The purpose of this paper is to propose a methodology based on analyze the impact of the brittleness index in hydraulic fracturing on shale gas reservoirs worldwide, and thereby define parameters to identify fraccable feasible sweet spots in shale plays prospects.
A literature review was made so as to gather the largest amount of mechanical, petrophysical and geochemical data from shale gas reservoirs from countries all over the world such as United States, China, Argentina, Holland, Norway, Denmark and Sweden. Once available the data, different methods were used to calculate the brittleness index of each study case considering the effect of the mineralogical composition and elastic moduli such as Young's modulus and Poisson's ratio, both static and dynamic.
The relation between the brittleness index at depth and the total organic carbon allowed to identify possible sweet spots within each prospect reservoir. Additionally, the analysis of brittleness index and mechanical behavior of those reservoirs permitted to establish what kind of fracturing fluid should be used in case of a hydraulic fracturing at those sweet spots, in order to achieve the most effective stimulation process.
Integrated analysis of mechanical, petrophysical and geochemical properties is a practical methodology that allows to identify shale gas prospects by establishing analogies with known productive shale reservoirs, especially in countries where unconventional resources potential have not been estimated yet.