Bibliographic record
Abstract
Abstract Abnormal water level fluctuations in Quaternary aquifers have been evident since early 1994 in parts of the Cold Lake Field undergoing Cyclic Steam Stimulation in the Clearwater. In other areas, no responses to steaming operations have been observed. Recent high resolution seismic of the Quaternary has demonstrated a complicated geology, with ice thrusting events leading to isolation of parts of the aquifers into small pockets. Coupling this geological observation with poro-elastic modelling of the effects of Clearwater dilation caused by steaming and subsequent recompaction by production has led to an explanation of the observed water level fluctuations. The mechanism causing water level rises is compression of a pocket of aquifer sand, due to Clearwater dilation as a result of steam injection. For aquifer pockets directly over the steam injection location, aquifer dilation, rather than compression, results from the Clearwater dilation, causing water levels to fall. Aquifer sands that are extensive allow pressure equilibration and no apparent water level changes due to nearby Clearwater dilation. Net injection to the Clearwater appears to be a significant correlative indicator of Clearwater dilation, but sensitivity of the aquifer water level change to net injection decreases with successive steam cycles. First principle numerical simulations coupling fluid flow and formation stress-strain behaviour support the relationships developed. Introduction At Cold Lake, Cretaceous age sands of the Clearwater formation located at a depth of 450 m contain bitumen that Imperial Oil Resources has been producing using Cyclic Steam Stimulation(1). These sands are overlain(2) by about 100 m of the Grand Rapids formation, a fluvial interbedded sand-shale sequence, which in turn is capped by the Colorado Shale Group. These marine shales vary in thickness from 150 - 200 m. Quaternary deposits containing fresh water aquifer sands overlie the Colorado Shales. Andriashek et al. have described the general stratigraphic framework for these deposits(3). It is important to know that bitumen recovery operations have not contaminated the aquifers with produced fluids. Therefore, there is an investigation whenever water levels in any aquifer well are observed to behave in an unexpected manner. Imperial monitors an array of regional groundwater wells. Recent expansion of the operations, into areas closer to some of these wells, has led to unexpected fluid level fluctuations. At the time of occurrence of these fluctuations, extensive inspections of operating CSS wells were undertaken to ensure there were no casing failures, or leaks of produced fluids from wellbores into Quaternary aquifers. Correlation of the water level fluctuations to Clearwater reservoir pressures, as steaming operations moved from one group of wells to another, suggested that highly improbable intermittent sequences of fluid transfers would be required to explain the fluctuations. Any such fluid transfer would have to be via some undetected pathway through 250 - 300 m of overlying sediments. Water chemistry evaluations at an aquifer well near steaming wells confirmed the absence of produced water. An explanation for the anomalous water level fluctuations in terms of stress transfer from the Clearwater to the overlying Quaternary was developed based on concepts from the theory of poroelasticity.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".