涠西南凹陷涠洲11区南部流沙港组流一段沉积微相特征

Sedimentary microfacies in the first member of the Liushagang Formation in southwestern Weizhou depression,Guangxi

涠西南凹陷涠洲11区南部流沙港组油气特征明显,但目的层段岩性复杂,储层横向变化快,连通性差,因此对沉积微相与砂体的成因分析很有必要。本文通过岩心精细观察描述,结合粒度资料、测井资料和地震资料的分析,对流一段沉积相类型进行了探讨,识别出两种沉积相类型:水进型扇三角洲和正常三角洲。其中扇三角洲可划分为扇中和扇端两个亚相,三角洲划分为三角洲前缘和前三角洲两个亚相,并在各相带内共识别出11种微相类型。探讨了流一段4个亚段的沉积微相特征、平面展布及垂向演化:早期(L1下)为湖平面逐渐上升的扇三角洲沉积,晚期(L1上)为不断向前进积的三角洲沉积。

Two types of sedimentary facies have been distinguished in the light of core examination, grain-size data, well logs and seismic data, including the transgressive fan delta and delta facies. The fan delta facies may be subdivided into the mid-fan and proximal fan subfacies, and the delta facies may be subdivided into the delta front and prodelta subfacies. There are eleven sedimentary microfacies altogether involved in the above-mentioned facies zones. The emphasis in this paper is placed on the characteristics, planar distribution and vertical evolution of the sedimentary microfacies in four submembers of the first member of the Liu district, southwestern Weizhou depression, Guangxi. The fan delta deposits lower part of the first member of progradational delta deposits were shagang Formation in the Weizhou-ll appeared during the deposition of the the Liushagang Formation, while till the deposition of the upper part of it, the accentuated.