四川盆地须家河组沉积体系与有利储集层分布

Depositional system and favorable reservoir distribution of Xujiahe Formation in Sichuan Basin

通过对四川盆地上三叠统须家河组沉积体系的综合分析和对储集层主控因素的解剖,研究低孔低渗背景下相对优质储集层的形成条件,并对有效储集层进行区域评价预测。须家河组除须一段局部发育海陆交互相沉积外,其余各段均属陆相沉积,发育冲积扇、河流、扇三角洲、河流三角洲和湖泊等沉积体系,相带展布和古地理演化均与区域构造运动密切相关。原始沉积相带(辫状河主河道砂坝微相)和后期溶蚀作用共同控制了有利储集层分布,石英Ⅱ、Ⅲ期加大和胶结物发育是砂岩致密化主要原因之一;有利储集层主要发育在三角洲平原高能河道中,中—粗粒砂岩最为有利。结合储集层有效厚度和储集性分析资料,对四川盆地须家河组二段、四段、六段有利储集层进行综合评价和预测,结果显示川中—川南过渡带是最有利的储集层分布区。

By comprehensive analysis on the depositional system and on the main controlling factors of reservoirs in the Upper Triassic Xujiahe Formation in Sichuan Basin,the formation conditions of high-quality reservoirs under low-porosity and low-permeability background were studied.Except the transitional facies of Xu-1 member,other members of Xujiahe Formation are of terrestrial deposit,with alluvial fan,fluvial,fan-delta,fluvial-delta and lacustrine deposit systems developed.Both the facies belt distribution and...