Buoyant Miscible Jets in the Plug and Abandonment of Oil and Gas Wells
Bibliographic record
Abstract
Abstract The plug and abandonment (P&A) operation is the final stage in the life cycle of oil and gas wells. The aims of the P&A operation are to seal the well and permanently maintain the well-integrity similar to that of the original natural caprock. Using this approach, it is possible to isolate fluids movement between different strata, to prevent environmental disasters. Generally, the main steps in the P&A operation are (i) accessing the annulus section of the well, (ii) cleaning the defected area, and (iii) placing the cement plug barriers into the target area. To prepare the target area and avoid cement plug contamination, a cleaning process is required inside and outside the casing. The jet cleaning process is one of the effective methods for the cleaning step, in which a liquid of a higher density is usually injected into the target area to displace a lighter ambient fluid. During the jet cleaning process, several forces affect the cleaning efficiency, including inertial, viscous and buoyancy forces. In this work, we analyze a fundamental component of the jet cleaning process in the P&A operation, via experimentally studying the characteristics of a miscible positively buoyant jet. In our work, a heavy fluid is injected downwards into a large rectangular tank filled with a light ambient fluid. Due to the large dimensions of the experimental tank, the wall effects on the flow are neglected, i.e. we consider a free jet. We investigate some of the parameters affecting the behaviour of our positively buoyant jets, such as the injection velocity, the nozzle diameter, and the ratio between the viscosity of the jet fluid to that of the ambient fluid. In the parameter ranges of our interest, the jet flow exhibits certain critical flow features, such as the laminar length (i.e. the initial stable part of the jet where the injection fluid remains laminar and does not mix with the ambient fluid) and the spread angle (i.e. the area occupied by the jet). Our results show that both the laminar length and the spread angle decrease by increasing the injection velocity. In addition, increasing the viscosity ratio results in increasing the maximum laminar length and decreasing the spread angle. These results can help to better design an efficient cleaning in the P&A operation of oil and gas wells.
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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".