Anti-corrosion method for mechanical oil extraction shaft

Abstract

The invention relates to an anti-corrosion method for a mechanical oil extraction shaft, and belongs to the technical field of oilfield development and oil extraction. The anti-corrosion method comprises the following steps: the amount of inert gas needed by corrosion-free residue in oil shaft products is determined through a laboratory test; an oil pipe valve is opened firstly, an inert gas source is connected with a sleeve pipe connection pipe through a pipeline, and then a sleeve pipe valve is opened, so that the connection pipe is communicated with an annular space of an oil pipe and a sleeve pipe; the inert gas is injected into the annular space of the oil pipe and the sleeve pipe through the sleeve pipe inlet; a sample is taken from an oil pipe outlet for a laboratory test in the injection process of the inert gas; and the inert gas is injected until no corrosive residue exists in the sample of the oil pipe outlet. The anti-corrosion method is simple in operation, low in cost, and good in anti-corrosion effect. The inert gas is used for isolating the air or diluting and drying corrosive gas, metal inside the shaft or a ground conveying pipeline is effectively prevented from being corroded, maintenance frequency and cost are lowered, and work efficiency is improved.

Description

technical field [0001] The invention relates to an anti-corrosion method for a mechanical oil recovery shaft, belonging to the field of oil field development and recovery technology. Background technique [0002] There are three sources of corrosion in wellbore casings, oil pipes, sucker rods and other downhole tools of mechanical oil production wells: external (such as air) corrosion, formation output (such as hydrogen sulfide, carbon dioxide) corrosion, and external addition of formation output material corrosion. Over the years, in order to solve the corrosion problem of mechanical oil production wells, people have invented a variety of treatment methods: 1 Covering method: a coating anti-corrosion layer, b steel surface anti-corrosion treatment, c adding lining pipe...etc.; 2 neutralization (or alternative) method: a anode protector, b filling corrosion inhibitor, c corrosion inhibition rod and so on. Due to the complexity, mutual superposition and interaction of corro...

AI Technical Summary

Problems solved by technology

Every time the pipe wall becomes thinner by 1 mm, its tensile strength, external extrusion resistance, and internal pressure resistance will decrease by more than 18% for Φ73 mm tubing, and 10% for Φ139.7 mm casing. operation; (except for the casing damage caused by the fault, most of the casing damage is caused by corrosion) oil well overhaul operations such as casing removal, casing replacement and casing subsidy have caused huge losses to the oil field, and in severe cases, the oil well has been scrapped; the passivation of shedding Film and other protective film debris pose a threat to the normal operation of the oil well pump

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