Regional Structure Of Central Asia And Distribution Characteristics Of Main Petroleum-bearing Combinations

Based on Central Asian oil and gas geological data and previous research results and using the theories of structural analyses of petroliferous basin and petroleum geology et al,study on the controlling effects of Central Asian regional tectonic framework on the formation and distribution of petroliferous basins and development and distribution of main petroleum systems has been carried out,started with the analyses of regional tectonic background,to provide tectonic geology base for oil and gas geological characteristics analyses and petroleum prospect optimization in this area.During the geological history,the tectonic and sedimentary evolution of Central Asian were dramatically related to the separating,expanding,subducting and disappearing of the Paleo-tethys ocean and Neo-tethys,on which the oil and gas geological characteristics of the Central Asian were depended.Especially,the tectonic stress fields with different properties resulted from the structural events including expanding of the Neo-tethys and disappearing of the Paleo-tethys,subducting and disappearing of the Neo-tethys and india-asia plate collision,arabian plate collision,continuous india-asia plate continent-continent subduction and Eurasian intracontinental deformation during the structural evolution of the tethys orogenic belt controlled the formation and distribution,the sedimentary sequences,the development of source rocks and reservoirs,longitudinal source-reservoir-cap assemblage and entrapment characteristics of sedimentary basins with different structure time and types in the Central Asian.The regional structure evolution of the Central Asian can be divided into Paleozoic,Mesozoic,and Cenozoic three tectonic cycles and seven original basin development phases.During the different structure evolution phases,the development and distribution of original basin was mainly controlled by the evolution of the paleo-tethys and Neo-tethys and various dynamic environments resulted from the interaction among the East Europe,Kazakhstan,Arab,and Tulane plate et al.There are various basin-forming mechanisms and basin types including the rift basin,passive continental margin,foreland basin and craton depression basin et al.The source,reservoirs and seals and source-reservoir-cap assemblage in the hydrocarbon-bearing series are controlled by the structural layer vertically.Obviously,the regional distributions of the main source rocks,reservoirs and seals are controlled by several factors including the size of the original basin,lithofacies paleogeography environment and basin structure types et al and are related to the evolution of the basin.The main source rocks,reservoirs and seals mainly occur in the passive continental margin and craton depression basin,and then occur in the rift basin,foreland basin and cratonic marginal depressions.In the craton depression and passive continental margin basins,the source rocks,reservoirs and seals distribute widely with relatively big area while they distribute limitedly and dispersedly with relatively small area in the narrow rift,foreland basins and cratonic marginal depressions.Generally,the distribution of favorable zone of Paleozoic-Cenozoic source-reservoir-cap assemblage in the Central Asian was evaluated in this paper.