Evaluating Polyacrylamide-Cr (III) Gel Performance for Conformance Control in Carbonate Porous Medium
Bibliographic record
Abstract
Abstract Application of different gel systems for reducing the production of unwanted water, and therefore improving the oil recovery, from mature oil reservoirs has been studied extensively. The main target for gel placement is to reduce channeling through fractures or high-permeability zones, while redirecting flow to less permeable unswept regions of reservoir. It is a common fact that many water based gels feature a disproportionate permeability reduction (DPR) effect, resulting in significantly higher reduction in permeability to water compared to that of oil. This phenomenon has been widely investigated by many researchers through observing gel behavior under conditions of injecting water and oil separately. However, these experiments do not represent a realistic reflection of the actual reservoir conditions where gel is subjected to multiple phase flow conditions during production, where both water and oil flow through the gelled media simultaneously. Thus, the main objective of this study was to evaluate gel performance during simultaneous injection of brine and oil. This research represents further studying of Alcoflood-935-Chromium(III)-Chloride (AF-935-Cr(III)-Cl) gel in crushed carbonate rock. The effect of residual oil saturation (Sor) on gel behavior was investigated by conducting experiments with and without presence of Sor prior to gel placement. Moreover, the study of gel behavior under two phase flow may provide a better understanding of the mechanisms causing DPR in carbonate porous medium. The results obtained during this study demonstrated efficiency of the application of this type of gel for reducing the permeability to water effectively. These results indicated the presence of DPR effect during both multiphase flow and subsequent alternative injection of individual oil and water. However, there were some concerns raised about AF-935- Cr(III)-Cl applicability for water shut-off treatments in carbonate porous medium. This is due to the chemical nature of the crosslinker and buffering action of the reservoir rock that induces in-situ chromium precipitation. Introduction Excessive water production is a major problem for many oil companies operating in mature oil reservoirs. In these fields, controlling water is a main challenge as produced water impacts the economic profitability of the oil production operations. There are many methods available to reduce excess water production, such as conformance control techniques that are considered of having high chance of success. Conformance control describes any technique that encourages the drive mechanism to mobilize rather than avoid unswept hydrocarbon zones (5), where application of chemical based treatments including polymers and gels are among the most widely used. Crosslinked polymeric gel systems have been extensively used for water shut-off treatments to reduce water channeling through fractures and highly permeable zones. The main objective of gel placement is to diminish water production without significantly damaging oil productivity, leading to improved overall hydrocarbon recovery. The most important criteria for gel placement is ensuring maximum gel penetration into high permeability, watered-out zones, while minimizing gel penetration into oil-bearing regions(1). Gel application is considered as an aggressive type of conformance control as it can block certain zones of porous medium(6) completely. Gel placement can be applied to both injection and production wells (3). Among the advantages of gel application is their flexibility for pumping without a work-over rig, high control of setting time, a deeper penetration into the form
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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 | 0.001 | 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".