Abnormal high pressure is widely distributed in Shahejie
Formation of Raoyang Sag, which is closely related with hydrocarbon accumulation. Based on the logging data, this paper analyzed the distribution and forming mechanism of abnormal high pressure by equilibrium depth method.The results show that abnormal high pressure is mainly distributed in hydrocarbon generation sag areas, and it decreases towards the margin of sag.Uncompaction caused by rapid deposition and the hydrocarbon generation are the main reasons for the forming of abnormal high pressure. The effects of abnormal high pressure on hydrocarbon accumulation are significant. On one hand,abnormal high pressure is an important dynamic source for hydrocarbon migration. On the other hand, abnormal high pressure controls the distribution of oil and gas under certain geologic conditions. The reservoirs are always found in high pressure formations or surrounding high pressure areas. Meanwhile the fluid potential resulted from abnormal high pressure drove fluids to migrate from the center to the margin of sag, and oil and gas are distributed around hydrocarbon generation sag.
