Long-service-life high-performance screw drill

Abstract

The invention relates to a long-service-life high-performance screw drill used for petroleum and natural gas well drilling. The long-service-life high-performance screw drill mainly comprises a bypass valve assembly, a motor assembly, a universal shaft assembly and a transmission shaft assembly. According to the technical scheme, the bypass valve assembly, the motor assembly, the universal shaft assembly and the transmission shaft assembly of the long-service-life high-performance screw drill are connected in sequence from top to bottom. The bypass valve assembly mainly comprises a gear sleeve used for controlling the area of an opening of a bypass hole, a gear follower, a piston sleeve and a piston core. The motor assembly mainly comprises a controllable-flow dropping prevention assembly, a stator shell body, a rubber bush, a hollow rotor and a rotor runner. The universal shaft assembly mainly comprises a limiting sleeve, an upper petal spherical hinge, a pressure bearing ball, a ball base connecting rod, a lower petal spherical hinge and a water cap. The transmission shaft assembly comprises an upper sealing assembly, a middle sealing assembly and a lower sealing assembly, wherein the upper sealing assembly, the middle sealing assembly and the lower sealing assembly are used for keeping balance of sealing pressure. The connecting contact position between the water cap and a transmission shaft is supported and is located through a disk spring. The long-service-life high-performance screw drill has the advantages of being reasonable in structure, high in reliability, long in service life, high in working efficiency and the like.

Description

technical field [0001] The invention relates to a tool for oil and gas exploration and development, in particular to a long-life and high-performance screw drilling tool suitable for gas-based fluid drilling technology and mud medium deep well and ultra-deep well drilling with high temperature and strong vibration. Background technique [0002] Screw drilling tools are currently the most widely used downhole dynamic drilling tools in the field of oil and natural gas drilling at home and abroad. With the continuous development of modern drilling technology, especially with the promotion of compound drilling, screw drilling tools play an important role in drilling operations. There are more and more functions, and the role is getting bigger and bigger. [0003] The screw drilling tool mainly includes a bypass valve assembly, a motor assembly, a cardan shaft assembly and a transmission shaft assembly. At present, the main problems of screw drilling tools include: the opening a...

AI Technical Summary

Problems solved by technology

At present, the main problems of screw drilling tools include: the opening and closing of the valve hole of the bypass valve is controlled by the flow rate of the drilling fluid. Once the flow value of the valve hole is reached, the drilling fluid will flow through the motor assembly. During the process, when the nozzle of the drill bit is blocked or the screw drilling tool is damaged or complex situations occur downhole, a common technical measure is to carry out large-displacement circulation. If it cannot be carried out in time, it will cause downhole accidents. When using large-displacement drilling, The motor assembly cannot be guaranteed to work under optimal parameters; the tooth petals of the commonly used petal cardan shafts require special equipment for processing, flame cutting and forming, and a large heat-affected zone, resulting in uneven metallographic structure around the cut, coarse grains, and low strength , it is easy to break near the tooth root, and the service life is short, while the transmission ball of the ball joint cardan shaft bears a large friction force during use, and the service life is also short; due to the large axial force, the transmission shaft The connection between the water cap of the assembly and the cardan shaft assembly is easy to break; and the transmission shaft assembly is one of the four main components of the screw drilling tool, and is also one of the most vulnerable components. Its function is to convert the output torque of the motor and rotating speed are transmitted to the drill bit, and simultaneously bear the axial and radial loads generated during the drilling process. Therefore, the thread at the upper end of the transmission shaft often breaks and trips; in addition, in recent years, Party A has required Using air drilling, air drilling has technical advantages such as greatly increasing the mechanical penetration rate, effectively discovering and protecting oil and gas layers, but at the same time it puts forward higher requirements for downhole drilling tools, especially screw drilling tools. Conventional screw drilling tools in air drilling Drilling tools cannot be used due to the lack of sufficient fluid lubrication; the oil-sealed drive shaft screw drilling tools that have appeared in recent years cannot prevent the intrusion of gas-based circulating media (pure gas, gas-solid, gas-solid-liquid) well after field experiments. The service life is low, and it usually fails after 40-50 hours of use. This not only leads to frequent tripping, but also the bearing is stuck and easily leads to drilling accidents, which will bring large economic losses and greatly reduce drilling efficiency. At present, the existing domestic transmission shaft seal When the device is used in deep well mud drilling, due to its own sealing ability, the use effect is poor, the service life is short, and the use requirements cannot be met, which even limits the application of screw drilling tools with sealing devices in deep wells

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