Identification of NW-Trending Faults in the Northwestern Junggar Basin (NW China) and its Significance of Hydrocarbon Migration

The presence of the NW-trending faults in the northwestern Junggar Basin (NW China) and their relation to hydrocarbon migration were discussed. The presence of the faults was confirmed by new seismic and stratigraphic studies. They formed a rectangular-shape fault system together with the previously and commonly acknowledged NE-trending faults. Hydrocarbon shows are present widely in the cross of the two types of faults on the basis of field survey. Representative shows were further analyzed by petrography and geochemistry, in order to understand hydrocarbon migration features. It is implied that the two types of faults are both significant for the migration. In particular, the newly identified NW-trending faults can act as the primary and ultimate pathway for migration from the petroleum source to accumulation areas. Thus a new complex fault-controlled hydrocarbon migration model was suggested. Favorable hydrocarbon exploration targets were predicted according to the model, providing new information for shaping exploration and exploitation strategies. The results also have wide implications for the study in elsewhere mountain-front piedmont areas where the hydrocarbon exploration and exploitation is generally related to fault.