Main controlling factors analysis of shale oil and gas accumulation in west sag of Liaohe depression

Study found that the key conditions for enrichment in mud shale are the organic matter content,maturity,organic matter type,apertures characteristics and thickness.By taking Es33 and Es41 of Shahejie formation as the examples,based on the influencing factors research of shale oil and gas,by use of comprehensive evaluation on multiple factors and key analysis of some factors,the main controlling factors of shale hydrocarbon accumulation in Es33 and Es41 of Shahejie formation have been revealed.The results show Es33 is characterized by big effective thickness,moderate organic matter abundance,moderate degree of thermal evolution,various organic matter types,abnormal gas logging,good oil-bearing properties and shale gas-oil association.Es33 ismainly affected by organic matter abundance.Compared with Es33,Es41 is of high organic matter abundance.However,the matching between organic matter type and thermal evolution degree is poor,and it failed to meet the conditions for shale gas accumulation,only developed with shale oil.Therefore,the main controlling factors of shale hydrocarbon accumulation should be made clear first,which is the basis for looking for shale oil and gas occurrence and has practical significance for shale oil and gas exploration and development in Liaohe depression.