In mid-l980, Kloepfer Coles Nikiforuk Pennell Associates Ltd. prepared an estimate of Alberta's ultimate natural gas reserve potential under the perceived economical, geological and technical constraints at that time (1). The study was commissioned by Trans Canada Pipelines Limited (TCPL) and Petro Canada for presentation to the 1980 NEB Energy Inquiry (NO. EHR-l-BO). This paper will discuss the methodology used to derive that estimate and, in particular, the economic and technical considerations.
The initial marketable gas reserves of Alberta recognized by the Alberta Energy Conservation Board (ERCB) increased from 1867.2 to 2554.7 billion cubic metres (66.3 TCF to 90.7 TCF) over the period year end 1973 to year end 1979. Although many factors played a role in this increase of reserves, the change in economic expectations throughout that period was likely the most significant. The estimate of ultimate reserve potential at any given point-in-time is a function of the available resources and perceived current and future economics at that point. The subject of the economics portion of this paper is the effect of the economic conditions of mid-l980 on the ultimate potential estimate.
Most ultimate potential estimates are based on anticipated economics and current technology. In the technology portion of this paper the influence of advances in exploration; drilling, coring and logging; and completion and stimulation technology on Ultimate potential has been analyzed and the magnitude of the various contributions estimated.
The results of certain case studies have been included to substantiate the findings of both the economics and technology sections of the paper.
Estimates of the Ultimate natural gas reserve potential for a given area are continually revised to reflect variations in economic expectations, technological advances, and trends in exploration successes. At year end 1973 the ERCB estimated Alberta's ultimate potential at 3.1 trillion cubic metres (110 TCF) (2). By 1980 the estimate had been revised upwards to between 3.5 to 3.7 trillion cubic metres of actual heating value gas (12b to 133 TCF) (3). Although a certain portion of this upward revision is the result of new discoveries, economic and technological changes during the 1970's played an important role in the conversion of resources to reserves.
An ultimate potential estimate consists of these elements. The base of the estimate is the recognized initial marketable gas reserves of the day which can be produced by proven technology from known geological reservoirs under generally accepted economic expectations. The ERCB recognized 1867.2 billion cubic metres (66.3 TCF) at year end 1973 and 2554.7 billion cubic metres (90.7 TCP) at year end 1979. The influence of economics and technology on this increase is apparent as follows (4):
during 1973 some 85 billion cubic metres (3.0 TCP) of marketable gas were added to the reserve estimates as a re3ult of recovery factor adjustments due to higher gas prices. (A subsequent adjustment in 1976 reduced recovery factors of pools with less than:282 million cubic metres (10 BCP) by a total of 39 billion cubic metres (1.4 TCP))
