Viscous Fluid Injections in an Inclined Closed-End Pipe With Applications in the Dump Bailing Method
Bibliographic record
Abstract
Abstract The final life stage of a hydrocarbon well is the plug and abandonment (P&A) which aims to prevent the leakage and migration of reservoir fluids towards the upper levels and atmosphere. The P&A operations consist of cement plug placement in the wellbores at the target area. As P&A operations costs constitute a significant proportion of the total decommissioning expenses, precise planning and execution are always required, since a failed P&A job often requires costly and complex remedial operations, and can potentially result in significant environmental costs and financial loss. To fulfill these requirements and reduce the failure risks, the cement plug placement should be run with minimum mixing with the wellbore fluid. The cement slurry is placed in the wellbore using several techniques, among which the dump bailing method is a common and rigless one. In this technique, a relatively small volume of cement slurry is injected into wellbore filled with another fluid held on a bridge plug to remove the in-place fluid. The cement slurry behaves as a high viscosity fluid while the in-place wellbore fluid is mostly water. Motivated by this technique, in this study, the high viscosity fluid injection into an inclined closed-end pipe (representative of well casing) filled with water is studied experimentally. The involved fluids are miscible with constant density difference. The effects of the aspect ratio on the dynamics of high viscosity fluid injection, the fluids mixing, and the quality of the placement flow are analyzed. The results show that the separation of the heavy fluid front from the bulk of the fluid may occur for the larger aspect ratios, while tilting the flow domain towards the vertical direction and increasing the velocity and viscosity of the heavy fluid induce the front separation. Also, for small aspect ratios, the average front velocity increases by the injection velocity while it remains constant approximately in larger aspect ratios. The outcomes of this study can be eventually employed for improving the cement plug placement in the dump bailing method during the P&A of the oil and gas wells.
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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".