SEQUENCE STRATIGRAPHY AND PETROLEUM ACCUMULATION IN FORELAND BASINS

From a tectonic point of view, foreland basins related to plate collision are areas favorable for petroleum accumulation.Collision of two plates form a series of orogenic belts, while foreland basins tend to form in the fronts of relatively stable plates.The characteristics of foreland basins make them favorable for petroleum generation, migration, accumulation and preservation.Foreland basins are one of the basins endowed with the most abundant petroleum in the world.Sequence stratigraphy of foreland basins is a special branch of applying the theory of sequence stratigraphy to fold belts and foreland basins, assuming that the material supply is stable and that the change in accommodation space of a foreland basin is controlled by structural effects and global sea-level change.Through summarizing stratigraphic sequences and cycles of different orders and their origin, the authors have revealed the inherent relationship of tectonic movement of orogenic belts, basin sedimentation and sea-level change and further studied the sedimentary-tectonic evolution of foreland basins.In addition, they propose that:the petroleum potential of foreland basins mainly depends on the devolopment degree of the early-formed passive margins and preservation conditions of petroleum; thin-skinned overthrust belts have fairly good petroleum potential; foreland basins have many types of traps; and the late-stage front sediments of basins is advantageous to burial, maturation and preservation of early-stage sediments.The four conclusions about the relationships between foreland basins and petroleum provide a theoretical basis for petroleum exploration.