【摘要】 四川盆地震旦系资源丰富,但发现率低,自威远、资阳气藏发现后,近20年未获重大突破。为此,在"十一五"国家攻关课题对该盆地震旦系新一轮评价研究的基础上,从地层和沉积、储层分布、烃源条件、圈闭特征等方面讨论了震旦系成藏地质条件。研究表明:震旦系灯影组白云岩厚度巨大,表生岩溶作用形成的裂缝—孔洞型储层具有多层段、厚度大、分布广的特点;相关烃源岩生烃强度最高达56×108 m3/km2,具备形成大中型气田的烃源基础;构造圈闭多,圈闭面积大,后续勘探目标充足;在对震旦系含油气地质条件综合分析的基础上,划分出了3个有利的勘探区带,即古隆起核部岩溶发育区、古隆起翼部构造圈闭和川东台缘高能相带,并指出了勘探方向及目标。该研究成果为四川盆地震旦系下一步天然气勘探部署提供了依据。更多还原

【Abstract】 Although there are rich hydrocarbon resources in the Sinian gas reservoirs of the Sichuan Basin,no more large discoveries have been made over the past two decades since the discovery of Weiyuan and Ziyan gas fields.Based on the achievements from the new round evaluation of this study area during the"Eleventh Five-Year Plan",the geological conditions for hydrocarbon accumulations in the Sinian reservoirs are discussed in terms of lithology and sedimentation,reservoir distribution,source rock quality,and trap characteristics,etc.The following conclusions are obtained.(1)The Dengying Fm dolomite in the Sinian is significantly thick and the fractured-vuggy reservoirs resulted from supergene karstification are characterized by multiple layers,great thickness,and extensive distribution.(2)Hydrocarbon generation intensity can reach up to 56×108 m3/km2,high enough for the formation of medium to large gas pools.(3)A great number of large structural traps with a large area are good targets for future exploration.(4)Based on the comprehensive analysis of geological conditions for hydrocarbon accumulation in the Sinian reservoirs,3play fairways are identified,including the karst area in the core of palaeohighs,structural traps on the limb of palaeohighs,and the high-energy facies belt at the platform margin of the eastern Sichuan Basin.These understandings lay a solid basis for future gas exploration in the Sinian reservoirs of the Sichuan Basin.更多还原