Removal liquid for removing blockage of weighting agent in drilling liquid

Abstract

The invention discloses removal liquid for removing blockage of a weighting agent in drilling liquid. The removal liquid comprises the following components by weight percent: 5%-10% of methane sulfonic acid derivatives, 2%-5% of erythorbic acid, 0.05%-0.1% of a nonionic surfactant, 0.1%-0.5% of a corrosion inhibitor and the balance of water, wherein the methane sulfonic acid derivatives are amino-methane sulfonic acid, ethyl methane sulfonate, methyl methane sulfonate or a mixture of amino-methane sulfonic acid, ethyl methane sulfonate and methyl methane sulfonate; the nonionic surfactant is fatty alcohol-polyoxyethylene ether, dinonylphenol polyoxyethylene ether or a mixture of fatty alcohol-polyoxyethylene ether and dinonylphenol polyoxyethylene ether; the corrosion inhibitor is propynol, methyl butynol, hexynol or a mixture of propynol, methyl butynol and hexynol. According to the removal liquid, the blockage of stratum pore throat caused by weighting agent particles in drilling slurry is well removed, and especially the blockage of barite particles can be effectively removed, so that an oil-gas well is smoothly exploited after being completed; the removal liquid can be used for carbonate rock and sandstone reservoirs.

Description

technical field [0001] The invention relates to a scavenging fluid for removing the clogging of a drilling fluid weighting agent in the process of increasing production in the field of oil and gas field development. Background technique [0002] In order to deal with high-pressure formations and stabilize the borehole wall, it is necessary to increase the density of the drilling fluid. The increase in the density of the drilling fluid is mainly due to the addition of a certain amount of weighting agents, which are generally limestone powder and barite. Limestone powder can increase the drilling fluid density up to 1.68 g / cm 3 , barite can increase the drilling fluid density to 2.30 g / cm 3 . These weighting agents enter the formation with the drilling fluid in the form of small particles, and the barite or limestone powder particles will enter the formation under the action of the pressure difference during the drilling process, and remain in the pore throat of the reservo...

AI Technical Summary

Problems solved by technology

Using this method will cause a large amount of acid liquid to be added, which will dissolve all the parts of the reservoir rock in contact with the acid liquid, resulting in instability of the well wall and potential safety hazards for subsequent production.

Moreover, the large amount of acid will increase the cost of construction operations.

Especially for mud plugging with barite aggravation, the plug barite cannot be dissolved by hydrochloric acid, and it is very likely to remain in the reservoir rock, which cannot finally solve the plugging problem

[0004] If the formation is a sandstone reservoir, the hydrochloric acid solution will not react with the matrix of the rock, cannot expand the pore throat, and the clogged particles cannot be discharged, so it is more difficult to remove the blockage of the weighting agent in the mud in the sandstone reservoir