鄂尔多斯盆地下寺湾地区延长组长2油层组储层特征

Reservoir characteristics of the Chang-2 oil unit in Yanchang formation of Xiasiwan area in Ordos basin

下寺湾地区为鄂尔多斯盆地主要勘探区域。在大量收集样品孔渗资料的基础上,对该油区岩石学特征、成岩作用特征、孔隙结构特征、储层物性特征进行了分析和评价。研究结果表明:在下寺湾地区长2油层组储层中,主要的岩石类型为浅灰色—灰色细粒长石砂岩;成岩作用主要有压实作用、胶结作用和溶解作用;孔隙空间类型主要为粒间孔和溶蚀孔隙;基于物性分析资料,根据碎屑岩储集层的划分标准断定研究区主要发育Ⅱ类储层,岩性主要为中—细砂岩,属于中低孔隙度、低—特低渗储层。研究结论对于研究区勘探开发具有十分重要的作用。

The Xiasiwan area is an important exploration region in Ordos basin.Based on an enormous amount of poroperm data,this paper analyzes and evaluates the petrology,diagenesis,pore structure and reservoir physical property of this area.The results show that,in the Chang-2 oil unit of Xiasiwan area,the dominant rock type is light grey-grey fine arkose;the diagenesis mainly involves compaction,cementation and dissolution;the pore space types mainly are intergranular pore and dissolved pore.Based on physical analysis data and the classification criteria for clastic reservoirs,it is determined that Class Ⅱ reservoirs are dominant in the study area,with medium-fine sandstone as the major lithology,belonging to mid-low porosity,low-ultra low permeability reservoirs.The study result is of significant importance to exploration and development in Xiasiwan area.