Relationship Between Facies and Fracture Characteristics, Cardium Formation, Western Alberta, Canada

Abstract

The Cardium Formation of the Western Canada Sedimentary Basin is commonly treated as a single mechanical unit for geological modeling and well design. Variable well completion and production results in horizontal multi-stage hydraulically fractured wells indicate a greater degree of mechanical complexity exists in the formation. Fracture characterization studies from four outcrop locations supplemented by hardness testing from two cores and well completion data from 14 horizontal multi-stage hydraulically fractured wells reveal three unique mechanical facies in the Cardium reservoir and reservoir analogues studied. Mechanical Facies (MF) 2; intensely bioturbated muddy sandstone, MF 3; thinly interbedded sandstone and mudstone, and MF 4; massive sandstone, are distinguished by their unique mechanical responses to natural and induced stresses observed in facies unique fracture intensities, heights, hardnesses, breakdown pressures and average pumping pressures. These MFs are largely defined by their rock fabrics, which exhibit stronger control on hydraulic fracture treatment than composition.