Bibliographic record
Abstract
Abstract It is a well established fact that discoveries of natural gas in Western Canada has declined over the last 30 or so years. However, statistical analyses of the declining trends have, to date, failed to provide a generally acceptable estimate of the conventional natural gas resources of the Western Canada Sedimentary Basin. This paper provides an explanation of why decline analysis appears to provide a valid method for estimating the conventional crude oil resources of the basin while the same is not true for natural gas. The paper proposes solutions to the problems encountered in the natural gas data and provides an estimate of the conventional natural gas resources of the basin by statistical analysis of the declining discovery rate trends. 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. Conventional natural gas is that portion of this spectrum which exists in solution in crude oil, or in the gaseous state in reservoirs having a permeability greater than 0.1 mD. Unconventional natural gas resources are those contained in low permeability reservoirs (tight gas), those associated with coal deposits (coalbed methane) and those contained in shale deposits (shale gas). Costs of extraction and transportation and natural gas prices are important determinants in the assessment of recoverable natural gas resources. However, consideration of the economic aspects of natural gas recovery is avoided by assuming a high natural gas price, in the order of $3.00 per Mcf, so that estimates of recoverable resources are not constrained by price considerations. The Canadian Gas Potential Committee (CGPC), in its recent inaugural report(1), focused on conventional natural gas in the WCSB. However, an analysis such as that reported in this paper was not included. FIGURE 1: Western Canada Sedimentary Basin. (Available in full paper) Categories of Resources Definitions for categories of resources are taken from the Petroleum Society Monograph Number 1,Determination of Oil and Gas Reserves(2). The definitions of primary interest in this paper are as follows: Resources of conventional natural gas are the total quantities of gas that are estimated, at a particular time, to be contained in, or that have been produced from, known accumulations, plus those estimated quantities in accumulations yet to be discovered. Discovered resources of conventional natural gas, which also may be referred to as initial volumes in place, are those quantities of gas that are estimated, at a particular time, to be initially contained in known accumulations that have been penetrated by a wellbore. They comprise those quantities that are recoverable from known accumulations and those that will remain in known accumulations, based on known technology under specified conditions that are generally accepted as being a reasonable outlook for the future.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.005 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".