基于测井信息对沁水盆地南部构造煤分布规律的研究

Study on Tectonoclastic Coal Distribution Pattern in Southern Qinshui Basin Based on Well Logging Information

基于构造煤和原生结构煤在力学、电学及声学等岩石物理性质方面的差异,采用自然伽马、电阻率、井径及声波时差等测井曲线对沁水盆地南部15#煤层中的构造煤进行了识别。通过对比不同煤体结构煤层的测井响应特征,建立了研究区深部构造煤识别图版。结果表明:构造煤电阻率呈低值,扩径较严重,自然伽马呈现负异常及声波时差正异常,局部出现"周波跳跃"的现象。研究该区15#煤层构造煤的分布规律发现:研究区构造煤分布呈东西厚、中部薄的特点,其分布主要受NE-NNE向的断裂及小规模的褶皱构造控制;西部断裂带内构造煤厚度可达5.25m,中部减薄以致尖灭;东部受局部构造变形影响,最大厚度达5.55 m。

Taking cognizance of differences between tectonoclastic coal and primary structure coal on rock physical properties including mechanics, electrics, acoustics etc., using gamma-ray, resistivity, caliper and sonic differential time logging traces carried out tectonoclastic coal identification from coal No.15 in southern Qinshui Basin. Through well logging response characteristic contrast of coal seams with different coal-body structures, established study area deep part tectonoclastic coal identification plot. The result has shown that the tectonoclastic coal presents low resistivity values, borehole diameter seriously expanded, gamma-ray traces present negative anomaly, sonic differential time positive anomaly, cycle skip occasionally happened. After coal No.15 tectonoclastic coal distribution pattern analysis has found that the distribution presents features of thick in east and west, thin in middle, thus controlled by NE-NNE faults and small-scale folded structures. In the western part faulted zone, the thickness of tectonoclastic coal can be 5.25m; middle part thinning or even pinch-out; eastern part because of local tectonic deformation, maximum thickness 5.55 m.