Publication Date:
2016-06-09
Description:
ABSTRACT Characterizing the hydraulic conductivity (K) of aquitards is difficult due to technical and logistical difficulties associated with field-based methods as well as the cost and challenge of collecting representative and competent core samples for laboratory analysis. The objective of this study was to produce a multi-scale comparison of vertical and horizontal hydraulic conductivity (K v and K h , respectively) of a regionally extensive Cretaceous clay-rich aquitard in southern Saskatchewan. Ten vibrating wire pressure transducers were lowered into place at depths between 25 and 325 m, then the annular was space was filled with a cement-bentonite grout. The in situ K h was estimated at the location of each transducer by simulating the early-time pore pressure measurements following setting of the grout using a 2D axisymmetric, finite element, numerical model. Core samples were collected during drilling for conventional laboratory testing for K v to compare with the transducer-determined in situ K h . Results highlight the importance of scale and consideration of the presence of possible secondary features (e.g. fractures) in the aquitard. The proximity of the transducers to an active potash mine (∼1 km) where depressurization of an underlying aquifer resulted in drawdown through the aquitard provided a unique opportunity to model the current hydraulic head profile using both the K h and K v estimates. Results indicate that the transducer-determined K h estimates would allow for the development of the current hydraulic head distribution, and that simulating the pore pressure recovery can be used to estimate moderately low in situ K h (〈10 −11 ms −1 ). This article is protected by copyright. All rights reserved.
Print ISSN:
0043-1397
Electronic ISSN:
1944-7973
Topics:
Architecture, Civil Engineering, Surveying
,
Geography
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