页岩储层可压裂性评价对页岩气勘探开发部署具有重要意义。以川南地区长宁、泸州区块龙马溪组页岩为研究对象,采用X射线衍射、岩石力学试验等手段,系统分析了页岩的矿物组成、物理性质及岩石力学特征,并从矿物组成和岩石力学性质方面分别评价了页岩可压裂性,进而筛选模量脆性指数、力学脆性指数、地应力差异系数、岩石抗压强度以及总有机碳(Total Organic Carbon,TOC)等参数,构建了页岩可压裂性综合评价模型。结果表明,龙马溪组页岩具有高脆性矿物含量、低孔隙度、较大抗压强度和杨氏模量等特征。页岩模量脆性指数、力学脆性指数、地应力差异系数、岩石抗压强度及标准化TOC在长宁区块为0.41、0.31、0.01、0.44、0.187,在泸州区块为0.49、0.60、0.11、0.59、0.298,长宁、泸州区块页岩可压裂性综合评价指数分别为0.46和0.57,显示该区域页岩具有良好的可压裂性,且泸州区块优于长宁区块,主要受有机质含量、石英含量及微观孔隙结构发育程度等因素影响。研究可为川南地区龙马溪组页岩气高效开发提供理论依据和技术支持。

The evaluation of shale reservoir fracability is of great significance for the deployment of shale gas exploration and development. This study focuses on the Longmaxi Formation shale in the Changning and Luzhou blocks of the Southern Sichuan Basin. By employing methods such as X-ray diffraction and rock mechanical tests, the mineral composition, physical properties, and rock mechanical characteristics of the shale were systematically analyzed. The fracability of the shale was evaluated from the perspectives of mineral composition and rock mechanical properties. Parameters including the modulus brittleness index, mechanical brittleness index, in-situ stress difference coefficient, rock compressive strength, and TOC(Total Organic Carbon) were selected to construct a comprehensive evaluation model for shale fracability. The results indicate that the Longmaxi Formation shale is characterized by high brittle mineral content, low porosity, relatively high compressive strength, and Young's modulus. In the Changning block, the modulus brittleness index, mechanical brittleness index, in-situ stress difference coefficient, rock compressive strength, and standardization TOC are 0.41,0.31,0.01,0.44, and 0.187 respectively; whereas in the Luzhou block, the corresponding values are 0.49,0.6,0.11,0.59 and 0.298. The comprehensive evaluation indices of shale fracability in the Changning and Luzhou blocks are 0.46 and 0.57 respectively, indicating favorable fracability of the shale in this basin, with the Luzhou block exhibiting superior fracability compared to the Changning block. This difference is primarily influenced by factors such as organic matter content, quartz content, and the development of microscopic pore structures. This study can provide theoretical foundation and technical support for the efficient development of shale gas in the Longmaxi Formation in the southern Sichuan Basin.