赵庄区块地下水特征对煤层气开发的影响分析

Influence analysis of groundwater characteristics to coalbed methane development in Zhaozhuang Block

为查明赵庄区块地下水运移、补给特征及其对煤层气开发的影响,采用地质分析与试验测试相结合的手段,对该区块地下水运移规律和煤层气井3号煤排采水来源进行了深入分析与研究,同时,结合区块内煤层气井生产实际,进一步分析了地下水对煤层气井产能的影响。结果表明:赵庄区块存在一条显著的地下水分水岭,分水岭北部地下水由南西向北东方向径流,南侧地下水由北向南方向径流,煤层气井3号煤排采水补给源主要为其顶板山西组砂岩裂隙含水层,排采水主要类型为Na-HCO_3型。3号煤层顶板以上的基岩中,砂岩比例高的区域,煤层气井产水量大,排采难度高;泥岩比例高的区域,气井产水量低,产气潜力高。研究结果利于该区块煤层气井排采和开发方案的制定与调整。

In order to find out the characteristics of groundwater migration and recharging and the influence of groundwater to coalbed methane（ CBM） development in Zhaozhuang Block,the migration law and recharging source of No.3 coal seam in the block were analyzed and studied by the means of geological analysis and experimental tests. Meanwhile,the influence of groundwater on the productions of CBM wells was further analyzed combining the actual productions in the block.The results showed that there was a significant groundwater divide in Zhaozhuang Block.In the northern side of the groundwater divide,water run from southern west to northern east.But in the southern side,the groundwater flowed from north to south.The main recharging source of No.3 coal seam was its roof sandstone fissure aquifer in Shanxi Formation.The main type of drainage water was Na-HCO_3.The higher sandstone proportion of No.3 coal roof bedrock was,the larger water production of CBM well was.Then,the drainage of CBM well was harder. On the other hand,the water production of CBM well was lower and the gas production potential was better in the area where the mudstone proportion of No.3 coal roof bedrock was higher. The findings were conducive to the formulation and adjustment of the CBM wells drainage and development plan in this block.