Researches of sequestration. CO2 in case of laboratory experiment and natural analogues. Speaker : Pei-Hua Hsu

Transcription

1 Researches of sequestration CO2 in case of laboratory experiment and natural analogues Speaker : Pei-Hua Hsu

2 References Fischer, S., Liebscher A., Wandrey M., the CO2SINK Group (2010). CO2-brine-rock interaction : First results of longterm exposure experiments at in situ P-T conditions of the Ketzin CO2 reservoir. Chemie der Erde 70 S3, Lu, H. Y., Lin, C. K., Lin, W., Liou, T. S., Chen, W. F., Chang, P. Y. (2011). A natural analogue for CO2 mineral sequestration in Miocene basalt in the Kuanhsi-Chutung area, Northwestern Taiwan. International Journal of Greenhouse Gas Control 5,

3 Outline Introduction Case for Laboratory Experiment Case for Natural Analogues Conclusion

4 CO2 sequestration by carbonation can be estimated by : Introduction Laboratory Experiments creates a simulated conditions of the reservoir and caprock. They can help identify the key geochemical reaction, but the timescales can not be too long. Natural Analogues tries to find the analogous condition (CO2 exist in formations) in large scale nature structures. It can provide the information for long-term storage.

5 Case for Laboratory Experiment The pilot storage site at Ketzin, Brandenburg (Germany) is situated in the Northeast German Basin about 40 km west of Berlin. The Ketzin locality is the first European on-shore CO2 storage site in a saline aquifer. the Ketzin Pilot Storage Site

6 View on the CO2SINK storage site at Ketzin

7 B m Samples B m B m B m B m Subset 1 Samples Subset 2 CO2-Treated

8 CO2 Heating Cabinet CO2 Rock Fragments Core Section Synthetic Brine Experimental Procedure Steel Pressure Vessel Subset 2 (CO2-treated) Time-Scale Pressure 15 months 5.5 MPa Temperature 40 Fluid (Förster et al.,2006) g/l NaCl 8.0 g/l MgCl2 6H2O 4.8 g/l CaCl2 2H2O 0.6 g/l KCl After 15 months, the samples were taken out of the autoclaves they have been washed several times with pure H2O and cautiously dried in a compartment drier at 45.

9 Methods Petrography Petrographic Analysis BSE Chemical Composition Electron Microprobes Analysis (EMP) X-Ray Powder Diffraction Analysis (XRD) Mineral Surfaces SEM

10 Qtz:Quartz Pl:Plagioclase Kfs:K-Feldspar Ms:Muscovite Bt:Biotite Anh:Anhydrite Anl:Analcime Dol:Dolomite Fe:Fe-Phase Chl:Chlorite Ill:Illite Results Sample B2-2 B2-3 B3-1 B3-3 B4-2 CO2 set Untreated Treated Untreated Treated Untreated Treated Untreated Treated Untreated Treated Qtz > 25 % > 25 % > 25 % > 25 % > 25 % > 25 % > 25 % > 25 % > 25 % > 25 % Pl > 25 % > 25 % > 25 % > 25 % > 25 % > 25 % > 25 % > 25 % > 25 % > 25 % Kfs 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 0 % Ms < 5 % < 5 % < 5 % < 5 % < 5 % < 5 % < 5 % < 5 % < 5 % < 5 % Bt 0 % < 5 % < 5 % 0 % 0 % < 5 % 0 % < 5 % < 5 % < 5 % Anh 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 0 % 5-25 % 0 % 5-25 % 0 % Anl 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 0 % Dol 5-25 % 5-25 % 5-25 % 5-25 % 0 % 0 % 0 % 0 % 0 % 0 % Fe < 5 % < 5 % < 5 % < 5 % < 5 % < 5 % < 5 % < 5 % < 5 % < 5 % Chl 0 % 0 % < 5 % < 5 % < 5 % < 5 % < 5 % < 5 % < 5 % < 5 % Ill < 5 % Basic mineralogy of samples determined by optical microscopy, XRD and EMP analyses.

11 Anh:Anhydrite Anl:Analcime Dol:Dolomite BSE images of B 2-2 thin sections. Untreated CO2-Treated Sample B2-2 B2-3 B3-1 B3-3 B4-2 CO2 set Untreated Treated Untreated Treated Untreated Treated Untreated Treated Untreated Treated Anh 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 0 % 5-25 % 0 % 5-25 % 0 % Anl 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 5-25 % 0 % Dol 5-25 % 5-25 % 5-25 % 5-25 % 0 % 0 % 0 % 0 % 0 % 0 %

12 Mineral Surfaces (SEM) Quartz Anhydrite Albite Plagioclase Plagioclase grains show either surfaces with crystallographically oriented etch textures or lamellar dissolution features resulting in a lumpy and irregular surface morphology.

13 Or:Orthoclase (K) Ab:Albite (Na) An:Anorthite (Ca) Mineral Composition - Feldspar Orthoclase Compositions

14 Mineral Composition - Sheet Silicates Mineral Composition - Cement Phases Anhydrite, analcime and dolomite consistently show stoichiometrical compositions before and after the experiments and provide no hints for any chemical alteration.

15 Mineral Alteration Discussion Dissolution of Anhydrite:absence in CO2-treated samples Dissolution of Plagioclase:distinct corrosion and etch textures Precipitation of Albite:euhedral albite grains on the other hand: Dissolution of certain minerals is consistent with results from porosity measurements on the same samples. These measurements generally indicate a slight increase in porosity during the experiments (Zemke et al., 2010). After 15 months, the calcium and sulfate concentrations in the brine have notably increased (Wandrey et al., accepted). The addition of CO2 triggered dissolution of the plagioclase and anhydrite and precipitation of albite.

16 In this study, no unambiguous evidence for such mica alterations or intensified clay mineral formation was found. And cement phases show no hints for any chemical alteration. Alterations of mica minerals could easily lead to the formation of clay minerals, such as kaolinite, illite and chlorite, which may have an impact on petrophysical properties of the reservoir. These authigenic clays could clog pore throats and fill open cleavages to reduce poroperm levels and in turn hamper the injection of CO2. Cements are in general a very important feature of reservoir systems because of influencing hydraulical parameters like porosity, permeability, and injectivity, which are vital for a successful site operation.

17 Summary The petrological investigations observed by thin section analysis and XRD showed no significant mineralogical or petrochemical changes after the experiments. Major Alteration 1. Dissolution of Anhydrite 2. Dissolution of Plagioclase 3. Precipitation of Albite

18 Case for Natural Analogues Miocene Basalt Magmatism

19 Samples Basalts Ultramafic Xenoliths

20 Methods Chemical Composition Petrographic Analysis X-Ray Powder Diffraction Analysis (XRD) Electron Microprobes Analysis (EMP) X-Ray Fluorescence Analysis (XRF) Carbonation Condition The Carbon and Oxygen Stable Isotopic

21 Analysis XRD and EMP analysis of a highly altered xenolith (LT-08). C:Calcite MC:Mg-Calcite M:Mica C Ca0.2Mg2Fe0.7Si3Al0.5O10 Ca0.25(Mg,Fe)3(Si,Al)4O10 Saponite? M MC M C MC MC C C MC C XRD Analysis EMP Analysis

22 Result of Mineralogical Assemblages The result determined by petrographic, XRD and EMP analysis. Mineralogical Assemblages LT Forsterite Enstatite Diopside Spinel Serpentine Saponite Smectite Nontronite Calcite Fe-Dolomite Fe-Magnesite Quartz Mica MF

23 Discussion According to petrographic observation, carbonate is usually associated with saponite, which is an alteration product of earlier serpentine. Two stages of geochemical processes are recognized in basalt and its enclosed ultramafic xenoliths: (1) Earlier Serpentinization Stage (2) Later Carbonate Mineralization Stage

24 Serpentinization The mineral assemblages of LT-11 and LT-12 demonstrate that the ultramafic xenoliths are mainly composed of forsterite, enstatite, diopside and accessory spinel. During the serpentinization processes, olivine and enstatite are readily converted into serpentine according to the simplified reaction: Mg2SiO4 + MgSiO3 + 2H2O Mg3Si2O5(OH)4 Forsterite Enstatite Serpentine

25 Spinel and Diopside Spinels are generally recognized as a predominantly resistant mineral. The stability of diopside is highly dependent on temperature, ph, and activity of Ca 2+ in fluid (Frost and Beard, 2007) Mg3Si2O5(OH)4 + 2CaMgSi2O6 + 2SiO2 Ca2Mg5Si8O22(OH)2 + 2H2O Serpentine Diopside Tremolite 3CaMgSi2O6 + 6H + + 2H2O Mg3Si2O5(OH)4 + 3Ca 2+ + H2O + 4SiO2 Diopside Serpentine

26 Carbonation According to studies on carbonates precipitating under temperatures lower than 150, magnesite siderite solid solutions show a considerable incorporation of CaCO3 in the crystal structures. (Romanek et al., 2009; Woods and Garrels, 1992; Konigsberger et al., 1999)

27 Isotope Geochemistry The isotopes of carbon and oxygen are predominant indicators of the fluid source and diagenetic environments during carbonation. Lohmann (1988) shows that meteoric carbonates will tend to have relatively low oxygen isotopic ratios due to the much lighter oxygen isotope of meteoric water, while marine carbonates have higher oxygen isotopic ratios. In addition, the δ 13 C values of carbonates at shallow depth will tend to be more negative than those in the deeper zone because of more direct access of infiltrating waters to light soil CO2 gas, which is associated with biochemical fermentation and/or thermochemical degradation of organic matter.

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29 Temperature is the other major factor affecting oxygen stable isotope ratios and could have caused the lower oxygen isotopic composition. T = (δ 18 O Calcite - δ 18 O Water ) (δ 18 O Calcite - δ 18 O Water ) 2 (Anderson and Arthur, 1983) T:the temperature of calcite precipitation in δ 18 O Calcite :the oxygen isotope ratio in calcite relative to the PDB standard δ 18 O Water :the ratio in water relative to the SMOW standard Assuming a possible maximum ratio δ 18 O Water = 0 The potential maximum temperatures of carbonation roughly range from 53 to 88 C, which is equivalent to a depth of 1 2 km with a normal geothermal gradient (30 /km).

30 Semi-Quantitative Evaluation of Carbonate Mineralization XRF Analysis

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32 Accordingly, the following reactions are considered as the simplified model for semi-quantitatively estimating the amount of CO2 sequestration. 2NaSi 3 O 8 + CO 2 + 2H 2 O + Ca 2+ CaCO 3 + SiO 2 + Al 2 Si 2 O 5 (OH) 4 + 2Na + Albite Calcite Kaolinite CaAl 2 Si 2 O 8 + CO 2 + 2H 2 O CaCO 3 + Al 2 Si 2 O 5 (OH) 4 Anorthite Calcite Kaolinite 3KAlSi 3 O 8 + CO 2 + 2H 2 O + Ca 2+ CaCO 3 + KAl 3 Si 3 O 10 (OH) 4 + 6SiO 2 + 2K + K-Feldspar Calcite Illite 2(Na, K)AlSiO 4 + CO 2 + 2H 2 O + Ca 2+ CaCO 3 + Al 2 Si 2 O 5 (OH) 4 + 2(Na, K) + Nepheline Calcite Kaolinite Mg 2 SiO 4 + 2CO 2 + 2Ca 2+ 2CaCO 3 + SiO 2 + 2Mg 2+ Forsterite Calcite MgSiO 3 + CO 2 + Ca 2+ CaCO 3 + SiO 2 + Mg 2+ Enstatite Calcite (Gaus et al., 2005; Lagneau et al., 2005; Worden and Barclay, 2000; Baines and Worden, 2001).

33 Stoichiometric ratios of generated calcite to primary minerals in these reactions are used for calculating the amount of CO2 potentially trapped. Assumptions (1) Basalt density is designated at 2890 kg/m 3. (2) Typical basalt porosity ranges from 15% to 20%, which is the space filled with fluid. Accordingly, the degree of carbonation of basalt is estimated to be 20%.

34 Summary The late Miocene sandstone and enclosed basalts of the Kuanhsi-Chutung area as potential sites for CO2 mineral sequestration has the potential to act as a natural analogue for CO2 sequestration. The potential maximum temperature of carbonation derived from the empirical equations ranges from 53 to 88, which is equivalent to a depth of 1 2km or shallower. This demonstrates that the carbonation process can take place at an acceptable depth for the creation of a practical CO2 sequestration reservoir.

35 The Laboratory Experiments of the pilot storage site at Ketzin shows the main reaction member in the formatiom. 1. Dissolution of Anhydrite 2. Dissolution of Plagioclase 3. Precipitation of Albite Conclusion The Natural Analogues of the Kuanhsi-Chutung area shows that the late Miocene sandstone was in the deep of 1 2 km. It is a good conditions for long term CO2 sequestration, and CO2 can be trapped into the minerals by Carbonation.

36 Thank you for your attention!

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38 Electron microprobe analysis (EMPA), also called electron probe microanalysis, is an analytical technique that is used to establish the composition of small areas on specimens. EMPA is one of several particle-beam techniques. A beam of accelerated electrons is focused on the surface of a specimen using a series of electromagnetic lenses, and these energetic electrons produce characteristic X-rays within a small volume (typically 1 to 9 cubic microns) of the specimen. The characteristic X-rays are detected at particular wavelengths, and their intensities are measured to determine concentrations. All elements (except H, He, and Li) can be detected because each element has a specific set of X-rays that it emits. This analytical technique has a high spatial resolution and sensitivity, and individual analyses are reasonably short, requiring only a minute or two in most cases. Additionally, the electron microprobe can function like a scanning electron microscope (SEM) and obtain highly magnified secondary- and backscattered-electron images of a sample.

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41 Graph showing the ranges of estimated carbonation temperatures by using the equation of Friedman and O Neil (1977).