Imbibition Oil Recovery From Tight Rocks With Dual-Wettability Networks in the Montney
Bibliographic record
Abstract
This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 185076, “Imbibition Oil Recovery From Tight Rocks With Dual-Wettability Pore Networks: A Montney Case Study,” by Ali Javaheri and Hassan Dehghanpour, SPE, University of Alberta, and James Wood, SPE, Encana, prepared for the 2017 SPE Canada Unconventional Resources Conference, Calgary, 15–16 February. The paper has not been peer reviewed. Previous studies demonstrate that Montney rock samples present a dual-wettability pore network. Recovery of the oil retained in the small hydrophobic pores is uniquely challenging. In this study, the authors applied dual-core-imbibition (DCI) methods on several Montney core plugs and introduced the imbibition-recovery (IR) trio to investigate the recovery mechanisms in rocks with dual-wettability pore networks. Introduction Spontaneous imbibition of aqueous phases (water, brine, or surfactant solutions) in fractured sandstone has been studied as a possible mechanism for enhanced oil recovery. Extensive experimental and mathematical investigations have been conducted for relating the imbibition rate and total oil recovery to the capillary and gravity forces and geometrical parameters. However, rock/fluid interactions in tight and shale reservoirs are more complicated than those seen in conventional reservoirs. In addition to capillary forces, organic materials and reactive clay minerals can influence the fluid flow and storage in the small pores of low-permeability rocks. The affinity of reservoir rock to a particular fluid in such formations depends especially on rock mineralogy and properties of the organic matter that coats and fills the pores. Previous comparative imbibition tests show that the affinity of the Montney samples to oil is significantly higher than their affinity to water. This behavior was explained by the presence of water-repellent pores within or coated by solid bitumen or pyrobitumen. In the complete paper, the authors focus on imbibition oil recovery of samples cored from the Montney Formation and investigate the role of rock-fabric complexities, such as dual-wettability characteristics, in oil recovery by water imbibition. A detailed discussion of materials used in the spontaneous-imbibition and oil-recovery tests, including rock and fluid properties, is included in the complete paper. Methodology The authors conducted three sets of comparative tests on five twin core plugs, which were dry cut from Montney cores. The samples are characterized by measuring mineral concentration, total-organic-carbon (TOC) content, porosity, and permeability. The methodology is fully described in the complete paper.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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".