An Improved Integrated Reverse Washing, Measuring and Adjusting Zonal Water Injection Process in the Bohai Oilfield

The Bohai Oilfield has experienced challenges with its conventional zonal injection processes. Specifically, there have been difficulties with reverse washing, along with low distributing efficiency and low distributing qualified rate. To improve the situation, a study was carried out on the integrated reverse washing, measuring and adjusting zonal water injection process. By developing the integrated measuring/adjusting water distributor and reverse washing packer, the structures of sand control and water injection strings were optimized, and the integrated reverse washing/measuring/adjusting function with fixed string were achieved, thus forming the integrated reverse washing, measuring and adjusting zonal water injection process in the Bohai Oilfield. This process was applied in 10 wells that had difficulty in water injection. In fact, thirty well times of distribution adjustment were performed in the Bohai Oilfield. Field applications suggested that the performance of reverse washing tool was reliable, the switching was flexible, and the well washing effect was good, which effectively alleviated the increased water injection pressure and reduced the frequency of acidizing. The measuring/adjusting efficiency was significantly improved, and the average single well distribution adjustment cycle was shortened to 10 hours, which was significant shorter than that of the conventional zonal injection processes (2–3 days). The successful applications of the integrated reverse washing, measuring and adjusting zonal water injection process verified the feasibility of this process and provided new technical ideas for the zonal water injection development of Bohai Oilfield and thereby improve the efficiency of acidizing.