A method for anti-corrosion of the annulus of the oil casing of the packer completion gas well

Abstract

The invention discloses a corrosion resisting method for a tubing-casing annulus in well gas well completion with a packer, and belongs to the field of pipeline corrosion resistance. The method comprises the following steps: the concentration of iron ions of liquid in the tubing-casing annulus is initially detected, and the initial concentration of the iron ions and the initial detecting date arerecorded; according to a pre-passivating treatment experience formula, the use level of an oil soluble corrosion inhibitor in the pre-passivating treatment is calculated; the oil soluble corrosion inhibitor is pumped into the tubing-casing annulus according to the use level of the oil soluble corrosion inhibitor to form corrosion resisting protective films on the inner wall of a casing and the outer wall of a tubing; the concentration of the iron ions of the liquid in the tubing-casing annulus is detected by every other preset time and recorded until the difference between the concentration ofthe iron ions and the initial concentration is smaller than 5-10 ppm, the date of the present day is recorded as the detecting completion date, and the interval days from the initial detecting date are calculated, and the days are used as the pre-passivating treatment period; and according to the pre-passivating treatment period and the use level of the oil soluble corrosion inhibitor, the oil soluble corrosion inhibitor is pumped into the tubing-casing annulus for termly pre-passivating treatment to realize corrosion resistance of the tubing-casing annulus. The method is convenient, feasibleand low in cost.

Description

Technical field [0001] The invention relates to the field of pipeline anticorrosion, in particular to an anticorrosion method for the annulus of a packer completion gas well oil casing. Background technique [0002] During the completion of oil and gas wells, the annulus between the tubing and casing (ie, the annulus of the oil casing) needs to be sealed by a packer to prevent the natural gas in the oil layer from entering the annulus of the oil casing and causing corrosion. In order to further ensure the anti-corrosion effect of the oil sleeve annulus, it is also necessary to inject annulus protection fluid into the oil sleeve annulus to reduce the corrosion of the oil sleeve annulus and extend the service life of the oil pipe and casing. However, with the development of oil and gas wells, packers are prone to deformation and failure, and oil pipes and threads will also leak, which will cause the oil sleeve annulus to communicate with the inside of the oil pipe, resulting in abn...

AI Technical Summary

Problems solved by technology

[0005] When anti-corrosion treatment is carried out on the oil casing annulus through the existing technology, the injection amount of corrosion inhibitor is large and the operation cost is high, and this method is not suitable for anti-corrosion treatment of oil and gas wells that have been shut down

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