【摘要】 东濮凹陷杜寨次凹PS12井钻遇的沙三段 2 8m砂岩气层以往被解释为该次凹东侧陡坡的三角洲前缘砂体 ,但后来在其东侧部署的井均因未钻遇该砂体而落空。在对三维地震、测井、岩心分析资料的综合性研究基础上重新解释 ,认为该砂体应属次凹北部的轴向河谷充填沉积 ,证据是 :①在倾角测井图上 ,该砂层西倾倾角呈向上逐渐变小的红模式特点 ,符合南北向河谷中砂岩层面应有的特征 ;②该砂体附近的三维地震层振幅切片平面图显示一些线形和微蛇曲形的南北向振幅异常带 ,具自北向南分支的特点 ,指示为轴向河道或分支河道 ;③该厚砂层顶底与深—半深湖泥岩突变接触 ,内部为块状、板状和平行层理的极细砂岩 ,自然电位曲线呈箱形 ,为河道或河谷充填 ,而非三角洲前缘砂体特征。图 8参 13更多还原

【Abstract】 The discovery of the Well PS12 in Duzhai Sub sag in 1991 disclosed 28m (in the interval ranging from 4793m to 4821m) of sandstone in the stratigraphic unit Es 3 3+4 with initial 35,000 m 3 /d of gas production. According to integrated research of the new 3 D data, well core and logs, the sandstone is reinterpreted as a trough fill channel that flowed from north to south. The evidences are as: ①The west dip angles of the sandstone on dip log decrease upward suggest a sandstone fill in a incised valley oriented in N S direction; ②3 D seismic horizon amplitude maps show narrow linear or sinuous belts of sand stone along the sub depression axis in north south direction. In addition, the narrow belts of amplitude anomalies tend to branch out southward. These characteristics also define a north to south channel and deltaic tributary channels; ③ the thick sandstone shifts sharply from lacustrine shale at its bottom and top and shows no vertical grain size variation interiorly.更多还原