关键词: 渤海海域, 湖盆成气, 汇聚脊, 凝析油气藏, 轻质油

Abstract: In accordance with the notion of "gas generation in lake basin" and "reservoir controlling by catchment ridge", deep buried hills and medium-shallow layers in the Bohai Sea have become the main fields where exploration breakthroughs were made in Bohai oilfield since "the Thirteenth Five-Year Plan" (2016-2020), and a number of oil and gas fields with the reserves over hundred million tons have been discovered. Further, according to the exploration in Bohai Bay Basin, the reservoir-forming conditions and controlling factors of condensate and light oil reservoirs in the basin have been clarified. The key factor for the accumulation of condensate oil and gas reservoirs in Bohai Bay Basin lies in the regional overpressure thick mudstone caprock covered above the oil and gas reservoirs. In the northern Bozhong sag and Liaodong Bay depression, the pressure coefficient of the caprock is greater than 1.4, and the lower buried hill is the important direction for the exploration of condensate oil and gas. The accumulation of light oil in shallow hill of the Bohai Sea is controlled by the deep catchment ridge, and the deep large catchment ridge is the dominant migration-accumulation way of oil and gas. In Bozhong sag, Liaozhong sag, Huanghekou sag and Qikou sag, the resource potential is great, and several kinds of large catchment ridges are developed in their slope belts, sags and low uplifts. The middle-shallow traps above the catchment ridges, especially the subtle lithologic traps, are important exploration fields for medium-light oil reservoirs with good quality and high yield.

Key words: Bohai Sea, gas generation in lake basin, catchment ridge, condensate reservoir, light oil