Multi-layer acidizing water injection string

Abstract

The invention relates to a multi-layer acidizing water injection string, which includes upper, middle and lower eccentric water distributors corresponding to the upper, middle and lower water injection layers, centralizers and seals are installed between the upper eccentric water distributor and the middle eccentric water distributor. Spacer 1, an intelligent acid injection valve and packer 2 are installed between the middle eccentric water distributor and the lower eccentric water distributor, an on-off valve is installed above the upper eccentric water distributor, and an intermediate oil pipe is installed below the lower eccentric water distributor. The bottom of the oil pipe is screwed with an acidizing check valve, the lower end of the acidizing check valve is screwed with a screen tube, the bottom of the screen tube is installed with an oil pipe holder, the bottom of the oil pipe holder is connected with a paint oil pipe, and the lower end of the paint oil pipe is screwed with a Silk plug. The middle section of the inner chamber of the lower joint of the acidizing check valve is provided with a sliding sleeve ball seat, the upper part of the lower joint is provided with a pressure ring, and the top of the pressure ring is provided with a sealing ball seat. The pipe string only needs to be lifted for one trip to realize acidification layer by layer from bottom to top, and there is no need to discharge residual acid. Water can be injected directly after acidification is completed and fished and tested.

Description

technical field [0001] The invention relates to a water injection well string, in particular to a multi-layer acidification water injection string, which belongs to the technical field of water injection well devices. 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, and communicate formation fr...

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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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