鄂尔多斯盆地三叠系延长组长8浅水三角洲沉积特征  

Sedimentary Features of Shallow Water Delta of Chang8 Reservoirs of Triassic Yanchang Formation in Ordos Basin

作　　者：李元昊[1,2] 蔺昉[2] 杜金良[2] 黄锦绣[2] 程党性[2] 

机构地区：[1]大陆动力学国家重点实验室（西北大学） [2]中国石油长庆油田勘探开发研究院

出　　处：《低渗透油气田》2007年第3期19-24,共6页

摘　　要：与典型的河控三角洲不同，鄂尔多斯盆地三叠系延长组长8浅水型三角洲没有明显的顶积层、前积层和底积层三层结构，沉积时水体较浅（数米至十余米），煤线、植物根、虫孔等浅水环境标志广泛分布。主要发育三角洲平原亚相和三角洲前缘亚相沉积，三角洲前缘亚相相带较宽，根据水深可将三角洲前缘细分为内前缘和外前缘。由于在不同前缘相带河道的稳定程度及砂体特征不同，将长8三角洲前缘砂体分为3种类型：内前缘等厚型，主要为分流河道：内外前缘过度型．砂体为分流河道和改造的席状砂；外前缘极端不等厚型，砂体横向厚度以透镜状和多层薄砂层为主．主要为受波浪改造的席状砂体。Different from the typical fiver-control delta, the shallow water-type delta of Chang8 reservoirs of Triassic Yan- chang Formation in Ordos basin has not obvious three-layered configuration of the topset, foreset, and bottomset beds. The water body was shallow when depositing （a few meters to more than 10 meters）. The shallow water environment marks, such as coal line, plant roots, wormhole, and so on, were extensively distributed. Delta plain subfacies and delta front subfacies are mainly developed in the delta, with wide zones of delta front subfacies. According to water depth, the delta front can be subdivided into the inner front and outer front. In the light of the different stability and sand characteristics of river channels of various front zones, the Chang8 delta front sand-bodies are divided into three types： iso-thick type of the inner front with mainly distributary channel; transitional type of inner to outer front with sand bodies of the distributary channel and rebuilding sheet sands; extremely unequal thickness type of outer front with mainly lens and multi-layer thin sands, was mainly sheet sands transformed by the waves.

关 键 词：鄂尔多斯盆地 延长组 长8油层组 浅水三角洲 

分 类 号：TE121[石油与天然气工程—油气勘探] P512.2[天文地球—地质学]