Some Key Tectonic Characteristics of Chinese Foreland Basins and Related Petroleum Geology

This paper concludes some key geologic characteristics of Chinese foreland basins based on the study of the sedimentary infill,tectonic evolution,tectonic dynamics,spatial location distribution and structural deformation geometry.The foreland basin is super imposition with the compression sedimentary stratigraphic sequence over the extension basin.Four-stage structural deformation of foreland basin and thrust-fold belt has occurred since Protozoic.The foreland basin developed under the control of two factors which are basin basement collaged by many small plates or terrains and the distance effect of India-Eurasia collision,so all the foreland basins and the rejuvenative ancient orogenic belt make up a giant basin-mountain system which locates at the outer circus of Tibet plateau.There are many structural styles of the thrust-fold belt in different basins.These tectonic characteristics result in the regularity and complexity of oil pooling.The regularity includes:(1) the orders of oil/gas spatial distribution from thrust-fold belts to Craton,(2)the availability of match among the petroleum pooling factors and accumulation dynamic qualifications,(3)regional sequences of target reservoirs in the whole western China,and(4)many periods of hydrocarbon generating but pooling late.The complexity manifests itself in four ways:(1)the difference of the geologic features of four-stage structural deformation,(2)the deformation and disruption of petroliferous reservoir and pool,(3)inhomogeneous reservoir resulted from nonmarine sedimentary,and(4)difficulties to define the structural traps resulted from strong deformation in the thrust-fold belts.