叠合型不整合结构与油气分布样式：以塔中石炭系东河砂岩为例

探讨了东河砂岩三级层序界面处发育的不整合结构在空间上有序分布所造成油气的差异运聚。将东河砂岩划分为底部不整合上覆层、原状输导层、风化残余层、风化黏土层、顶部不整合上覆层和区域盖层6类成藏结构单元。成藏结构单元在塔中西北地区和塔中东南地区组成不同，构成两类7种不整合成藏结构样式。两类成藏结构样式分别对应两类的油气藏组合:(1)在塔中地区西北部成藏结构单元被分隔，油气沿东河砂岩段顶部风化黏土层及盖层底部发生运移，形成不整合遮挡型油气藏组合，包括不整合上覆层背斜油气藏、不整合上覆层岩性油气藏和风化残余层低幅背斜油气藏3种油气藏；(2)在东南地区成藏结构单元之间发生连通，油气底部不整合上覆层和盖层底部向隆起部位侧向输导，形成不整合连通型油气藏组合，包括连通型背斜油气藏和连通型地层超覆油气藏2种油气藏。这为东河砂岩的进一步勘探开发提供了指导。

Hydrocarbon Distribution Pattern of Superimposed Unconformity Structure: A Case of Carboniferous Donghe Sandstone in Tazhong Area,Tarim Basin,NW China

In this paper, we discuss: (1) the unconformity types along the Donghe sandstone third order sequence boundary; (2) different ways of hydrocarbon migration and accumulation caused by space time orderly distribution of unconformity structures. The Donghe sandstone can be divided into superstratum of the unconformity (bottom), in place carrier bed, residual regolith, weathered clay bed, superstratum of unconformity (top) and regional cap rock. Pool forming units are different in the northwest and southeast of the district. They can form 2 groups and 7 types of pool forming structures, with the former corresponding to two groups of reservoirs. Major structures are separated in the northwest. Hydrocarbon can migrate below the weathered clay bed and regional cap rock, forming the unconformity blocked reservoir group, including anticlinal reservoir of superstratum of unconformity (top), lithologic reservoirs of superstratum of unconformity (top) and low amplitude anticlinal reservoir of residual regolith. Structures are connected in the southeast, and the hydrocarbon may have migrated below the superstratum of unconformity (bottom) and regional cap rock, forming the unconformity connected reservoir group, including connected anticlinal and connected stratigraphic overlap reservoirs. This finding facilitates further hydrocarbon exploration in the Donghe sandstone.