Production Optimization through Casing Vapor Recovery System for Gas Locking & Gas Interference Challenges in Beam Pumps for Highly Fractured Tight Carbonate Reservoirs

Abstract

Abstract This paper discusses the challenges to production caused by gas interference and gas locking in beam pump wells in highly fractured tight carbonate reservoirs in the Bahrain field. It will describe casing vapor recovery (CVR) project that was implemented in the Bahrain field to overcome these challenges. It will also highlight the project strategy that was adopted to reduce the uncertainty on gas measurements and production performance. Case study on the Bahrain field showed a small amount of produced gas can significantly reduce beam pump efficiency and production. Therefore, this paper will describe the profound positive production and pump efficiency impact of removing all produced gas from the well annulus via casing vapor recovery system. It will illustrate a "Design of Experiment" before implementing a full field system. The paper will also describe the phase approach for implementing the project to reduce the uncertainty on gas measurements and therefore, insure cost efficiency for project implementation. Beam Pumping as a method of oil production has been used for more than 100 years in a vast variety of oil fields due to its simple operations. The usage increases in pressure-depleted reservoirs due to pumps’ ability to maximize drawdown; hence production. Nevertheless, even after 100 years, production engineering challenges persist in dealing with issues such as gas production. Complication is also added when operating beam pumps in low reservoir-pressure highly-fractured tight and complicated carbonate reservoirs. Many gas interference issues can be solved with some success by different well completion configurations such as gas anchors or optimizing the pumping parameters. However, casing recovery system in the Bahrain field was proven to be the most efficient and technically suitable. The project started by proving the CVR concept through Design Experiment. Then, phase approach for project implementation was taken place. The CVR project is considered a great success not only because of oil production improvement but due to its implementation strategy which led to proper designing of CVR surface network and therefore, cost efficiency.