Research on a Model of Nonlinear Coupled-Vibration of Directional Well Drill String
Bibliographic record
Abstract
Drill string vibrations are inevitable movement patterns during drilling process, the drill string vibrations form including longitudinal, lateral and torsional are recognized by most scholars. In the actual drilling process, the coupled vibration exhibits nonlinear features due to the impact of the eccentric rotation of the drill string and the influence of drilling fliud. Taking the whole drill string of directional well as the research object, a three-direction of longitudinal, transverse and torsional nonlinear coupled vibration model of drill string is established based on the nonlinear coupled deformations analysis in the longitudinal, transverse and torsional directions by using finite element analysis method. The nonlinear coupled vibration of drill string is studied by considering the effects of viscous forces of drilling fluid during the drilling process. The results show that the drill string resonance interval is relatively concentrated and the nonlinear coupled vibration frequency increase with the decrease of the length of the drill string.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".