Formation condition of deep gas reservoirs in tight sandstones in Kuqa Foreland Basin  

作　　者：Xuesong Lu Mengjun Zhao Keyu Liu Qingong Zhuo Junjia Fan Zhichao Yu Yanjie Gong 

机构地区：[1]PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China [2]CNPC Key Laboratory of Basin Structure and Hydrocarbon Accumulation,Beijing 100083,China [3]School of Geosciences,China University of Petroleum,Shandong 266580,China

出　　处：《Petroleum Research》2018年第4期346-358,共13页石油研究（英文）

基　　金：The work was supported by the National Science and Technology Major Project of the Ministry of Science and Technology of China(No.2016ZX05003-002);the Scientific Research and Technology Development Project of PetroChina(No.2016B-0502).

摘　　要：Due to the high expense of deep oil and gas exploration,prediction of gas-bearing properties before drilling is crucial for deep gas reservoir of tight sandstone.Deep tight sandstone gas fields in Kuqa Foreland Basin are characterized by high abundance,high gas saturation,high pressure,high and stable yield,which belong to high-efficiency tight gas reservoir.Based on theoretical analysis of controlling factors and mechanisms of gas-bearing properties for tight sandstone gas reservoir,and taking tight sandstone gas fields with high effectiveness such as Dibei,Keshen and Dibei gas fields in Kuqa Foreland Basin as examples,formation condition and mechanism of high-efficiency tight sandstone gas reservoir in Kuqa area are studied through a comparative analysis of typical tight sandstone gas reservoir in Sichuan Basin and Ordos Basin.The results show that the formation condition of deep gas reservoir of tight sandstone in Kuqa foreland basin includes four factors:i.e.,overpressure gas charging,fracture development,“early-oil and late-gas”accumulation process and favorable preservation condition.The overpressure gas charging and fracture development are the most important factors for formation of high-efficiency tight gas reservoirs in Kuqa Foreland Basin.High-quality source rocks,high sourcereservoir pressure difference,and overpressure filling induced thereby are preconditions for formation of tight sandstone with high gas saturation.The fracture development controls gas migration,accumulation,and high yield of tight sandstone gas reservoir.The reservoir wettability changed by the early oil charging is beneficial to late natural gas charging,and the preservation condition of high-quality gypsum cap rocks is the key factor for gas reservoirs to maintain overpressure and high gas saturation.Matching of above four favorable factors leads to the tight sandstone gas reservoir with high abundance,high gas saturation and high gas production in Kuqa Foreland Basin,which is very different from other basins.Under the condi

关 键 词：Deep gas reservoir Tight sandstone OVERPRESSURE FRACTURE “Early-oil and late-gas”accumulation process Preservation condition Kuqa foreland basin 

分 类 号：P61[天文地球—矿床学]