【摘要】 通过地质、测井、地震资料对元坝地区须三段沉积相进行了深入细致的研究,结果表明:①元坝工区西部地层为砂岩与泥岩的不等厚互层,东部地层为底部厚套砂体与顶部泥岩的叠置层;纵向上五期砂组相互叠置.②须三段沉积时期龙门山北段、米仓山—大巴山同时为元坝工区提供物源.母岩的不同导致元坝工区发育2类砂岩,西部以钙屑砂砾岩为主,东部以岩屑石英砂岩为主.③元坝工区须三段西部发育辫状河三角洲沉积体系,垂向上呈现三角洲前缘—三角洲平原向盆地内进积的沉积序列;东部发育曲流河沉积体系,呈现三角洲前缘向盆缘退积的沉积序列.更多还原

【Abstract】 High oil yield was obtained from the 3th member of Xujiahe Formation of YL7 and YL10 wells in Yuanba area,which subverts the traditional understanding that the 3th member of Xujiahe Formation( T3X3) is hydrocarbon generation rock and the calcarenaceous sandstone is non-reservoir rock. The sedimentary facies of T3X3is studied deeply according to geologic,logging and seismic data. The results show that,①there is sandstone and mudstone interbeds of unequal thickness in the western Yuanba area,while in the eastern Yuanba area is overlaying layer of sandstone and mudstone,the sandstone at the bottom and the mudstone on the top. In vertical direction,five sand groups overlap each other. ②In the sedimentary period of T3X3,the northern segment of Longmen mountain and Michang- Daba mountain provide sedimentary source at the same time. Due to the different sedimentary source,there are two kinds of sandstone in Yuanba area,calcarenaceous sandstone deposits mainly in the west,while lithic quartz sandstone deposits mainly in the east. ③ in the west of T3X3develops a braided river delta sedimentary system,which is characterized by the acceleration sedimentary sequence from delta front-delta plain to basin in vertical direction. In the east of T3X3,develops a meaning river delta sedimentary system,which is characterized by the retrogradation sedimentary sequence from delta front to basin edge.更多还原