Monitoring of ground surface and subsurface deformations at oil sands using radar interferometry
Bibliographic record
Abstract
ABSTRACT Conventional monitoring methods, such as surveying and tiltmeter, require labor-intensive and time-consuming fieldwork, and they are limited to specific locations, either survey stations or an array of tiltmeters. Furthermore, none of the studies about the geomechanical inversion of cumulative surface deformations for the inference of subsurface volumetric changes in Canadian oil sands has yet been published. Radar interferometry has been widely used for monitoring surface deformations over a large area in all weather conditions with high accuracy. We have developed a method to detect surface deformations by radar interferometry techniques and to estimate subsurface volumetric changes by geomechanical inversion of surface deformation measurements. Differential interferometric synthetic aperture radar was implemented using first advanced land observation satellite phased array type L-band synthetic aperture radar data; the resulting interferograms indicated the vertical surface deformations between July 2007 and March 2011. An additional investigation into the detected surface deformations was performed to retrieve time-series maps of cumulative surface deformations, which accounted for the temporal evolution of the changes in surface elevation. The temporal analysis confirmed that the ground surface experienced nonlinear time-varying vertical deformations, reaching up to −33 and +72 cm for a 3.7 year time period starting in July 2007. The surface deformations were interpreted using cubic polynomial regression with historical information on fluid injection and withdrawal. The positive curvilinear relationships between the fluid volume changes, which were caused by steam injection and bitumen/water production, and the surface deformations, were found with an R2 of greater than 0.73. The fractional volumetric changes in the reservoir were examined by applying geomechanical inversion to surface deformation measurements. The fractional volumetric changes ranged from −1.8% to +3.9% with respect to the initial reservoir volume for the 3.7 year period. A positive linear relationship between fluid volume changes and subsurface volumetric changes was determined with R2 ranging from 0.515 to 0.992.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.000 | 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".