3D-PS Converted Waves – Solving 3D-imaging Challenges under Gas Clouds - Offshore Malaysia

In offshore peninsular Malaysia there are strings of major hydrocarbon bearing fields which are affected by shallow gas clouds. This poses a major problem in imaging using the P-wave data from conventional streamer or OBC 2C surveys which suffer from frequency dependent attenuation, multipathing, scattering, internal multiples, velocity inversions and mode conversions due to the gas charged sediments. 2D–4C data is proven to be useful in areas affected by shallow gas where 2D-PS-wave imaging provides clearer image as compared to 2D-P-wave imaging. Imaging of 3D-PS-converted-wave data presents its own unique challenges which discourage companies from processing the converted wave component of 3D–4C-OBC data. Through this case study we showcase three processes which have brought about significant improvements in the 3D PS-wave time-imaging and outline the results of 3D-PS-PSDM depth-migration, rendering the data to be highly useful for interpretation and inversion work inside the gas cloud affected area.