Impact of Rapid Cooling and Depressurization on Limestone Compressive Strength: Implications for CO2 Injection in Carbonate Reservoirs.
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| Title: | Impact of Rapid Cooling and Depressurization on Limestone Compressive Strength: Implications for CO |
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| Authors: | Verberne, Bart1 (AUTHOR) bart.verberne@shell.com, Wolterbeek, Tim2 (AUTHOR), van der Linden, Arjan1 (AUTHOR), El Azouzi, Khalid1 (AUTHOR), van Schalm, Robert1 (AUTHOR), Coorn, Ab1 (AUTHOR) |
| Source: | Rock Mechanics & Rock Engineering. May2026, Vol. 59 Issue 5, p5725-5742. 18p. |
| Subjects: | Carbon dioxide injection, Carbonate reservoirs, Rock properties, Rock mechanics, Carbon sequestration, Thermal shock, Hydrocarbon reservoirs |
| Abstract: | CO2-injection into depleted hydrocarbon reservoirs can lead to rapid cooling and a CO2 phase change in the near-wellbore region, which may have adverse effects on rock strength. We report on the effects of thermal shock (ΔT) and rapid CO2 depressurization (ΔP) on the compressive strength of dry and brine-saturated limestones. Plugs were prepared from Indiana Limestone and a partially dolomitized limestone outcropping in Sanpete County, Utah, USA, and subjected to compressive strength tests untreated and after ΔT- or ΔP- treatment. The ΔT-treatment consisted of emplacement of samples from 60 ºC into dry ice (− 78 ºC), while the ΔP-treatment consisted of three cycles of decompression-recompression between 9 MPa and atmospheric pressure using CO2 as working fluid. Decompression was achieved in ~ 10 s and carried out at background temperatures of 24 ºC and 60 ºC. Virgin, ΔT-, and ΔP-treated samples were subjected to unconfined compressive strength (UCS) and thick-walled cylinder (TWC) collapse strength tests. A comparison between virgin and treated samples is made using the mechanical data, micro-CT scans, and optical microscopy on sectioned trim-ends. Dry samples are generally stronger than their brine-saturated counterparts, but the effects from ΔT- or ΔP-treatment on rock strength or stiffness are insignificant given sample variability. Based on these findings we suggest that CO2-injection into depleted limestone reservoirs can lead to strengthening of desiccated regions, but with negligible negative impact from thermal shock or CO2 depressurization on rock mechanical integrity. More research is needed to understand if these conclusions extend to a wider range of carbonate reservoirs. Highlights: The compressive strength of brine-saturated Indiana and Sanpete Valley limestone plugs measured 63–88% of their dry counterparts. Thermal shock from 60 to − 78 °C does not lead to a discernible decrease of the compressive strength of Indiana and Sanpete Valley limestone. CO2 depressurization from 9 MPa to atmosphere in 10 s does not lead to a discernible decrease in the compressive strength of these limestones. [ABSTRACT FROM AUTHOR] |
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| Abstract: | CO2-injection into depleted hydrocarbon reservoirs can lead to rapid cooling and a CO2 phase change in the near-wellbore region, which may have adverse effects on rock strength. We report on the effects of thermal shock (ΔT) and rapid CO2 depressurization (ΔP) on the compressive strength of dry and brine-saturated limestones. Plugs were prepared from Indiana Limestone and a partially dolomitized limestone outcropping in Sanpete County, Utah, USA, and subjected to compressive strength tests untreated and after ΔT- or ΔP- treatment. The ΔT-treatment consisted of emplacement of samples from 60 ºC into dry ice (− 78 ºC), while the ΔP-treatment consisted of three cycles of decompression-recompression between 9 MPa and atmospheric pressure using CO2 as working fluid. Decompression was achieved in ~ 10 s and carried out at background temperatures of 24 ºC and 60 ºC. Virgin, ΔT-, and ΔP-treated samples were subjected to unconfined compressive strength (UCS) and thick-walled cylinder (TWC) collapse strength tests. A comparison between virgin and treated samples is made using the mechanical data, micro-CT scans, and optical microscopy on sectioned trim-ends. Dry samples are generally stronger than their brine-saturated counterparts, but the effects from ΔT- or ΔP-treatment on rock strength or stiffness are insignificant given sample variability. Based on these findings we suggest that CO2-injection into depleted limestone reservoirs can lead to strengthening of desiccated regions, but with negligible negative impact from thermal shock or CO2 depressurization on rock mechanical integrity. More research is needed to understand if these conclusions extend to a wider range of carbonate reservoirs. Highlights: The compressive strength of brine-saturated Indiana and Sanpete Valley limestone plugs measured 63–88% of their dry counterparts. Thermal shock from 60 to − 78 °C does not lead to a discernible decrease of the compressive strength of Indiana and Sanpete Valley limestone. CO2 depressurization from 9 MPa to atmosphere in 10 s does not lead to a discernible decrease in the compressive strength of these limestones. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 07232632 |
| DOI: | 10.1007/s00603-024-04085-0 |
