An Environmentally-Friendly Process for Improved Recovery From Light Oil Reservoirs
Bibliographic record
Abstract
Abstract The injection of flue gas is a promising cost-effective process for improving recovery from light oil reservoirs. The flue gas could be obtained directly from power plants or other surface sources. It could also be indirectly generated in situ from the spontaneous ignition of oil when air is injected into a high temperature, high pressure (light oil) reservoir. When operating at high pressures commonly found in deep light oil reservoirs, the flue gas may become miscible with the oil, thereby displacing it more efficiently. The efficiency of oil recovery during flue gas injection in light oil reservoirs was studied by flue gas displacements of light oil in a 2.44-m long Berea sandstone core at pressures up to 41.58 MPa and temperature of 116 °C in the laboratory. The laboratory results were history-matched using a compositional simulator. This study attempts to understand and explain the success achieved in field high pressure air injection projects in light oil reservoirs. The high oil recovery obtained from this study suggests that flue gas injection is a promising process for enhanced oil recovery from light oil reservoirs. The results show that the level of oil recovery was accompanied by the level of approach to miscibility between the flue gas and the oil. Both were found to increase with an increase in reservoir pressure, as well as an increase in the carbon dioxide content of the flue gas. When injected from a surface source, the sequestration of the carbon dioxide component of the flue gas (a greenhouse gas) makes the flue gas injection process an environmentally- friendly process. Introduction The solvent extraction and/or miscible-type processes are among the dominant enhanced oil recovery (EOR) methods in Canada(1). These processes include the injection of nitrogen, flue gas, carbon dioxide, hydrocarbon-miscible methods, and solvent extraction of mined, oil-bearing ores(2). They have the potential to add 300 to 400 million cubic metres (~50%) to Canada's remaining recoverable oil reserves(3) and multiples of this to the world's recoverable reserves. Other than compressed air, nitrogen and flue gas are the cheapest gases available(4). The potential for cost-effective oil recovery by flue gas injection from currently producing light oil reservoirs as well as depleted and mature waterflooded reservoirs is most important, especially for reservoirs with little or no water production and those with low porosity and low permeability(5–8) where water injection is not feasible. In recent studies carried out by the authors in a slim-tube apparatus(9–11), flue gas has been found to displace oil by mass transfer of intermediate components of the oil into the injected flue gas, and subsequent condensation of the higher molecular weight intermediates back into the liquid phase from the enriched gas phase through a multi-contact combined vapourizing-condensing gas drive mechanism(12). Although the flue gas may never displace the light oil in a truly miscible fashion because of this mechanism, the oil recovery in such a process is significant enough to make it cost-effective(10).
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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 | 0.000 | 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) | 0.001 | 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".