| HYDROCARBON POTENTIAL OF THE UPPER CRETACEOUS OF ARSHAD FORMATION, ARSHAD FIELD, CONCESSION 6, ZALTAN PLATFORM, SIRT BASIN, LIBYA |
| Paper ID : 1018-ISCHU |
| Authors |
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Dr. Milad Mohamed Burki * Exploration Department, Sirte Oil Co.
P O Box 385
Tripoli-Libya |
| Abstract |
| The Arshad Field is located in Concession 6, Zaltan Platform, Sirt Basin, Libya. It’s a significant horst block trending NW–SE fault rifting systems being proved by 3D and 2D seismic data. The stratigraphic and lithologic section is differentiated into Cambro-Ordovician quartzites followed by the Upper Cretaceous and Tertiary deposits across the Arshad Field. The Upper Cretaceous sandstone is derived from the underlying older Paleozoic sediments. Sandstone is the most important part of the Arshad; it forms the main hydrocarbon-bearing reservoirs in this field. Sandstone is interpreted as quartz-arenites with abundant silica, dolomite, kaolinite, iron oxides and calcite cement in terms of their modal composition. The sedimentological interpretation of the core study and integration with wireline logs revealed that the sandstone was classified into five lithofacies (F1-F5). The first four lithofacies were deposited in shoreface to foreshore with variable energy conditions while lithofacies F5 represented the deposition of an alluvial fan which indicates the basal conglomerates. The sandstones have potential reservoir quality as oil-bearing units in central and southern structures whereas gas-bearing zones were encountered in the northern sector of Arshad Field. Oil has migrated from the Campanian Sirte Shale source rock which has reached the oil-window at the western flank of the South Ajdabiya Trough to the Arshad sandstone as well as Gas migration took place from Sirte Shale buried in the gas-window in the deep Wadayet (NW Ajdabiya Trough) to Arshad Field. Porosity (mainly secondary porosity) and permeability of reservoir sandstone are variables between poor to good depending on the presence of the cement types. Core analysis, petrographic analysis and petrophysical interpretation (IP software) revealed that the reservoir quality ranged from poor to good in Arshad Field. |
| Keywords |
| Keywords: Campanian Upper Cretaceous; Ajdabiya - Wadayet Trough; Arshad Filed; Zaltan Platform; Sirt Basin; Libya. |
| Status: Abstract Accepted (Oral Presentation) |