Layer-by-layer acidizing layer-by-layer water injection method

Abstract

The present invention relates to a multi-layer acidification layer-by-layer water injection method, which comprises the following steps: injecting an integrated string of acid into the casing, after the normal circulation of the liquid, the pretreatment liquid is being replaced, and then a 31mm steel ball is thrown, Falling into the acidizing check valve, the cement truck is pressurizing to set the two packers; the cement truck continues to increase the pressure, cuts off the shear nails of the inner sleeve ball seat, and falls into the paint tubing; then sends the lower layer of acid liquid downhole, Flow out from the screen pipe and enter the lower water injection layer; throw 40mm sealed steel balls, inject acid into the middle water injection layer through the intelligent acid injection valve; then throw 48mm soluble balls and fall into the switch valve setting seal, pressing to make the acid liquid channel on the wall of the switch valve cylinder Open, then inject the upper layer of acid liquid into the upper water injection layer; then close the well, and continue to acidify the three formations; after the acidification reaction is completed, the soluble ball dissolves; after the intelligent acid injection valve is closed, after the fishing and sealing test is passed, the normal water injection . The method only needs to lift the next pipe string, has low operating cost and less well-occupancy cycle, can reduce oil field development cost, and has good environmental benefits.

Description

technical field [0001] The invention relates to a layered water injection method, in particular to a multi-layer acidification layered water injection method, which belongs to the technical field of water injection well acidification technology. Background technique [0002] After a period of development of water injection wells, especially in the late stage of oilfield development, the water injection pressure of most water injection wells will increase greatly, and it will show a trend of increasing year by year, resulting in less and less water injection, which will affect the water injection development effect. Severe impact, ultimately greatly reducing oil field production. [0003] Acidizing is a measure to remove plugging and increase injection that is often taken on the formation. It uses the chemical dissolution of acid liquid and the hydraulic action when squeezing acid into the formation to dissolve formation blockages and some formation minerals, expand, extend, ...

AI Technical Summary

Problems solved by technology

[0005] The traditional acidizing plugging removal process mainly has the following problems: (1) Due to the pressure relief or liquid drainage after acidizing, the oil layer may be excited, causing particle migration and causing damage to the reservoir, and there is a certain risk; (2) After acidizing plugging removal, it is necessary to Long-term flowback treatment takes up a long time in the well; (3) There are many construction procedures, long periods, and many tools are used, which increases the operating cost; (4) During the swabbing and drainage process, in order to prevent the coating damage of the paint tubing under the screen, it is necessary to A new set of ordinary oil pipes is used for acidification and liquid drainage construction, which increases the cost of materials; (5) The acid liquid discharged from the return cannot be discharged on site, and needs to be transported to a designated place by special vehicles for treatment, which increases subsequent treatment costs

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