Enhanced Integration to Characterize Heavy Oil in Complex Environment

Abstract Heavy Oil Exploration is one of the great challenges faced in upper Ordovician in Murzuq basin due to the geological & petrophysical complexity. Few wells were explored earlier & resulted in water production. Leaving high uncertainty behind. Hydrocarbon exploration in the Upper Ordovician, Mamuniyat Formation in Murzuq Basin is known to be challenging, being a product of fluvioglacial and glaciomarine processes, it is characterized by episodes of erosion and deposition. This resulted in stratigraphic units with limited lateral extent and varying reservoir quality, mostly tight due to quartz overgrowth cementation except when fractures are observed. Furthermore, from petrophysical aspect the tight quartzite sandstone with the presence of fresh water, causes the resistivity to be high, beyond conventional tool limit. This leads to a difficulty to compute saturation profiling & distinguishing between oil & water. Full evaluation techniques were utilized to characterize & identify potential zones to enable flow of black & heavy oil in such poor quality, complex reservoirs. The advancement in the interpretation of image logs, petrophysical logs lead to guide the reservoir Formation Testing Tools to enable flowing of black & heavy oil in such tight, complex reservoirs & conducting a Mini-Drill Stem Testing for reservoir potential assessment. These wells when produced earlier had no signatures of heavy oil. This paper describes the advancement in integrated approaches in Wireline logging to fully characterize such complex environments which resulted in the discovery of black & heavy oil in unprecedented area.