Shale Gas: an Unconventional Hydrocarbon Resource in South Africa? Some Preliminary Observations

Abstract

Gas shales are currently amongst the hottest plays in the United States as a result of high gas prices, and the remarkable technological successes exploiting the Barnett Shale of the Fort Worth Basin. Furthermore, viable gas shales most likely occur in many developed basins where an underutilized distribution infrastructure exists and markets are readily accessible. Annual natural gas production from shale gas reservoirs in the US is approximately 1.0 Tcf and comes from more than 40,000 shale gas wells (around 610% of total natural-gas production in the US today; numbers vary according to reference). While high energy prices and advances in fracturing technology have enabled shale gas production to become a lucrative reality, it is the prediction of gas concentration, partition behaviour and rock properties ahead of drilling that is of paramount importance for reducing risk and identifying “sweet spots” or fairways. In other words, there is still a lot to learn scientifically about how shale gas systems actually work. Significant advances have been made over the last five years, but there are great opportunities for major advances in science and technology. No commercial shale-gas enterprises are currently known from outside of North America. Estimations of more than 16,000 Tcf worldwide shale-gas resources are indications that a tremendous potential exists for future growth. Approximately 500 Tcf is forecast for Europe, and targets in Europe include the Posidonia Shale (Jurassic), Alum Shale (Cambrian), Wealden (Cretaceous), Mikulov Formation (Jurassic) and Riga Formation (Silurian).