Application of New Downhole Oil-Water Separation in the Same Well Injection-Production Technology

摘要

Daqing placanticline has entered a period of ultra-high water cut development, a large number of produced water ineffective circulation, resulting in a significant increase in the investment and operation costs of lifting, gathering and processing links. Reducing the cost of comprehensive development has become a key problem which is restricting the sustainable economic development of high water cut oilfields. In order to solve this problem, the downhole injection-production test of oil-water separation in the same well was carried out. The hydrocyclone was used as the core separation component to separate oil-water two-phase in the tube of production wells, and the high oil-bearing liquid was lifted to the surface and the high water-cut liquid was reinjected to the injection water layer. According to different injection pressure and flow volume, two downhole tubes is researching to suitable for different well conditions: screw pump production - screw pump injection technology tubing string, screw pump production - electric pump injection technology tubing string. 16 wells are experimenting in this process, the average daily production liquid decreased three-quarter, average daily reinjection sewage volume was 60 m~3 almost, the water-oil ratio decreased obviously in the surface. The max repair-free period of the test wells was 600 days. The technology greatly reduces the surface sewage treatment volume and the replacement water reinjection volume. The downhole oil-water separation and injection-production technology in the same well realizes "dual-function and injection-production in the same well", shortening the water cycle treatment process, prolongs the economic recovery period of the oilfield, changing the traditional oilfield production mode. It is one of great significance to reduce the surface input-cost and sewage treatment volume, improving the economic ultimate recovery rate, and has great application value in commerce.