Corrosion resisting method for tubing-casing annulus in well gas well completion with packer

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 anti-corrosion, in particular to an anti-corrosion method for annulus of an oil casing of a packer well completion gas well. Background technique [0002] During the completion of oil and gas wells, the annulus between the tubing and casing (that is, the annulus of the casing) needs to be isolated by a packer to prevent the natural gas in the oil layer from entering the annulus of the 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 prolong the service life of the oil pipe and casing. However, with the development of oil and gas wells, the packer is prone to deformation and failure, and the tubing and threaded fasteners will also leak, which will lead to the connection between the oil casing annulus and the ins...

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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