摘要
为了研究煤层气井排采过程中煤储层水系统的动态传播特征,基于煤系不同岩层不同含水状态的导电性差异,在沁南地区选择一口煤层气排采井,分别在该井排采前、排采半年后进行了煤储层水系统瞬变电磁动态探测。在该井排采范围内设置400 m×300 m的矩形测网,垂直地层走向布置16条测线,每条测线上布置400个测点,在测网内部形成20 m×10 m的观测坐标网格,通过数据采集、资料处理与定量解释,获得排采前、排采半年后各测线、测点煤系视电阻率对比图、视电阻率拟断面对比图、视电阻率顺层切片图,分析结果表明排采前煤储层水系统分布相对较均一,排采半年后煤储层水系统非均质性十分明显。在连通性差的区域,排采半年后煤储层水系统中静水储量部分被排出,煤层及其顶板砂岩视电阻率有不同程度地升高;在连通性较好区域,由于地下水动态补给,煤层及其顶板砂岩视电阻率降低。
In order to study dynamic propagation characteristics of coal reservoir water system during drainage process of coalbed methane well, based on different electrical conductivity of different lithology and water content of coal stra- ta, a CBM production well in Qinnan area was chosen to conduct transient electromagnetic dynamic detections of coal reservoir water system before drainage and after half a year respectively. A rectangular survey grid of 400 rex300 m was set up with 16 survey lines perpendicular to the strata strike and 400 survey points distributed in each line, resul- ting in an observation coordinate network of 20 m~ 10 m within the survey grid. By means of data acquisition, data pro- cessing and quantitative interpretation, apparent resistivity bedding slice chart, comparison diagram of coal apparent re- sistivity and apparent resistivity section of each survey line and point were available before drainage and after half a year. The analysis results show that, distribution of coal reservoir water system is relatively uniform before drainage, while its anisotropy becomes very obvious after half a year. In the poor connectivity regions, apparent resistivity of coal seam and roof sandstone increases in different degrees because static water reserves of coal reservoir water system are partly dewatered, to the contrary, that of coal seam and roof sandstone in the preferable connectivity regions decreases in a certain range because of hydraulic dynamic supply.
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2014年第1期26-31,共6页
Journal of China Coal Society
基金
国家重点基础研究发展计划(973)资助项目(2009CB219605)
国家科技重大专项资助项目(2011ZX05034)
新疆维吾尔自治区引进高层次人才和"天山学者"启动基金资助项目(11100213)
关键词
煤层气
煤储层水系统
地下水动态传播
瞬变电磁技术
视电阻率
沁南地区
coalbed methane
coal reservoir water system
dynamic propagation of groundwater
transient electromag- netic method
apparent resistivity
Qinnan area
