Abstract Traditional methods for characterizing horizontally anisotropic aquifers are all based on pumping tests. In this paper, we present a new method for the identification of horizontal anisotropy using cross-hole slug tests, which is much more easily accessible comparing to pumping tests. Through scaler transform, an anisotropic medium was converted into an equivalent isotropic medium. When applying the analytical solutions derived for isotropic media to interpret cross-hole slug tests performed in anisotropic media, the estimated transmissivity is the geometrical mean of the anisotropic transmissivity tensor, regardless of sampling direction. However, the apparent storativity calculated from different observation wells, is equal to the true storativity scaled by a factor defined by the formation anisotropy. Thus, anisotropy can be resolved through apparent storativity that bears directional information. The proposed method was first validated by a numerical experiment and then applied to field data. It was found that the tensor results obtained by this new method with cross-hole slug tests are consistent with that obtained by applying the classical Papadopulos’ method with cross-hole pumping tests conducted in the same wells. When applied to heterogeneous media, tensor results produced by the new method may be subject to considerable errors. This is because the results are strongly sensitive to the connectivity between measurement boreholes and the formation medium. To reduce the error level, responses from a large number of observation wells located in various directions around the source well are needed. In addition to the adopted KGS solution for confined aquifers, the proposed methodology can be applied to incorporate other analytical methods for a variety of aquifer types, as long as the characteristic relationship between the measure scale and the aquifer storativity can be established.

中文翻译：

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使用跨孔段塞试验表征水平透射率各向异性

摘要 表征水平各向异性含水层的传统方法都是基于抽水试验。在本文中，我们提出了一种使用跨孔段塞试验识别水平各向异性的新方法，与泵送试验相比，该方法更容易获得。通过标量变换，将各向异性介质转换为等效的各向同性介质。当应用为各向同性介质导出的解析解来解释在各向异性介质中执行的跨孔段塞测试时，估计的透射率是各向异性透射率张量的几何平均值，与采样方向无关。然而，从不同的观测井计算出的表观储量等于由地层各向异性定义的因子缩放的真实储量。因此，各向异性可以通过带有方向信息的表观存储性来解决。所提出的方法首先通过数值实验进行验证，然后应用于现场数据。发现通过这种新方法与跨孔段塞试验获得的张量结果与应用经典Papadopulos'方法在相同井中进行跨孔抽水试验获得的结果一致。当应用于异构媒体时，新方法产生的张量结果可能会出现相当大的误差。这是因为结果对测量钻孔和地层介质之间的连通性非常敏感。为了降低误差水平，需要来自位于源井周围各个方向的大量观测井的响应。