Abstract

One hundred nineteen wells drilled in the Mesozoic structural play of western Sverdrup Basin resulted in one of the technically most successful Canadian petroleum exploration efforts discovering 19 major petroleum fields, including 8 crude oil and 25 natural gas pools. The total original in-place reserve of 294 × 106 m3 crude oil and 500 × 109 m3 natural gas at standard conditions is about equivalent to 10% and 23%, respectively, of the remaining national reserves of conventional crude oil and natural gas. Using and comparing both discovery process and volumetric petroleum assessment methods the petroleum resource can be confidently estimated to be between 540 × 106 m3 and 882 × 106 m3 original in-place crude oil, and 1242 × 109 m3 to 1423 × 109 m3 original in-place natural gas at standard conditions. The total resource is expected to occur in approximately 93 fields, containing about 25 crude oil pools and 117 natural gas pools larger than or equal to the smallest oil and gas pools discovered. Both exploration data and resource assessment results suggest that the largest natural gas pools were found efficiently, and that 9 of the 17 largest gas pools are now discovered. The two largest natural gas pools are believed to have been discovered in the Drake and Hecla fields. There remain undiscovered 17 or 18 natural gas pools larger than or equal to 10 × 109 m3. In contrast, oil pools, of which no significant discoveries were made during the first nine years of exploration, appear to have been found inefficiently, if not randomly. Although five of the ten largest crude oil pools have been discovered, there remain undiscovered between 7 and 9 crude oil pools expected to have individual resources greater than or equal to 10 × 106 m3.

Among these is an undiscovered oil pool predicted to be greater than or equal to 100 × 106 m3, similar in size to the largest discovered crude oil pool at Cisco in the Awingak Formation. The ability to compare discovery process and volumetric methods of assessment increases confidence in these results, while illustrating the relative merits of each technique. The Geo-anchored discovery process model analyzes oil and gas pools simultaneous while it independently and objectively estimates numbers of accumulations, without reference to subjective exploratory risk evaluations or efficiencies of geophysical prospecting. This suggests that similar assessments could be improved by:

  • the use of the Multivariate Discovery Process Model to obtain unbiased distributions of reservoir volumetric parameters,

  • the simultaneous estimation of oil and gas pools numbers using the Geo-anchored method, and

  • the validation of assessments by comparing the predictions of different methods.

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