INTERRELATIONSHIPS BETWEEN IN-SITU GAS HYDRATES AND HEAVY OIL OCCURRENCES ON THE NORTH SLOPE OF ALASKA.

In 1973, during the drilling of the West Sak #1 well on the North Slope of Alaska, oil was first recovered from a shallow Cretaceous sand interval which was later informally named the West Sak sands by ARCO Alaska. Stratigraphically above the West Sak sands there are two additional oil bearing sands, and are informally referred to by ARCO as the Ugnu and the 2150 horizons. Gas hydrates are interpreted to exist in the West Sak #6 well in conjunction with heavy oil and the physical properties of this oil may have been influenced by the gas hydrate. Prior to this work, only experimental evidence suggested that hydrates and oil could exist in the same reservoir.