Anti-corrosion coating process in oil casing pipe

Abstract

The invention provides an anti-corrosion coating process in an oil casing pipe. The process comprises the following steps that firstly, the inner wall of the flat-end oil casing is cleaned; secondly,anti-corrosion layer coating treatment and curing treatment are conducted on the inner wall of a flat-end oil casing pipe body; thirdly, threads at the pipe end of the oil casing pipe are machined; inthe thread machining process, the highest temperature of the inner wall of the thread machining part does not exceed 90% of the upper limit value of the temperature resistance of an anti-corrosion layer of the pipe body in terms of the celsius degree; cutting fluid used for thread machining does not damage the anti-corrosion layer coated on the inner wall of the oil casing pipe; and fourthly, theoil casing pipe is subjected to coupling tightening and pipe end protection, and the whole anti-corrosion coating process in the oil casing pipe is completed. The technological process is simple, thedefective product generation probability is low, and the anti-corrosion coating process can be well suitable for coating in the oil casing pipe of high-temperature-resistant anti-corrosion paint, andcoating in the low-end and conventional paint oil casing pipe for temporary storage and transportation is achieved at a low price.

Description

technical field [0001] The invention belongs to the field of internal anti-corrosion of oil casings, and relates to an internal anti-corrosion coating process of oil casings. Background technique [0002] Oil casing and other downhole string components (such as drill pipe) are mainly made of carbon steel and low alloy steel, and corrosion is one of the main reasons for their function reduction or failure. Corrosion of oil casing and other products mainly occurs in two links: the first type is corrosion in the atmospheric environment during transportation and storage, especially in high-temperature, high-humidity, and high-salt environments; the second type is corrosion in the application environment Corrosive media (such as H 2 S, CO 2 and SRB, etc.) corrosion. The corrosion damage of the oil and casing will cause the delay and stop of the production operation if it is light, and it will lead to the scrapping of oil and gas wells and other major economic losses and seriou...

AI Technical Summary

Problems solved by technology

This process route meets the coating requirements of the inner coating of the oil casing, but the cumbersome procedures such as repeated loading and unloading of the thread protection cap, repeated cleaning and application of thread grease not only result in complex process, high cost, but also low efficiency and high error rate ( mostly manual implementation)

More importantly, although temporary thread protection caps are installed at both ends of the oil casing during the sandblasting and coating stages, the strong penetration of fine sand particles often causes sand particles to be embedded in the thread gaps, which is harmful to subsequent manual cleaning and Checking the thread poses a great challenge. Once the sand particles are not cleaned up in time, it will pose a great threat to the subsequent connection and sealing of the oil casing, and the consequences will be serious! Due to the above, the practical application of the anti-corrosion process of the inner coating of the oil casing is greatly limited, especially the inner coating of the oil casing of the high-temperature resistant coating and the inner coating of the oil casing of the low-end anti-corrosion material used for storage and transportation.

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