摘要
利用钻孔岩心观察、煤体结构频度统计及取心化验数据统计等资料,研究黔北煤田JP区块上二叠统煤层气的综合地质条件、含气规律及机制。结果表明:JP区块中、下煤组煤岩结构完整性优于上煤组的,东南翼优于西北翼的,煤层及围岩组合形式、构造应力释放方式决定煤储层结构完整性。煤层有机组分平均为79.29%,煤层镜质体最大反射率平均为3.08%,进入热裂解阶段晚期。煤层气组分以甲烷为主,储层平均含气量为12.17m3/t。煤层含气量受多种因素影响,其中与煤层埋深、热演化程度、高位热量等呈正相关关系,与煤层挥发分产率、地层倾角等呈负相关关系。三大主要控气要素——煤层埋深、地质构造稳定性和热演化程度决定煤层气的分布特征,相对宽缓的向斜西北翼为有利含气区。该结果为黔北地区的煤层气勘探提供指导。
Based on the observation of borehole core,the frequency statistics of coal lithostructure and the statistical analysis of core testing data,the comprehensive geological conditions,gas bearing mechanism of the upper Permian coalbed methane were studied in JP block,northern Guizhou.The results show that the lithostructure integrity of middle and lower coal group is better than that of upper coal group,and the coal lithostructure integrity in the southeast is better than that in the northwest in JP block.The combination of coal seam and surrounding rock,and releasing form of tectonic stress determines the lithostructure integrity of coal reservoirs.The average organic component of coal is 79.29%,and average Romaxof coal is 3.08%,that reached the late stage of thermal cracking.Methane is the main component of coalbed methane,with an average gas content of 12.17 m3/t.The gas content of coal seam is controlled by a variety of factors.The CBM has a positive correlation with coal seam depth,thermal maturity and high quantity of heat,etc.,a negative correlation with the volatile yield and the dip of coal seam.The distribution characteristics of CBM is determined by the three main control factors,including depth,structural stability and thermal maturity,and the synthetical favorable gas-bearing areas should be locked in the relatively wide and gentle northwest wing.These research results provide enlightenment for the exploration of CBM in northern Guizhou.
出处
《东北石油大学学报》
CAS
北大核心
2018年第2期33-42,119,共10页
Journal of Northeast Petroleum University
关键词
黔北煤田
煤层气
含气量
煤体结构
成藏规律
影响因素
northern Guizhou coal field
coalbed methane(CBM)
gas content
coal lithostructure
accumulation mechanism
affecting factors
