The Control Action Of Tectonic Evolution Over Oil And Gas In Akekule Lobe Of Tarim Basin

Akekule lobe first appeared during the Caledonian period and finally formed in theHimalayan period after several tectonic movements. In the formation of oil and gasreservoir of Tahe oil field which is located in the southwestern wing of structural belt ofAkekule, tectonic evolution plays an important role of control action.Through studyingthe regional geology, sedimentary characteristic and tectonic evolution in Akekule, thispaper explained in detail the influence of tectonic evolution on structural configuration,tectonic framework and sedimentary characteristic in Akekule lobe during theCaledonian period, Hercynian period, Indosinian-Yanshanian period and Himalayanperiod.The Ordovician carbonate rocks in Akekule lobe do not possess percolation abilityand its reservoir space is fracture and cave reservoir. Palaeokarst,which is controlled byplane of unconformity and fault system, plays an important role in reservoirreconstruction in Ordovician carbonate rocks. After several tectonic evolution, tectonicmovements is of great significance to reservoir reconstruction in Ordovician carbonaterocks. This paper analyses the controlling factors of fracture and cave reservoirdevelopment in terms of lithology, pre-existent pore structure, plane of unconformity,palaeogeomorphology, sea-level, fracture, palaeoclimate and palaeotectonic, and thenexpounds the palaeokarst during the Caledonian period and early Hercynian period.Source rock distribution, thermal evolution history,the influence of hydrocarbonmigration time on reservoir formation and passage system are controlled by tectonicmovement.The formation and disruption of oil and gas trap, hydrocarbon migrationand accumulation are also controlled by the tectonic evolution of Akekule lobe. Finally,based on research into the source rock distribution and evolution, reservoir,sealingcontition, trap type, passage system and reservoir-forming pattern,this paper explainsthe control action over hydrocarbon migration and accumulation during the process ofthe tectonic evolution in the Akekule lobe.