标题：ANALYSIS OF SHALE STRUCTURAL FRACTUREDEVELOPMENT CHARACTERISTICS AND FORMATIONTIME IN THE STRONG DEFORMATION ZONEIN THE SOUTHERN QINSHUI BASIN, CHINA
摘要：The structural evolution and fracture development characteristics of the strong deformation zone have important reference value for shale gas exploration. In this paper, taking the Upper Paleozoic Shanxi Formation in the south of the Qinshui Basin as an example, the strong deformation structure and fracture characteristics of the stratum are systematically analyzed, and the relationship between them is analyzed. The results show that horizontal bedding fractures are m ainly developed in the shale of the Shanxi Formation, and some tectonic shear fractures and a small number of tensile fractures are also developed. For carbonaceous shale, some diagenetic shrinkage fractures, dissolution fractures and slip fractures are often developed. Fractures are m ainly distributed in a single shale layer, and generally do not penetrate the layer. Natural gas can be better stored in a single shale. Sem i-filled fractures and fu lly-fille d fractures account for the largest proportion of shale shear fractures. Fully fille d fractures are usually "early-stage fractures". Shale fracture linear density is m ainly distributed in the range of 0.2 〜15 m"1, w ith an average of about 5m "1. Although the shale fractures in the Shanxi Formation are developed to a high degree, they are dominated by bedding fractures and shear fractures, and these fractures are less effective under underground stress environments. Closed fractures can effectively prevent the natural gas from escaping. Based on the tectonic background and fault evolution characteristics since the Late Triassic, it is considered that the structural fracture system of the Shanxi Formation shale m ainly formed in the Late Jurassic.
