Immiscible Exchange Flows in Near-Horizontal Rotating Pipes With Applications in Well Cementing
Bibliographic record
Abstract
Abstract Primary and remedial cementing are critical in well construction to ensure zonal isolation and structural support. In horizontal or tilted wellbores, gravity-driven exchange flows, caused by density differences between drilling mud and cement slurry, can occur and result in stratified layers, weak spots, or voids, compromising cement quality. These challenges intensify during complex procedures such as rotating-while-cementing or operational pauses, where fluid redistribution occurs. Our study numerically examines immiscible exchange flows in near-horizontal pipes with axial rotation, modeling rotating-while-cementing conditions. A heavier displacing fluid occupies the upper pipe section, while a lighter fluid fills the lower section, creating a density-unstable configuration. Simulations assess the effects of rotational speed, density differences, and pipe inclination. Our results reveal predominantly counter-current stratified flows, with increased rotational speed amplifying interfacial instabilities and kinking waves but reducing displacing fluid frontal velocity. Conversely, greater density differences and inclinations away from horizontal affect exchange flows by increasing interfacial frontal velocities.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".