Depositional Environment and Facies in Units 2A, 2B and 2C of The Graben Trend in Arthit Field, North Malay Basin, Gulf of Thailand

Abstract

This study focused on cores from the Arthit Area. The depositional environment was interpreted to be a tide-dominated shoreline and the facies represent a stacked mouth bar and a variety of tidal sediments. The thin individual mouth bar sands indicate a small fluvial system not more than a few hundred meters across. The small delta system may have generated stacked mouth bar sands that are well-connected over an area of a few km² by lobe switching, but they would not have extended the multi-km distance between wells. The tidal sands, although laterally extensive, have poor reservoir properties. Well log patterns correspond to lithology in the cored intervals but the log signatures are not always reliable indicators of depositional environment. They often are recording minor local events and not the regionally significant flooding surface that are parasequence boundaries. This is problematic for well to well correlation over distances of several km and can easily lead to miscorrelation.