Rock characterization and geomechanical properties of a shale gas field in the Horn River basin, Canada, is presented. The Horn River basin is a middle-Devonian aged shale that traps approximately 11.1 TCF dry gas accumulation in Northeastern British Columbia, Canada. The three main gas bearing shale lithofacies studied are the Muskwa, Otter Park, and Evie.
The main observation and conclusions of this study include:
Average permeability of intact cores was about three orders of magnitude higher than crushed cores. This is because of the existence of nano, micro, and macro fractures that contribute to flow in intact cores.
Comparison of dynamic versus static Young's modulus and Young's modulus versus Poisson's ratio of Horn River shale samples show that these shale formations are "prospective shale" from geomechanical properties point of view.
Static and dynamic mechanical properties and brittleness index (BI) versus Schmidt rebound hammer hardness were analyzed, and acceptable correlations were observed; hence, these relations can be used to estimate mechanical properties form hardness measurements within the basin.
Stress dependent permeability and porosity values of Muskwa, Otter Park, and Evie shales were observed to correlate with Schmidt rebound hammer hardness values; however no correlation is seen when all core samples (i.e., Muskwa, Otter Park, and Evie shales) are analyzed together.
Mineralogy versus TOC, TOC versus Grain density, Porosity versus TOC, Gas Content versus TOC and maturity, and multiple permeability correlations were analyzed and presented. These correlations can be used in nearby Horn River basin reservoir wells in the absence of experimental data.
Petrophysical, mineralogy, and geomechanical studies show that Horn River basin shale exhibit similarity to the Barnett shale of the USA; hence, hydraulic fracturing fluids and completions strategies (such as number of stages, proppant concentrations, pumping volume, etc.) similar to the Barnett shale could be implemented or used as a guide to optimize gas production of Horn River basin shales.
