Trap architecture of the Early Cretaceous Sarir Sandstone in the eastern Sirt Basin, Libya

Abstract

Abstract The Sarir Sandstone is the principal reservoir for oil accumulations in the eastern Sirt Basin in Libya. The main phase of the rifting in this area took place in the Late Jurassic-Early Cretaceous, during which time the Sarir Sandstone was deposited as a non-marine, intra-continental clastic syn-rift sequence. Although successfully explored from 1959 onwards, the prolific eastern Sirt Basin is in a relatively immature stage of exploration regarding wildcat drilling and 3D seismic data acquisition. The most recent phase of exploration, utilizing 3D seismic techniques, revealed a complex structural development. The trap geometries are often related to E-W trending, basement-controlled fault systems, oblique to the NNW-SSE Sirt Basin trend. The fault systems were active during the Sarir Sandstone deposition, giving rise to structural as well as well as combined structural-stratigraphic traps. An increased understanding of trap architecture has led to both re-evaluation of older fields and new discoveries. Complex structural traps exhibiting four-way dip or fault closures, and combined structural-stratigraphic traps, have been successfully explored in recent years, and will continue to provide exploration opportunities. The prospective areas comprise the faulted basin margins and the Sarir Sandstone depositional and erosional edges. Modern geophysical techniques including high-resolution 3D seismic data acquisition are critical in discovering and developing the remaining potential.