Oil seal structure of downhole power tools

Abstract

The invention discloses an oil seal structure of an underground power tool, and belongs to the technical field of oil and gas drilling. The oil seal structure of the underground power tool comprises the underground power tool and a seal piston, wherein the underground power tool comprises an oil cavity fixing shell and a main shaft; the oil cavity fixing shell is provided with a hollow oil cavity; the main shaft is fixedly installed in the hollow oil cavity; the seal piston is installed in the hollow oil cavity, and can slide in the hollow oil cavity along the main shaft; the first end of the hollow oil cavity is communicated with the external environment; a sealed lubricating oil cavity is formed between the seal piston and the second end of the hollow oil cavity. According to the oil seal structure, the seal piston slides under the action of pressure difference between the external environment on the first end of the hollow oil cavity and the lubricating oil cavity, so that the pressure of the external environment and the pressure in the lubricating oil cavity reach dynamic balance; therefore, the persistent supply and seal requirements of lubricating oil in the lubricating oil cavity are realized, and the reliability and the service life of the oil seal structure of the underground power tool provided by the invention are improved / prolonged, so that the underground power tool is effectively protected.

Description

Technical field [0001] The invention relates to the technical field of oil and natural gas drilling, in particular to an oil seal structure of a downhole power tool. Background technique [0002] Downhole power tools, drill bits, drill collars, etc. form the bottom hole assembly, which is located at the bottom of the entire drill string and directly provides rock breaking power for the drill bit, which can effectively increase the mechanical drilling speed and realize the directional deflection function. And with the development of oil and gas exploration and development, more and more downhole power tools are used in deep and ultra-deep well drilling operations. [0003] During drilling operations, downhole power tools are affected by various solid media and corrosive substances in the drilling fluid, and their life will be reduced. Therefore, the existing downhole power tools are often provided with an oil cavity, and the external drilling fluid environment is separated by an oi...

AI Technical Summary

Problems solved by technology

However, the oil seal structures of the existing downhole power tools are all static seal structures. In deep wells and ultra-deep wells, the absolute pressure of the drilling fluid column is very high, the solid content of the drilling fluid is high, and the bottom hole temperature is relatively high. Large, these working conditions may cause damage to the sealing structure of the lubricating oil chamber, resulting in premature failure

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