Optimization of Metal-on-Metal Lubricants for Coil Tubing Applications
Bibliographic record
Abstract
Abstract The development of horizontal well completion techniques has untapped a massive amount of hydrocarbon resources previously economically unreachable. Extended-reach horizontal well designs are now the rule rather than the exception and introduce a myriad of new challenges associated with downhole operations. Numerous mechanical approaches have been implemented to overcome deleterious frictional forces intrinsic to extended reach Coil Tubing (CT) interventions; cutting edge mechanical techniques rely on devices such as downhole tractors and fluid hammer tools to avoid helical buckling, and eventual CT lock-up. The most daunting factor associated with the application of these tools is the cost which is especially important in the current energy resource industry downturn. Drag-reducing agents (DRA) appear to be the common denominator in extended reach CT interventions. To date, synergistically paired metal-filming lubricants and fluid friction reducers provide a cost-effective method to enhance weight on bit (WOB) required while running in and/or pulling out of hole (RIH/POOH) CT strings. Given the dynamic nature of CT operations, carrier fluids experience extreme conditions changes (temperature, pressure and/or physicochemical), during their tubular residency time. The change in environmental conditions can result in poor dispersibility of DRA's, and therefore, render them ineffective through a lack of contact with the metal. Herein, this paper presents details of a thorough tribology and rheological analysis of commercially available DRA's in different oil field brines, and the corresponding field case studies evaluating data reproducibility. Lab testing data includes 4 ball (ASTM D4172A) testing as well as Reichert friction and wear analysis test results. The OFITE EP (extreme pressure) lubricity tester type equipment, which was originally conceived to reproduce coefficients of friction (COF) for drill string/mud simulations, has been historically included in metal-on-metal (MOM) lubricant analysis. A rapid method was implemented involving a sled and plate COF type tester. Normally used for measuring the friction between two dry surfaces, it was adapted for measuring COF of MOM lubricants currently in use during CT operations in the Western Canadian Sedimentary Basin (WCSB). Lubricity testing on the top MOM lubricant performers showed a COF reduction in the range of 11 −28%, when 150 mm/min sled speed was tested. Also, through the rheological and qualitative analysis of the carrier fluid, dispersibility appears to be improved with the addition of the fluid friction reducer. In addition to the sled-plate COF testing analysis and field case data validation, this study will include an oscillatory shear rheological analysis of the carrier fluid, by using the Haake RheoStress®6000. This will help us to understand the viscoelastic behavior and its relationship with MOM dispersibility.
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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".