Geocellular Modelling of the Fluvial Deltaic and Shallow Marine Reservoirs, Tangga Barat Field, PM313 Offshore Malay Basin

The Tangga Barat field discovered in 1985 by Esso Production Malaysia Inc well Tangga Barat-1A is one of a series of Middle Miocene Gas Fields aligned along the axis of the Malay Basin offshore Peninsula Malaysia. The reservoirs of this Greenfield range in age from mid Middle Miocene H Group shallow-marine sands, through the fluvial-deltaic dominated E Group, to the early Upper Miocene D Group neritic sands. The primary reserves of the Tangga Barat field are contained within the E Group reservoirs that contain circa eighty percent of the hydrocarbons in place. However, a relatively high degree of uncertainty is inherent in the subsurface understanding as a result of both the low density of well coverage and due to gasshadow effects immediately overlying the field that degrades the seismic image of the reservoirs. This paper focuses on the attempt to quantify the subsurface uncertainty by the construction of a 3D Geological Model utilising the results of the interpretation of a recently acquired 3D seismic survey and integrated with all log, engineering and drilling data. The paper also summarises the impact of the model on the Field Development Plan for Tangga Barat.