A Key Performance Driver Type Curve: Correlating Well Productivity to Oil Wettability in Tight Reservoirs

Summary Since 2010, nearly half of the drilled wells in the Duvernay Formation have underperformed and been suspended, raising concerns about completions in low-quality reservoir zones. Field observations reveal up to a fivefold difference in hydrocarbon productivity between adjacent wellpads with similar completion designs and petrophysical properties, differences that conventional analyses fail to explain. In this study, we investigate oil wettability as a key driver of well performance in tight reservoirs and introduce a key performance driver (KPD) type curve that links oil wettability to well productivity, enabling more accurate sweet-spot identification. The analysis includes data from more than 1,500 Duvernay multifractured horizontal wells (MFHWs), integrating field production data, completion design, core analysis, well logs, and public reserve data. Hydrocarbon production is normalized to account for variations in completion design and petrophysical properties, followed by kriging interpolation to generate contour maps of normalized well productivity. We then examine the correlation between core-scale wettability and field-scale productivity. A semi-empirical KPD type curve is developed based on a power-law correlation, conceptually analogous to the oil relative permeability-saturation relationship. To extend applicability, we introduce a data-driven proxy for oil wettability derived from thermal maturity parameters obtained through Rock-Eval pyrolysis. The results show that hydrocarbon productivity in the Duvernay Formation is right-skewed, with most wells underperforming relative to the average, and that conventional petrophysical properties along with completion design fail to explain this variation. Unlike conventional metrics, the oil wettability index (WIo) explains over 90% of the observed variation in normalized productivity. Wells with higher WIo consistently exhibit superior productivity, establishing the KPD type curve as a robust tool for early performance prediction and sweet-spot identification. The results also highlight a key limitation of relying solely on thermal maturity for reservoir quality assessment, particularly in less mature zones.