鄂尔多斯盆地东缘上古生界太原组储层特征及评价方法

Reservoir characteristics and evaluation methods of the Upper Paleozoic Taiyuan Formation in the eastern margin of Ordos Basin

针对太原组致密岩储层储层的岩性和物性非均质性强,有效储层发育特征不清楚,影响了对天然气储层富集规律的认识,以测、录井等基础地质资料进行深入挖掘,详细分析太原组储层特征,发现以下几点认识:(1)太原组储层是典型致密砂岩,岩性主要是细-粗粒岩屑砂岩,石英砂岩,低孔低渗,潮坪、砂坝、水下分流河道等强水动力沉积形成的储层是有利于成藏区,易形成致密砂岩甜点区;(2)应用气测衍生数据与甲烷异常倍数以及测井资料中的敏感参数,伽马、渗透率与补偿密度与补偿中子的差值φD-N交会图进行评价有比较好的效果,能够快速识别储层含气性,有效指导后期勘探开发以及压裂选层。

In view of the strong heterogeneity of lithology and physical properties of tight rock reservoirs in Taiyuan Formation and the unclear development characteristics of effective reservoirs,the understanding of natural gas reservoir enrichment law has been affected.In this paper,the basic geological data were deeply excavated to analyze the reservoir characteristics of Taiyuan Formation in detail,and the following understandings were found:(1)The reservoir of Taiyuan Formation is a typical tight sandstone.The lithology is mainly fine-coarse grained lithic sandstone,quartz sandstone,low porosity and low permeability,and the reservoir formed by strong hydrodynamic deposition such as tidal flat,sand bar and underwater distributary channel is conducive to gas reservoir formation and easy to form a sweet spot of tight sandstone;(2)The application of gas measurement derived and methane abnormal multiple,as well as the sensitive parameters in logging data,gamma,permeability andφD-N crossplot has a good effect,can quickly identify the gas reservoir,effectively guide the later exploration and fracturing formation selection.