川南威远地区W201井古生界海相页岩矿物特征

页岩的矿物学特征是页岩气储集层裂缝、渗流运移和后期压裂改造等相关研究的重要基础。应用X射线衍射分析，对川南威远地区W201井下寒武统筇竹寺组和下志留统龙马溪组两套海相页岩岩心样品进行了岩石矿物组成的定性和定量分析。结果表明，川南威远地区筇竹寺组和龙马溪组海相页岩主要由石英、黏土矿物和碳酸盐矿物组成，还含有少量黄铁矿等矿物，样品中石英含量分别为38.7%和31.8%，黏土矿物含量分别为26.1%和37.3%，形成于海相强还原沉积环境，有利于有机质的富集和保存，为页岩气的生成提供了良好的条件；筇竹寺组和龙马溪组脆性矿物含量均较高，平均含量分别为70.5%和58.7%，脆性指数分别为73.0%和61.1%，整体上具有良好的脆性和可压性，有利于后期压裂改造，是四川盆地页岩气勘探开发的重要目的层。

Mineralogical Characteristics of Paleozoic Marine Shales in Well W201 of Weiyuan Area,Southern Sichuan Basin

The study on mineralogical characteristics of shales is an integral part of shale gas reservoir research, which lays an important foundation for the research on fracture evaluation, seepage flow migration and fracturing and so on. Using X ray diffraction (XRD) analysis technique, the paper qualitatively and quantitatively analyzes the mineral compositions of core samples obtained from 2 sets of marine shales of the Lower Cambrian Qiongzhusi formation and Lower Silurian Longmaxi formation in Well W201 of Weiyuan area, southern Sichuan basin. The results show that the minerals of the 2 sets of marine shales in Weiyuan area of the southern Sichuan basin are mainly composed of clay, quartz, carbonate and a few pyrites. The quartz contents of the marine shale samples from Qiongzhusi formation and Longmaxi formation are 38.7% and 31.8%, respectively, and the clay contents of the 2 formations are 26.1% and 37.3%, respectively. The shales were formed in a marine strong-reduction depositional environment which was good for the enrichment and preservation of organic matters and could provide good conditions for shale gas generation. Brittle mineral contents of the 2 formations are relatively high with the averages of 70.5% and 58.7%, respectively and the brittleness indexes of 73.0% and 61.1%, respectively, which indicates that the 2 formations have good brittleness and fracability. Both Qiongzhusi formation and Longmaxi formation are the key target zones for shale gas exploration