Understanding the Plugging Performance of HPAM-Cr (III) Polymer Gel for CO2 Conformance Control
| Autor: | Ali K. Alhuraishawy, Baojun Bai, Xindi Sun, Daoyi Zhu |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
chemistry.chemical_classification
Materials science 020209 energy Energy Engineering and Power Technology chemistry.chemical_element 02 engineering and technology Polymer Geotechnical Engineering and Engineering Geology Chromium chemistry.chemical_compound 020401 chemical engineering chemistry Chemical engineering Carbon dioxide 0202 electrical engineering electronic engineering information engineering Polymer gel 0204 chemical engineering Relative permeability |
| Zdroj: | SPE Journal. 26:3109-3118 |
| ISSN: | 1930-0220 1086-055X |
| DOI: | 10.2118/204229-pa |
| Popis: | SummaryWith the demand for conformance control in carbon dioxide (CO2) flooding fields, hydrolyzed polyacrylamide-chromium [HPAM-Cr (III)] polymer gel has been applied in fields for CO2 conformance control. However, the field application results are mixed with success and failure. This paper is intended to understand the HPAM-Cr (III) polymer gel plugging performance in CO2 flooding reservoirs through laboratory experiments and numerical analysis. We conducted core flooding tests to understand how the cycles of CO2 and water affect the HPAM-Cr (III) polymer gel plugging efficiency to CO2 and water during a water-alternating-gas (WAG) process. Berea Sandstone cores with the permeability range of 107 to 1225 md were used to evaluate the plugging performance in terms of residual resistance factor and breakthrough pressure, which is the minimum pressure required for CO2 to enter the gel-treated cores. We compared the pressure gradient from the near-wellbore to far-field with the gel breakthrough pressure, from which we analyzed under which conditions the gel treatment could be more successful. Results show that HPAM-Cr (III) polymer gel has higher breakthrough pressure in the low-permeability cores. The polymer gel can reduce the permeability to water much more than that to CO2. The disproportionate permeability reduction performance was more prominent in low-permeability cores than in high-permeability cores. The gel resistance to both CO2 and brine significantly decreased in later cycles. In high-permeability cores, the gel resistance to CO2 became negligible only after two cycles of water and CO2 injection. Because of the significant reduction of pressure gradient from near-wellbore to far-field in a radial flow condition and the dependence of breakthrough pressure on permeability and polymer concentration, we examined hypothetical reservoirs with no fractures, in which impermeable barriers separated high- and low-permeability zones and in which the gel was only placed in the high-permeability zone. We considered two scenarios: CO2 breaking through the gel and no CO2 breakthrough. No breakthrough represents the best condition in which the gel has no direct contact and can be stable in reservoirs for long. In contrast, the breakthrough scenario will result in the gel's significant degradation and dehydration resulting from CO2 flowing through the gel, which will cause the gel treatment to fail. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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