Mobilisation of organic compounds from reservoir rocks through the injection of CO2 —Comparison of baseline characterization and laboratory experiments

Abstract In the framework of CO 2 storage activities, the aim of our investigations is mainly to evaluate the effects of supercritical CO 2 (sc CO 2 ) on the quantitative and qualitative extraction of organic compounds from reservoir rocks. Within the scope of the CO 2 storage project CO 2 SINK the major task was to identify key mechanisms occurring in the reservoir as a result of the injection of CO 2 into a saline aquifer. Here, it is of special interest what types and amounts of organic matter will be extracted and mobilized from the reservoir rocks in conjunction with the injection of sc CO 2 . Thus, our investigations may help to evaluate the efficiency and reliability of the long-term storage of CO 2 in such a geological system. Here, we present compound-specific results from laboratory sc CO 2 -extraction experiments on reservoir rock samples from the CO 2 storage site in Ketzin, Germany. Low molecular weight organic acids (LMWOA) as well as polar lipid fatty acids (PLFA) extracted by sc CO 2 were analysed using ion chromatography and gas chromatography-mass spectrometry, respectively. Through the exposure to sc CO 2 mainly formate and acetate, but also other LMWOA were released from the rock samples in varying amounts. PLFA profiles of sc CO 2 extracts were dominated by saturated and unsaturated fatty acids with 16 and 18 carbon atoms of bacterial origin. The results of sc CO 2 extraction are compared with the characterization of the organic inventory of pristine rock samples and fluid samples from observation wells of the Ketzin site to obtain information on quantitative and qualitative significance of the solvent potential of sc CO 2 .

[1]  David R. Cole,et al.  Potential environmental issues of CO2 storage in deep saline aquifers: Geochemical results from the Frio-I Brine Pilot test, Texas, USA , 2009 .

[2]  J. Rullkötter.  Organic Matter: The Driving Force for Early Diagenesis , 2006 .

[3]  A. Vieth,et al.  Biomarker and stable carbon isotope analyses of sedimentary organic matter from Lake Tswaing: evidence for deglacial wetness and early Holocene drought from South Africa , 2010 .

[4]  C. W. Moss,et al.  Lipids in bacterial taxonomy - a taxonomist's view. , 1977, CRC critical reviews in microbiology.

[5]  G. Maciel,et al.  Enhanced signal-to-noise ratios in the nuclear magnetic resonance analysis of solids, using large-sample magic-angle spinners , 1990 .

[6]  Jillian F. Banfield,et al.  Biogeochemical weathering of silicate minerals , 1997 .

[7]  Bernhard Prevedel,et al.  The CO 2 SINK Boreholes for Geological Storage Testing , 2008 .

[8]  D. Barth,et al.  Extraction of hydrocarbons from sedimentary rocks by supercritical carbon dioxide , 1988 .

[9]  J. Grimalt,et al.  Lipid biogeochemistry of Phormidium and Microcoleus mats , 1992 .

[10]  D. Welte,et al.  Removal of soluble organic matter from rock samples with a flow-through extraction cell , 1978 .

[11]  Hilke Würdemann,et al.  Re-establishment of the proper injectivity of the CO2-injection well Ktzi 201 in Ketzin, Germany , 2010 .

[12]  Gunter Borm,et al.  Status Report on the First European on-shore CO2 Storage Site at Ketzin (Germany) , 2008 .

[13]  Christopher Juhlin,et al.  The Geology of the CO2SINK Site: From Regional Scale to Laboratory Scale , 2009 .

[14]  D. White,et al.  Determination of the sedimentary microbial biomass by extractible lipid phosphate , 2004, Oecologia.

[15]  Lechevalier Mp.  Lipids in Bacterial Taxonomy - A Taxonomist's View , 1977 .

[16]  David R. Cole,et al.  Gas-water-rock interactions in Frio Formation following CO2 injection: Implications for the storage of greenhouse gases in sedimentary basins , 2006 .

[17]  Steven B. Hawthorne,et al.  ANALYTICAL-SCALE SUPERCRITICAL FLUID EXTRACTION , 1990 .

[18]  Robert C. Burruss,et al.  Geochemical Investigation of the Potential for Mobilizing Non-Methane Hydrocarbons during Carbon Dioxide Storage in Deep Coal Beds , 2006 .

[19]  Hilke Würdemann,et al.  Monitoring of the microbial community composition in saline aquifers during CO2 storage by fluorescence in situ hybridisation , 2010 .

[20]  Michelle Bentham,et al.  CO2 Storage in Saline Aquifers , 2005 .

[21]  B. Metz.  IPCC special report on carbon dioxide capture and storage , 2005 .

[22]  H. Burton,et al.  Pigment and lipid compositions of algal and bacterial communities in Ace Lake, Vestfold Hills, Antarctica , 1988, Hydrobiologia.

[23]  A. Vieth,et al.  Water extraction of coals – potential for estimating low molecular weight organic acids as carbon feedstock for the deep terrestrial biosphere , 2008 .

[24]  Sam Holloway,et al.  Carbon dioxide capture and geological storage , 2007, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[25]  Jillian F. Banfield,et al.  Geomicrobiology : interactions between microbes and minerals , 1997 .

[26]  R. Findlay,et al.  The use of a classic lipid extraction method for simultaneous recovery of organic pollutants and microbial lipids from sediments , 1996 .

[27]  Michael Kühn,et al.  Progress report on the first european on-shore CO2 storage site at ketzin (Germany) — Second year of injection , 2011 .