The Mechanism of PCP Wells' Tubing and Rod Wear Issue in Polymer Flooding in Daqing Oil Field

Abstract Although PCP technology has been used in Daqing Oilfield from 1980s, and the number of PCP wells in the whole oilfield has reached 2429 till September in 2006, it wasn’t applied in polymer flooding producers with displacement of over 150m3/d until 2004. However, the application of the high volume PCP systems has witnessed severe wear issue both in tubing and rods. Study indicated that, due to the great increment in displacement, the original design for smaller volume PCPs showed serious incompatibility with high volume PCP systems. For instance, bigger structure parameter resulted in higher rod oscillation in operation, and pipe string bending issue in high volume PCP was more popular than in lower ones using the traditional anchor. In addition, improper rod guiding also played an important role in wear of tubing and rod string. This paper analyzes the mechanism of tubing & rod wear for high volume PCPs in detail, and presents a series of harness treatments including: 1) optimizing pump selection method and operation parameter; 2) improving tubing anchoring method; and 3) optimizing rod string guiding method. Based on the above treatments, a set of optimum design model for high volume PCPs was created. Experiments and application showed that, using this optimum design model, tubing & rod wear failure rate was decreased sharply, and the operation performance was improved effectively for high volume PCPs in polymer flooding area. This study contributed a lot in not only improving the design method of traditional PCP technology, expanding the application scale of PCP system, but also presenting a good reference on how to squeeze the benefit of artificial lift technology in EOR stage.