Study about the Hydrocarbon Accumulation Characteristics in the South Steep Slope Belt of Chengbei Low Uplift in Bohai Bay Basin

Steep slope belt is characterized by close to the oil sources, with extremely well developed sand bodies, and rapid changes in sedimentary facies, being an important tectonic belt for hydrocarbon accumulation in dustpan-like depression. Therefore, it is an important target for hydrocarbon exploration. In recent years, in order to increase reserves and production of the Chenghei Oilfield, several rounds of rolling exploration have been conducted in the south steep slope of Chengbei low uplift, but the results of exploration are not good enough. Based on analyzing results on the tectonic characteristics, stratigraphy, hydrocarbon accumulation conditions in the south steep slope of Chengbei low uplift, combined with fine analysis of structures, the hydrocarbon accumulation characteristics are summarized as followings： Firstly, the trap effectiveness might control the oil and gas enrichment. Secondly, sedimentary facies might control the favorable position of hydrocarbon accumulation. It is believed through analysis that the effectiveness of traps is mainly controlled by the sealing capability of faults, and can determine whether hydrocarbon accumulation can occur. In different sedimentary facies belts, the sand bodies are very strong in the lateral heterogeneity, with great difference in physical properties. It is found through study that the mid-fan is the best reservoir facies belts and the most favorable part for hydrocarbon accumulation. The study about the main controlling factors on hydrocarbon accumulation has a crucial role for the next exploration in the south steep slope of Chengbei low uplift and other similar steep slope belts, and is significant for improving the exploration efficiency.