煤层气群井排采地层水来源判识及其意义  

Discrimination of source of formation water during CBM drainage with the multi-well pattern and its significance

作　　者：刘会虎[1] 桑树勋[2] 李梦溪 胡友彪[1] 徐宏杰[1] 刘世奇[2] 

机构地区：[1]安徽理工大学地球与环境学院,安徽淮南232001 [2]中国矿业大学资源与地球科学学院,江苏徐州221116 [3]中国石油股份有限公司山西煤层气分公司,山西晋城048000

出　　处：《水文地质工程地质》2015年第1期29-34,共6页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金(41330638;41302129;41402140);山西省煤层气联合研究基金(2012012008);安徽省自然科学基金(1408085QE88);安徽理工大学青年科学研究基金(2012QNZ04)

摘　　要：为指导煤层气生产区煤层气井排采,以沁水盆地南部樊庄区块生产监测区为例,通过系统采样测试分析了不同时间节点煤层气井产出地层水样的离子浓度变化特征、溶解性总固体、电导率和总硬度的变化特征,判识了产出地层水的水质类型和水化学相。研究表明:产出地层水的离子浓度、溶解性总固体、电导率和总硬度呈现出波动性变化的特征,具有明显的一致性,地层水中离子浓度除受地层水来源、矿物和离子性质影响外,还受区域井间干扰形成条件下煤层气井产出地层水的流体场影响。产出地层水质类型主要为HCO3—Na型,部分为Cl—Na型,产出地层水水化学相主要为煤层水,部分煤层气井产出地层水水化学相为顶底板围岩水(砂岩或泥岩水)或混有顶底板围岩水的煤层水。生产监测区煤层气群井排采地层水来源的判识有利于指导煤层气生产区排采控制。The Fangzhuang block in the southern Qinshui basin is taken as an example. The temporal characteristics of the ion concentrations, TDS, electrical conductivity and hardness of the produced water from the CBM wells during different producing times were examined by systematic sampling. The water quality types and the hydrochemical facies of the produced formation water were analyzed in order tO scenically guide the CBM drainage in the CBM production area with the multi-well pattern. The results suggest that the ion concentrations, TDS, electrical conductivity and total hardness of the produced formation water from the CBM wells are characterized by the fluctuation variation, and the variation of the ion concentrations has the obvious uniformity with TDS, electrical conductivity and total hardness of the produced formation water. The ion concentrations in the formation water are not only affected by the source of the formation water, the characteristics of the minerals, but also by the fluid field of the formation mater from the CBM wells during the formation of the regional well interference. The hydroehemical type of the formation water from the CBM wells is mainly of HCO3-Na type, with some formation water from the CBM wells of Cl-Na type. The hydrochemical facies of most of the formation water are coabed water, and the hydrochemical facies of some of the formation water are the formation water from the sandstone or mudstone aquifers. There is the mixed formation water of coalbed water and the roof water or floor water, which is from the sandstone or mudstone aquifers. The judgment of the water source of the formation water produced in the CBM wells is helpful in guiding the drainage in the CBM production area.

关 键 词：煤层气 群井排采 地层水 水化学类型 水化学相 沁水盆地南部 

分 类 号：P641.2[天文地球—地质矿产勘探]