Correlation Between Resistivity and Petrophysical Parameters of a Carbonate Rock During Two-Phase Flow Displacements
Bibliographic record
Abstract
ABSTRACT In formation evaluation and reservoir engineering, resistivity index, relative permeability, and capillary pressure are crucial parameters for estimating oil reserves and planning a production scenario. They can be determined in the laboratory using Special Core Analysis, or SCAL techniques. Since they are all functions of fluid saturation, correlations between them may exist; but the literature on their inter-relationships is lacking. In this paper, experimental relative permeabilities and relative permeabilities obtained from resistivity measurements using Li’s model (2007) are compared for different immiscible brine-oil displacements. An experimental study on a water-wet grainstone rock was initiated in order to measure its resistivity response during different ambient water-oil flow displacements. Three different flooding techniques were performed and compared. The most popular technique is the resistivity porous plate Pc-RI method where resistivity and capillary pressure are measured at equilibrium. The steady-state flooding method was also tested; resistivity and steady-state relative permeability were measured at the equilibrium state. Finally the fastest yet least reliable method is the transient technique or unsteady-state flooding method where resistivity and unsteady-state relative permeability are measured under transient conditions. A comparison between resistivity index obtained from the three flooding techniques showed that the unsteady-state technique cannot give reliable resistivity index curve, and so should be avoided to infer Kr from resistivity measurements. The Pc-RI method provides the most reliable resistivity index curve but relative permeability can only be derived from the capillary pressure curve. Finally, the steady-state displacement was found to be the best method to compare experimental relative permeability with relative permeability inferred from resistivity. In spite of an acceptable match between them, an improvemnent of Li’s model is proposed. Additional investigations such as effects of wettability and rock heterogeneities on these results will be necessary to validate the generality of the overall workflow.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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 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".