Study of Alkaline/Polymer Flooding for Heavy Oil Recovery Using Channeled Sandpacks
Bibliographic record
Abstract
Abstract For heavy oils with viscosities ranging from 1,000 to 10,000 mPa·s (cP) in Western Canada, primary production and waterflood together can only recover 8 – 15 % original oil-in-place (OOIP) at their economic limit due to the adverse mobility ratio, severe water channeling and low reservoir pressure and formation voidage. These heavy oils usually have a relatively high content of acids which can react with alkalis to form in-situ surfactants. The loosely consolidated sandstone formations where these oils are deposited are characterized by high porosity, permeability and low reservoir temperature. These reservoir conditions are favorable for polymer application. Therefore, there is a potential to improve waterflood in these reservoirs by applying alkaline/polymer (A/P) flooding. This paper presents the results of a laboratory study of A/P flooding for heavy oil recovery, including viscosity measurements, flood tests conducted in channeled sandpacks, residual resistance factor (Frr) determination, and residual oil distribution tests. A heavy oil with a viscosity of 1,202 cP and an acid number of 1.07 (mg KOH/g-oil) and produced brine collected from a heavy oil reservoir in Alberta are used in this study. The experimental results show that addition of polymer to alkaline solution reinforces stability and strength of in-situ formed emulsions. It is found that the distribution of the injected chemical solution into the high permeable cannels leads to the diversion of the subsequently injected chemical solution to low permeable zones with higher oil saturation due to the formation of blockage in the channel zones. Consequently, pressure build-up during chemical slug injection is the key to the improvement of displacement efficiency. Flood tests also show that alkaline-polymer flooding is more efficient than either alkaline flooding or polymer flooding. The optimal formulation for the heavy oil used in this study is 0.4% NaOH + 0.2% Na2CO3 + 1,000 mg/l polymer, with a tertiary oil recovery of 25 – 30 % OOIP over waterflood. Analysis of the results of the residual oil distributions in the channeled sandpacks at the end of A/P flooding shows that A/P flooding can effectively improve the sweep efficiency of waterflood for the heavy oil.
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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 | 0.000 | 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".