Research on the Accumulation Pattern of Lithologic Reservoir in Zhoufan Fault Zone of Qianjiang Depression

Through fully understanding the basic petroleum and geological conditions in the oilfield,it was considered that the accumulation models of reservoir was the key of oil and gas exploitation.Most of the lithologic reservoirs in Zhoufan fault zone of Qianjiang Depression were mainly distributed in Zhoufan zone and structural slope of fault.The thickest source rocks were developed in Qian 3 and Qian 4 sections with good maturity,great potential and favorable oil-generating indexes;the delta front provided a good reservoir space for oil and gas;evaporate sediments were the most ideal regional cap-rocks in Qianjiang depression;the development zone of fault with rule exhibition in Qianjiang formation made the large area of oil lithologic forming some effective composite traps by the fault and structure.Zhoufan fault zone mainly forms two kinds of lithologic reservoirs;one is through the background of monoclie formed lithologic reservoir with sand body upward pitchout,the other is through the background of fault nose and fault anticline,channel sand body incised by fault formed fault+lithologic reservoir or structure+lithologic reservoir.