An oil-sealed cavity pressure-balanced screw drilling tool transmission shaft assembly

Abstract

The invention relates to a driving shaft assembly of a screw drilling tool capable of maintaining the pressure balance of an oil seal chamber for oil and gas drilling. The technical solution is: oil seal chamber pressure balance screw drilling tool transmission shaft assembly includes upper seal assembly, middle seal assembly and lower seal assembly, etc.; upper seal assembly and middle seal assembly, middle seal assembly and lower seal assembly The cavity between the sealing assemblies is filled with lubricating oil; the upper sealing assembly includes the annular cavity, the piston cylinder and the upper sealing check valve, etc., and the lower sealing device includes the flow channel, the piston chamber, the piston and the lower sealing check valve. Valves, etc.; the balance between the pressure in the sealing cavity and the external drilling fluid pressure is controlled by the up and down sliding of the piston cylinder and the piston, and the opening and closing of the upper sealing check valve and the lower sealing check valve. The invention has the advantages of good sealing performance, long service life, high temperature and high pressure resistance, small friction coefficient and simple structure, and can be used in gas drilling and mud medium drilling with high temperature and strong vibration.

Description

technical field [0001] The invention relates to an oil-sealed screw drilling tool drive shaft assembly used in oil and gas drilling, especially suitable for gas-based fluid drilling technology and high-temperature strong-vibration mud medium deep well and ultra-deep well drilling process for oil-sealed cavity pressure balance Screw drilling tool drive shaft assembly. Background technique [0002] The screw drilling tool is one of the downhole power tools used in oil drilling or workover operations, and the drive shaft assembly is one of the four main components of the screw drilling tool, and it is also one of the most vulnerable components. Its function is Transmit the output torque and rotational speed of the motor to the drill bit, and at the same time bear the axial and radial loads generated during the drilling process. The transmission shaft assembly includes transmission shaft, transmission shaft housing, radial bearing group, thrust bearing group and other component...

AI Technical Summary

Problems solved by technology

Conventional screw drilling tools in air drilling cannot be used due to lack of sufficient fluid lubrication; the oil-sealed drive shaft screw drilling tools that have appeared in recent years have been unable to prevent air-based circulating media (pure gas, gas-solid, gas, etc.) solid-liquid) intrusion, the service life is low, and it usually fails after 40 to 50 hours of use, which not only leads to frequent tripping, but also the stuck bearing is likely to cause drilling accidents, which will bring large economic losses and greatly reduce drilling efficiency

[0003] At present, when the existing transmission shaft sealing device in China is used in deep well mud drilling, due to its own sealing ability, the use effect is poor, the service life is short, and it cannot meet the use requirements, which even limits the use of screw drilling tools with sealing devices in deep wells. application in

Images