Regularity Of Reservoirs Petroleum Accumulation And Distribution In Wujiawan Area,Zizhou Oil Field

By comprehensive application of theories of sedimentology, petroleum geology, reservoir geology, and logging geology and the latest progress, on the full use of drilling, well logging, and dynamic data of production, analysises the Yanchang formation, the sedimentary system, and reservoir characteristics of turbidity. Taking basic analysis of reservoir forming conditions as the means, this article undertakes the study of hydrocarbon source rock, cap rock and reservoir cap assemblage, and transport conditions and other aspects, puts forward the factors of controlling Chang4+5and Chang6oil and gas enrichment. These provide theoretical basis for guiding the further oil and gas exploration and the other similar oil and gas reservoirs’ discovery and forecasting in other regions.Chang4+5formation are subdivided into2subgroups and Chang6formation are subdivided into4subgroups. on this basis,this article focuses on the subgroups’research of sedimentary facies, subfacies, microfacies, deeply discusses the characteristics and the time and spatial distribution. Channel sand is fine and has grain size cumulative probability curves all these constitute the main features of Chang4+5and Chang6typical sedimentary. In the plane, it mainly develops four channels in this zone. Each reservoir subgroup channels swings and changes slightly.The study on reservoir shows that Chang4+5and Chang6reservoir is sand of channels of the delta plain. The lithology is mainly fine-grained feldspathic sandstone, the composition maturity is relatively low and the structure maturity is relatively hight Due to the differences of sedimentary microfacies and diagenesis, Chang4+5and Chang6turbidity reservoir has strong macroscopical heterogeneity.The study of Chang4+5and Chang6oil and gas enrichment regularity show that: Chang4+5and Chang6reservoir distributes in the most developed area of the channels sand body, in the plane, it has the characteristics that oil and sand body distribution has small area and the connection is poor. But in the local area, as the sand thickness is thick, many periods of channels sand body are staggered and superposed, the reservoir distribution are also exhibiting staggered and superposed characteristics, so these can form large scale oilfield. Looking for the better performance turbidity channel sand body and good cap rocks, and to strengthen the study on cracks become the key to the research and exploration in the next step.