Experimental Study of Laminar Displacement Flows in Narrow Horizontal Eccentric Annuli
Bibliographic record
Abstract
Abstract Wells with poor cement jobs are prone to develop paths where the hydrocarbons might leak to the surface. Such events cause environmental risks and costly repairs. Even though horizontal wells have been drilled since the 1980s, studies on the dynamics of the fluid-fluid displacement under this configuration are scarce. In this work, we present experiments on the displacement of two Newtonian fluids in laminar regime in a horizontal uniform annulus. The minimum non-dimensional parameters required to describe the flow under such conditions include a buoyancy number (b), viscosity ratio (μ2/μ1) and eccentricity (e). We have designed and built a flow loop that mimics the annular displacement under controlled and dimensionlessly comparable conditions found in field. Within this apparatus we can set key process parameters: flow rate, eccentricity, fluid rheology and density. Data acquisition is through imaging with high sensitivity cameras and partially automated instrumentation. Preliminary results of the experiments show that there is a subtle balance between eccentricity and buoyancy. Sufficiently high values of |b| will end up in stratification of the fluids. The secondary flows created in an eccentric annulus compete against a positive buoyancy, driving the flow to the wide side (top) at moderate values of b. The effect of the viscosity ratio is most relevant at small values of b. The experimental data from this work can be compared against both mathematical model predictions and computational simulations used in the design of primary cementing jobs.
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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 | 0.000 | 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".