Reconstruction and Significance of Palaeopressures of the Jurassic Formation in the Hinterland of the Junggar Basin, NW China

Palaeopressures of the Jurassic formation in the hinterland of the Junggar Basin were reconstructed at different geological time with the method of fluid inclusion thermodynamic modeling. The results indicate that, the generation of overpressure in the east is earlier than that in the west. The overpressure center was first located in the east part of the Changji depression, and then migrated northwestward. The evolution of the formation pressure displays a trend of pressure decrease as a whole, and this trend is composed of three cycles of pressure down and up in block I and IV, but just one in block III and two in block II. Block III is a potential prospective area for hydrocarbon accumulation due to the long-term pressure releasing, and the last cycle which resulted in current formation pressure status in all of the four blocks suggests that the later gas charging had an obvious effect on the pressure accumulation.