Publications

The Asri Basin is a result of intrabasinal faulting and folding. The basin has proven recoverable oil reserves. Alpha Field is located on North East of Asri Basin that's firstly found on 1988 and the first drilled well was done in Alpha 01 well. Study focused on facies and depositional analysis of sandstone "X" in Talang Akar Formation based on core and log. The facies model was generated from 272 feet core data of well Alpha 01. Sequence stratigraphic methods were applied to carry out vertical succession within the well and lateral correlation between wells. Detailed core description of Alpha 01 was done to get detailed vertical facies succession of sandstone. Sandstone can be classified into 4 depositional facies, there are braided channel facies, fluvial meandering channel/point bar facies, tidal point bar facies, and tidal estuarine point bar facies. Average porosity of the sandstones shows a good reservoir, which has variety from 28.8% of fluvial meandering channel/point bar sand to 29.6% of tidal estuarine point bar sand. Tidal point bar sand is one of interesting reservoir since it has thicker and wider sand, 15 - 53 feet thickness and approximately 1500 meter width. The tidal point bar facies tends north - east. Tidal point bar sand is deposited in meandering deltaic fluvial system. Trap mechanisms in Alpha Field are structural and stratigraphic traps. Based on seismic data, faulted-structural trap was found in north of Alpha Field, with the normal fault direction is southwest - northeast. The stratigraphic trap is recognized from facies change.