Maturity trends for the Late Devonian Duvernay Formation and identification of the Willesden-Green Maturity High

Maturity trends appearing in the literature for the Late Devonian Duvernay Formation within the Western Canada Sedimentary Basin (WCSB) are inconsistent and do not reflect hydrocarbon production. To address these inconsistencies and more accurately delineate Duvernay maturity trends, this study produces solid-state 13C Nuclear Magnetic Resonance (NMR) spectroscopy and Rock-Eval Tmax data from 38 wells throughout the WCSB. The Duvernay is divided into three different assessment areas that include, from east to west, Innisfail, Willesden-Green, and Kaybob. Based upon the proportion of aromatic to aliphatic carbon of the source rock organic matter, the Duvernay maturity generally increases towards the southwest and mimics structural depth, except within the Willesden-Green area. The Innisfail area has the shallowest depths and only the southern portion reaches oil maturity. The Willesden-Green and Kaybob areas range from oil to dry gas maturity. Although Willesden-Green and Kaybob have similar structural depths (P = 0.24), they have a significant difference in solid-state 13C NMR proportion of aromatic to aliphatic (P = 0.05) and Tmax values (P = 0.00). The average residuals from the depth vs solid-state 13C NMR proportion of aromatic carbon and Tmax best fit line show an increase of 0.09 and 10 °C respectively in Willesden-Green compared to Kaybob. Maps of the maturity indicators show the increase in maturity within Willesden-Green is perpendicular to structural strike. This study names this anomalous feature the Willesden-Green Maturity High.