Drilling Fluids Rheological and Volumetric Characterization Under Downhole Conditions
Bibliographic record
Abstract
Abstract Accurate estimation of equivalent circulating density (ECD) and circulating bottom hole pressure (CBHP) are essential components of successful managed pressure drilling operations. Normally, calculated frictional pressure losses do not match actual frictional losses recorded during drilling operations. Discrepancies between calculated and measured pressure losses are more severe in operations where synthetic based drilling fluids are used because synthetic based drilling fluid rheologies vary with changes in downhole conditions. In order to deal with differences between actual and theoretical pressure losses, rheological and volumetric characterization of the fluid under downhole conditions was performed. N-paraffin-based drilling fluid (NPDF) was used in this study. Effects of pressure and temperature under HPHT conditions were determined using a mercury-free PVT cell. The volumetric behavior of the NPDF was compared with the behavior of water-based muds and less toxic mineral oil-based muds. An empirical relation for density as a function of pressure and temperature is introduced. In addition, rheological characterization of the NPDF was conducted using an HPHT rotational viscometer. The rheological model that defines the shear stress – shear rate relation of the drilling fluid used in this study at all pressure and temperature conditions is the Yield Power Law model. The effects of downhole conditions on the rheological parameters consistency index (K), flow behavior index (n) and yield stress (τo) are analyzed.
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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".