Safety and Security for CO 2 Geological Storage while CO 2 /H 2 O/Rock Reaction Bo Peng Enhanced Oil Recovery Research Center, China University of Petroleum, Beijing, China Sep.23, 2009 Canberra,Australia

Content  1. Background  2. CO2 and Salt Solution Reaction  3. CO2 and Rocks Reaction  4. Wettability of the Rock  5. Permeability of the Rock  6. Safety and Security for CO 2 Storage  7. Conclusion

1.Background 1.Reduction of Green House Gas Emission---A topic which concerned around the world nowadays. Carbon Capture and Storage(CCS) is one of the most important technology. ① ② 2-3 ℃

1.Background 2. Chinese Government Concerns Greatly about Reduction of CO2 Emission and Utilization of It as Resources Chairman Hu Jintao Primer Wen Jiabao “973”, “863” Reseach Projects…. Petrochina,HuanengPil ot Test….

1.Background 3. CO2 Storage and EOR in China Oil&Gas Reservoir, Subsurface Salaquifer, coal bed, ideal Place for CO 2 Storage 923 billion tons of CO2 can be storaged in reservoir, which is 45% of global cumulative emission in 2050.

1. Background 4. Safety and Security for CCS have attracted more and more attention.

1. Background CO2/H2O/Roc k Reaction Wettability EOR and CO2 storage Permeability EOR and CO2 Storage

NaCl Salt Solution (Aqueous Solution ) Na 2 SO 4 MgCl 2 CaCl 2 CaCO 3 Ca(HCO 3 ) 2 Daqing Formation Water The Effect Factors Pressure Tempreture 2. CO2 and Salt Solution Reaction

C CO2 ； 5.Higher Pressure Vessel ； 8. p H S － 3C Meter pH Measurement System in Higher Pressure 2. CO2 and Salt Solution Reaction

NaCl SolutionNa2SO4 Solution 2. CO2 and Salt Solution Reaction Effect on pH by Pressure on Aqueous Systems Effect on pH by Pressure on Aqueous Systems (25 ℃ ) pH ≈ 3.0 CO2:H 2 CO 3 in Water,

CaCl 2 Solution MgCl 2 Solution 2. CO2 and Salt Solution Reaction Effect on pH by Pressure on Aqueous Systems Effect on pH by Pressure on Aqueous Systems (25 ℃ ) ≈ pH ≈ 3.0 CO2:H 2 CO 3 in Water,

2. CO2 and Salt Solution Reaction Effect on pH by Pressure on Aqueous Systems Effect on pH by Pressure on Aqueous Systems (25 ℃ ) Na 2 CO 3 SolutionNaHCO 3 Solution pH ≥ 3.0 CO2:HCO 3 － in Water,

NaClNaHCO 3 Na 2 CO 3 Na 2 SO 4 CaCl 2 MgCl 2 · 6H 2 O Daqing Formation Water （ mg/L ） 2. CO2 and Salt Solution Reaction pH ≥ 3.5 CO2:HCO 3 － in Water,

10% CaCl 2 10% MgCl 2 Effect on pH by Temperture on Aqueous Systems 2. CO2 and Salt Solution Reaction pH decrease while T goes up. H 2 CO 3 give more H +

Calcite Pieces H 2 O + CO 2 Rock Surface Topographic Image Rock Surface Topographic Image Formation of the Solution Calcite Powders H 2 O + CO 2 Permeability of Sand Pipe SEM Ions Spectrum Permeability Measurement Unit 3. CO 2 and Rocks Reaction Formation of the Solution Rock Surface Topographic Image Rock Surface Topographic Image Formation of the Solution Permeability of Sand Pipe

取样 P2P2 P1P1 1.CO 2 ； 3.Reaction Vessel ； 4.Heating System ； Reaction Unit in High Pressure 3. CO2 and Rocks Reaction

Rock Characteristic Calcite:97.8% ； Dolomite:2.2% 3. CO2 and Rocks Reaction

Before Reaction Rock Surface Topographic Image Pressure ： 2 MPa ； Temperature ： 25 ℃； Reaction Time ： 20days 3. CO2 and Rocks Reaction After Reaction

Before Reaction Rock Surface Topographic Image Pressure ： 2 MPa ； Temperature ： 25 ℃； Reaction Time ： 20days 3. CO2 and Rocks Reaction After Reaction

Ion Time K+K+ Na + Ca 2+ Mg 2+ Before Reaction After Reaction Ion in the solution before/after CO2 and Rock Reaction （ mg/L ） 3. CO2 and Rocks Reaction Pressure ： 2 MPa ； Temperature ： 25 ℃； Reaction Time ： 20days Rock Surface Topographic Image

Ions in Formation Water 3. CO2 and Rocks Reaction Pressure ： 2 MPa ； Temperature ： 25 ℃； Ca 2+, HCO 3 - ↑. 8 days Stably

Ions in Formation Water 3. CO2 and Rocks Reaction Pressure ： 2 MPa ； Temperature ： 60 ℃；

Ions in Formation Water 3. CO2 and Rocks Reaction Pressure ： 2 MPa ； Temperature ： 90 ℃； CO2 ↑

Sand Core + Daqing Formation Water CO2 Permeability of Sand Core Rock Pieces + Non-ion water Daqing Formation Water Dilute Daqing Formation Water NaCl CaCl 2 CO2 Contact Angle CO2 Contact Angle CO2 Contact Angle 4. Wettability of the Rock

Silica Sand: 97.7% ； Potash feldspar: 0.6% ； Calcite: 0.1% Dolomite: 0.6% others: 1% ； 4. Wettability of the Rock

Non-ions Contact Angle: Rock Pieces + Non-ions + CO 2 Time （ d ） θ a0 θaθa θ a0 -θ a °120.52°0.07° °119.09°0.48° °118.08°2.06° °120.61°0.04° 时间（ d ） 0246 θ a °120.30°120.94° Pressure ： 1MPa Tempreture ： 25 Tempreture ： 25 ℃ θ a0 –No-CO2 ； θ a – CO2 ； θ a1 – Water Treatment 4. Wettability of the Rock

Daqing Formation Water Contact Angle: Rock Pieces + Non-ions + CO 2 Pressure ： 1MPa Tempreture ： 25 Tempreture ： 25 ℃ θ a0 –No-CO2 ； θ a – CO2 ； θ a1 – Water Treatment 4. Wettability of the Rock 时间（ d ） θ a0 θaθa θ a0 -θ a °61.61°59.17° °43.55°73.80° °51.63°67.86° °42.31°76.09° 时间（ d ） 0246 θ a °106.23°107.06°111.88° Contact angle ↓ 。 NO CO2, NO Contact Angle Change.

Pressure ： 1 MPa Tempture ： 25 ℃ Effect of Ions on Contact Angle 4. Wettability of the Rock More Daqing Water, More change on contact angle

Pressure ： 1 MPa Tempture ： 25 ℃ Effect of Ions on Contact Angle 4. Wettability of the Rock NaCl CaCl 2

5. Permeability of the Rock 1.N2 2.CO Sand Filling Model 6. Pumper

Silica Sand:98.1.7% ； Potash feldspar:0.3% ； Calcite:0.3% Dolomite:1.2% others:0.1% ； 5. Permeability of the Rock

Time(CO 2 ) （ d ） P（kPa） Permeability （mD） Changement （％） － Time(CO 2 ) （ d ） P（kPa） Permeability （mD） Changement （％） － Effect of CO2 on permeability of Sand Core L ： mm ； D: mm ； S ： 25.57% ； T ： 30 ℃ L ： 51.60mm ； D ： 25 mm ； S ： 31.23% ； T ： 30 ℃ 5. Permeability of the Rock CO2 Increase the permeability 。

P:2MPa ； Reaction T: 65 ℃； Test T ： 25 ℃ Silica sand: Calcit=1 ： 1 5. Permeability of the Rock Effect of CO2 on Permeability of Sand Filling Model

6.Safety and Security for CO 2 Storage

6.Conclusion 1. After carbon dioxide injection, pH of single brine, Daqing modeled water dropped and then gradually decreased to a steady value. Magnesium chloride and calcium chloride solution (wt%=10%) pH decreased with temperature increase. 2. The SEM study shows that dissolution occurs on calcite surface. The Ca2+ and HCO3- concentration increased with reaction time to steady values. The time reach to steady is shorter with temperature increase. 3. The permeability of sand pipe filled with calcite and quartz increased with reaction time. 4.When inject into CO2, contact angle of cores slice in Daqing modeled water decreased and the proportion of Daqing modeled water is bigger, the change of contact angle is bigger. 5.The Safety and Security for CO2 Storage is correlated to the CO 2 /H 2 O/Rocks Reactions

Thanks for your attention!