CN-117365330-B - Flexible shaft, universal shaft, drilling machine system and application of universal shaft

CN117365330BCN 117365330 BCN117365330 BCN 117365330BCN-117365330-B

Abstract

The invention discloses a flexible shaft, a universal shaft, a drilling machine system and application of the universal shaft, wherein the flexible shaft can comprise a flexible shaft body and a first connector arranged at one end of the flexible shaft body, the first connector is used for externally connecting with a flexible shaft lower connector and is connected with a drill bit through the flexible shaft lower connector, the first connector comprises a meshing part, a hinge ball connected with the meshing part and a limit post connected with the hinge ball, spline teeth are formed in at least part of the outer surface of the meshing part, the meshing part is used for meshing with spline grooves on the externally connected flexible shaft lower connector through the spline teeth, the hinge ball is connected with a ball seat ball on the flexible shaft lower connector through the hinge ball, and the limit post is used for connecting a safety ball for limiting. The flexible shaft of the invention greatly slows down the violent impact and vibration from the rotor and the drill bit, and the spline teeth of the flexible shaft are meshed with the spline grooves of the lower joint of the flexible shaft for transmission, thereby improving the service lives of the flexible shaft and the universal shaft while transmitting high torque and high rotating speed.

Inventors

YANG WENJING
SHI HONGJIANG
PAN XINGMING
LU YIPING
WANG ZHIGUO
LI HEXIANG
SHI QIAN

Assignees

中国石油天然气集团有限公司
中国石油集团工程技术研究院有限公司
北京石油机械有限公司

Dates

Publication Date: 20260508
Application Date: 20220629

Claims (18)

1. The universal shaft is characterized by comprising a shell, a flexible shaft lower joint, a safety body, a sealing assembly and a flexible shaft, wherein the flexible shaft lower joint, the safety body, the sealing assembly and the flexible shaft are arranged in the shell; the flexible shaft comprises a flexible shaft body and a first connecting head arranged at one end of the flexible shaft body, wherein the first connecting head is used for externally connecting a flexible shaft lower joint and is connected with a drill bit through the flexible shaft lower joint; The first connector comprises a meshing part, a hinge ball connected with the meshing part and a limit column connected with the hinge ball, wherein spline teeth are formed in at least part of the outer surface area of the meshing part; the engagement part is used for being engaged with a spline groove on the external flexible shaft lower joint through the spline teeth, and is in spherical hinge connection with a ball seat on the flexible shaft lower joint through the hinge ball, and the limit post is used for being connected with a safety ball for limiting; The flexible shaft lower connector is connected with the first connector and is sealed through the sealing component; The lower flexible shaft joint is of a hollow structure, a spline groove matched with the spline teeth is formed in the inner side of the side wall of the lower flexible shaft joint, and the lower flexible shaft joint comprises a ball seat matched with the hinge ball and an ellipsoidal groove matched with the safety ball; The flexible shaft is arranged in the shell, is meshed with the spline grooves on the lower connector of the flexible shaft through the spline teeth, is connected with the ball seat ball hinge on the lower connector of the flexible shaft through the hinge ball, and is connected with the safety ball through the limit post and is limited in the ellipsoidal groove on the lower connector of the flexible shaft.
2. The universal shaft according to claim 1, wherein the flexible shaft further comprises a second connector arranged at the other end of the flexible shaft body; the second connector is used for being externally connected with an upper flexible shaft connector and is connected with the motor rotor through the upper flexible shaft connector.
3. The universal shaft according to claim 2, wherein the diameter ratio of the engagement portion, the flexible shaft body and the second connector is (1.4-1.5): 1 (1.2-1.3).
4. The cardan shaft of claim 3, further comprising a boss between said flexible shaft body and said engagement portion, said boss having a diameter no greater than a diameter of said engagement portion.
5. The universal shaft of claim 4, wherein a chamfer transition of less than 20 ° is provided between the flex shaft body and the boss and between the flex shaft body and the second connector.
6. The cardan shaft of claim 5, wherein the chamfer between the flexible shaft body and the boss and between the flexible shaft body and the second connector transitions with a radius greater than R150 mm.
7. The universal shaft according to any one of claims 1 to 6, wherein the number of teeth of the spline teeth is 6 to 8, and the tooth surface area of the spline teeth is not less than 1500mm 2 .
8. The universal shaft according to any one of claims 2 to 6, wherein the outer surface of the second connector is provided with threads, the flexible shaft is used for being in threaded connection with the upper connector of the flexible shaft through the second connector, and/or The outer surface of the limiting column is provided with threads, and the flexible shaft is used for being connected with the safety ball through the limiting column and is limited in an ellipsoidal groove of the lower connector of the flexible shaft through the safety ball.
9. The universal shaft of claim 1, wherein the seal assembly comprises a seal ring, a seal piston, a seal sleeve, a lock nut, and a seal plug; the flexible shaft further comprises a boss, a connecting piece and a connecting piece, wherein the boss is positioned between the flexible shaft body and the meshing part, and the diameter of the boss is not larger than that of the meshing part; the boss is provided with an annular groove, and the sealing ring is positioned in the annular groove; The sealing sleeve is sleeved outside at least partial areas of the boss and the sealing piston and is abutted with the meshing part and/or the flexible shaft lower joint; The locking nut is sleeved outside at least part of the area of the sealing sleeve and the upper end of the flexible shaft lower joint; The sealing plug is connected with the lower end of the lower flexible shaft connector, so that a sealing cavity is formed between the first connecting connector and the lower flexible shaft connector.
10. The universal shaft according to claim 9, wherein the sealing plug is provided with a plug hole and a plug, and the plug hole is used for injecting lubricating oil or lubricating fluid into the sealing cavity.
11. The universal shaft according to claim 9, wherein the upper end of the flexible shaft lower joint is provided with external threads, and the lower end of the flexible shaft lower joint is provided with internal threads; the locking nut and the sealing plug are respectively in threaded connection with the lower joint of the flexible shaft.
12. The universal shaft according to claim 9, wherein the outer surface of the sealing piston is provided with a dovetail groove, and the inner surface of the sealing sleeve is provided with a dovetail-shaped protrusion matched with the dovetail groove.
13. The universal shaft according to claim 9, wherein the lower end of the flexible shaft lower joint is provided with external threads, and the flexible shaft lower joint is used for being in threaded connection with a water cap.
14. The cardan shaft according to any one of claims 9-13, wherein the spherical curvature of the reamer ball is greater than the spherical curvature of the tee.
15. The universal shaft according to any one of claims 9-13, further comprising a flexible shaft upper joint arranged in the shell, wherein the flexible shaft comprises a second connector arranged at the other end of the flexible shaft body; The flexible shaft is connected with the flexible shaft upper joint through the second connector and is externally connected with a motor rotor through the flexible shaft upper joint.
16. The cardan shaft according to any one of claims 9-13, characterised in that said housing comprises a fixed/adjustable curved housing and a stator housing, said fixed/adjustable curved housing being detachably connected to said stator housing; The flexible shaft lower joint, the safety ball and the sealing assembly are located in the fixed bending shell/the adjustable bending shell, the flexible shaft upper joint is located in the stator shell, the flexible shaft part area is located in the fixed bending shell/the adjustable bending shell, and the part area is located in the stator shell.
17. Use of a cardan shaft according to any one of claims 1-16 in a drilling system.
18. A drilling machine system comprises a motor and a drill bit, and is characterized by further comprising a universal shaft according to any one of claims 1-16; The flexible shaft lower joint in the universal shaft is connected with the drill bit through a water cap, and the flexible shaft upper joint in the universal shaft is connected with a motor rotor in the motor.

Description

Flexible shaft, universal shaft, drilling machine system and application of universal shaft Technical Field The invention relates to the field of drilling equipment, in particular to a flexible shaft, a universal shaft, a drilling machine system and application of the universal shaft. Background Today oil and gas exploration is increasingly complex, conventional reservoirs develop towards unconventional reservoirs such as tight oil and gas, shale gas and the like, and homogeneous reservoirs develop towards reservoirs such as heterogeneous reservoirs, thin layers, faults, cracks and the like. Shale oil lithology changes greatly, stratum production is difficult to predict, and in order to improve the drilling meeting rate of horizontal section desserts of horizontal wells, multi-branch wells and large-displacement wells, the drilling time of a screw drilling tool and a downhole while-drilling instrument is required to be improved, namely the drilling time of one drilling of the screw drilling tool or the downhole while-drilling instrument is required to be improved. The screw drilling tool is matched with the high-efficiency PDC drill bit, is a main means for improving the drilling speed and the orientation of a well with a complex structure at present, and has great use amount. The most commonly used universal shaft structure of the screw drilling tool at present mainly comprises a flexible universal shaft, a flap type universal shaft and a spherical universal shaft. The flexible universal shaft has a relatively simple structure, one end of the flexible universal shaft is connected with the rotor, the other end of the flexible universal shaft is connected with the transmission shaft, the transmission shaft and the central line of the stator are provided with a corner, generally 1 degree, 1.25 degree, 1.5 degree, 1.75 degree and 2 degree, the most common use at present is the deflection of a bent shell screw drilling tool assembly, and the degree of a common bent shell screw drilling tool is generally about 1.5 degree. The left end of the flexible shaft moves in a planetary mode, the right end of the flexible shaft is connected with a transmission shaft with a bent angle, the stress is complex, the flexible shaft is subjected to large torque and bending moment by itself, and fatigue fracture occurs after the flexible shaft works for more than 100 hours under the fatigue fracture of periodic load. The universal shaft assembly is characterized in that two ends of the intermediate shaft body are respectively connected with a universal joint, the universal joints are mutually meshed by the valve bodies in various shapes, under the working state, torque transmission among the valve bodies is carried out through meshing valve teeth, the intermediate shaft body generally plays a role in auxiliary transmission, and some universal shafts can transmit torque together with the intermediate shaft through structural design. But in the movement process, the valve teeth are in sliding friction, and are simultaneously eroded by high-pressure drilling fluid, so that the wear is faster, and the service life is less than 50 hours. The third kind of universal shaft is spherical one, its structural feature is that the contact surface is point contact or line contact, the tie rod swings certain angle with the steel ball as the axle center and transmits rotational speed and torque at the same time, has realized the use of the adjustable curved shell screw drilling tool, but it carries on the special strengthening treatment to some parts, such as tie rod, living hinge, etc., increase its surface wearability, its sealed design requirement is very strict; the service life of the parts is about 100 hours after tracking the service condition of the site, and the parts are found to be not wear-resistant or have a sealing failure frequently, so that the parts are failed and must be drilled. According to analysis, the first rubber sealing sleeve is thin (the rubber sleeve with the thickness of 5 mm), the mechanical strength is low, rubber tearing occurs in the working process, so that the universal shaft is invalid, the second cylindrical block, ball or other form of block for transmitting torque is small in transmission area, and the effective area is about 700m 2, so that the transmission block is crushed, and the universal shaft is invalid. The underground while-drilling instrument is an instrumented screw drilling tool, namely a measuring nipple is added on a shell part of a screw drilling tool universal shaft assembly, the inside of the measuring nipple needs to pass through a universal shaft, and the measuring nipple is provided with a sensor, a battery and a circuit board on the side wall due to the structural characteristics of the measuring nipple, so that the size of an inner hole is limited, the underground while-drilling instrument is generally used in a horizontal section, has orientation requirements, needs to be connected wi