鄂尔多斯盆地西部青石峁地区断裂体系特征及油气地质意义OA

In recent years,Changqing Oilfield discovered a 100 billion cubic meters gas field in Qingshimao area of western Ordos Basin,which has strong structural activities with multi-stages developed faults.Research on charac-teristics of fault system is important for clarifying enrichment law of gas reservoirs.Based on 3D seismic interpreta-tion results,geometric and kinematic characteristics of faults are analyzed to study fault system types and active stages of Qingshimao area in western Ordos Basin,and then to discuss geological significance of petroleum in differ-ent types of fault systems during gas reservoir accumulation period.The results show that,taking angular unconfor-mity of upper Paleozoic bottom as the boundary,Qingshimao area is divided into upper set and lower set of structur-al strata.5 sets of fault systems are identified and 3 structural activity periods are divided.Among them,SN-strike tensile fault system was mainly active in Caledonian-Hercynian,NWW-strike en echelon fault system and NW-strike brush fault system were mainly active in Indosinian,and SN-strike compressive fault system and NEE-strike tensile fault system were mainly active in Yanshan-Himalayan.Based on matching relationship between fault activi-ty period and gas reservoir accumulation period,it is clarified that Caledon-Hercynian faults are trap-controlling faults,Indosinian faults are transport faults,and Himalayan faults are adjustment faults.The research provides the-oretical basis for exploration and development of deep gas reservoirs in Ordos Basin.