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.