川西南部须二段致密砂岩储层构造裂缝特征及其形成期次

摘要

The reservoir physical property of tight sandstone is dominated by fractures of the Second Member of the Upper Triassic Xujiahe Formation in southwestern Sichuan Basin. Based on the outcrop and core fractures observation, paleomagnetism core orientation and ESR data, the characteristics and formation stage-times of structural fractures were analyzed. The results indicate that there are 4 groups of fractures in this area. The fractures trend NE, NW, EW and EES respectively, with the main directions being NE-SW, NW-SE and EW. Structural fractures were developed in late Indosinian period, late Yanshanian period and Himalayan period, with the strong tectonic movement in Late Himalayan, which resulted in well-developed fractures.%四川盆地西南部晚三叠世须二段致密砂岩储集物性受构造裂缝明显影响.根据研究区露头地层、钻井岩芯及岩石薄片实物资料,同时利用古地磁岩芯定向和ESR测年分析,对研究区构造裂缝优势方位、宽度、间距、充填物以及裂缝发育程度和形成期次进行了分析.结果表明,研究区主要发育有4组构造裂缝,分别为北东向、北西向、近东西向和东东南向,其中优势方位为北东—南西、北西—南东和近东西方向.构造裂缝发育期次主要为印支晚期、燕山晚期、喜马拉雅早期与喜马拉雅晚期,其中印支晚期与喜马拉雅期构造活动最为强烈,裂缝较为发育.