Performance of Polyacrylamide-Chromium (III) Gel in Carbonate Porous Media: Effect of Source of Crosslinker on Disproportionate Permeability Reduction and Gel Strength
Bibliographic record
Abstract
Abstract Different gel systems have been extensively used to reduce unwanted water production and improve overall hydrocarbon productivity in many reservoirs. The main target for gel placement is to reduce channeling through fractures or highpermeability zones, while redirecting flow to less permeable unswept zones(1). It is a common fact that many water based gels feature 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 in sandstone porous media; however there is a lack of information available on gel performance in carbonate porous media. The main objective of this study is to verify the presence and extent of DPR effect when placing gels in carbonate porous medium. High molecular weight polyacrylamide and two crosslinkers, chromium(III)-acetate and chromium(III)-chloride, were used as main components of gel system. A series of brine and oil injections were performed to examine performance of gel, its stability and its contribution to DPR in carbonate porous medium. The effect of residual oil saturation was also studied by conducting experiments with and without residual oil present prior to gel placement. Gel stability study was carried out by subjecting gel to different pressure gradients under applied range of flow rates. The obtained results clearly indicate effectiveness of water based gel application to significantly reduce permeability to water in carbonate rock, as well as verifying DPR phenomenon in carbonate porous medium. Introduction Excessive water production turns into a major problem for oilfield industry when hydrocarbon fields become mature. Controlling water becomes a main objective as produced water significantly impacts economic profitability of the reservoir. There are many methods available to reduce water production problems, and conformance control methods are considered by far the most successful. Conformance control describes any technique that encourages the drive mechanism to mobilize rather than avoid unswept hydrocarbon zones (5). 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 shutoff treatments to reduce water channeling through fractures and highly permeable zones. The main objective of the gel placement is to diminish water production without significantly damaging oil productivity, leading to improved overall hydrocarbon recovery. The most important target for gel placement is to ensure maximum gel penetration to high permeability, watered-out zones while minimize gel penetration to oil-bearing zones (1). Gel application is considered one of the most aggressive types of conformance control as it can totally block certain zones of porous medium(6). Gels 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 formation, ease of cleaning, lack of milling time, and an easy removal from the wellbore by water recirculation(4). The most widely used gel system, used in the past years, has been based on chromium(III) crosslinker. ChromiumIII) crosslinked with polyacrylamide gels considered to be good choice materials to selectively restrict a flow to the water phase.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 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".