Study Of Reservoir Evaluation And Affecting Productivity Of Gas Pools Of Daniudi Gas Field In Ordos Basin

Reservoir is the main study object of oil and gas exploration and production,and that the valuation of reservoir is the most important content of reservoir description. In my thesis,the study object is the sand body of Upper Paleozoic of Daniudi Gas Field in Ordos Basin.Based on the study of the predecessors,with the data of lithology,physical characteristic,electrical characteristic and test information in the area of Taiyuan formation of Carboniferous,Shanxi formation and Shihezi formation of Permian,I have made a further study on the subfacies distribution,the characteristics of sedimentary microfacies of different formations and their distribution,every feature of reservoir bed and the relationship,the communication and the containing oilness among the smaller layers of sand body,and further analyze the characters of bearing oil and the standard of identifying oil,which have value for exploration and exploitation of reservoir.The Upper Paleozoic of Daniudi Gas Field is fluvial faces and the river direction is from north to south.The stratum is varied from bottom to top in three layer-members. The lithology of Upper Paleozoic are quartzose sandstone and arkose,the granularity of reservoir is the fine sand stage.And the reservoir is the less poral and percolating dense reservoir,porosity is distriuted from 0.2%to 21.4%,6.19%on average,from2% to 12%at most time,and whose permeability is distributed from 0.001 to 60×10^-3μm², 0.627×10^-3μm² on average,from 0.01 to 0.6×10^-3μm² at most time,its pore structure is bad with heavy aeolotropism.The thickness of sand body varied greatly in both length and breadth.In breadth,sand bodies in the primary creek are better connectedness.Net gas keeps main part of gas pool.Shanxi formation and Shihezi formation of Permian are the leading gas pay which are effected by geofactor,such as sedimentary facies,sand body thickness,physical property,heterogeneity and so on.Deliverability of every well varies in wide discrepancy.The most is 21.08×10⁴m³/d while the least is 0.277×10⁴m³/d.