Buoyancy effects on turbulent displacement of viscoplastic fluids from strongly eccentric horizontal annuli
Bibliographic record
Abstract
We present an experimental and numerical study of the turbulent displacement of viscoplastic fluids in a horizontal eccentric annulus. Several experiments where a weighted Newtonian fluid displaces a yield stress fluid under a turbulent flow condition are presented and discussed. These are also used to validate the turbulent displacement model that we use in this study. The model simulator is used to study the mechanisms by which buoyancy influences turbulent displacement in more detail and outside of the range of our experiments. Extreme cases where the generated wall shear stress of the displacing fluid is smaller than the yield stress of the displaced Carbopol are investigated. The results show that buoyancy is ineffective in countering the tendency of the fluid to disperse along the wide gap of the annulus. In both model and experiment, the outcome of the displacement appears to be controlled by the yield stress of the in situ fluid and the eccentricity of the annulus. For fully turbulent flows, the viscosity of the displaced fluid has a negligible effect, and having also negated buoyancy, there appears to be no mechanism to stabilize the turbulent displacement of a yield stress fluid in a severely eccentric horizontal annulus. For the underlying industrial process, this means that extreme caution should be used in designing turbulent flow displacements for horizontal wells. There are two solutions: (i) increase the flow rate to generate sufficient stresses (usually not possible due to pump and formation fracture pressure limits) and (ii) ensure a better centralized annulus (unpopular because of operational constraints).
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".