Publications

The Gelam Field, located in South Sumatra, is a high permeability, retrograde gas condensate reservoir (Talang Akar formation) that started production in 1999. Pressure and production data gathered throughout the field history have been instrumental in improving the understanding of the subsurface. This paper discusses a recent reanalyses of this data, which was undertaken to improve the understanding of compartmentalization and its impact on field performance. Gelam is divided by a large fault into two main areas called West Gelam and South East Gelam (SE Gelam). Pressure data initially suggested compartmentalization between the main areas, but in later years the pressure performance suggested communication was occurring. This pressure data has been analyzed using material balance techniques and using this analysis together with observations of production data, an explanation for the apparent change in behavior has been hypothesized. This paper explains the analysis performed including an analysis of PVT behavior and an analysis of pressure performance using material balance techniques. Some sensitivity analysis has been performed to examine uncertainties in key variables i.e. aquifer presence and compartmentalization. The conclusions of the study are presented together with the sensitivity analysis. Based upon the experience and lessons learned from Gelam, the paper also summarizes best practices to help narrow the range of uncertainty for this and analogous types of fields.