Abstract:

Before the discovery of Fula oilfield, previous studies consider that there developed source rock of semi-deep to deep lacustrine in Abu Gabra Formation,Fula depression,which were comprehensively evaluated to be good to very good source rocks but with lower thermal evolution degree, and the other main factors controlling the formation of oil pools were uncertainty, so Fula depression were considered lack of the oil and gas exploration potential. Based on detailed study of gravity data, seismic data and well data, analysis stratigraphic sequence, structure development and evolution, sedimentary facies combined with lithofacies, log-facies and seismic facies, this study reveals that the development of structure and deposition in Fula depression were controlled by shear-extensional regional tectonism. There developed a certain and effective hydrocarbon generation sag of the Abu Gabra Formation in Lower Cretaceous. Three favorable sourcereservoirseal assemblages and 4 reservoirforming zones are identified. The rollover anticline-faulted nose zone in the middle structure belt, the faulted noses zones in west margin of south sub-depression, in the south faulted step belt and in east margin of the north subdepression are evaluated prospect reservoir plays. Fula 1 rollover anticline and Fula 2 faulted nose are regarded as the best of prospect targets. These study results play an important role on oil and gas exploration and development in Fula depression. This research methods and exploration strategy can provide references for early petroleum exploration and basin analysis.

Key words: reservoir-forming main control factor, plays, exploration target, Fula depression； Muglad Basin