Augmenting a Conventional Gas Lift System via Annulus Injection of Homogenized Foam and Gas: From Paper Plan to Execution

Abstract

BKR is a producing field, offshore Malaysia with almost 100 strings producing either naturally or utilizing gas lift as its primary artificial lift method. BKR being a mature field with increasing watercut production and declining reservoir pressures, experiences gas lifting issues such as an ever increasing lift gas demand and deteriorating lift gas utilization factor (GUF). To improve the gas lifting efficiency a pilot project utilizing foam to assist gas lifting was attempted. Based on a literature studies, foam assisted gas lift is expected to be able to reduce the gas lift consumption by gas lifted wells, as well as further improving the lifting performance of gas lifted wells by introducing a foaming agent into the flow stream. After performing the feasibility studies, 2 wells were identified at BKR field for the pilot execution, based on the candidate screening criteria. This paper presents the problems and opportunities which led to the foam assisted gas lift pilot trial in BKR field, as well as the trial results and key learnings. The theoretical background of the approach and few case studies done at other fields previously are summarized. It also details candidate screening criteria, chemical/foam lab tests to ensure foam performance and compatibility to the well system, evaluation approach, as well as potential application methods. The second part of the paper discusses the planning and actual job implementation which includes logistics, treatment well on paper exercise, well and chemical surveillance plan and detailed treatment procedures. The result of the pilot will be elaborated in detail in the paper covering the well's baseline production rate and production well test trends along the execution phase, pressure and temperature data collected, lessons learnt during pilot execution and potential way forward for the next pilot. Based on the field trial results, the foam assisted gas lift approach has proven to be one of potential solutions to overcome gas shortage and poor GUF problems in the field. The results were very promising with almost a 100% improvement in production in one of the candidates. These results meet the goal of the pilot implementation which is to find a technology with good results with minimum expenditure. Nonetheless, several operational and logistic issues need to be addressed to have sustainable results, as well as prudent cost management.