Evaluation of a Casing Drilling Connection Subjected to Fatigue and Combined Load Testing
Bibliographic record
Abstract
Abstract The initial requirements for casing drilling connections included fatigue resistance, high torque capacity, and economics. As casing drilling becomes more prevalent, the wells become more critical. These wells exhibit increasing depth, higher down-hole pressure, more load cycles and elevated temperature. The performance of connectors under these conditions must be verified. Fatigue life, pressure containment and combined axial and pressure capacity are of particular interest. To accomplish this, various tests are required.3 Included are:Fatigue testing to target cycles followed by high pressure capped end test.Fatigue testing to failure.Combined load testing.Fatigue testing to target cycles followed by ISO 13679 combined load test. This paper will detail the results to date of such a program. Current status of the 4 phases mentioned above included completion of Phase 1, partial completion of Phase 2, and a rehearsal sample for Phase 4. Significant conclusions from this effort thus far include:API modified thread compound out performedan anaerobic thread compounds.Teflon seal rings exhibited superior pressure containing performance compared to thread compounds.Static capacity can be affected by dynamic loading.Seal systems, both thread compound and seal rings, may exhibit cyclical failure before mechanical failure.SN data for 9 5/8 inch, .545-inch wall, 53.50 lb/ft, P- 110 exhibits sufficient fatigue life to drill wells under current conditions.ISO Configuration 1 resulted in the poorest fatigue performance thus far. Introduction The objective of this project has four distinct goals. The first was design selection. The design selection phase considered three designs:DWC/C connector using API Modified thread compound.DWC/C connector using Anaerobic thread Compound.DWC/C-SR connector using a Teflon Seal Ring (SR) and API Modified thread compound. The preferred design was filtered out through harmonic fatigue testing of connectors machined to nominal tolerances, with subsequent capped end testing. The designs were also ranked and a second best performer or secondary design was determined. The second goal was to generate an SN curve for the preferred design and compare it to a limited number of samples of the second best design. This was accomplished through harmonic fatigue testing of the preferred design with limited comparison to the secondary design. The third goal was to determine the static capacity of the preferred design. This will be accomplished through combined load testing per ISO 13679. The final goal was to determine if the static capacity of the connectors was affected by dynamic loading. This will be accomplished by fatigue testing to a percentage of the connectors expected life, followed by subsequent combinedload testing to ISO 13679. Statement of Theory and Definitions The designs were compared by fatigue testing with internal pressure to targeted cycles below failure with subsequent high-pressure hydrostatic test. Those that attained more cycles while maintaining their pressure integrity determined the preferred designs.
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".