Sandstone wettability in supercritical CO2-brine-rock interactions evaluated with 13C and 1H magnetic resonance
Bibliographic record
Abstract
• 13 C and 1 H MR methods were employed for the first time to evaluate sc-CO 2 , brine, and sandstone under reservoir conditions. • A novel variable field superconducting MR and MRI instrument was employed to undertake sequential 1 H and 13 C measurements. • 13 C and 1 H relaxation times indicate Berea remained strongly water-wet when it was exposed to sc-CO 2 under field conditions. • The amounts of CO 2 and brine in the core plug were quantified from the MR signal intensities of 13 CO 2 and brine. During the first decades of geologic CO 2 storage in saline formations and depleted reservoirs, structural trapping is the most important storage mechanism. The effectiveness of CO 2 containment hinges on the assumption that the sealing formation remains water wet in the presence of dense CO 2 . In this work, multiple 13 C and 1 H magnetic resonance (MR) methodologies were employed for the first time to evaluate the interactions between supercritical CO 2 , brine, and the pore surface of a Berea sandstone core plug under reservoir conditions. These studies employed a novel variable field superconducting MR and magnetic resonance imaging (MRI) instrument which permitted sequential 1 H and 13 C measurements of core plugs at high-pressure and high-temperature. To systematically study the wettability of rock core exposed to supercritical CO 2 , four experiments were designed including bulk CO 2 in a high-pressure vessel, bulk CO 2 -brine, 13 CO 2 in dried rock core, and a 13 CO 2 -brine-rock experiment. The measured 13 C and 1 H MR relaxation times in this work indicate that the Berea sandstone remained strongly water-wet when the brine saturated core plug was exposed to supercritical CO 2 under reservoir conditions. For both 13 C and 1 H, T 1 relaxation times provide more reliable wettability evaluation as compared to T 2 due to the impact of molecular diffusion through internal magnetic field gradients. One-dimensional (1D) MRI was employed to spatially resolve 13 CO 2 and brine in the core plug. Two-dimensional (2D) MRI was able to image 13 CO 2 and brine in a PEEK vessel. The quantities of CO 2 and brine in the core plug were determined from the MR signal intensities of 13 CO 2 and brine.
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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 | 0.001 |
| 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".