Isolation of gas inflow in oil wells is one of the most complicated types of repair and insulation works. Traditional methods for these purposes are ineffective. So, to blockade gas flows into the well, cement slurry cannot be pumped in the required volume, and gel screens create only a temporary blockade, since gas easily penetrates the gel structure and forms new channels. For gas isolation in horizontal wells, the authors proposed to carry out two-stage injection. A self-generating foam polymer system consisting of gel-forming and gas-forming compositions should be used at the first stage. Because of the components interaction, a foam-gel structure with increased rheological and filtration characteristics is formed in a controlled time. In the second stage of processing, the foam polymer system is reinforced with a hydrogel based on polyacrylamide, cross-linked with an organic cross linker. For successful processing it is very important to diagnose clearly the sources of gas inflow, taking into account the design features of each horizontal well and the geology of the development reservoir. Only comparison of all these factors results to plan the treatment design correctly for each well. Output and input quality chemicals control, their conveying and storage conditions have also a great importance. The experimental work carried out on three horizontal wells confirmed the correctness of the chosen approach. Purpose of gas inflow seal was achieved at two wells, and unsuccessful processing of the third well, provided material for changing the treatment design. It depends on the design of the well and the sources of gas inflow. The purpose of pilot field tests has been achieved, the proposed technology can be used on objects with similar geological and physical properties.
References
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