Publications

The Paleocene-aged deep water basin floor fan and slope channel reservoirs of Wiriagar Deep field are trapped in a NW-SE orientated large four way dip closure created during Oligocene compression, subsequently reactivated during the Late Miocene-Pliocene. There are two key components to reservoir compartmentalisation at Wiriagar Deep field, which comprise the deep water lobe and channel stratigraphic trap in combination with the strike slip fault pattern Seismic visualization of both the reservoirs and the faults at Wiriagar Deep Field is challenging, due primarily to the karstified Eocene-Miocene overburden which limits the 3D seismic resolution. E-W orientated strike-slip faults with Riedel shears dominate the structural framework. Shale gouge ratios, sand-on-sand cataclasis, and the component of dip slip vs strike slip deformation all contribute to the nature and likelihood of fault seal and hence structural compartmentalization. Initiation of sedimentation post the late Cretaceous high stand resulted in the abrupt entry into the basin of fine grained, well sorted stacked basin floor fans. Stacking patterns up to 250ft thick can be correlated across the field, and by utilizing outcrop analogues the stratigraphic margins of lobes and lobe complexes can be predicted. The subsequent deposition of isolated slope channel reservoirs also has implications for stratigraphic compartmentalization, albeit in the south of the field there is DST data to support an interpretation of a wider, better connected reservoir fairway in a channel lobe transition zone. The stratigraphic trap uncertainty in the deep water basin floor fan and slope channel reservoirs at Wiriagar Deep, along with the structural overprint, has been partially resolved through a combination of core-based sedimentology, fault seal analysis and incorporation of deconvoluted DST data to assure Paleocene gas volumes.