Scaling issue of artificial lift systems is the main bottleneck for ASP flooding, and has considerably negative influence in commercial stage. In the past decade, different anti-scaling technologies have been developed and applied in Daqing Oilfield. However, high pump failure still exists in severely scaling producers. This paper presents an innovative artificial lift method – a patented bailing pumping unit production system, which has been applied successfully in field test stage in Daqing Oilfield.
The system consists of soft plunger, special designed wire line, winch system and surface control. Produced liquid mixed with large quantity of scale particles is lifted to surface by the soft plunger connected to wire line. The plunger is made of high molecular materials and steel skeleton support which ensures good flexibility and reliability after long term of operation in abrasive environment. The wire line is specified designed and processed to enhance operation life. It connects downhole gauge and surface control. Down hole pressure can be monitored in real time, which provides references for adjustment.
This innovative bailing pumping unit production system has been applied in 80 wells in 3 ASP flooding blocks with severe scaling issue in Daqing Oilfield. The average running life was improved from several weeks to 710 days. Considerable benefits have been achieved by the 60% operation cost decline. It has been the premier artificial lift method for the severely scaling producers. Additionally, there is no need for flushing or acidizing treatment to deal with scale deposited in downhole pump, rod string, and tubing string compared with pumping unit production system in ASP flooding, which significantly reduces normal management intensity and cost.
Field test showed that this innovative bailing pumping unit production system has outstanding scale resistance capability for severe scaling wells in ASP flooding. It also provides a great reference for other oilfields in worldwide with similar issues both in ASP flooding and high salinity conditions.