The Tombak gas field located in offshore Sabah with geology structure is a well-defined four-way dip closure that developed as a result of inversion along the deep-seated NE-SW faults, a series of N-S oriented shear faults formed during the inversion and divided the anticline into several fault blocks. Reservoirs encountered at the Tombak field include fluvial and nearshore / esturine sandstones of Early to Middle Miocene age. A good to high quality 3D near (10⁰-23⁰) and far angle stacks (35⁰-46⁰) seismic is available and 7 wells have been drilled and logged. The lithology is divided into shale, gas sand, brine sand and coal using volume shale cut off as well as saturation logs where several hard streak coals appear above some gas reservoirs which can potentially mask the amplitude interpretation. From the AI/EI logs crossplot: several shale, brine sand and gas sand acoustic and elastic properties points are identified overlay each other while coal are identified having low acoustic and elastic properties.