Lateral Vibration Characteristics Analysis and Vibration Mode Study of Drill String in Deep Horizontal Well
Bibliographic record
Abstract
Abstract This study examines lateral drill string vibrations under factors including preload torque, rotational inertia, and fluid density. Theoretical models analyze dynamic characteristics, vibration frequencies, and critical loads (Tcr), with experimental validation. Key findings reveal drill string length, drilling fluid density, and external loads critically influence lateral vibration frequencies. When string length is below 1500 m, vibration frequencies decrease sharply, with a marked reduction in decay rate beyond this threshold. Increased fluid density further reduces frequencies. Boundary condition variations alter load-bearing capacity and induce mode transitions between stable sinusoidal buckling and helical buckling. Analyses of transverse displacements, phase diagrams, and Poincare maps demonstrate system instability near critical loads (T ≈ Tcr), where steady-states transition to severe sinusoidal buckling vibrations. At T > Tcr, lateral vibrations exhibit 0.5 s periodic behavior, evolving from sinusoidal to helical buckling with quasi-periodic chaotic features. Phase diagrams reveal periodic convergence, annular motion regions, and attractors, indicating multiperiodic bifurcations between stability and chaos. Notably, the transition from nonperiodic to quasi-periodic motion highlights the system's sensitivity to load thresholds. These results provide insights into vibration mitigation strategies by clarifying relationships between operational parameters (length, fluid density, torque) and dynamic responses. The identified buckling phase transitions and chaotic patterns enhance predictive capabilities for drill string failure prevention under complex downhole conditions.
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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) | 0.000 | 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".