鄂尔多斯盆地姬塬地区上三叠统延长组长8油层组有利储集层分布及控制因素

Favorable reservoir distribution and its controlling factors of the Chang 8 interval of Upper Triassic Yanchang Formation in Jiyuan area,Ordos Basin

鄂尔多斯盆地姬塬地区上三叠统延长组长8油层组为低孔特低渗储集层,研究该区相对优质储集层展布特征以及形成条件,并进行有利目标区域的优选和预测,对于油气挖潜具有很大的意义。通过砂岩物性、砂岩薄片及扫描电镜等资料的研究,探讨了储集层的岩石学类型、孔隙类型与物性特征、胶结物种类及成岩作用特点及其对有利储集层的控制作用。研究表明,姬塬地区长8油层组主要发育岩屑长石砂岩,铁方解石等胶结物普遍发育,储集层物性整体较差,非均质性强,主要孔隙类型为残余粒间孔和溶蚀孔隙;沉积、成岩及构造共同控制了有利储集层的分布。在此基础上,预测了姬塬地区有利储集层的分布。

The Chang 8 interval of the Upper Triassic Yanchang Formation is a typical low-porosity and low-permeability reservoir in Jiyuan area of the Ordos Basin.Researches of the main controlling factors,the formation conditions of high quality reservoirs and forecast of the favorable target have great significance for the exploration of potential oil and gas resources.Comprehensive analyses have been made on the sedimentary characteristics,property characteristics,rock thin sections,casting thin sections and so on.This paper discusses the distribution of favorable reservoir,the petrology characteristics,the pore texture and pore types,the physical property and the diagenesis types,which finally makes a comprehensive prediction of the distribution characteristics of favorable reservoir area.The results reflect that the lithic arkose is developed well and the cement,especially the ferrocalcite,is general in the Chang 8 interval of the study area.It is poor of the physical properties of the whole reservoir which is characterized by strong heterogeneity.The pore types mainly include residual intergranular pore and dissolution pore.The reservoir is controlled by the sedimentation,diagenisis and tectonism.Based on the above analyses,we forecasted the favorable reservoir in the Jiyuan area.