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Title: Sensitivity study of CO2 storage capacity in brine aquifers withclosed boundaries: Dependence on hydrogeologic properties

Abstract

In large-scale geologic storage projects, the injected volumes of CO{sub 2} will displace huge volumes of native brine. If the designated storage formation is a closed system, e.g., a geologic unit that is compartmentalized by (almost) impermeable sealing units and/or sealing faults, the native brine cannot (easily) escape from the target reservoir. Thus the amount of supercritical CO{sub 2} that can be stored in such a system depends ultimately on how much pore space can be made available for the added fluid owing to the compressibility of the pore structure and the fluids. To evaluate storage capacity in such closed systems, we have conducted a modeling study simulating CO{sub 2} injection into idealized deep saline aquifers that have no (or limited) interaction with overlying, underlying, and/or adjacent units. Our focus is to evaluate the storage capacity of closed systems as a function of various reservoir parameters, hydraulic properties, compressibilities, depth, boundaries, etc. Accounting for multi-phase flow effects including dissolution of CO{sub 2} in numerical simulations, the goal is to develop simple analytical expressions that provide estimates for storage capacity and pressure buildup in such closed systems.

Authors:
; ; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE
OSTI Identifier:
928388
Report Number(s):
LBNL-63388
R&D Project: 0; BnR: YN0100000; TRN: US200815%%633
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Conference
Resource Relation:
Conference: The Sixth Annual Conference on Carbon Capture andSequestration, Pittsburgh, PA, 02/15/2007
Country of Publication:
United States
Language:
English
Subject:
54; AQUIFERS; BRINES; BUILDUP; CAPACITY; CARBON; COMPRESSIBILITY; DISSOLUTION; HYDRAULICS; PORE STRUCTURE; SENSITIVITY; SIMULATION; STORAGE; TARGETS

Citation Formats

Zhou, Q., Birkholzer, J., Rutqvist, J., and Tsang, C-F.. Sensitivity study of CO2 storage capacity in brine aquifers withclosed boundaries: Dependence on hydrogeologic properties. United States: N. p., 2007. Web.
Zhou, Q., Birkholzer, J., Rutqvist, J., & Tsang, C-F.. Sensitivity study of CO2 storage capacity in brine aquifers withclosed boundaries: Dependence on hydrogeologic properties. United States.
Zhou, Q., Birkholzer, J., Rutqvist, J., and Tsang, C-F.. Wed . "Sensitivity study of CO2 storage capacity in brine aquifers withclosed boundaries: Dependence on hydrogeologic properties". United States. doi:. https://www.osti.gov/servlets/purl/928388.
@article{osti_928388,
title = {Sensitivity study of CO2 storage capacity in brine aquifers withclosed boundaries: Dependence on hydrogeologic properties},
author = {Zhou, Q. and Birkholzer, J. and Rutqvist, J. and Tsang, C-F.},
abstractNote = {In large-scale geologic storage projects, the injected volumes of CO{sub 2} will displace huge volumes of native brine. If the designated storage formation is a closed system, e.g., a geologic unit that is compartmentalized by (almost) impermeable sealing units and/or sealing faults, the native brine cannot (easily) escape from the target reservoir. Thus the amount of supercritical CO{sub 2} that can be stored in such a system depends ultimately on how much pore space can be made available for the added fluid owing to the compressibility of the pore structure and the fluids. To evaluate storage capacity in such closed systems, we have conducted a modeling study simulating CO{sub 2} injection into idealized deep saline aquifers that have no (or limited) interaction with overlying, underlying, and/or adjacent units. Our focus is to evaluate the storage capacity of closed systems as a function of various reservoir parameters, hydraulic properties, compressibilities, depth, boundaries, etc. Accounting for multi-phase flow effects including dissolution of CO{sub 2} in numerical simulations, the goal is to develop simple analytical expressions that provide estimates for storage capacity and pressure buildup in such closed systems.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Feb 07 00:00:00 EST 2007},
month = {Wed Feb 07 00:00:00 EST 2007}
}

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  • Careful site characterization is critical for successfulgeologic sequestration of CO2, especially for sequestration inbrine-bearing formations that have not been previously used for otherpurposes. Traditional site characterization techniques such asgeophysical imaging, well logging, core analyses, interference welltesting, and tracer testing are all valuable. However, the injection andmonitoring of CO2 itself provides a wealth of additional information.Rather than considering a rigid chronology in which CO2 sequestrationoccurs only after site characterization is complete, we recommend thatCO2 injection and monitoring be an integral part of thesite-characterization process. The advantages of this approach arenumerous. The obvious benefit of CO2 injection is to provide informationon multi-phasemore » flow properties, which cannot be obtained from traditionalsitecharacterization techniques that examine single-phase conditions.Additionally, the low density and viscosity of CO2 compared to brinecauses the two components to flow through the subsurface differently,potentially revealing distinct features of the geology. Finally, tounderstand sequestered CO2 behavior in the subsurface, there is nosubstitute for studying the movement of CO2 directly. Making CO2injection part of site characterization has practical benefits as well.The infrastructure for surface handling of CO2 (compression, heating,local storage) can be developed, the CO2 injection process can bedebugged, and monitoring techniques can be field-tested. Prior to actualsequestration, small amounts of CO2 may be trucked in. Later, monitoringaccompanying the actual sequestration operations may be used tocontinually refine and improve understanding of CO2 behavior in thesubsurface.« less
  • Sedimentary basins in general and deep saline aquifers in particular, are being investigated as possible repositories for large volumes of anthropogenic CO2 that must be sequestered to mitigate global warming and related climate changes. To investigate the potential for the long-term storage of CO2 in such saline aquifers, 1600 t of CO2 were injected at 1500 m depth into a 24-m-thick C sandstone section of the Frio Formation, a regional aquifer in the U.S. Gulf Coast. Fluid samples obtained before CO2 injection from the injection well and an observation well 30 m up dip showed a Na-Ca-Cl type brine withmore » ~93,000 mg/L TDS at saturation with CH4 at reservoir conditions; gas analyses show CH4 comprised ~95% of dissolved gas, but CO2 was low at 0.3%. Following CO2 breakthrough, 51 h after injection, samples showed sharp drops in pH (6.5 to 5.7), pronounced increases in alkalinity (100 to 3000 mg/L as HCO3) and in Fe (30 to 1100 mg/L), a slug of very high DOC values, and significant shifts in the isotopic compositions of H2O, DIC, and CH4. These data coupled with geochemical modeling indicate rapid dissolution of minerals, especially calcite and iron oxyhydroxides caused by lowered pH (initially ~3.0 at subsurface conditions) of the brine in contact with supercritical CO2.« less
  • Various approaches are used to evaluate the capacity of saline aquifers to store CO 2, resulting in a wide range of capacity estimates for a given aquifer. The two approaches most used are the volumetric “open aquifer” and “closed aquifer” approaches. We present four full-scale aquifer cases, where CO 2 storage capacity is evaluated both volumetrically (with “open” and/or “closed” approaches) and through flow modeling. These examples show that the “open aquifer” CO 2 storage capacity estimation can strongly exceed the cumulative CO 2 injection from the flow model, whereas the “closed aquifer” estimates are a closer approximation to themore » flow-model derived capacity. An analogy to oil recovery mechanisms is presented, where the primary oil recovery mechanism is compared to CO 2 aquifer storage without producing formation water; and the secondary oil recovery mechanism (water flooding) is compared to CO 2 aquifer storage performed simultaneously with extraction of water for pressure maintenance. This analogy supports the finding that the “closed aquifer” approach produces a better estimate of CO 2 storage without water extraction, and highlights the need for any CO 2 storage estimate to specify whether it is intended to represent CO 2 storage capacity with or without water extraction.« less
  • No abstract prepared.
  • This paper sets out the advantages of using off-the-shelf equipment to produce an effective compressed air energy system (CAES) and to develop the storage parameters of those geological entrapments that can be pressurized with air for the generation of electrical energy on demand. Off-the-shelf hardware and predesigned turbo-machinery specified herein is readily adaptable to aquifer storage parameters and can be manufactured without the expense and uncertainty related to developmental hardware. Hence, normal equipment manufacturer's assurances and guarantees are available for these applications.