Estimating Unconventional Oil Resources and Reserves

R.A. Marsh, Energy Resources Conservation Board

Given its history, the Petroleum Reserves Management System (PRMS) is well suited to industry personnel trying to define a financial asset but somewhat less so to a resource manager trying to define potential, even more so when the potential is unconventional. To fully suit an unconventional world PRMS likely needs some adjustments and the value of non-proven reserve and resource estimates needs to be better appreciated by a wider audience. Current international mineral standards may better suit unconventional needs and Canadian regulatory standards are showing the growing usage of Contingent Resources.

By its very nature, unconventional means looking at resources lower down in the resource pyramid, but just how much lower is an open ended question. Alberta has a long track record, especially with oil sands, of dealing with this issue, both from a government and industry perspective. Combining these perspectives yields common general categories of (constrained) total in-place, developable in-place, and recoverable resources (reserves).

Experience leads to the conclusion that for a resource assessment geologist the production engineer is an important colleague. The geologist and the engineer are both charged with the same overall mission; find it and get it out of the ground at a profit. When dealing with unconventional resources however, ‘it’ isn’t necessarily obvious and neither is ‘out of the ground’; that’s why it’s called unconventional and properly estimated resources and reserves are the forecaster of success. The key middle ground for both disciplines is developable in-place (within the reservoir) and caprock integrity (external to the reservoir).

AAPG Search and Discovery Article #90098©2009 AAPG Education Department, Houston, Texas 9-11 September 2009