Abstract

The Lower Cretaceous Parsons sand, to date, has proved to be hydrocarbon bearing on four structures – Kugpik, Imnak, North and South Parsons Lake. The North and South Parsons pools together constitute a major gas accumulation with current proven reserves of approximately 60 × 10⁹m³ (2.0 tcf). South Parsons contains only dry gas with no evidence of condensate. The North Parsons, however, contains wetter gas, considerable condensate, and one oil well.

Source-rock geochemistry suggests that the hydrocarbons were generated by the Cretaceous-Jurassic Husky shale where it was deeply buried, basinward of the main structure. At Parsons Lake the gases and liquids migrated from the deep, thermally mature Husky, across a fault zone, into the adjacent Paleozoic carbonates under the structure, and then upwards into the Parsons sand reservoir.

The deep Husky was sufficiently mature at two periods in its burial history to generate hydrocarbons - mostly oil at the end of Early Cretaceous and mostly gas late in the Tertiary. Only the North Parsons field showed closure at the time of Early Cretaceous oil migration so only it trapped, and still contains, oil and condensate.