Hydrochemical and Hydrogeological Impact of Hydraulic Fracturing in the Karoo, South Africa

Steyl, G. (Golder Associates Pty Limited, University of the Free State) | van Tonder, G.J. (University of the Free State)

OnePetro 

ABSTRACT

Hydraulic fracturing has become a prevalent public and regulatory issue in most countries developing shale gas. South Africa has only recently been exposed to terrestrial gas resource development and this has created unique regulatory issues which are currently being resolved. One of the key issues under debate is the protection of groundwater resources in rural areas, since most of South Africa’s rural and some inland cities are dependent on groundwater for potable water supply. A second concern is the infrastructure requirements to handle the material movement processes during the development of each wellfield and subsequent processing of waste generated on site. Regarding the waste material production, a phased approach is required which considers the initial well development activities, production and subsequent well abandonment. Each phase has a unique risk associated with it and thus would require different management options. At the current stage most of the focus is on the initial stages of well development but the long term view has been neglected to some extent. Due to the unique geological structure of the Karoo, the presence of dolerite structures, a number of risk mitigation methods might be required to succesfully develop hydraulically fractured wells. In all aspects the chemical and hydrogeological impacts related to wellfield development cannot be ignored in the Karoo aquifer system, as it may directly influence human and environmental health. This paper will present chemical perspective on the hydraulic fracturing perspective that will deal with the impact of hydraulic fracturing fluid and flowback water. Additionally, the interaction of wellfield development and hydrogeology of the Karoo area will be discussed and how it relates to future water quality issues.

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