable (6), a lifting platform (8) is arranged at the lower end of the steel cable (6), and a pulley frame (3) is arranged on the derrick (5) and used 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. The drilling system based on electrical 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, and are respectively wrapped with an insulating layer I (205); the high-voltage core (201) and the grounding core (202) are wrapped with a braided layer (204) and an outer insulating layer (203) outside, and the braided layer (204) is filled with an insulating filler (206) inside for supporting and fixing the high-voltage core (201) and the grounding core (202).

4. The drilling system based on electrical pulse rock breaking technology according to claim 2, characterized in that, The conductive drill pipe (9) is composed of a drill pipe shell (901), a high-pressure male joint (902), a copper bar (903), a high-pressure female joint (904), an insulation layer two (905), a grounding wire bar (906), and a drill pipe grounding head (907). The drill pipe shell (901) is in a cylindrical structure. The upper part of the drill pipe shell (901) has a shell outer taper thread (901a), and the lower part has a shell inner taper thread (901h). An axial through hole is arranged in the inside as a shell high-pressure through hole (901j). Two ends of the shell high-pressure through hole (901j) are respectively provided with an expansion hole as a shell upper counterbore (901b) and a shell lower counterbore (901i). At least one drilling fluid flow channel (901c) penetrating through the drill pipe shell (901) is arranged on the outside of the shell high-pressure through hole (901j). The bottom of the drilling fluid flow channel (901c) is provided with an expansion hole as a flow channel annular groove (901f). The copper bar (903) is arranged in the shell high-pressure through hole (901j). The two ends of the copper bar (903) are respectively provided with the high-pressure male joint (902) and the high-pressure female joint (904). A plurality of through holes as grounding wire through holes (901e) are arranged on the shell shoulder (901k) outside the shell outer taper thread (901a) and penetrate through the entire drill pipe shell (901). The bottom of the grounding wire through hole (901e) is a joint annular groove (901g) located in the shell inner taper thread (901h) and the end face outside. The grounding wire bar (906) is arranged in the grounding wire through hole (901e). A threaded hole is arranged at one end of the grounding wire bar (906), and the drill pipe grounding head (907) is arranged in the threaded hole. The other end of the grounding wire bar (906) is an outer taper surface.

5. The drilling system based on electrical pulse rock breaking technology according to claim 4, characterized in that, The insulation layer two (905) is arranged in the shell high-pressure through hole (901j) to insulate the copper bar (903) from the drill pipe shell (901). The high-pressure male joint (902) and the high-pressure female joint (904) are in a gyroscopic structure. The size of the outer circumferential surface of the high-pressure male joint (902) is greater than the bottom opening of the shell upper counterbore (901b), and the size of the outer circumferential surface of the high-pressure female joint (904) is greater than the top opening of the shell lower counterbore (901i), so as to fix the copper bar (903). The contact surfaces of the high-pressure male joint (902) and the high-pressure female joint (904) with the drill pipe shell (901) are also provided with the insulation layer two (905).

6. The drilling system based on electrical pulse rock breaking technology according to claim 5, characterized in that, The drilling fluid circulation inner channel is composed of the drilling fluid flow channel (901c) and the flow channel annular groove (901f) of the drill pipe shell (901) in the water pool (14), the drilling fluid pump (13), the drilling fluid pipeline (12), and the conductive drill pipe (9), and the drilling fluid hole (1704i) of the insulator (1704) in the electric pulse drill bit (17). The drilling fluid circulation outer channel is composed of 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 debris filter (10), the suction pump (20), the cyclone (11), and the water pool (14).

7. A method of drilling a well based on electrical pulse rock breaking technology, characterized in that, The drilling system based on the rock breaking technology of electric pulse as claimed in any one of claims 1-6 comprises the following specific steps: S1, before drilling, fixing the high-voltage pulse power supply (1), the pulley frame (3), the derrick (5), the large-size rock debris filter (10), the cyclone (11), the drilling fluid pump (13), the pool (14) and the suction pump (20) on the ground, and grounding the high-voltage pulse power supply (1) as a whole; S2, installing the winch (4) on the top platform of the derrick (5), then installing the steel cable (6) on the winch (4), fixing the conductive drill pipe (9) with the lifting platform (8), and installing the cable high-voltage connector (7) on the top end of the conductive drill pipe (9); fixing the pulley frame (3) with the derrick (5) through the sling (301); connecting the head of the cable (2) with the output end of the high-voltage pulse power supply (1), then passing the cable (2) through the pulley frame (3), and connecting the tail of the cable (2) with the cable high-voltage connector (7); fixing the head and tail of the drilling fluid pipeline (12) with the conductive drill pipe (9) and the drilling fluid pump (13) respectively; fixing the blowout preventer (18) on the wellhead, and installing the sealing head (19) on the top of the blowout preventer (18); finally, fixing the electric pulse drill bit (17) with the conductive drill pipe (9) through the inner cone thread (901h) and the outer cone thread (1705a) of the cone head; S3, after the preparation work is completed, starting drilling, opening the drilling fluid pump (13), lowering the steel cable (6) by the winch (4), making the lifting platform (8) drive the conductive drill pipe (9) and the electric pulse drill bit (17) to descend to the bottom of the well, opening the high-voltage pulse power supply (1) to start drilling and rock breaking, and making the drilling fluid (15) in the pool (14) be sucked into the drilling fluid pump (13), then enter the conductive drill pipe (9) through the drilling fluid pipeline (12), pass 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), the drilling fluid hole (1704i) of the insulator (1704) in the electric pulse drill bit (17), and reach the bottom of the well; then making the drilling fluid (15) carrying the upward rock debris pass 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 debris filter (10), the suction pump (20) and the cyclone (11), and finally flow back to the pool (14), completing the drilling fluid circulation; S4, during the drilling fluid circulation, the large-size rock debris in the upward rock debris is left in the large-size rock debris filter (10), and the small-size rock debris and the sand are sent into the cyclone (11) by the suction pump (20); the cyclone (11) separates the small-size rock debris and the sand from the drilling fluid (15); when the length of the steel cable (6) is insufficient for further drilling, making the winch (4) recover the steel cable (6) to make the lifting platform (8) drive the conductive drill pipe (9) and the electric pulse drill bit (17) to rise, adding new conductive drill pipes (9) between the conductive drill pipes (9), and then repeating the above work until the drilling task is completed.

8. The method of claim 7, wherein the method further comprises, The high-voltage pulse power supply (1) outputs direct current, the pulse rising edge time is less than 500 ns, the output voltage is 100 kV-400 kV, and the discharge frequency is 1 Hz-10 Hz; the high-voltage pulse power supply (1) is integrally grounded; and the conductivity of the drilling fluid (15) is below 200 μs / cm.

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