Depositional Architecture of Eocene and Cretaceous Reservoirs (Blending Seismic and Well Data) in Mubarik Area, Central Indus Basin, Pakistan

Abstract

Structural and stratigraphic geometries in the Central Indus Basin of Pakistan are subjects of interest for explorers. The thickening and thinning sequences in conjunction with structural anomalies often provide an environment for hydrocarbon accumulation. Hydrocarbons play a vital role in the energy mix of Pakistan. With the help of well correlation, work on seismicity can be confirmed by marking terminations, depositional extent and thickness variation at different stratigraphic levels. Therefore, this work presents depositional geometries of Eocene and Cretaceous reservoirs [Sui Main Limestone (SML) and B-sand interval of Lower Goru Formation], keeping in view the vertical and lateral resolution of the seismic data and the distance between the wells for correlation. The Eocene SML and Cretaceous B-sand are extensively mapped as isochrones using 20 seismic lines and correlated with ten wells. The results give evidence of a building up of shallow marine shelf carbonate in Eocene SML. The isochrone maps also indicate that Eocene SML has untapped potential east of the study area. The Cretaceous B-sand demonstrates sheet-like geometry of sand-filled delta progrades in the west to southwest direction in a ramp setting. This geometry suggests an updip hydrocarbon potential in Cretaceous B-sand reservoir in the north of the study area. Because of the pinching out behavior and excellent stratigraphic trapping system, these two reservoirs can be considered future exploration targets.