基于微生物烃检测技术的陕北煤层火烧区绿色探测

Green detection method of coal burning area in northern Shaanxi based on microbial hydrocarbon detection technology

煤层中含有各类轻烃,当煤层燃烧后,上覆地层完整性被破坏,给煤层内的烃类散逸提供了良好的通道,这一过程符合轻烃微渗漏原理。因此,引入轻烃微渗漏的微生物烃检测技术对煤层火烧区及其范围进行识别。在陕北侏罗纪煤田郝家梁煤矿进行了2条测线的试验,选择丁烷氧化菌作为检测指标,通过土壤样品采集、微生物培养、菌落计数等微生物检测工作后,结合地质钻孔对微生物值进行标定和异常值分组,并对煤层火烧区轻烃微渗漏的微生物响应特征进行研究。结果表明,在完全火烧区微生物以背景值分布为主,在火烧过渡区微生物以连续高值异常为主,在正常煤层区微生物以中低值为主,从而建立了研究区煤层火烧区微生物响应模型。微生物烃检测技术所解释的煤层火烧区地质成果与磁法解释的火烧边界吻合,且有钻孔验证。微生物烃检测技术的野外实施简单环保,大部分工作在室内完成,更适用于类似陕北生态脆弱区的煤层火烧区探测,有显著的实际意义和经济价值。

Coal seams contain all kinds of light hydrocarbons.When coal seams are burned,the integrity of overlying strata is destroyed,which provides a good channel for hydrocarbon escape from the coal seam.This process conforms to the principle of light hydrocarbon microseepage.Then,microseepage associated microbial hydrocarbon detection technology is introduced to test its recognition ability of coal seam burning area.In Haojialiang Coal Mine of Jurassic Coalfield in northern Shaanxi,two survey lines were tested and butane bacteria was selected as microbial detection index.After microbial analysis process such as soil sampling,microbial culture,and colony count,combined with geological drilling results,microbial values were calibrated and grouped into abnormal and background values.The microbial response characteristics of light hydrocarbon microseepage in coal burning area were studied.The microbial values in the fully burned area were background low values.In the transition area,the continuous high anomaly microbial values can be seen,while in the normal coal seam area,the microbial anomaly is mainly medium low value.Therefore,the microbial response model of coal burning area was established.The geological results of coal seam burning area explained by microbial hydrocarbon detection technology are consistent with the combustion boundary interpreted by magnetic method,and verified by drilling holes as well.The application of microbial hydrocarbon detection technology in the field is simple and environmentally friendly,and most of the work can be completed indoors.Therefore,it is more suitable for the detection of coal seam burning areas similar to the ecologically fragile area in northern Shaanxi,and has significant practical significance and economic value.