Novel Push-Pull Displacement Method to Determine Relative Permeability Hysteresis in Heavy Oil Reservoirs
Bibliographic record
Abstract
Abstract For heavy oil reservoirs it has been a very difficult task to determine relative permeability curves using reservoir fluids. In the steady-state method, saturation is quite insensitive to variation of fractional flow of phases due to the severe mobility contrast between the injected phase and the displaced phase. The Displacement method works fine for the imbibition process where high-mobility water displaces low-mobility heavy oil; however, it does not work for the drainage process where the displacement is almost piston-like, hence the information on fractional flow obtained is limited to a very narrow high oil saturation range and is not useful. The new method consists of two test stages. First, to determine the imbibition relative permeability using the displacement method. Second, to undertake a push-pull displacement test to determine the drainage relative permeability. The first portion of the push-pull test is a repetition of the imbibition test to the point of breakthrough. Having known the imbibition relative permeability, one can determine the saturation profile in the sample core at the end of the imbibition process. At the expected breakthrough point, the flow is reversed by oil injection from the original producing end of the core. The well-distributed saturation profile at the start of the drainage process provides information on the fractional flow in a wide range of saturation. History of production of water and oil from the original injection end and pressure drop across the core determines the drainage relative permeability. The method was applied to preserved cores from the Clear Water formation of the Cold Lake oil-sand reservoir as well as to silica-sand packs. The tests were performed using cleaned Cold-Lake bitumen and simulated formation brine at a temperature range from 100 C to 180 C which represent stages in the cyclic steam stimulation process in Cold Lake. The test results exhibited little evidence of relative permeability hysteresis.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".