Abstract
Bankers Petroleum has grown its Patos Marinza field in Albania to a 16,000 barrels of oil per day (bopd) heavy oil operation over a 9 yr period, with significant potential growth possible in the future. One of the areas where significant value can be added to Bankers' operations is to extend the runlife of artificial lift systems in the field. The use of Progressing Cavity Pumps (PCPs) has allowed Bankers Petroleum to unlock significant resources; however the pump systems come with challenges. The current MTBF for the PCP systems of 120 days can be attributed to high oil viscosities, high elastomer swell, high bottom hole pressures, and high pump pressure loading. This paper discusses the collaborative effort between Bankers Petroleum and Weatherford to understand the issues affecting artificial lift system run life in this field and working to improve it. Results from an extensive laboratory test program undertaken by Weatherford to look at pressure and temperature build up in pumps running with viscous fluid and up to 95% gas are included. A field trial was undertaken with three instrumented PCPs at Patos Marinza to investigate the downhole pump pressure distribution, and the effect of various rotor fits and diluent injection rates on pump and well performance in an effort to optimize run life in this challenging environment.
