Active solvent for relieving sump oil blockage of water injection well

Abstract

The invention provides an active solvent for relieving sump oil blockage of a water injection well. The active solvent is prepared by mixing fatty acid methyl ester, a penetrating agent and organic alkali, wherein the weight percent of the penetrating agent is 1-5%; the weight percent of the organic alkali is 5-20%; and the others are fatty acid methyl ester; the penetrating agent is selected from isooctyl alcohol polyoxyethylene ether-4, isooctyl alcohol sulphonated succinate or isooctyl alcohol polyoxyethylene ether phosphate-4; the organic alkali is selected from one or more of triethanolamine, triethylamine, diethylamine or dimethylamine; the fatty acid methyl ester is selected from one or more of methyl laurate, methyl palmitate, methyl oleate and methyl stearate; and the fatty acid methyl ester has strong dissolving capacity on the sump oil; the sump oil injected on an infiltration surface of the water injection well can be dissolved, and pushed away from the infiltration surface of the water injection well; tallate and methanol can be generated after the sump oil is hydrolyzed in stratum; the carried sump oil can be precipitated to advance towards the deep part of the stratum continuously. Thus, the effect of the sump oil on the infiltration surface of a near well is relieved.

Description

Technical field: [0001] The invention relates to an active solvent, which is mainly used for treating water injection wells blocked by oil pollution in low-permeability oil fields, so as to restore the water injection capacity of the water injection wells. Background technique: [0002] Although low-permeability oil fields have strict requirements on the quality of injected water, due to unstable treatment processes and water treatment failures, occasionally substandard injected water is injected into wells. Suspended solids and a small amount of dirty oil carried in the injected water can accumulate on the percolation surface near the well, resulting in a continuous decline in the water injection capacity of the well and making it difficult to meet the injection requirements. In this case, acidification is usually used to remove plugging. The acid liquid can react with formation rocks and suspended solids, and the surfactant contained in the acid liquid can weaken the Jami...

AI Technical Summary

Problems solved by technology

When the Jamin effect produced by dirty oil is strong, the surfactant system cannot fully contact with the oil droplet, and even the surfactant system flows around the oil droplet, so that the plugging removal system can effectively control the blockage mainly caused by dirty oil. Unsatisfactory processing effect

If oil-soluble solvents such as diesel oil and heavy aromatics are injected into the water well, although the dirty oil on the percolation surface of the water well can be pushed to the formation, as these oil-soluble solvents continue to disperse, new damage will be generated near the well

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