Sugarloaf Gas and Condensate Project >> Eagle Ford Shale - Introduction
The hydrocarbons found in the Austin Chalk were originally generated in an underlying shale system called the Eagle Ford Shale, which is known as the ‘source rock’ for this reservoir. Most shales have a high clay content which limits their efficiency as potential productive reservoirs in their own right. However within a geological time frame these source rocks allow the hydrocarbons they generate to leak out and in classic chalk fields like Brookeland they are trapped in the overlying reservoir quality Austin Chalk.
In the USA a number of shale plays have recently been developed, where differing geological composition and technology advances has allowed some of the source rocks to be developed as reservoirs in their own right. As industry understanding improves, the characteristics that allow any given shale to be developed as a reservoir are being better understood. Shale plays such as the Barnett, Fayetteville, Bakken and Haynesville are now significant contributors to the US domestic gas production figures. In the last year it has become clear that many gas shale developments have a minimum commodity price threshold for development. However, based on 2009 and 2010 activity within the Eagle Ford Shale, this threshold was not reached even with the low gas commodity prices observed during this period.
Reports from the Austin Chalk discovery well Sugarloaf #1 made reference to an underlying formation that also portrayed reservoir quality as well as having a high organic content. At the time the participants at Sugarloaf referred to this zone as being the ‘New Chalk’ because of the calcareous chalk inter-bedded with the organic shales that were seen in core and on electric logs taken whilst drilling. During late 2008, all through 2009 and at an increasing rate in 2010, a number of large US companies have made announcements of a new shale play within which they have made substantial land investments. This shale play trend has been named the Eagle Ford Shale and Sugarkane is located centrally within it.