Petroleum Geology Condition Analysis to the Deep Zone of Bohai Gulf Basin

Key words: 
• oil－gas /
• exploration /
• petroleum

Abstract: Based on the actual situation of the Bohai Gulf Basin,its deep zone is the reali stic new exploration region at present.Although it has the characteristics of l ow porosity ad permeability,large depth and some difficulty,its oil and gas reso urces potential is large in the deep zone of Bohai Gulf Basin,and there is good exploration prospects. In the deep zone of Bohai Gulf Basin,there are three series of source rocks,the fourth member dark mudstone of Shahejie Formation and Kongdian Formation,the thi rd and first member dark mudstone Shahejie Formation.The source rock of the thi rd m ember of Shahejie formation is the major source rock for the deep zone of Basin. It has the character of large thickness of black mudstone,good hydrocarbon gener ation indicators,high thermal evolution degree and large hydrocarbon generation potential. Reservoir condition is one of the major controlling factors to the formation of oil and gas pools in the deep zone of Bohai Gulf Basin.There are multi－type res ervoir rocks,but the sandstone is the major reservoir type,including sandstone a nd conglomerate of alluvial fan,fan-delta and delta as weu as,gravity flow san dstone.In add ition,the buried－hill reservoir is the another important type in the deep zone exploration.Based on the research results,diagenesis,sandstone thickness,supper －pressure abnormal belt and secondary porosity development belt are the major controlling factors to the reservoir property in the deep zone of Bohai Gulf Bas in. There is good seal condition in the deep zone of Bohai Gulf Basin,and the self－ source,self-reservoir and self－seal is the major combination type of oil and poo l formation.In the deep zone of Bohai Gulf Basin,the play is characterized by mu lti－types,early formation and large scale traps. In general,in the deep zone of Bohai Gulf Basin,there are good formation conditi on of oil-gas pools,and rich in resources.Without doubt,in the future,i t will be the most important new exploration region in Bohai Gulf Basin.