Experimental Investigation of Rock Dynamic Geomechanical Properties at Seismic Frequencies
Bibliographic record
Abstract
Time-lapse seismic reservoir monitoring has advanced quickly over the past decade to become a common technique for monitoring subsurface processes, especially for steam and CO2 injection. It has been widely used to determine and monitor changes occurring in a reservoir during hydrocarbon production or injection of water or gas into the reservoir. Petroleum engineers can predict the evolution of pressure and temperature and the saturation of oil, gas, and water during reservoir production with time-lapse seismic data. To understand the changes in seismic attributes during oil and gas production, researchers are challenged to combine rock physics models, geomechanics and laboratory measurements. Traditional laboratory measurement of reservoir rocks is conducted in the high kHz to MHz frequency range, which differs from seismic surveys (0.1-100Hz). Additionally, dynamic moduli determined from the elastic wave velocity and static moduli derived from the slope of a stress-strain curve from a deformational experiment are different for reservoir rocks due to the different strain measurement levels. Consequently, it is valuable to measure both dynamic and static elastic properties of rocks in the laboratory on core scale samples from seismic frequencies to ultrasonic frequencies. From this perspective, experimental research was undertaken to design reasonable and feasible experimental protocols that guide the infrastructure and process required to conduct seismic frequency dynamic property measurements under shear stress at elevated temperatures. A new experimental system within the Reservoir Geomechanical Research Group at the University of Alberta has the capacity to measure dynamic and static elastic properties at seismic and ultrasonic frequencies under deviatoric stress. This rock physics research is based on stress-strain method, and focus on the temperature, frequency (seismic – 0.01 Hz to 20 Hz) and most critically deformation (both isotropic compressibility and shear stress-induced) dependent properties of the poorly consolidated oil sands and highly overconsolidated (clay) shales associated with the McMurray and Clearwater Formations of NE Alberta. The results were shown that the frequencies within the reservoir are capable of significantly influencing reservoir properties. Acoustic impedance changes 59% at different effective pressures and up to 40% at different frequencies. An interpretation workflow based on the application of the newly gained understanding of frequency-dependent elastic properties was developed and validated by previous experimental studies. The newly acquired seismic frequency properties can then be applied in forwarding modelling using sequentially coupled reservoir geomechanical simulations to assess whether improvements in the a priori predictions of fluid saturations and steam chamber development are altered.
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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 | 0.001 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".