The Characteristics Of Petroleum Geology Of Chang6 In Li 60 Wellarear Located In Zi Bei Oilfield

Zi Bei oilfield Li60 well area located in the Ordos Basin in northern Shaanxi slope of the central, and Yanchang Yan 6 oil group is main layer. According to lithology, electricity and oil-bearing characteristics, further divided Chang6 reservoir into Chang6 groups, and Carried out stratigraphic subdivision and correlation usingdrilling information of study area. Thickness of sedimentary strata is flat, formation from west to east gradually uplift, the whole is a West dump monoclinic.In the light of rock type and characteristics, sedimentary structure, composition and palaeontologic marker and electrofacies, adopt phase analysis method, Identified Zi Bei oilfield Li60 Chang 6 oil group is delta plain sediments. On the basis of the regional deposition background, Comprehensive analysis geologic feature and electrofacies, and lumped the flat distribution law of the sand thickness and the ration, further divided the distributaries channel and nackswamp two sedimentary microfiches.Chang 6 oil layer sandstone reservoirs are mainly fine-grained sandstone, followed by a small number of sandstone, fine sandstone and siltstone; based on the results of this study and observed, that Zi Bei oilfield Li60 well area Chang 6 oil groups reached late diagenetic sandstone A period. The whole reservoir with low porosity - permeability - ultra-low-hole -the characteristics of low permeability, the main three types porosity are dissolution porosity, intergranular porosity and cracks, mainly is intergranular pore. Pore structure dominantly small micro-jets. Reservoir heterogeneity studies show that Layer, interlamination and the plane heterogeneity are stronger. Comprehensive analyzed that Sedimentary microfiches and digenesis are two main factors to control and affect the development and distribution of Reservoir.Analysis of frofit nature and rock wettability test results show that, the oil of ZiBei oilfield Li60 well Chang 6 reservoir belonged to low-density, low viscosity, low freezing point, low-sulfur crude oil in conventional terrestrial, formation water is CaCl₂, the total salinity is higher. Reservoir sandstone wettability is slightly water wet. The trap is Construction -lithologic, Lithology in the main, belong to room temperature low-voltage systems, and flexibility - dissolved gas drive reservoir Summarized the law of oil and gas-rich in Chang 6 reservoir: the space distribution of ZiBei oilfield Li60 well area Chang 6 reservoir mainly controlled by Delta plain distributaries channel, distributaries channel development area is generally the main oil and gas-rich region; moreover, the cover of the high-quality regional also provides a good for keeping out and sealed condition for oil and gas reservoir accumulate.; and in a certain degree, nose-like structure controls the law of oil and gasBased on the types, spatial distribution of ZiBei oilfield Li60 wellarea, combined with the results of previous studies, summed up the characteristics of petroleum geology and reservoir model of Chang 6 reservoir, that, the context of regional tectonic pinch-out of the dump reservoir accumulation model and sedimentary fancies and tectonic activity under the control of the "ladder-style" type of accumulation mode.