准噶尔盆地玛湖凹陷二叠系风城组岩性对岩石力学特性的影响

以准噶尔盆地玛湖凹陷下二叠统风城组储层岩石为研究对象，基于室内力学试验研究了风城组储层不同岩性岩石的力学行为，从而揭示风城组储层不同岩性岩石的力学特性。在此基础上，讨论了矿物组成对风城组储层岩石强度参数的影响。玛湖凹陷风城组储层岩石具有较强的非均质性，造成不同岩性岩石力学特性存在较明显的差异，其中云质类岩石的力学强度和弹性模量较大而泊松比较小；岩石破坏形式较单一，其中单轴条件下，岩样脆性较强，表现为拉张破坏特征，而高围压条件下，岩样脆性减弱、延性增强，主要表现为单剪切破坏特征；岩石的抗压强度、抗张强度、断裂韧性值随着硅质矿物含量的增加呈减小的趋势，而随着钙质矿物含量的增加呈增大的趋势。 

Lithological influences to rock mechanical properties of Permian Fengcheng Formation in Mahu Sag,Junggar Basin

To reveal the mechanical properties of the rocks of the Fengcheng Formation, the rocks of the Lower Permian Fengcheng Formation in the Mahu Sag of Junggar Basin were taken for the laboratory mechanical tests to obtain mechanical behaviors of the rocks, the influence of mineral compositions on strength parameters of the rocks of the Fengcheng Formation was then discussed. The rocks of the Fengcheng Formation in the Mahu Sag have strong heterogeneity, which results in obvious differences of mechanical properties of rocks with different lithologies. The mechanical strength and elastic modulus of dolomitic rocks are higher, but the Poisson's ratio is lower. The form of rock fracturing is relatively simple. Under uniaxial conditions, rock samples have strong brittleness, which is characterized by tensile fracturing, while under high confining pressure, rock samples have weaker brittleness and enhanced ductility, which is mainly characterized by single shear fracturing. The compressive strength, tensile strength and fracture toughness of rocks decrease with the increase of siliceous mineral content, while increase with the increase of calcium mineral content.