鄂尔多斯盆地延安组标志层特征及形成机理  

The characteristics and forming mechanism of marker bed in Yanan Formation,Ordos Basin

作　　者：庞军刚[1] 陈全红 李文厚[3] 郝磊[1] 李赛[1] 

机构地区：[1]西安石油大学油气资源学院,陕西西安710065 [2]中国海洋石油研究中心,北京100024 [3]西北大学地质学系,陕西西安710069

出　　处：《西北大学学报（自然科学版）》2012年第5期806-812,共7页Journal of Northwest University（Natural Science Edition）

基　　金：国家科技重大专项基金资助项目(2011ZX05044);西安石油大学博士科研启动基金资助项目(YS29031212)

摘　　要：目的准确划分鄂尔多斯盆地延安组地层,为沉积相及层序地层分析奠定基础。方法利用钻屑、测井、露头观察等综合分析本区延安组标志层特征。结果延安组地层广泛发育构造等时面、煤层及碳质泥岩或油页岩、大型砂体及冲刷面等标志层,其岩电特征明显,可作为地层划分与对比的标志层。在延安组所划分的3个三级层序中,砂体主要发育于低位体系域,煤层或油页岩主要分布在水进体系域的晚期或高位体系域的早期。平面上,标志层的岩性、厚度、分布规律等受沉积相控制。结论针对延安组底部及顶部地层厚度变化大的现状,准确的地层划分要注意以标志层控制结合邻井对比,同时充分考虑侏罗纪沉积前古地貌及延安组顶部地层的剥蚀情况。Aim To correctly divide the strata of Yan＇an Formation, which is the basis for sedimentary facies and sequence stratigraphy. Methods Based on comprehensive analysis of cuttings debris, logging, outcrop observa- tion, etc, a research is maded on the marker beds＇ characteristic of Yan＇an Formation. Results Such marker beds as structure isochronous surface in origin, coal bed and carbargiliteor oil shale, large scale sandbody and scouring surface are well developed in Yan＇an Formation, which carry obvious characteristic of lithology and electrical prop- erty, can be good marker beds for strata division and comparison. Coal bed or oil shale are formed during late peri- od of transgression system tract and early stage of high system tract of the three third-grade sequence in Yan＇an For- mation. Lithology, thickness and distribution feature of marker beds are controlled by sedimentary facies. Conclu- sion In view of the fact that thickness in lower part and upper part of Yan＇an Formation changing quickly in short distance, in order to correctly divide strata, such factors as marker beds, adjacent well comparison, palaeogeomor- phology before Jurassic deposition and denuding upper part of Yan＇an Formation should be sufficiently considered.

关 键 词：标志层 层序地层 形成机理 延安组 鄂尔多斯盆地 

分 类 号：P313.1[天文地球—固体地球物理学] TE122.3[天文地球—地球物理学]