New understanding of shallow hydrocarbon migration and new exploration progress in the Bohai Sea

The shallow Neogene is the main strata that affect the reserves and production of oil fields in the Bohai Sea. However, with the improvement of exploration, it is more and more difficult to discover large and medium oil and gas fields in the Bohai Sea. Based on the exploration and practice in the Bohai Sea, the characteristics of shallow hydrocarbon accumulation outside the source in large and medium oilfields, and the analyses of the coupling relationship between the deep migration and shallow enrichment of hydrocarbons, this paper clarifies the control effects of "catchment ridge" formed by the primary and secondary hydrocarbon migration of the Paleogene source bed on the accumulation and enrichment in shallow overlying strata, and classifies the hydrocarbon pooling patterns according to the combination of carrier systems. Guided by the reservoir-controlling mode of the "catchment ridge", several structural belts in the Bohai Sea have made breakthroughs in oil and gas exploration and obtained a series of new discoveries of 100 million tons, thereby ensuring the continuous discovery of high-quality oil and gas reserves in shallow strata of the Bohai Sea, and further guiding the subsequent exploration progress.