Kevin de Bruin, Umvoto’s Junior Hydrogeologist, attended the Midwest Geosciences Group webinar titled “Packer Testing: Step-wise Techniques and New Technologies for Hydrogeologic Projects” in early March. This informative webinar will aid us in the effective re-analysis of packer tests that were initially carried out on the Table Mountain Group Aquifer (TMGA) during the Exploratory Phase of the project during 2008-2009 (in the Wemmershoek, Nuweberg and Steenbras areas), for comparison with recent borehole magnetic resonance (bMR) downhole geophysical data.
Packer tests are a type of aquifer test which allows for the cordoning off of certain sections of a borehole, resulting in more detailed aquifer parameters (transmissivity and hydraulic conductivity) with greater resolution which target specific fractures. This proves to be useful data that, in conjunction with the analyses of the recent pumping tests carried out on the TMGA (and downhole geophysics mentioned above), will vastly improve the hydrogeological understanding of the Steenbras Wellfield that has recently been developed under the City of Cape Town’s New Water Program.
The webinar, with the aid of case studies, covered topics such as:
- Where is packer testing appropriate and in appropriate
- Single vs multiple packer systems
- Types of hydraulic packer testing
- Step-by-step guide to a packer test
- Determining your project and test objectives
- Understanding the appropriate response time – this is important as responses can be several weeks long in poorly transmissive rock
- Calculating inflation pressure – you do not want to burst your packer
- Typical test response curves
- Methods of analysis
The internationally recognised hosts included Dave Hart (PhD), a hydrogeologist/geophysicist specialising in regional groundwater flow and recharge, near-surface geophysics, and measurement of porosities and permeabilities in aquifers and aquitards; as well as Ken Bradbury (PhD), a hydrogeologist and professor who’s applied research includes groundwater flow in fractured media, aquitard hydrogeology, groundwater recharge processes, wellhead protection, and the hydrogeology of glacial deposits.