Publications

Kaji Semoga (KS) field has produced primarily from Baturaja Formation, which is a limestone formation 2,600-2,700 ft TVD. In early 2001, when the reservoir pressure was decreasing and the wells ceased to flow, gas lift was installed and became the main artificial lift in KS. But due to the decline in gas production, and to reduce the decline, an artificial lift implementation project was conducted in 2007. The objective of the project was to convert some gas lift wells to ESP wells. As a result of implementing these projects, ESP will be the dominant artificial lift for production wells in KS, contributing to approximately 70% of total oil production. During the artificial lift implementation project and ESP operated system, the possibility of predictable and unpredictable problems arose. One predictable problem was that installation of ESP and tie-in of the new electrical network caused a shut-down of a few hours duration. Some unpredicted problems which caused several days or weeks downtime were mainly due to down-hole problems which needed rig deployment or spare part(s). An evaluation of the ESP - Gas Lift hybrid design and implementation was required in order to optimize the recovering system. Basically, there were 3 designs, but only two designs were chosen and implemented. These 3 designs were based on some expectations and limitations. 2 designs were implemented in KS. The first required 1 SPM and 1 SSD aligned with ESP string, and the second required an additional 1 SPM Design B (1 SPM and 1 SSD) was considered as the most optimal ESP - GL Hybrid design for KS field. All ESP wells in KS (currently 82 wells) use design A configuration. The gas lift system has been used as a backup during ESP downtime. Since the first installation at the end of 2008 until January 2010, this ESP - GL Hybrid configuration produces only35% liquid compared to that of normal ESP liquid production, as a result minimizing total KS production loss by up to 5,800 bbls of oil.