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Characterisation of a Fractured Aquifer Using Open-Well Dilution Tests
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 80th EAGE Conference and Exhibition 2018, Jun 2018, Volume 2018, p.1 - 5
Abstract
The Chalk aquifer in England derives its aquifer properties essentially from a well-developed network of solutionally-enhanced (karstic) fractures and conduits. Like other fractured aquifers, identification and characterisation of flow pathways is necessary for source catchment and effective management and protection of the groundwater resource. The nature and vertical extent of permeability development within the saturated zone of the aquifer influences its response to extreme event and the rate of contaminant migration and characterisation enables the targeted sampling of flowing zones e.g. for monitored natural attenuation (MNA).
In this study, open-well uniform and point dilution testing is applied to existing groundwater monitoring wells in the Cretaceous Chalk aquifer in East Yorkshire, UK to determine discrete inflow, outflow, and crossflow zones within the wells to be identified and the direction and rates of flow to be determined. The results of the flow zone characterisation are combined with stratigraphic information to identify geological controls on features such as solutionally-enhanced (karstic) fractures or conduits. The results will are applicable to groundwater modelling approaches currently used for assessment, evaluation and protection of the aquifer. The open-well dilution technique used in this study is potentially applicable for characterising fractured aquifers and hydrocarbon reservoirs worldwide.