Looking Through the Haze - How CSEM can Improve Reservoir Imaging Where Seismic Struggles - A Case Study from Malaysia

We present a CSEM survey case in offshore Sarawak, Malaysia showing how CSEM can help reservoir imaging where seismic struggles due to poor seismic reflection. The Seismic data at the prospect depth shows poor reflection due to low saturated gas seepage The CSEM data was acquired in 2008 along two receiver lines assuring azimuth data coverage between the lines.. EMGS performed 2.5D inversion along both the tow lines and the result showed resistive anomalies in one of the structures in each lines. In 2009 Newfield drilled a well in one of the structure which resulted in a gas discovery. Pre-drill 2.5D inversion result matches well with the well log. In early 2012, Newfield drilled a second well a few Km off the CSEM line in the other structure, which was believed to be oil charged but was dry. CSEM inversion did not show any anomaly in that structure. Unconstrained anisotropic 3D inversion was performed in 2012 and the results were then correlated with the well logs. The result of 3D inversion matches very well with the well logs and also laterally with the structure.