Design and Engineering of an Early Production and Mini-Gas Processing Facility for 1000 BOPD and 15 MMSCFD Natural Gas: An XYZ Marginal Field Strategy

XYZ is an onshore marginal field located in the Niger Delta region of Nigeria. Following the 2020 bid round, it was acquired, and geological studies commenced. After confirming economically recoverable hydrocarbon and successfully completing a well test campaign, plans to produce from the dual-completed XYZ-1 well were conceived. This necessitated the front-end engineering design (FEED) and detailed engineering design (DED) of an early production facility (EPF) capable of processing 1000 barrels of crude oil per day, alongside a mini gas processing facility capable of handling 15 million standard cubic feet of natural gas per day. This paper explains the strategies employed to conduct the FEED and DED for both the EPF and the mini gas facility to optimize production efficiency while meeting operational and safety standards. The EPF combines streams from the two strings of the well and separates hydrocarbon into oil, gas, and water. The oil is evacuated via trucking, while the gas is routed to the mini gas plant, which dehydrates the natural gas and compresses the dry gas. The compressed natural gas is then utilized and commercialized through pipeline delivery to off-takers, Compressed Natural Gas (CNG) trucks, gas lift, and power generation. The paper also reviews fluid characterization as a critical criterion for the FEED, process equipment selection, and facility layout optimization. The design accounted for gas-liquid separation, crude stabilization, and associated utilities, with a focus on minimizing environmental impact and ensuring operational reliability. Engineering decisions were guided by the need for scalability, cost efficiency, and adaptability to marginal field constraints. This paper provides detailed insights into the technical processes, design methodologies, and engineering approaches adopted during the project. It aims to serve as a practical reference for industry professionals involved in the development of similar production facilities for marginal fields.