Characteristics of Source Rocks and Exploration Potential in Bodong Sag,Bohai Sea Area

The exploration of oil and gas in Bodong Sag has come to a low stage because no breakthroughs have been achived in recent years.The unclear main hydrocarbon source rocks restrain the oil exploration in Bodong Sag.Based on interpretation of seismic profiles and plotting of basic pictures,geochemical parameters,the distribution characteristics and formation environment of hydrocarbon source rocks in Bodong Sag were analyzed.The main hydrocarbon source rocks and exploration potential of Bodong Sag were illustrated by basin simulation and oil-source correlation analysis results.The study shows that there are four sets of source rocks in Bodong Sag including Ed3,Es1,Es3 and Es4.Es3 source rocks,with best organic matter type and higher organic matter abundance,are the main hydrocarbon source rocks of Bodong Sag,while the hydrocarbon generation of Es3 source rocks accounts for 61% of the total hydrocarbon amount.The oil of PL9-1Oilfield mainly migrated from Bodong Sag,indicating the large exploration potential of Bodong Sag.The result of oil-source correlation shows that 75% of the oil of PL9-1Oilfield was derived from Es3 source rocks,so the exploration in Bodong Sag should focus the oil and gas mainly produced by Es3 source rocks.