济阳坳陷车镇凹陷沙二段浅水三角洲沉积特征及模式

车镇凹陷沙二段沉积时期地形相对平缓，普遍发育了浅水三角洲沉积。在钻井岩心描述及相关测试分析的基础上，结合录井、测井等资料分析，对浅水三角洲沉积特征及沉积模式进行了系统研究。车镇凹陷沙二段浅水三角洲前缘亚相是沉积主体，可划分为内前缘和外前缘，具有相带宽、水下分流河道骨架砂体发育、席状砂大面积分布的特征。浅水三角洲砂体以中细砂岩、粉细砂岩和粉砂质泥岩为主;粒度概率图以滚动跳跃加悬浮式、一跳一悬式和两跳一悬式为主;发育反映河流作用的各种层理构造、反映湖浪改造作用的浪成层理和波痕以及生物扰动等沉积构造。

Sedimentary characteristics and models of shallow-water delta deposits in the second member of the Shahejie Formation in the Chezhen Sag,the Jiyang Depression

Shallow-water delta depositswere generally developed during the sedimentation of the second member of the Shahejie Formation in the Chezheng sag of Jiyang Depression with a relatively flat topography.A systematic study of the sedimentary characteristics and models of these delta depositswas performed by integrating core observation and relevant testdatawith logging data.The shallow-water delta front subfacies dom inates the second member of the Formation and can be divided into the inner front and the outer front.It is characterized by large width of facies belt，highly developed underwater distributary channel and largescale distribution of sheet-like sandbody.The shallow-water delta sandbodies are dom inated by medium-to-fine sandstone，siltstone/fine sandstone and siltymudstone.The grain size probability curves present patterns of“rolling+skip+suspension”，“1skip+1suspension”and“2skip+1suspension”.Several types of sedimentary structures were developed，including various fluviatile beddings and wave beddings and marks aswell as bioturbation.