The longitudinal modulus of bitumen: Pressure and temperature dependencies
Bibliographic record
Abstract
ABSTRACT Bitumen retains significant solid-like behavior even in temperatures in excess of 50°C. Traditional ultrasonic wave-propagation studies have, however, largely ignored the existence of the shear modulus in such materials, and they have mostly assumed that the observed longitudinal (P) wave speeds solely depend on the fluid’s bulk modulus. To further study this, we have measured ultrasonic longitudinal (P) wave transmission speeds through viscous bitumen at different pressures (0.1–15 MPa) and temperatures (7–132°C) using an adapted version of the technique that consists of two piezoelectric receivers placed at unequal lengths from the transmitter. As such, we are able to calculate the P-wave attenuation and velocity that is used to derive the material’s complex longitudinal modulus. Using parallel measurements of the bitumen’s complex shear modulus, we find that the bulk modulus differs from the longitudinal modulus particularly at lower (reservoirs) temperatures. The results, together with the realization that bitumen experiences a sequence of various compositional and thermophysical phase that is primarily temperature-dependent, can be implemented to improve the fluid-substitution analyses of rock-physics studies of bitumen-saturated reservoirs.
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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".