Baram field - the 3D marine re-processing challenge

Abstract

The Baram Field is the largest field in the Baram Delta Operations/Sarawak Oil portfolio and forms part of the PETRONAS CarigalilS.sB joint venture agreement. Several development projects are currently being considered for the Baram Field. In order to resolve the structural complexity and provide more information for future drilling campaigns a 3D marine seismic survey was acquired in 1988 over the Baram Field. The 1989 processing results suffered from severe statics still -present in the final data caused by shallow gas effects. The fault resolution was considered poor throughout the survey. Several DHI's had been identified and used during interpretation of the data set. The reliability and usefulness of these DHI's and other seismic anomalies was doubtful in areas affected by shallow gas and close to faults. Initial suggestions of re-shooting the data in 1997 were rejected due to cost and timing considerations. In order to address the observed uncertainties a re-processing project was awarded to the SSB/SSPC in-house processing centre in 1997. Within tight deadlines comparisons between 3D post-stack time migration, 3D pre-stack time migration and 2D pre-stack depth migration were made available and the latest processing-technology was employed. Based on these results the processing route for the entire data set was determined. In this paper displays of the seismic data set illustrate the observed problems. Comparisons with the former processing results highlight the benefits of the re-processing project.