Oil families in Mannville Group reservoirs of southwestern Alberta, Western Canada sedimentary basin

Lower Cretaceous oils in southern Alberta have been assessed using column c hromatography, sulphur analysis, gas chromatography (GC) and gas chromatogr aphy-mass spectrometry (GCMS). These oils can be divided into four oil fami lies, E, Q, EQ and F, on the basis of biomarker characteristics, Family E o ils are characterized by low pristane/phytane ratios and a C-35 homohopane prominence. Family Q oils are identified by the presence of so-called "Q co mpounds" (Q/R ratio > 0.5) and have high C-27 diasterane to regular sterane ratios. Family EQ oils are a mixture of Family E and Family Q oils, with b iomarker characteristics intermediate between these two families and low ab undance of "Q compounds" (Q/R ratio < 0.5). Family F oils have high saturat e/aromatic ratios, high pristane/phytane ratios (>1.2) and no C-35 homohopa ne prominence. Oil-source rock correlation to available source rock data su ggest that Family E oils are derived from the Upper Devonian-Mississippian Exshaw Formation and Family Q oils correlate to the Lower Cretaceous Ostrac ode Zone. Family F oils are likely derived from shales of the Upper Jurassi c Rierdon Formation, however additional geochemistry data from this potenti al source rock are required to confirm this interpretation. (C) 1998 Publis hed by Elsevier Science Ltd. All rights reserved.