A combined adjustment-dissolution process for water injection wells

Abstract

The invention discloses a profile control-unplugging combining technique for a water injection well. The profile control-unplugging combining technique comprises the steps that (1), well input fluid is prepared; (2), pressure is gradually increased, water is injected into a stratum, a relation curve of injection pressure and displacement is drawn, and an injection pressure curve knee P* is determined; (3), a cellulose plugging agent A is injected at the injection pressure smaller than P* and used for remote well profile control; (4), a profile control agent B forming glue through acid catalysis is injected at the injection pressure smaller than P*; (5), displacement fluid is injected; (6), well shutting for waiting on cement setting is carried out for 2-6 hours; (7), acid liquor C is injected at the injection pressure larger than P*; (8), pressure release is carried out; (9), normal water injection is restored, and if normal water injection can be achieved, construction is completed. According to the profile control-unplugging combining technique for the water injection well, water reducing oil increase of a high water content oil well is achieved, profile control and unplugging ofthe multilayer oil deposit water injection well are achieved, an injection profile is improved, and the oilfield development effect is improved; and construction operation of the water injection wellis easy, convenient, safe and efficient, and wide market application prospects are achieved.

Description

technical field [0001] The invention relates to profile control technology and acidizing technology of water injection wells in the oil development process, in particular to a combined adjustment-dissolution process for water injection wells in heterogeneous reservoirs. Background technique [0002] For nearly a century since water injection development was put forward, water injection has been the mainstream oil production method in oilfields all over the world. A reservoir often consists of multiple oil layers. Due to the difference in permeability of each oil layer, the injected water will rush along the high-permeability layer, resulting in premature water flooding of the oil well. Therefore, in the process of water injection development, the high-permeability layer of the reservoir has a strong water absorption capacity, and fingering and tongue-ingress phenomena appear to form water flow channels. The injected water circulates ineffectively, and the low-permeability la...

AI Technical Summary

Problems solved by technology

From the perspective of the development of profile control and acidizing plugging removal, simple acidizing and profile control of water wells cannot simultaneously increase injection of water wells and reduce interlayer conflicts

For heterogeneous reservoirs, when the distribution fails to meet the requirements, acidification and plugging removal measures are taken. After the acid solution is injected into the reservoir, most of it will be consumed in the high-permeability layer, and less acid will enter the low-permeability layer, which will eventually deepen the reservoir. layer heterogeneity contradiction

Due to the low water injection sweep efficiency due to the difference in permeability of the heterogeneous reservoir itself, profile control measures are implemented. No matter what plugging agent is high or low permeability after entering the reservoir, it will be injected into the plugging agent. Therefore, after the profile control operation, not only improved The water injection profile also reduces the water injection volume of a single well, which cannot meet the production needs

Usually, plugging removal measures will be taken for wells that cannot be injected. The acid solution used for plugging removal will also remove the plugging agent that has entered the hyperpermeable layer, resulting in futile results.

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