Significant work remains to be done to detail the complex geology of the Karoo and to identify all subsurface aquifers in the areas where shale gas exploration and production will occur to determine the potential risks, which will be regulated by the National Environmental Management Act (Nema), says law firm Norton Rose Fulbright South Africa head of energy practice Matt Ash.

Nema has been brought into force by the recent promulgation of a 2008 amendment to the Mineral and Petroleum Resources Development Act (MPRDA) and, pending yet further proposed amendment of the MPRDA, now regulates the environmental management of shale gas, traditional oil and gas and traditional mining, he notes.

A detailed geological survey will be required to understand the potential risk of migration to subterranean aquifers through fractures in the shale and intrusions, such as kimberlite and dolerite, as well as other intrusions created by ancient volcanic activity.

“The risk of contamination appears to be reduced, owing to shale gas normally being found at depths of 1.5 km and 2 km, whereas aquifers are generally within 400 m of the surface. Further, intense pressure also reduces the potential migration of shale gas through fractures. However, this can only be determined through the geological survey and the close monitoring of shale gas wells,” he says.

There are significant international best practices that can be used as standards for well bore integrity and monitoring systems can be deployed to measure gas escaping.

Mineral Resources Minister Susan Shabangu has now gazetted proposed technical regulations for petroleum exploration and production. Among other things, fracture fluids and structures to be used in any hydraulic fracturing process will have to be fully disclosed and closed well areas fully rehabilitated, in accordance with the draft regulations. In addition, there are detailed provisions governing well construction in order to ensure the integrity of the bore seal. The proposed technical regulations also stipulate that relevant American Petroleum Institute Standards must be met.

Further regulatory control comes in the form of a notice issued by Water and Environ-mental Affairs Minister Edna Molewa that the department intends to list hydraulic fracturing as a controlled activity, which means no one will be able to undertake shale gas exploration without a water use licence, says Ash.

“This process [to gain a water use licence] involves a detailed inquiry into the advisability of granting a water use licence and much depends on the availability of water in proximity to the exploration site.”

However, freshwater is not the only source of water that can be used in hydraulic fracturing. Successful hydraulic fracturing has been done in the US and Canada using seawater and brackish water – these may mitigate many of the concerns around water scarcity in South Africa.

“Carbon dioxide is another option, which would obviate the use of water entirely,” he adds.