Gas and Water Distribution and Influencing Factors of Shan23 Gas Reservoir in North Part of Yanan Gas Field of Ordos Basin
The Upper Paleozoic is important natural gas productivity in Ordos Basin,and the water production in development has gradually attracted attention.To clarify the distribution of gas and wa-ter,based on the fine description of Shan23 sand body,this paper analyzes the characteristics of gas res-ervoir fluid and horizontal distribution characteristics of gas and water,explores the influence of gas res-ervoir unit,reservoir micro pore-throat structure,sealing system and structure on gas and water dis-tribution,to guides exploration.The gas and water distribution of Shan23 in the east area of Ordos basin is mainly controlled by the connected sand units,with uneven distribution of horizontal gas reservoirs and poor continuity of pure gas layers.The suture line contact between debris particles and the large a-mount of siliceous cementation result in poor pore throat connectivity,leading to a reservoir bound wa-ter saturation of up to 60％.The resulting closed system further exacerbates the residual mobile water in the reservoir.The gas water interface of the Shan23 gas reservoir is distributed between -1500 m and -1590 m,and local water layer enrichment is formed in areas with structural undulations exceeding 40 m.Accordingly,in exploration and development,finding high-quality connected sand units becomes crucial,while paying special attention to the formation of low water layers in the structure.
Shan23 gas reservoirgas and water distributiongas reservoir unitinfluence factor
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