Publications

Fault characterization, which is the focus of this paper, relates to the prediction of whether pressure communication or fluid flow is likely to occur across a fault. Detailed fault characterization can assist in optimizing development decisions and strategies. This study focuses on Area-1 of the Minas oil field in the Central Sumatra Basin and combines fault seal analysis and interference pressure testing. The data used in this study includes 3D seismic, wireline logs, reservoir pressures and pressure transient data, regional and localized geology references. The Shale Gouge Ratio (SGR) fault seal analysis technique forms the basis of this study, and is aimed at identifying communication across the fault plane in Minas Field Area-1. SGR is an estimate of the proportion of shale material in the fault plane and is an indicator of whether or not the fault is likely to be sealing. The range of the SGR in the fault is 10 to 65%: these values represent the potential for the fault to be sealing or partially leaking. The calibration based on reservoir pressure and interference test data indicates that an SGR of approximately 16% represents the threshold between a leaking and sealing fault. In terms of reservoir management, recognition of the sealing capacity of faults helps in deciding whether a pattern injection approach (across a leaking fault) or mini-peripheral injection approach (against a sealing fault) will lead to better recovery.