Lateral correlation of sediment facies in the Panuke and Venture fields, Scotian Basin: implications for reservoir connectivity

Gamma logs and conventional core have been correlated in Upper Jurassic–Lower Cretaceous deltaic successions from closely spaced wells in two areas of the Scotian Basin: around the Panuke and Cohasset fields, and the West Venture-Venture fields. In the PanukeCohasset area, the Como P-21, Panuke B-90, Cohasset A-52, Balmoral M-32, and Lawrence D14 wells, located 3–8 km apart, have been correlated in the upper part of the Missisauga Formation and the Cree Member of the Logan Canyon Formation. In the West Venture-Venture area, the West Olympia O-51, West Venture N-91, West Venture C-62, Venture B-52, and Venture H-22 wells, located 2.5 to 11.5 km apart, have been correlated in the Lower Member of the Missisauga Formation. This precise correlation of cores is provided by lithologically similar transgressive surfaces in the form of shelf lag deposits or coals. In both areas, they make effective benchmarks with which to correlate equivalent packages above and below these surfaces, but some transgressive surfaces are of limited extent, and may represent delta progradation and subsequent distributary switching rather than regional changes in sea level. Further correlation indicates that major sandstone packets are laterally correlative (15 km in the Panuke–Cohasset area, and up to 27 km in the West Venture–Venture area), but commonly show lateral changes in lithofacies. For example, at the top of the Missisauga Formation tidal channel sandstones bioturbated by Ophiomorpha at Panuke B-90 pass laterally into thin-bedded by-passing river-mouth turbidites at Cohasset A-52 and thicker bedded delta-front turbidites at Lawrence D-14, over a distance of 15 km. In the Venture Field, lateral continuity is determined by the margins of incised valleys, however continuous sandstone packages that overly the valleys can be correlated up to 27 km, implying that reservoir connectivity may not be limited by the incised valleys. The application of a standard lithofacies scheme in well correlation provided useful information about reservoir shape and conductivity.