Feasibility Analysis of Early Gas Monitoring at the Bottom of Marine Riser in Deepwater Drilling
Bibliographic record
Abstract
ABSTRACT Gas influx is a phenomenon which causes serious outcome, and consequently the early and accurate detection of gas influx is crucial for deepwater drilling operation security. The detection method outside marine riser (DMOMR) is widely utilized in deepwater drilling as a complement of the traditional wellhead detection method (WDM). In this study, an extended two-fluid model (TFM) is developed to describe the gas-liquid two-phase flow when gas influx occurs and to compare the advantages of the DMOMR and the WDM in marine riser. By comparing the simulation results with the measured data of a well in the Bohai Sea, China, it is demonstrated that this model provides an excellent description for the gas-liquid two-phase flow in marine riser. The tip gas position, overflow and detection time are predicted using this model, and parameters such as water depth, wellbore depth, and formation permeability and equivalent density are controlled to vary respectively. The comparisons present that the DMOMR can detect gas influx in advance than the WDM under most conditions, and the lead time of the DMOMR increases by the increasing water depth and reducing wellbore depth. Moreover, the simulation results agree that the DMOMR has a great advantage in low or medium permeability (< 300 mD) formation and lower pressure formation. With the increase of formation permeability and formation equivalent density, the advantage of the DMOMR weakens compared with the WDM.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| 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".