地下水源热泵水井泵砂与堵塞原因分析

Analysis of sand entry and clogging in wells in the ground source heat pump system

摘要:

地下水源热泵系统常会出现抽水井泵砂、抽水井和回灌井堵塞等问题，影响系统的正常运行或系统效率。以湖北省荆州市某地下水源热泵工程为例，分析了江汉平原广泛分布的卵砾石夹细砂含水层中成孔方法选择、滤料及过滤管设计中存在的问题；指出了目前在过滤管外包不锈钢丝网是防止在细砂层中水井泵砂的有效手段之一，但宜与泥浆密度轻、对地层污染小的反循环成孔工艺配合使用，且仍要根据含水层的颗粒级配曲线选择滤料，发挥滤料的过滤作用，避免过滤压力转移到包网过滤管，以减少抽水井堵塞。

Abstract:

Sand entry and well clogging in the groundwater heat pump system often affect the operation and efficiency of the system. Taking a project in Jingzhou City as an example, analysis is made of selection of the water well drilling method in gravel with fine sand aquifer occurring widely in Jianghan Plain and the problems with pack material and the screen design. It is pointed out that one of the effective means to prevent sand entry from the fine sand layer is to wrap the stainless steel wire mesh around the screen pipe at present; anyhow it’s better to be used in conjunction with the reverse circulation drilling method, and the pack material should be selected according to the gradation curve of the aquifer to avoid the transfer of the filtration pressure to the screen pipe, thus reducing well clogging.