Successful Implementation of Continuous Circulation Technology in Exploratory Drilling in Ultra-Deepwater Offshore Nova Scotia
Bibliographic record
Abstract
Abstract During the second half of 2018, an operator faced significant downhole issues during exploration drilling on a semisubmersible rig in ultra-deepwater Nova Scotia. While these challenges would have made this well a candidate for the use of traditional surface backpressure managed pressure drilling (MPD) technology, the predrill forecast did not indicate the need for MPD, and during execution, it was not practical to install MPD because of the required time and detailed engineering to retrofit the rig. During the original attempt to drill this well, the operator was forced to abandon the 12 1/4- × 14 1/2-in. hole section after mud losses, followed by wellbore breathing and associated gas events from the mud flowback. The well was undrillable with conventional methods, and the wellbore was plugged back and sidetracked. On the sidetrack, continuous circulation technology was implemented to help maintain a more constant bottomhole pressure, navigate the narrow drilling margin between pore pressure and fracture gradient, and help prevent wellbore breathing and associated gas on connections. The planning and execution of this technology that allowed the operator to successfully drill through previously difficult targets are discussed, along with lessons learned for future wells. Overall, more than 30 connections were performed, with an average of 600-gal/min connection flow rate with synthetic oil-based mud over the two hole sections.
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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".