f Acoustic Impedence Inversion and AVO Analysis of Pre-SDM versus Pre-STM Data

Both Guntong and Irong Barat fields are located off the East Coast of Peninsular Malaysia in the southeastern part of the Malay Basin. EMEPMI acquired the most recent 3-D seismic over the hong Barat and Guntong field in 1998. These data were processed through Pre-Stacked Time Migration (Pre-STM) and subsequently re-processed through Pre-Stacked Depth Migration (Pre-SDM), in 2001 and 2002 respectively, in order to address remaining imaging issues assocaited with faults and continuity below shallow gas. EMEPMI Geophysical Application group analyzed the Ore Stack Depth Migrated (Pre-SDM) data over these two fields to determine whether these datasets were suitable for reservoir characterization. The results were compared to the equivalent analysis using Pre-Stack-Time-Migrated (Pre-STM) data. Pre-Stack AVO and Post-Stack amplitude analysis was performed over the Irong Barat C (TB-C) development area to confirm the robustness of the Pre-SDM amplitude observations for the H20 reservoir. Acoustic impedance inversion was performed over the Guntong field for both the Pre-SDM and Pre-STM datasets. The results from both field studies indicate that the Pre-STM and Pre-SDM data are in general agreement. However, the Pre-SDM data seems to have a more consistent and geologically meaningful amplitude response than that of the Pre-STM data. The result of AVO analysis over Irong Barat was subsequently used in the DHI risking analysis and as partial justifiaction for full funding of the TB-C development. The Pre-SDM acoustic impedance (Al) inversion volume over Guntong is currently being interpreted.