Stress state and stress path evaluation to address uncertainties in reservoir rock failure in CO2 sequestration in deep saline aquifers: An experimental study of the Hawkesbury sandstone formation

T. D. Rathnaweera, P. G. Ranjith, M. S. A. Perera, W. A. M. Wanniarachchi, K. M. A. S. Bandara

Research output: Contribution to journalArticleResearchpeer-review

2 Citations (Scopus)

Abstract

Injecting CO2 into aquifer pore fluid (high salinity brine) in deep saline aquifers during the sequestration process causes the chemico-mineral structure to be altered through complex chemically-coupled mechanical deformations. This is as yet poorly understood in the field. The authors conducted a series of tri-axial strength tests on Hawkesbury sandstone under in-situ stress and temperature conditions to characterise the behaviour of reservoir rock upon exposure to super-critical CO2 (ScCO2) to determine this chemically-coupled mechanical behaviour. According to the findings, injection of CO2 into a brine-saturated reservoir rock mass may cause a considerable strength reduction, probably due to the rock's mineralogical alteration-induced mechanical weakening of grain contacts. This was confirmed by SEM analysis, according to which the mineral dissolution process upon exposure to ScCO2 is significant, and considerable quartz and calcite dissolution were noticed in the tested samples. Importantly, this rock mineral dissolution may alter the reservoir's natural pore geometry. This eventually affects the effective stress patterns acting on the rock matrix. In addition, the slip tendency of brine+CO2-reacted reservoir rock is increased with increasing injection pressure, revealing the fate of the resulting pore pressure-dominant effective stress field through the CO2 injection process. The results were then incorporated in the effective stress field model. This model can be used to predict the possibility of mechanical failure of reservoir rock upon CO2 injection into saline aquifers.

Original languageEnglish
Pages (from-to)184-201
Number of pages18
JournalJournal of CO2 Utilization
Volume26
DOIs
Publication statusPublished - 1 Jul 2018

Keywords

  • Brine
  • CO2 sequestration
  • Compaction
  • Mean effective stress
  • Pore pressure
  • Reservoir rock
  • Stress-strain
  • Tri-axial

Cite this

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title = "Stress state and stress path evaluation to address uncertainties in reservoir rock failure in CO2 sequestration in deep saline aquifers: An experimental study of the Hawkesbury sandstone formation",
abstract = "Injecting CO2 into aquifer pore fluid (high salinity brine) in deep saline aquifers during the sequestration process causes the chemico-mineral structure to be altered through complex chemically-coupled mechanical deformations. This is as yet poorly understood in the field. The authors conducted a series of tri-axial strength tests on Hawkesbury sandstone under in-situ stress and temperature conditions to characterise the behaviour of reservoir rock upon exposure to super-critical CO2 (ScCO2) to determine this chemically-coupled mechanical behaviour. According to the findings, injection of CO2 into a brine-saturated reservoir rock mass may cause a considerable strength reduction, probably due to the rock's mineralogical alteration-induced mechanical weakening of grain contacts. This was confirmed by SEM analysis, according to which the mineral dissolution process upon exposure to ScCO2 is significant, and considerable quartz and calcite dissolution were noticed in the tested samples. Importantly, this rock mineral dissolution may alter the reservoir's natural pore geometry. This eventually affects the effective stress patterns acting on the rock matrix. In addition, the slip tendency of brine+CO2-reacted reservoir rock is increased with increasing injection pressure, revealing the fate of the resulting pore pressure-dominant effective stress field through the CO2 injection process. The results were then incorporated in the effective stress field model. This model can be used to predict the possibility of mechanical failure of reservoir rock upon CO2 injection into saline aquifers.",
keywords = "Brine, CO2 sequestration, Compaction, Mean effective stress, Pore pressure, Reservoir rock, Stress-strain, Tri-axial",
author = "Rathnaweera, {T. D.} and Ranjith, {P. G.} and Perera, {M. S. A.} and Wanniarachchi, {W. A. M.} and Bandara, {K. M. A. S.}",
year = "2018",
month = "7",
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language = "English",
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journal = "Journal of CO2 Utilization",
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Stress state and stress path evaluation to address uncertainties in reservoir rock failure in CO2 sequestration in deep saline aquifers : An experimental study of the Hawkesbury sandstone formation. / Rathnaweera, T. D.; Ranjith, P. G.; Perera, M. S. A.; Wanniarachchi, W. A. M.; Bandara, K. M. A. S.

In: Journal of CO2 Utilization, Vol. 26, 01.07.2018, p. 184-201.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Stress state and stress path evaluation to address uncertainties in reservoir rock failure in CO2 sequestration in deep saline aquifers

T2 - An experimental study of the Hawkesbury sandstone formation

AU - Rathnaweera, T. D.

AU - Ranjith, P. G.

AU - Perera, M. S. A.

AU - Wanniarachchi, W. A. M.

AU - Bandara, K. M. A. S.

PY - 2018/7/1

Y1 - 2018/7/1

N2 - Injecting CO2 into aquifer pore fluid (high salinity brine) in deep saline aquifers during the sequestration process causes the chemico-mineral structure to be altered through complex chemically-coupled mechanical deformations. This is as yet poorly understood in the field. The authors conducted a series of tri-axial strength tests on Hawkesbury sandstone under in-situ stress and temperature conditions to characterise the behaviour of reservoir rock upon exposure to super-critical CO2 (ScCO2) to determine this chemically-coupled mechanical behaviour. According to the findings, injection of CO2 into a brine-saturated reservoir rock mass may cause a considerable strength reduction, probably due to the rock's mineralogical alteration-induced mechanical weakening of grain contacts. This was confirmed by SEM analysis, according to which the mineral dissolution process upon exposure to ScCO2 is significant, and considerable quartz and calcite dissolution were noticed in the tested samples. Importantly, this rock mineral dissolution may alter the reservoir's natural pore geometry. This eventually affects the effective stress patterns acting on the rock matrix. In addition, the slip tendency of brine+CO2-reacted reservoir rock is increased with increasing injection pressure, revealing the fate of the resulting pore pressure-dominant effective stress field through the CO2 injection process. The results were then incorporated in the effective stress field model. This model can be used to predict the possibility of mechanical failure of reservoir rock upon CO2 injection into saline aquifers.

AB - Injecting CO2 into aquifer pore fluid (high salinity brine) in deep saline aquifers during the sequestration process causes the chemico-mineral structure to be altered through complex chemically-coupled mechanical deformations. This is as yet poorly understood in the field. The authors conducted a series of tri-axial strength tests on Hawkesbury sandstone under in-situ stress and temperature conditions to characterise the behaviour of reservoir rock upon exposure to super-critical CO2 (ScCO2) to determine this chemically-coupled mechanical behaviour. According to the findings, injection of CO2 into a brine-saturated reservoir rock mass may cause a considerable strength reduction, probably due to the rock's mineralogical alteration-induced mechanical weakening of grain contacts. This was confirmed by SEM analysis, according to which the mineral dissolution process upon exposure to ScCO2 is significant, and considerable quartz and calcite dissolution were noticed in the tested samples. Importantly, this rock mineral dissolution may alter the reservoir's natural pore geometry. This eventually affects the effective stress patterns acting on the rock matrix. In addition, the slip tendency of brine+CO2-reacted reservoir rock is increased with increasing injection pressure, revealing the fate of the resulting pore pressure-dominant effective stress field through the CO2 injection process. The results were then incorporated in the effective stress field model. This model can be used to predict the possibility of mechanical failure of reservoir rock upon CO2 injection into saline aquifers.

KW - Brine

KW - CO2 sequestration

KW - Compaction

KW - Mean effective stress

KW - Pore pressure

KW - Reservoir rock

KW - Stress-strain

KW - Tri-axial

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U2 - 10.1016/j.jcou.2018.05.008

DO - 10.1016/j.jcou.2018.05.008

M3 - Article

AN - SCOPUS:85046873138

VL - 26

SP - 184

EP - 201

JO - Journal of CO2 Utilization

JF - Journal of CO2 Utilization

SN - 2212-9820

ER -