In the last decade, shale resource exploitation has transformed North American production capacity through technological improvements in horizontal drilling and the ability to efficiently stimulate horizontal wellbores using multiple hydraulic fractures. The 2011 U.S. Energy Information Administration estimates there are unproved, technically recoverable shale gas resources of 827 Tcf (in addition to 20.1 Tcf of reserves) in the USA alone. Exploration and exploitation of Middle East organic-rich shales are just beginning, and discovery of economically viable resources requires a concerted effort. While Middle East resources in place could be much greater than those in North America, "sweet spots" need to be found in which established source rocks can also function as reservoirs. Evaluating these opportunities requires refined reservoir characterization workflows rather than the statistical approach that characterized early development of North American shale plays, which benefited from high gas prices, numerous existing wells, and infrastructure to support drilling and fracturing. With lower well density and higher well costs than in North America, successful exploration for unconventional hydrocarbon resources in the Middle East will necessarily rely more on modeling.
A petroleum systems–oriented approach defines sweet spots by predicting reservoir quality and potential completion quality. Using proven and effective tools, sweet spots are identified early in the life of unconventional plays. Since reliable, comprehensive data concerning the behavior of shale resource systems under varying conditions are not widely available in the Middle East, petroleum systems modeling would yield key risk and value information.
Standard petroleum systems modeling tools have recently been improved, providing more accurate results based on experience of modeling unconventional plays. By extending traditional basin and petroleum systems modeling with sophisticated adsorption functionality, the modeling of hydrocarbon adsorption on kerogen and primary migration within tight source rocks has been significantly enhanced. These methods have the potential to improve the efficiency and effectiveness of Middle East shale resource evaluation.