东营凹陷樊东地区沙三段层序地层与储层预测

The Sequence Stratigraphy and Reservoirs Forecast in the Third Member of Shahejie Formation , Fandong Area of Dongying Sag

袁光祥 李建明 李道轩 石世革

YUAN Guang-xiang LI Jian-ming LI Dao-xuan SHI Shi-ge

长江大学(原江汉石油学院)地球科学系, 湖北荆州 434023; 中国石化胜利油田纯梁采油厂, 山东博兴 256504

Geo-science Department, Yangtze University, Jingzhou 434023, China; Chunliang Oil Production Plant, Shengli Oil Field, SINOPEC, Shandong 256504, China

综合地震、测井、钻井等资料分析,东营凹陷沙三段~沙二下二级层序由四个中期基准面旋回(三级层序)组成。主要研究层段跨两个中期基准面旋回,由沙三中中期基准面下降半旋回 (SA)和沙三上~沙二下中期基准面上升半旋回(SB)构成,并识别出三个界面,即地震标志层T4(湖泛面)和T6(最大湖泛面),以及此两界面之间的一个层序界面(SB)。基准面下降半旋回晚期发育了一些三角洲前缘砂体,基准面上升半旋回早期发育了一些盆底扇、斜坡扇,这些砂体具有良好的成藏条件,极易形成岩性隐蔽油气藏。

The third member to lower submember of the second member in Shahejie Formation of Dongying Sag can be divided into four third-order sequences on the basis of seismic date, lithology and electric characteristics, etc. Two middle base-level cycles(third-order sequences) are distinguished in the strata studied, which are the middle submember of the third member of Shahejie Formation, middle base-level dropping half-cycles, and the upper submember of third member to the lower submember of the second member of Shahejie Formation middle base-level raising half-cycles. Three sequence boundaries among T4, T6 and SB are recognized in the strata studied. T4 and T6 are seismic symbol-layers, which are in response to the maximum flood surfaces. The development characteristics of the middle base-level cycles control the distribution of reservoir sand bodies and the delta front sands bodies are developed in the middle of the basin bottom fans and slop fans. Sand bodies are developed in the early of middle base-level raising half-cycles. They are favorable for oil bearing, so that the sand bodies are prospected districts for subtler reservoirs.