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Petroleum industry benefits from new geology exhibition facility

Engela Duvenhage

A new home for underground core drilled out during a multinational geological project in the Ceres/Tanqua Karoo has recently been opened on the Inverdoorn Game Farm outside Ceres. The facility will provide support to geological field training, in the petroleum industry in particular.

The establishment of this new storage space, in which cylindrical core samples are exhibited, was funded by the Norwegian petroleum company StatoilHydro. The exhibition space will be administered by the Department of Geology, Geography and Environmental Studies at Stellenbosch University (SU).

This is the only facility in the Western Cape where core is exhibited for training and research purposes in petroleum geoscience.

According to Dr De Ville Wickens, former SU lecturer and now geological consultant, the facility is extremely valuable both for petroleum geoscientists and for students researching deep-water fan sediments. These are typically those rock formations from which oil and gas are exploited along the west coast of Africa and in the North Sea, the Gulf of Mexico and the offshore area south of Mossel Bay in South Africa.

According to Dr Wickens, there are no oil sources in the Ceres/Tankwa Karoo, since the rock formations there were subject to high pressures and temperatures, due to deep burial after the sedimentation process. Outcrop exposures of the Skoorsteenberg Formation are, however, excellent examples of submarine fan sediments in which scientists can see exactly what the petroleum-bearing formations look like. This area is therefore a valuable study site for geoscientists. Companies such as StatoilHydro, ConocoPhilips, Total, ChevronTexaco, BP, Petrobras, Shell and ExxonMobil undertake regular educational geological tours to these world-renowned outcrops. To the outcrops they can now add the core, which gives them a valuable view into the character of the rocks at depth.

The south-western Karoo was once an inland sea. It was filled in with sediment approximately 250 million years ago. After the breaking up of Gondwana, plate tectonic forces lifted the region high above sea level. Deep weathering and erosion have produced the current appearance of the landscape.

The core material currently on display at Inverdoorn was drilled a few years ago, from the Skoorsteenberg Formation, as part of the NOMAD drilling project in the Ceres Karoo. These samples were then processed by researchers from the universities of Stellenbosch (in South Africa), Liverpool (in the United Kingdom) and Delft (in the Netherlands), by StatoilHydro, and by Schlumberger, a service provider for the oil industry.

Altogether six boreholes, varying from approximately 100 to 250 m deep, were drilled in areas between the farms Soutrivier in the north and Bizansgat in the south. Thanks to NOMAD, a considerable amount of geological and geophysical information was obtained from these boreholes.

"The sawn-through and polished drill core provides detailed sedimentary information on a millimetre scale," explains Dr Wickens. "You can see information in this fresh core material that's not visible in weathered rock formations. This is enabling us to refine our geological models on sedimentation even further," he says.

According to Dr Wickens, sustained geologically related activities also entail financial benefits for the area. He foresees that research and training for the petroleum industry will continue here for some time to come.

More information:

 www.sun.ac.za 

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