Evaluation of Oil Recovery Performances of Surfactants Using Organic Conception Diagrams
Bibliographic record
Abstract
Abstract Capillary imbibition experiments conducted on sandstone, chalk, and limestone samples using different oils (crude and processed with different viscosities) and different surfactant solutions were evaluated for surfactant screening. In this evaluation, IFT, surfactant type, and concentration were considered. In addition to these, a new technique has been adopted to facilitate the surfactant screening process. This technique is based on assigning inorganic and organic property values and plotting Organic Conception Diagrams (OCD) for surfactants. OCD defines the property of a compound in terms of physical chemistry in such a way that the property that depends to a large extent on Van der Waals force is called "organic" and the one that depends greatly on electric affinity is called "inorganic." By using the OCD, hydrophilic and lipophilic characters of surfactants have been established to evaluate their potential to minimize oil/water interfacial tension. Introduction Using surfactant solutions as a displacement fluid to recover matrix oil in naturally fractured reservoirs (NFR) has gained a great deal of attention in recent years. Capillary imbibition recovery can be enhanced by the addition of surfactant into water to reduce the IFT(1). Typically an increase in the ultimate recovery with lowered IFT was observed for sandstones(2, 3). The imbibition rate also changes with reduced IFT . Due to the less water-wet character of carbonates, in many cases, very low imbibition recovery was obtained with brine(4). Reduction of IFT by the addition of surfactant yielded a significant increase in recovery due to enhanced capillary imbibition and additional contribution due to gravity effect(3–4). More attention was devoted to chalky carbonates as they are found to be more responsive to low-IFT capillary imbibition recovery compared to the dolomitic carbonates(5–7). It was observed that the response to the surfactant capillary imbibition recovery could be very different depending on the rock type and fluid properties even if the same surfactant type and concentration are used. For example, sandstones yielded initially faster recovery with high IFT solution (typically brine with no surfactant addition) but ultimate recovery becomes higher with decreasing IFT(1, 4). Carbonates, however, behaved in a different manner. It was previously reported that both the recovery rate and ultimate recovery increased with decreasing IFT for dolomitic limestone(3,4). Experiments on chalk samples showed that the type of surfactant plays a critical role on the ultimate recovery as well as the recovery rate(7–9). In this paper, we present an analysis to correlate the capillary (spontaneous) imbibition recovery performance of surfactant solutions to surfactant, rock, and fluid properties. We also introduced a newly adopted technique known as Organic Conception Diagrams (OCD). Experiments In this study, experimental results obtained from different Studies(3, 4, 7, 9–12) were used. In addition, seven experiments were conducted on chalk samples using 17 cp oil at 20 °C. Four different surfactants were selected as a representative of non-ionic, anionic, and cationic types. Spontaneous imbibition experiments were conducted on 100% oil saturated cylindrical rock samples with all sides open to flow.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".