THERMAL MATURITY AND SOURCE‐ROCK POTENTIAL OF THE SEDIMENTARY SUCCESSION FROM THE DRAKE FIELD, SVERDRUP BASIN, ARCTIC CANADA

Abstract

The thermal maturity and source‐rock potential of the sedimentary succession in the Drake field, Melville Island, Arctic Canada, have been studied using reflected‐light microscopy and Rock‐Eval pyrolysis. The Mesozoic sediments are immature to mature (% Ro = 0.35‐0.80). Vitrinite reflectance in Cretaceous sediments ranges from 0.35 to 0.56%; in Jurassic sediments, it ranges from 0.40 to 0.66%, and in Triassic sediments, from 0.50 to 0.80%. The Triassic Schei Point Group shales and siltstones contain organic matter of marine origin, whereas the predominantly plant‐derived organic matter present in the Jameson Bay, Ringnes and Deer Bay Formations has higher TOC. Among the Schei Point Group sediments, the Eden Bay Member of the Hoyle Bay Formation has high TOC content (approx. 5.0%) and high HI values (in excess of 600 mg HC/g Corg). It is followed by the Cape Richards Member and the Cape Caledonia Member of the Murray Harbour Formation (approx. 5.0% TOC).Regional variations in the level of thermal maturity of Mesozoic sediments in the Sverdrup Basin are mainly a function of burial depth. Thermal subsidence, uplift, erosion and heat associated with periods of diapiric and igneous intrusions may have been responsible for the thermal maturity pattern in the Drake field. The Jurassic Jameson Bay, Ringnes and Deer Bay Formations are immature to marginally mature, and have limited oil‐generation potential due to their high terrestrial input. The organic matter is these formations has good gas potential.