A kind of test method for depositing sulfur corrosion of oil well pipe material and its test fixture

Abstract

A test method for depositing sulfur corrosion of oil well pipe materials, comprising: (1) a simulation method for depositing sulfur corrosion environment, 1) using analytically pure elemental sulfur powder, sieving with a standard sieve after being ground in a mortar, and taking -400 mesh sulfur powder for use ; 2) Simulate the formation water composition of oil and gas wells to prepare a solution, the concentration of Cl in the solution ranges from 0 to 150g / L; 3) Put the sieved sulfur powder into a beaker, drop NaCl solution into the beaker, stir and roll , so that the sulfur powder is wetted; 4) Tighten the plug at one end of the sleeve, stand the cylindrical sample in the center of the sleeve, fill the sulfur into a paste around the sample and press it tightly, screw on the other end of the plug, Put the conical plug on the conical holes at both ends of the sample so that the sample is fixed and in the center of the sleeve; (2) high temperature and high pressure corrosion test, (3) measure the weight loss of the sample and the depth of the local corrosion pit, Calculate the uniform corrosion rate and the localized corrosion rate. According to the invention, the corrosion behavior of materials under the action of deposited sulfur can be effectively simulated, and the test results are reliable.

Description

technical field [0001] The invention belongs to the technical field of corrosion and protection. Specifically, the invention relates to a corrosion test method for high-alloy oil well pipe materials under the condition of deposited sulfur and a fixture for the test. Background technique [0002] In the oil and gas extraction industry, CO 2 and H 2 S is two relatively common corrosive media, which have a relatively strong corrosive effect on oil well pipes. In recent years, with the development of oil and gas field exploration technology, a large number of high-sulfur gas reservoirs have been discovered in my country. These gas reservoirs not only contain CO 2 and H 2 S, the sulfur content is relatively high. During the production process of high-sulfur gas, the formation pressure continues to drop. After reaching the critical saturation state, elemental sulfur will be precipitated from the gas phase and deposited on the inner wall of the tubing. The deposition of sulfur ...

AI Technical Summary

Problems solved by technology

[0010] 3) After sulfur powder is added to the solution, it floats on the liquid surface, and it is easy to lose when nitrogen is purged to remove oxygen;

[0011] 4) At a high temperature exceeding 120°C, sulfur becomes liquid and deposits to the bottom of the container, causing uneven corrosion of the sample

[0012] Due to the above reasons, traditional corrosion test methods cannot effectively simulate the corrosion behavior of materials under the action of deposited sulfur, resulting in a lack of reliability in test results

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