Study On Oil And Gas Distribution Of Typical Fold Thrust Belt And Adjacent Basin In North America

North America is rich in oil and gas resource,fold and thrust belt(FTB)and the number of oil and gas basins.On the basis of collecting the data of the predecessors,this paper makes a comprehensive study on the structural evolution,the sedimentary evolution characteristics and the characteristics of the oil and gas distribution in the FTB,and summarizes the main control factors of oil and gas distribution,The main understanding is as follows:The tectonic evolution stages of the fold and thrust belt and foreland basin are compared and analyzed.The tectonic evolution of fold and thrust belt and the foreland basin have two stages: the formation stage of Pangea continent during Paleozoic,the main types of evolution are the rift stage,the passive continental margin stage,the craton stage;the breakup of pangea stage duiring Mesozoic-Cenozoic,the main evolution type is the foreland stage.The orogeny period of fold and thrust belt and the type of tectonic stress control the zonation difference of fold and thrust belt.The lateral zonation is controlled by the tectonic stress type in the orogenic period.The compressed strik e-slip attribute FTB is divided into three main belts,main mountain belt,piedmont belt and foothill belt.The squeeze type FTB is divided into two main belts,main mountain belt and foothills belt.The vertical zonation is controlled by the orogeny period of FTB and the effect of other orogenic belt,the United States Sevier FTB is influenced by Marathon-Ouachita orogenic belt,and is divided into five sections of the north and south distribution,the formation time of northern section central section and southern section in Appalachian orogenic belt is different,it is divided into three sections.The sedimentary evolution is divided into two stages,which correspond to the tectonic evolution of FTB and basin: the Paleozoic carbonate sediments are mainly marine sedimentary sequences,and the Mesozoica and cenozoic clastic sediments are mainly land continental sedimentary sequence,The whole sedimentary evolution process is the evolution of marine facies to continental facies.The distribution of oil and gas distribution in FTB and basin is controlled by tectonic evolution and sedimentary evolution :(1)Control factors of conventional oil and gas distribution,Hydrocarbon source rock and reservoir development are controled by sea level changes and tectonic movement;Thermal evolutionsof Hydrocarbon source rock are controled by rapid settlement of foreland stage;Structural trapsare controled by tectonic evolution,sedimentary evolution control basin stratigraphic lithologic traps;The tectonic evolution controls the development of faults,providing vertical migration channels for hydrocarbon migration,sedimentaryevolution controls the development of unconformity and permeability formation.(2)Control factors of unconventional oil and gas distribution,shale oil and gas are mainly controlled by the TOC content and thermal evolution degree of the source rock.In the high TOC and high thermal evolution area,the shale oil and gas are formed and store in the source rock.The coalbed methane is controlled by the coal seam development horizons,coal seam is developed in the frequent transgression and regression.The oil sands develop in the shallow strata,the original oil and gas migrate laterally to the shallow strata,subjecting to biodegradation to form oil sands.