Low-speed large-torque downhole hydraulic motor and operating method thereof

Abstract

The invention provides a low-speed large-torque downhole hydraulic motor and an operating method thereof. The low-speed large-torque downhole hydraulic motor comprises a flow distribution assembly, an axial reciprocating driving assembly, an axial rotary conversion assembly and a reverse turning preventing assembly. The axial rotary conversion assembly comprises a driving spindle, a power sleeve, a rotary sleeve, a first spring and a distribution valve, wherein the driving spindle is provided with an external straight-groove spline and an external threaded spline, the power sleeve is provided with an internal threaded spline groove and third clutch teeth, and the rotary sleeve is provided with fourth clutch teeth. The clutch teeth are arranged at the lower end of the power sleeve, the third clutch teeth make contact with the fourth clutch teeth at one end of the rotary sleeve, and the first spring is used for providing pretightening force. The external threaded spline on the driving spindle is engaged with the internal threaded spline groove in the power sleeve. The external straight-groove spline on the driving spindle is matched with a straight groove in the distribution valve. Compared with a screw motor, the low-speed large-torque downhole hydraulic motor is much lower in manufacturing cost, longer in service life, more excellent in fluid adaptability and capable of being maintained on site more easily.

Description

【Technical field】 [0001] The invention relates to an oil drilling and production downhole tool, especially a low-speed and high-torque downhole hydraulic motor and a working method thereof. 【Background technique】 [0002] Conventional tubing and coiled tubing workover operations (drilling, fishing, cleaning) in the prior art play an important role in the development of petroleum oil and gas and shale gas, and due to the particularity of tubing and coiled tubing operations, the occurrence of The probability of complexity is significantly higher than that of conventional well operations, and once a complexity occurs, the difficulty of subsequent processing will also increase significantly, and the available processing tools are currently extremely limited. [0003] When fishing for tubing and coiled tubing, it may be difficult for fishing tools to lure or return fish. Installing some kind of slow-speed and high-torque rotary downhole tool on the upper part of the fishing tool ...

AI Technical Summary

Problems solved by technology

The length of the small-diameter screw motor is generally 3-4m, and the reduction mechanism is added to make the tool longer and the internal structure more complicated. On the one hand, the manufacturing cost is high, and on the other hand, the maintenance after use is cumbersome, requiring special workshops and Special tools are used for disassembly and maintenance, and the more common method is to send them back to the original factory for maintenance. Therefore, the maintenance cost is high and the maintenance cycle is long, which is not suitable for the needs of low-cost operations.

[0006] In addition, when the working fluid is a multiphase fluid such as foam, the screw motor must be equipped with a downhole gas separator to maximize the motor’s effectiveness. Application of Long Horizontal Section Horizontal Wells and Low Pressure Gas Reservoirs

[0007] When the downhole temperature is high or contains chemical substances that are corrosive to rubber, it will often cause the rubber stator of the screw motor to fail, causing downhole complex

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