PLUGGING REMOVAL AND INJECTION ENHANCEMENT TECHNOLOGY FOR THE WATER INJECTION WELLS IN BOHAI OILFIELD

To solve the problem of difficult water injection in Bohai oilfield, a study was carried out on the plugging mechanism of water injection wells, and BHJ series plugging removal agents were developed based on the study. Laboratory tests were conducted on the performances of the series agents, e.g., of the organic plugging removal agent, its dissolving ability to asphalt and wax, its crude oil cleaning and gel-breaking ability; of the inorganic plugging removal agent, its dissolution to packing sand and core samples, its dissolution to inorganic scale and iron rusts, its iron ions stability, static slice corrosion, and tough scale conversion rate. Tests showed that BHJ series agents achieved a plugging dissolution rate as high as 90% and over. The series products have been used for 12 times in Bohai Oilfield, and the water sucking index of the operated wells went up remarkably, with a 100% operation success rate achieved. The field using proved their advantages such as high plugging removal efficiency, free of formation damage, wide application range, good permeability recovery, etc.