大型凹陷斜坡区倒灌式成藏模式—以三肇凹陷扶杨油层为例

利用300条地震剖面、672口测井曲线、6口井岩心对松辽盆地三肇凹陷扶杨油层断层特征及运动期次、储层沉积特征进行了综合研究,结合探井试油和试验区动态资料分析认为,T2断层受控于基底断层具有平面密集成带、剖面"似花状"组合特征,且油气成藏期活动的油源断层多为断层密集带边界断层.沉积微相研究表明三肇凹陷南部扶杨油层为西南保康沉积体系而非多物源交汇区,属于典型的河控浅水缓坡三角洲沉积体系,即主要储层为分流河道砂体,且主要含油目的层扶Ⅰ油层组为向上逐渐退积的演化序列.明水组末期青一段源岩达到生油高峰,油气在超压作用下沿开启的油源断层下排,首先充注断层上升盘一侧河道砂体,即断层密集带两侧上升盘为油气运聚富集区,而断层密集带内多为地堑式组合,不利于油气聚集,在成藏模式指导下刻画出47个有利圈闭,预测新增石油地质储量0.5亿t.

Study on the hydrocarbon accumulation model in the slope area of a large sag-taking Fuyang reservoir in Sanzhao Sag as a case

the features and moving periods of fault and the sedimentary characteristics of reservoir in Fuyang reservoir are comprehensively studied according to 300 seismic sections,logging curves of 672 wells and core data of 6 wells.Combining the study results with oil testing results of exploration wells and the performance data of experimental zone,it is held that:T2 faults are controlled by basement faults and featured by dense ribbons in plane and "flower-like" combination in section,and the most of the active oil-source faults in hydrocarbon accumulation period are the boundary faults in the dense fault zone.The study on microfacies shows that Fuyang reservoir in southern Sanzhao Sag belongs to Baokang sedimentary system in southwestern Sanzhao Sag,but it is not a multi-source intersection zone.The sedimentary system is the typical shallow gentle slope delta sedimentary system controlled by river,the main reservoir is distributary channel sandbody,and the main oil layer F1 of Fuyang reservoir has the sequence frame of gradually upward retrogradation.At the end of Mingshui Formation,No.1 member of Qingshankou Formation reaches to oil generation peak.Hydrocarbon first fills in the channel sandbody in the upthrown block of the fault when migrateing along the open oil-source fault under the action of overpressure,that is,the hydrocarbon enrichment areas are in the upthrow sides in two sides of the dense fault zone.while within the dense fault zone is not favorable for hydrocarbon accumulation,because there is always graben combination.under the guidance of hydrocarbon accumulation mode,47 favorable hydrocarbon traps are found in Fuyang reservoir,the new oil geological reserves of 50 million tons is found,which will provide a reliable theoretical guidance for the exploration of Fuyang reservoir in Sanzhao Depression.