Wired BHA Applications in Underbalanced Coiled Tubing Drilling
Bibliographic record
Abstract
Abstract Underbalanced directional drilling with coiled tubing is emerging as an instrumental technique for accessing new and bypassed reserves while enhancing overall reservoir recovery since, unlike jointed-pipe operations, circulation does not have to be interrupted every 30 feet to make connections. Coiled tubing drilling (CTD) thus offers the potential to achieve genuine steady state underbalanced conditions resulting in the elimination of formation damage, lost circulation and differential sticking. One of the enabling technologies assisting the growth of underbalanced directional CTD is the wireline-steerable bottom hole assembly (BHA). In contrast to conventional mud pulse telemetry systems, these purpose-built wired BHAs have been designed to accommodate efficient, continuously underbalanced drilling operations while also providing an opportunity for reservoir evaluation while drilling. The paper details the operational results for several underbalanced and low-head CTD projects involving an integrated wireline-steerable BHA. The most recent wells were completed in the North Sea, Canada and United States in 1999. Topics discussed include equipment performance, nitrified fluids, wellbore stability, well results and learning points. An analysis of time-based underbalanced CTD data is also presented.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".