A method for prolonging the effective period of acidification

Abstract

The invention provides a method for prolonging the validity period of acidification. The specific steps are as follows: step 1, combining the reservoir parameters and well history of under-injection wells, analyzing the main causes of under-injection, and determining whether acidification and plugging removal are needed; The acid liquid is injected from the wellhead in the way of pipe string and non-stop well; then when the acid liquid injection is about to end, the acid liquid carries the solid slow-release anti-scaling agent into the wellbore, the acid liquid enters the formation, and the slow-release anti-scaling agent settles at the bottom of the well ; After acidizing, as the injected water enters the formation, the anti-scaling agent slowly dissolves, effectively inhibiting Ca 2+ , Mg 2+ 、Ba 2+ and other scaling, thus prolonging the effective period of acidification. The construction process of the present invention is simple, the construction steps are reduced, and the well occupation time is greatly shortened; the present invention effectively inhibits Ca 2+ , Mg 2+ 、Ba 2+ and other scaling, thus prolonging the effective period of acidification. From a long-term perspective, it is of great significance to effectively reduce the number of under-injection well measures, reduce the cost of measures, and reduce production costs.

Description

technical field [0001] The invention belongs to the field of reducing pressure and increasing injection of water injection wells, and in particular relates to a method for extending the effective period of acidification. Background technique [0002] Water injection is an effective means to replenish formation energy and ensure long-term stable production of oilfields. During the water injection development process of some reservoirs in Changqing Oilfield, due to the incompatibility of injected water and formation water, scaling and blockage near the wellbore caused the water injection volume of the wells to drop, and even If the injection fails, the output of the corresponding oil well will decline, which will have a great impact on the stable production of the oil field. [0003] At present, the acidizing method is mainly used to remove plugging and increase injection in reservoirs. Acidification technology is low in cost and quick in effect. However, after the applicati...

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Problems solved by technology

[0004] In order to overcome the existing problems of complex technology, high cost of measures and low oil recovery, the present invention provides a method for prolonging the effective period of acidification, which has the advantages of simple construction technology and low safety risk, and effectively reduces the number of under-injection well measures , reduce the cost of measures, improve the effect of water injection development, and increase oil recovery