Main Controlling Factors Of Hydrocarbon Accumulation In Northeastern Liaodong Bay Depression

The main research area of this paper is located in the north of Liaozhong,northeast of Liaodong Bay to the northern part of Liaodong uplift,and the whole is long strip-banded to NNE.This paper mainly studies the hydrocarbon enrichment characteristics and main control factors of three blocks in JZ21-1 oilfield,JZ23-1 oilfield and JZ23-2 oilfield,and finally establishes the reservoir-forming model.The oil and gas in the study area are mainly distributed in the eastern Liaodong steep slope belt,the Liaodong low uplift and the double slip Transition belt,and the hydrocarbon accumulation in the longitudinal upper JZ21-1 well area is mainly in the Paleogene,the JZ23well area is mainly enriched in the Neogene,and the JZ23 well area is larger than the JZ21-1well area The total crude oil in the region is medium normal crude oil,low sulfur and high wax,but the shallow layer crude oil in the JZ23 well suffers a certain biodegradation,which leads to the decrease of wax content.Hydrocarbon sources,reservoir and cover,traps and transport conditions have important controlling effects on hydrocarbon accumulation in this area,the three-stage hydrocarbon source rocks are the main source strata in the study area,which provides a sufficient material basis for hydrocarbon accumulation;the reservoir conditions in the area are general;The most important regional cover is the Lower East to the east and the three segments.Structural traps related to faults are mainly developed in the study area,and small lithologic traps are seen locally.The effectiveness of traps affects oil and gas accumulation in a large extent,and the oil-gas transport framework is mainly composed of faults and sand bodies,and there are some unconformity in some areas,such as fault type,fault-sand complex type and fault-unconformity compound type three passage system.The fault control and reservoir effect is obvious,theⅠandⅡfaults mainly play the role of channeling,the secondary faults developed by shallow layer have the function of transporting and destroying traps,and the areas with relatively dense fault development are favorable for hydrocarbon accumulation.The characteristics of oil and gas enrichment in different blocks and the main control factors of hydrocarbon accumulation are differences,the reservoir physical properties of the East two section of JZ21-1 well,the poor performance of the sand,the scattered traps and the small scale,lead to less and smaller tectonic reservoirs in the East two section of the area,and a few lithologic reservoirs with relatively low hydrocarbon enrichment degree.The cover quality of JZ23-1 well area is general,the trap development is few,it is the most poor oil and gas area,the JZ23-2 well area is the richest hydrocarbon,the fault passage is the important control factor of hydrocarbon accumulation,but because of the poor quality of the caprock,the N₁g group oil and gas suffer some biodegradation thickening.Because of the difference of main control reservoir factors,there are different hydrocarbon migration and accumulation models in JZ21-1,JZ23-1 and JZ23-2 wells.