Conventional Crude Oil Resources of the Western Canada Sedimentary Basin

Abstract

Abstract This paper provides estimates of "in place" and recoverable conventional light and heavy crude oil resources for the Western Canada Sedimentary Basin. Components of the oil resource base considered are currently established reserves, resources available through infill drilling and the application of enhanced recovery techniques in currently established pools, extensions to these pools and new pools, which available geological and statistical information indicates could reasonably be expected to be discovered in the future. The Geological Survey of Canada (GSC) last made an estimate of Western Canadian conventional light crude oil resources in 1988(1). Estimates of conventional heavy crude oil resources have been previously reported in the reports "Canadian Energy Supply and Demand" prepared by staff of the National Energy Board (NEB)(2, 3). Recently, techno logical progress, and in particular 'the application of horizontal drilling, has, led, to the potential for significant improvements in recovery efficiencies for conventional oil. This paper reviews and updates the previous resource assessments by NEB staff in light of the recent technological advances. Introduction The Western Canada Sedimentary Basin (WCSB) occupies an area of 1.4 million square kilometres of southwestern Manitoba, southern Saskatchewan, Alberta, northeastern British Columbia and the southwest corner of the Northwest Territories (Figure 1). Petroleum resources of the basin range from natural gas at the light end of the spectrum through conventional crude oil to bitumen, 'which is also referred to as unconventional oil. Conventional crude oil is that portion of this spectrum which exists in the reservoir in the liquid state and is sufficiently fluid that it flows naturally from the reservoir into a well bore. We adopt the light and heavy conventional crude oil categories of the provincial agencies but classify as light crude oil that designated as medium by the Alberta Energy and Utilities Board (AEUB), and classify as heavy crude oil that designated as medium by the Saskatchewan Department of Energy and Mines. Costs of extraction and crude oil prices are important determinants in the assessment of recoverable crude oil resources(4). However, 'we avoid focussing on the economic aspects of crude oil recovery by assuming a high crude oil price, in the order of $35(Cdn.) per barrel, so that estimates of recoverable resources are not constrained by price considerations. The assessment uses historical data based on definitions for reserves and resources that have been traditionally used by the NEB and the provincial agencies. These definitions differ from those given in the monograph recently published by The etroleum Society(5). FIGURE 1 Available In Full Paper. Categories of Resources We define the conventional crude oil resource base of the WCSB as the volume of conventional crude oil originally in place in the basin before any production. This crude oil resource base can be divided into discovered and undiscovered resources(Figure 2). Discovered resources are that part of the resource base that has been proven by drilling, testing or production.