基于测井信息的韩城地区煤体结构的分布规律

The distribution of coal structure in Hancheng based on well logging data

韩城地区煤层受多期构造破坏,煤体结构复杂,煤层气井出粉较为严重,目前对区内煤体结构分布规律研究尚且不足,制约了区内煤层气产能提高。通过对韩城地区测井资料与钻井取芯样品进行对比分析,总结出了不同煤体结构的深侧向电阻率测井、双井径测井及自然伽马测井曲线组合特征,并利用测井曲线组合特征识别煤体结构及分层定厚,进一步通过对研究区24口煤层气井测井资料的分析,揭示3号、5号和11号煤层煤体结构平面分布规律及其与区域构造的关系。研究表明:①I类煤(块煤)扩径轻微,电阻率偏高;II类煤(块粉煤)扩径严重且差异扩径现象明显,电阻率偏低;III类煤(粉煤)扩径严重且部分出现轻微差异扩径现象,电阻率偏低。②边缘浅部隆起构造带、龙亭构造带、东泽村构造带和龙骨岭构造带控制了区内3号、5号和11号煤层煤体结构分布,II类煤和III类煤基本沿着构造带走向展布,同一构造带对不同煤层的破坏程度不同。

The coal structure of Hancheng Mine is very complicated underwent multi-phase structure destruction and the coal powder production of coalbed methane wells is relatively high. The research of coal structure distribution in the study area is not enough at present, which restricts the gas production increasing. Based on the comparative analysis of well logging data and core samples in Hancheng Mine, the combined characteristics of resistivity logs, caliper logs and natural gamma logs of different coal structure were summarized and the coal structure and thickness of stratifications in different coal structure were identified. According to the analysis of 24 wells＇ logging data in the study area, the distributions of coal structure of Nos. 3,5 and 11 coal seam were discovered and the relationships between coal structure distribution and structure belt were discussed. The results show ： ① The diameter extension of Class Ⅰ （ lump coal） is minor and its resistivity is high;the diameter extension of Class Ⅱ （lump-powder coal） is serious and anisotropic and its resistivity is relative low ; the diameter extension of Class Ⅲ（ powder coal） is serious and slightly anisotropic and its resistivity is relative low;② The distributions of coal structure at Nos. 3,5 and 11 coal seam are controlled by Margin structure belt, Longting structure belt, Dongzeeun structure belt and Longguling structure belt. Class Ⅱ and Class Ⅲ coal structures spread along the structure belt and the influences of the same structure belt to different coal seams are different.