| Popis: |
For the first time, polar organic compounds in extracted bitumen from the Lower Triassic Montney Formation have been analyzed. This stratigraphic unit is one of the most prolific low-permeability reservoirs in Western Canada. However, its organic geochemical characterization is a challenge due to low biomarker concentration in the liquids and frequent mixing of gas/condensate hydrocarbons. Since typical biomarkers were not available, this study focused on another group of molecules, polar oxygen-compounds, which were derivatized and subsequently resolved using chromatographic techniques. In the polar fractions, based on their contrasting molecular distributions, n-fatty acids and alkan-2-ones do not seem to share a common origin and do not have an apparent association with the n-alkanes. This study is also the first report of 1,13-, 1,14- and 1,15-diols in fossil organic matter; and in carbon number ranges of C15-C29, C16-C29 and C17-C29 respectively. The similar distributions of 1,14- 1,15-diols suggests a common origin for these compound classes, whereas theand 1,13-diols seem to derive from a different source or mechanism. A series of alkan-3-ols has also been identified in the C12-C28 range, sharing a common distribution pattern with the n-fatty acids. The large variability detected in the molecular distribution of oxygen-containing aliphatic compounds introduces the question whether they may record a geochemical signature that precedes thermal degradation and hydrocarbon migration events within Montney reservoirs. |
