巴基斯坦塔尔地区煤层下部含水层回灌试验研究

Study on recharge for aquifer beneath coal seams of Thar area,Pakistan

巴基斯坦塔尔地区某燃煤电站冷却水计划回灌至煤层下部承压含水层,为了确保回灌的可行性,开展了一系列的抽水、注水试验。根据非稳定流抽水试验,计算了含水层的导水系数和渗透系数;根据非稳定流抽水试验的s～lgt曲线形态以及三段降深稳定流抽水试验结果判断出煤层下部含水层为稳定分布的承压含水层;采用补给影响半径的概念,基于三段降深稳定流抽水试验结果,计算了合理的回灌井距;结合短周期回灌试验和设计要求确定了单井回灌量;通过对比稳定流抽水试验数据和短周期回灌试验数据,分析了回灌阻力,并确定了回灌阻力曲线;将长期回灌试验曲线划分为回灌阻力阶段和阻塞效应阶段,分析了阻塞效应。通过试验观测数据以及试验曲线的一阶导数,认为阻塞效应并不明显。研究成果可为未来回灌工程建设提供一定的理论基础和技术依据。

Cooling water from a coal -fired power plant in Thar area,Pakistan was planned to recharge to the confined aquifer beneath the coal.In preparation of future recharge,a series of hydro -geological tests were carried out.Permeability coefficient and transmissivity coefficient were determined by the result of unsteady flow pumping test.According to the s -lgt curve of unsteady flow pumping test and the results of steady flow pumping test,the aquifer was determined as a stable confined aquifer. Based on the concept of supply radius,the influence radius was calculated by steady flow pumping test of three stages.The single -well recharge volume was obtained through the preliminary infiltration tests and design requirements.By contrasting the steady flow pumping tests and preliminary recharge tests,the recharge resistance was analyzed and the recharge resistance curve was determined.The curve of long -term re -charge test could be divided into recharge resistance stage and blockade effect stage. Blockage effect was analyzed by the result of long -term re -charge test and the first -order derivative of the test curve.The test data showed that re -charge capability had no remarkable change with time.Research results mentioned above could offer a certain theoretical basis and technical base for future recharge project.