A Screening Process for Shale Gas Prospecting

Abstract

Abstract While North American shale gas recovery efforts are booming, Europe and other parts of the world are just entering the game. The first main hurdle for operators today is to decide if and where to plant a flag in these vast and essentially uncharted territories. This paper presents a process developed to support exploration teams in the screening and ranking of shale play candidates. It is based on the Analytical Hierarchy Process methodology. The decision problem is first broken down into a treelike structure, or hierarchy, of controlling criteria. These criteria can relate to any aspect of the decision—tangible or intangible, accurately or roughly estimated, quantitative or qualitative. They are weighted as a function of their relative importance in meeting the set goal. Secondly, the candidates are scored according to how well they fulfil the criteria. Finally, these evaluations are converted into overall ranks, enabling straightforward comparison of the various courses of action. The sensitivity to both weights and scores is assessed to capture the impact on rank of uncertainty in criterion importance or in supporting data. The methodology is implemented in a software application. A hierarchy is proposed for shale gas play prospecting that considers as root criteria the resource—amount of gas in place, drilling and completion risks— as well as the commercial, regulatory, and operational/environmental contexts. Relative weights are assigned based on North American experience. For illustration purposes, a selection of plays in Europe and North Africa are then canvassed, and results are presented and discussed. The proposed criteria and weights can be fully customised to honour stakeholders’ objectives and suit the focus of the current exploratory phase (from the high-level screening of sedimentary basins to comparative analysis of economic conditions at country level to in-depth reconnaissance of "sweet" spots within a play).