Petrophysical and geomechanical characteristics of Canadian tight oil and liquid-rich gas reservoirs: II. Geomechanical property estimation

Abstract

The results from an ongoing laboratory study investigating geomechanical characteristics of the Montney and Bakken formations in Canada are presented. The primary objectives are to (1) characterize the basic geomechanical properties of these formations in areas with limited datasets and (2) investigate the interrelationship between various petrophysical and geomechanical characteristics of these fine-grained tight reservoirs.For two petrophysically well-characterized core slabs from Montney and Bakken formations (Part I), mechanical hardness tests were performed using a portable Equotip® Piccolo 2 hardness tool at the same spots as profile permeability tests. For Montney core slabs, the mechanical hardness values range between 590 and 820 HLD, while for Bakken core slabs, the mechanical hardness values range between 480 and 640 HLD. The mechanical hardness data are roughly correlated to profile permeability values; permeability decreases with increasing mechanical hardness. Using mechanical hardness data and available correlations in the literature, the unconfined compressive strength (UCS) values are further estimated for the analyzed core slabs. The obtained interrelationships between mechanical hardness, profile permeability and UCS data can be used to roughly predict permeability profile and mechanical stratigraphy along the drilled core by performing simple, inexpensive, fast mechanical hardness tests.