--> Unconventional Oil and Gas Extraction and Groundwater: Exploiting One Natural Resource at the Expense of Another?

2018 AAPG International Conference and Exhibition

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Unconventional Oil and Gas Extraction and Groundwater: Exploiting One Natural Resource at the Expense of Another?

Abstract

With coal resources that are being depleted, South Africa is currently exploring the possibility of extracting unconventional oil and gas (UOG) in the Karoo geological basin to augment energy requirements in the country. Oil and gas exploration in the 1960s by the Southern Oil Exploration Corporation (SOEKOR) revealed the presence of gas in the tight shale formations of the Karoo Supergroup. Recent estimates of these unconventional resources in the Karoo Basin range from 13 – 390 trillion cubic feet, which could significantly augment energy resources, if proven viable. However, South Africa is also a country with limited freshwater resources, receiving on average less than 500 mm rainfall per year. The availability of surface water in the Karoo is specifically limited, with the majority of rivers being ephemeral, making groundwater the most important source of water in the Karoo. The recent drought has focused additional attention on groundwater in the wider South African context, with the City of Cape Town currently targeting shallow and deep groundwater resources in the Cape Flats and Table Mountain Group aquifer systems to augment water supply in the seriously drought-stricken Western Cape. Other deep aquifer systems could also be used for potable water supply, and potentially also for water supply during UOG extraction. However, our limited current understanding of the localities, extent and aquifer characteristics of these groundwater resources and our limited understanding of the possible impacts of UOG extraction on groundwater systems, requires the application of the precautionary principle in targeting these resources for either human consumption or UOG extraction. This paper will illustrate the complexities of groundwater resources in South Africa and will ask if and how UOG resources can be extracted without compromising valuable groundwater resources, by discussing the way forward in protecting groundwater resources, specifically in South Africa, during UOG extraction.