Canadian Discovery Ltd. has recently made one of our Duvernay geomechanics posters publicly available through its Discovery Digest Journal website . This poster is an example of the CDL’s integrated geomechanical characterization workflow for unconventional reservoirs applied to a specific well in the Kaybob Area, Alberta. It includes the results of mechanical properties and brittleness calculations, petrophysical analysis, fracture fabric characterization, drilling experience review, maximum horizontal in-situ stress (SHmax) determination, wellbore integrity modeling/history-matching, and critically-stressed fractures analysis. My favorite part is the fracture fabric characterization that tries to tie the depth of observed fractures (that are mostly coring-induced) on the core and image log with rock mechanical and mineralogical data from sonic logs and petrophysical analysis . The results are interesting as:
i) There exists a strong correlation between mechanical and mineralogical brittleness indices. Nevertheless, both of these parameters are defined differently from the regular brittleness indices used in the industry.
ii) Mechanical properties and brittleness indices can be efficiently used for fracture fabric characterization. In my view, if we want to find the characteristics of fraccable rock, the best approach is to find out where, in reality, the rock has been fractured (either naturally or induced).
iii) There are quantifiable ranges of brittleness indices or mechanical properties that determine the brittle rock that favors fracturing. Such ranges come very handy when quantitative interpretation (QI) method is implemented for characterization of brittle rock using seismic data.
One other thing on this poster is the CDL’s graphical representation of drilling experience that I personally like a lot due to its inclusive and abstract nature. This particular well is probably not the funnest one as it is a simply vertical well that does not show so many drilling problems but several of the 43 wells that we reviewed in this project showed sever drilling problems from all different types.