Application of DOWS (Downhole Oil Water Separation) Technology Used in High Water-Cut Oilfield: Case Study

Abstract

Abstract High water-cut is a common problem affecting oilfield stabilized production in the late period of oilfield development. Downhole oil water separation (DOWS) technology provides an effective way for the long-term economic development of high water-cut oilfield. DOWS can separate the oil and water in the wellbore directly with a hydrocyclone. The oil-rich stream is produced to the surface while the water stream is injected into the water-injection layer or abandoned layer. DOWS technology has made new developments in China as the progress of downhole date monitoring and control technique. The DOWS system consists of hydrocyclone, downhole date monitoring system, two pumps used for lifting and injection respectively. Hydrocyclone contour line was optimized and increased the separation efficiency to 98% or more. Date monitoring system includes flow meter and pressure gauge to surveil the flow and pressure of injection layer in real time. These dates can be transmitted to the ground through the cable and then to the remote terminal by GPRS modem. Engineers can monitor working situation of the DOWS system and control the separation effect using PC or mobile phone in the office. The inlet of hydrocyclone and the injection pump was designed to adapt to the limited space in 5½" casing well. This paper reports the characteristics of DOWS technology used in China and the latest advances we developed. This technology has been used in high water-cut blocks in Daqing Oilfield and Jidong Oilfield in China. Field tests show that DOWS technology can reduce the ground water production more than 75% and maintain the oil production unchanged in high water-cut oilfield. DOWS system has worked properly more than 400 days.