Internal surface local hardening (alloying) eccentric wear prevention oil pipe

Abstract

When an oil pipe is in a working state, an oil sucker rod and a centering device of the oil sucker rod make reciprocating movement on the inner surface of the oil pipe. If the reciprocating movement happens to an inclined well and a horizontal well, the centering device of the oil sucker rod can form long-term friction on the inner surface of the oil pipe, the centering device of the oil sucker rod and the inner surface of the oil tube are in clearance fit within a certain tolerance range, negative pressure is formed inside the oil pipe through the reciprocating movement and a one-way sealing principle, and therefore crude oil is extracted to the earth surface from the underground of thousands of meters. In order to prevent or retard the eccentric wear phenomenon, the invention provides wear simulation equipment to test the anti-wear cycles under various conditions.

Description

[0001] At present, some enterprises at home and abroad use integral coating, nitriding and other internal surface integral hardening methods to solve the problem of anti-eccentric wear of oil pipes, but these integral hardening processes have a drawback. Namely: At present, domestic well depths range from 2,000 meters to 7,000 meters. In the process of on-site installation, the oil pipes are vertically downward and connected one by one, so the longitudinal load on the pipe body when the oil pipes are assembled ranges from 20 to 70 tons (even greater), under this gravity condition, the tubing will undergo longitudinal plastic extension. To put it bluntly: the 4,500-meter oil pipeline placed on the surface water will extend to 4,522.5 meters in total length when installed vertically (calculated according to the data in column 4 of API5CT Table C6). The tubing itself is designed to withstand such self-weight extension, but the plasticity of the hardened layer decreases due to the i...

AI Technical Summary

Problems solved by technology

During the working process of the pumping system, long-term longitudinal friction is formed between the sucker rod joint and the inner surface of the oil pipe, and finally friction grooves are formed on the inner surface of the oil pipe, thereby losing the seal, reducing the production of the oil well, and increasing the cost of replacing the oil pipe

[0004] At the same time, when working in casings during oil drilling and when drilling in casings in geological crossing industries, a large number of casings are used for one-time use due to the friction between the joints of the drill pipe and the inner surface of the casings, which has a great impact. Wasted resources and increased operating costs

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