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系统阐明致密砂岩储层裂缝发育的控制因素,是准确预测裂缝分布规律的重要基础。在对裂缝精细定量表征的基础上,系统分析了库车地区致密砂岩中裂缝分布的控制因素。研究区主要发育构造裂缝,裂缝发育程度除受岩性、岩石力学层、沉积微相及成岩相等内因控制以外,还受构造部位和异常高压等外因的控制。脆性矿物含量高、粒度细、孔隙度低、分选好的岩石有利于裂缝的发育;裂缝往往发育在能干性强的岩石中,其高度受岩石力学层厚度控制;单层厚度薄、累积厚度大、粒度细的沉积微相更有利于裂缝的发育;强压实强胶结致密型成岩相是裂缝发育的有利区;断裂附近及褶皱转折端是局部应力集中区,裂缝发育程度明显升高;异常高压降低了有效应力,促进岩石发生破裂。
The systematic explanation of the controlling factors for the development of fractures in tight sandstone reservoirs is an important basis for accurately predicting the fracture distribution. Based on the detailed and quantitative characterization of fractures, the control factors of fractures distribution in tight sandstone in Kuche area are systematically analyzed. In the study area, structural fractures are mainly developed. Besides the internal control of lithology, lithomechanics, sedimentary microfacies and diagenesis, the degree of fracture development is also controlled by external factors such as structural parts and abnormal high pressure. The brittle minerals are high in content, fine in grain size and low in porosity. The well-sorted rocks are good for the development of the fractures. The fractures often develop in highly competent rocks with the height controlled by the thickness of the rock mechanics layer. The thickness of the single layer is thin and the cumulative thickness Large and fine granular sedimentary microfacies are more conducive to the development of fractures; strong compaction strong cementation dense diagenetic facies is a favorable area for the development of fractures; fractures near the fracture and the turning point is a local stress concentration zone, the fracture development significantly increased; Abnormal high pressure reduces the effective stress and promotes rock rupture.