The impact of structural inversion on the hydrocarbon system, northwest Mosul area, Case study Sasan (Sarjoon) Oil Field.

Abstract

Sasan field is in Nineveh governorate, 46 Km northwest Mosul city. The present Sasan structure was discovered from surface mapping and 2D seismic defined the Upper Cretaceous reservoir but due to poor data quality, any estimate of oil in places are highly uncertain. Sasan structure from seismic shows Block-Faulted anticline covering a small area (Sasan East). Several normal faults appear to separate SA-2 from SA-1 affected the hydrocarbon system in these two wells. The more possible realistic interpretation is an inverted graben, thick Shiranish Formation in Sasan wells support this interpretation.The model suggest that normal faults created the accommodation during Late Cretaceous (Sinjar trough) and subsequent Tertiary compression uplifted the depocenter creating the topographic depression which interpretated as a fault propagation fold. The last compressional structures can only have been filled with remigrated petroleum from breached, older traps, earlier structures could have been filled by migration from an actively generating source rocks. The exploration potential in the old Sasan structure configuration is good but it is still an exploration play not a commercial oil discovery, although oil is present in Shiranish, Hartha/Mushora and Wajnah formations but not clear if it is recoverable.Gas present in deeper formations, both the oil and gas traps are breaching traps. The best exploration targets should, therefore, be old structures, produced by Late shoulders of Sinjar basin contain many such leads as the prospective leads nominated A, B, C and D.Second best are old structures which have been partially restructured and whose closure has been modified, but not breached. The prospective reservoirs will be at Late Cretaceous, Early Cretaceous and Late Triassic.