岩溶热储井间连通性的示踪研究

岩溶热储储层的不均匀性强，采灌井之间的连通性不易确定。示踪技术可以将运移参数量化，有效刻画储层流体的特征，研究回灌井和开采井之间的水力联系，包括导水通道，流体流速等信息，对长期回灌可能引起的开采井的冷却进行预测，是岩溶热储井间连通性研究十分有效的技术。本文以华北牛驼镇地热田雄县地区为例，针对蓟县系雾迷山组岩溶热储，采用荧光素钠示踪剂，进行了1口井注入，10口井观测的群井示踪试验。采用裂隙介质溶质运移模型，对示踪试验数据进行了解释，得到优势通道的长度、渗透流速、纵向弥散度、回收率等储层性质，获得了试验区内采灌井之间的连通特征。对调整采灌井布局提出了建议。

Interwell connectivity in a karstic geothermal reservoir through tracer tests

The inhomogeneity of karstic geothermal reservoirs makes it difficult to determine the inter-well connectivity between injection and exploitation wells. Tracer technology can quantify the flow parameters,depict the characteristics of karstic reservoirs effectively,reveal the extent of hydraulic connections,detect flow channel and flow velocity between an injection and a production well,and predict possible cooling of production wells due to long term waste water reinjection. Therefore,it is very effective to study inter-well connectivity of karstic geothermal reservoirs. This paper presents a tracer test in Xiongxian karstic geothermal reservoir of the Niutuozhen geothermal field in North China as an example. The targeted geothermal reservoir of the tracer test is Wumishan Formation of Jixian System. In the multi-well tracer test,sodium fluorescein was chosen as tracer and was injected into a well called WQ2. 10 other wells around it were used as monitoring wells. The test data were interpreted by solving mass transport model in fractured medium. The geothermal reservoir's properties of preponderant channel's length,flow velocity,longitudinal dispersivity and recovery rate were obtained through interpretation of tracer test data. The inter-well connectivity information are gained correspondingly and suggestions are made to adjust the layout of reinjection and production wells in the studied geothermal field.