Study On Deposition System Of Shasan Section And Reservoir-forming Rule Of Lithologic Reservoir In Huanxi Oilfield

Lithologic oil and gas reservoir refers to the reservoir lithology changes in the transverse direction, around or updip direction is a non permeable rock shelter and then formate traps, the reservoirs is formed after oil and gas gathering.Its basic characteristic is the reservoir continuity is poor, most is pyroclastics,generally small, mostly self storage and primary oil and gas reservoirs.Huanxi oilfield is tectonically located on the west slope of the southern section of Liaohe depression,it has a very favorable conditions for hydrocarbon accumulation, good reservoir and lithologic trap conditions, it is adjacent to two big oil source sag of the Yuanyanggou and Qingshui,the oil source is sufficient, it has the basic to form lithologic oil and gas reservoirs.West slope developed a variety of oil and gas migration channel type, provides a reliable channel for oil and gas migration and accumulation,the variety of cover layer formed good system of complementary sealing.Due to the technical constraints, the oil workers have a lack of sufficient knowledge of the oil gas accumulation and distribution in the area.We have deeply study of the accumulation regularity and distribution characteristics of oil and gas of Shasan sections of lithologic oil reservoirs of Huanxi oilfield, the results show that the formation the west slope of Liaohe depression where the Huanxi oilfield located was experienced four periods of early extension, middle trap, late systolic and return, the overall structural shape is relatively simple, with the characteristics of the high northwest and low southeast, it is a block structure controlled by EW and NE trending faults.Through the research of the sedimentary characteristics of the reservoir,we think the Rehetai reservoir area station and Dalinghe reservoir are sublacustrine fan depositional system,their reservoir is development,and the sand body is thickness, but the change of plane lateral is big,the difference of sand body development of each layer is large.The reservoir properties are affected by burial depth, the deeper the vertical buried, the poorer physical property.Through the research of the law of the forming conditions and distribution on oil and gas, we think that the area of oil and gas accumulation conditions are favorable: the region nearest neighbor water- Yuanyanggou source sag, oil source is sufficient; the area of reservoir is development, the sand body is thickness; fracture is development, the area divides into a plurality of fault block、 fault nose structure; a number of reserves and oil and gas well block is found in the area, oil and gas have accumulation. Oil and gas distribution is mainly controlled by the tectonics and formate fault block traps, but greatly influenced by lithology, it’s generally lithologic- structural traps.