http://arks.princeton.edu/ark:/88435/dsp016q182k13h 2013-05-04T15:12:15Z 2013-05-04T15:12:15Z Cuisiat, Fabrice http://arks.princeton.edu/ark:/88435/dsp01h128nd697 2012-09-25T14:10:12Z 2011-09-15T14:54:52Z

Title: Cap rock fracturing criteria for assessment of CO2 storage capacity Authors: Cuisiat, Fabrice Abstract: In this technical note, the conditions leading to fracturing of the cap rock are reviewed. The overall objective of the work is to implement simple analytical models into computational codes to assess the integrity of a cap rock during CO2 injection. Advanced geomechanical modelling of the stress and pressure conditions leading to cap rock failure, goes beyond the scope of the study. Such modelling may be required to understand the mechanisms at play, in particular of fluid pressure – stress coupling (Mourgues et al., 2011) and fracture propagation in the cap rock during CO2 injection. This report has been developed at the request of the Norwegian Computing Center and the Norwegian Research Council Project: Impact of Realistic Geological Models on Simulation of CO2 storage.

2011-09-15T14:54:52Z Court, Benjamin http://arks.princeton.edu/ark:/88435/dsp01ms35t861f 2013-02-07T14:36:22Z 2011-07-14T13:31:30Z

Title: PhD Dissertation - Safety and Water Challenges in CCS: Modeling Studies to Quantify CO2 and Brine Leakage Risk and Evaluate Promising Synergies for Active and Integrated Water Management Authors: Court, Benjamin Abstract: Carbon dioxide Capture and Sequestration, or CCS, is the only technology available to mitigate the high CO2 emissions from coal-fired electricity production. Since coal is projected to continue to dominate worldwide electricity production, any global atmospheric CO2 concentration stabilization strategy will need to include CCS. There is therefore a strong need to increase the number and scale of CCS projects by several orders of magnitude over the next two decades. Such a ramp-up in CCS projects, however, faces several potential barriers. This dissertation focuses on two such barriers: the previously identified issue of CO2 sequestration safety, and the newly identified CCS issue of water management coupled to CCS operations. In regard to safety, this dissertation advances the capability to model CO2 injection and migration, and the associated pressure build-up to quantify large-scale CO2 and brine leakage risk. Limitations associated with different modeling approaches are evaluated. Regarding water issues, this dissertation improves the current CCS paradigm by considering water requirements for the overall CCS operations and identifying beneficial synergies associated with coupled carbon and water managements. The first part of this dissertation (Chapters 2 through 4) addresses one of the outstanding unanswered CO2 sequestration safety questions, identified by the 2005 IPCC Special Report on CCS, of how to develop reliable quantitative risk assessments of CO2 and brine leakage. In North America, the century-long legacy of oil and gas exploration and production has left millions of old oil and gas wells. Many of these wells are co-located with otherwise good geological sequestration sites, and because the hydraulic properties of the well materials are uncertain, quantitative assessment is challenging. Chapter 2 reviews the hierarchy of vertically-integrated CO2 injection and migration models recently developed to provide such a risk assessment. Chapter 3 presents the quantification of field-scale CO2 and brine leakage risks through abandoned wells of an industrial CO2 injection using a specialized sharp-interface model that is computationally very efficient. Model comparison to results from the industry-standard model ECLIPSE are presented in Chapter 4 to better understand when this vertically-integrated modeling approach is applicable and when the sharp-interface assumption is valid, focusing respectively on the time scale of brine drainage and the spatial scale of capillary effects. The second part of this dissertation (Chapters 5 and 6) presents a paradigm shift in the way a CCS system is considered. We argue that the CCS surface facility and subsurface environment ought to be considered jointly, and that their respective implementation challenges, particularly concerning water management, should be examined collectively across all CCS operations. Retrofitting an existing power plant to capture CO2 implies a doubling of cooling-water requirements. This additional water requirement can be technically challenging and highly publicly sensitive in water-stressed areas. At the same time, the extensive area of subsurface pressure perturbation and the CO2 and brine leakage risks of the CO2 sequestration operation will present regulatory and public acceptance challenges. Chapter 5 therefore provides a complete review of water, sequestration, legal, and public acceptance CCS implementation barriers and proposes a novel active and integrated CCS operation management framework to address them. Examining these barriers and challenges collectively allows us to identify multiple potentially advantageous synergies. Active management of water resources, including production and treatment of subsurface brines, can synergistically provide additional surface cooling water while reducing both the subsurface leakage risk and pressure perturbation, which will facilitate regulatory permitting and increase public acceptance. Chapter 6 quantifies the advantageous impacts of three of these identified synergies coupling simultaneous brine production to a large-scale CO2 geological sequestration operation. Brine production can reduce the injection well pressure, which enables higher injectivity potential; can reduce the extent of the Area of Review; and can reduce the risk of CO2 and brine leakage. This dissertation provides novel and important contributions in advancing the fields of CO2 sequestration safety modeling focusing on leakage risk, and in addressing CCS potential implementation barriers with a focus on water challenges. By integrating modeling progress and the broader considerations of the CCS surface and subsurface environments, presented in this dissertation, future work has the potential to provide a more complete understanding of both the CCS system and implementation barriers. The exploitation of all the identified synergies provides the best possibilities for successful large-scale implementation of CCS.

2011-07-14T13:31:30Z Court, Benjamin Celia, Michael Nordbotten, Jan Dobossy, Mark Elliot, Thomas Bandilla, Karl http://arks.princeton.edu/ark:/88435/dsp01rf55z769f 2013-02-07T14:34:45Z 2011-07-08T15:46:32Z

Title: Modeling Options to Answer Practical Questions for CO2 Sequestration Operations Authors: Court, Benjamin; Celia, Michael; Nordbotten, Jan; Dobossy, Mark; Elliot, Thomas; Bandilla, Karl Abstract: Mitigating climate change requires addressing both the CO2 atmospheric concentration and thus coal dominant share of baseload-electricity production. This necessitates a worldwide ramping up of CO2 capture and sequestration implementation in the next decades. This will come with several challenges. One of them is CO2 sequestration reliability which is impaired by very numerous leakage pathways. Traditional complex numerical tools are useful to provide physical insights of the CO2 behavior. But they are often inappropriate to investigate risk associated with leakage, especially when significant uncertainty leads to the need for computationally intensive probabilistic assessments. A range of models may be developed which become sequentially simpler as more assumptions are applied to the system. The models, and the assumptions, are often associated with specific scales of resolution in the model, both in space and in time. A clear accounting of these models, and their associated assumptions as well as the length and time scales, allows models to be chosen that are best suited to answer the questions being asked. Almost all sequestrations operations will involve three questions about the size of the CO2 and pressure-perturbation footprints, the possibility of leakage of fluids out of the injection formation, and the long-term fate of the injected CO2. These ubiquitous questions are all associated with large space and time scales, and models to answer these questions should be associated with those same scales. This leads to a set of accurate simplified models that can provide meaningful answers to all three of these questions, with a broader multi-scale framework proposed that can accommodate other scales of importance and can combine different models into a so-called hybrid modeling approach. Examples include simplified and CPU-efficient analytical and semi-analytical models for multiple formation (10+) with multiple wells (1000+) within the context of many thousands of simulations required for a probabilistic of leakage risk along old wells; to more complex vertically-integrated numerical models solving injection and post-injection CO2 and brine migration, incorporating heterogeneity and complex topography. Such a multi-scale hybrid modeling approach represents a very promising direction that has evolved in the geological sequestration field since the SRCCS publication in 2005, and it provides a broad platform for on-going and future work across a wide range of modeling approaches.

2011-07-08T15:46:32Z Celia, Michael A. http://arks.princeton.edu/ark:/88435/dsp018g84mm25v 2013-02-07T14:36:17Z 2010-08-12T20:14:48Z

Title: Geological Storage as a Carbon Mitigation Option (The Darcy Lecture) Authors: Celia, Michael A. Abstract: Anthropogenic emissions of carbon dioxide have increased atmospheric concentration of CO2 by about 35% over the past 200 years. The current concentration, at about 385 parts per million, represents the highest CO2 concentration in the last 500,000 years. Projected future emissions will lead to doubling of pre-industrial CO2 concentration within the next 50 years. If this relentless increase of atmospheric CO2 is to be reduced, or reversed, technological solutions must be implemented on a massive scale. While many options are being considered, one attractive approach is carbon capture and storage, or CCS. The 'geological storage' version of CCS involves capture of CO2 before it is emitted into the atmosphere, and subsequent injection of the CO2 into deep geological formations. Injection of CO2 into deep formations leads to a multi-phase flow problem that may involve important mass exchange between phases, non-isothermal effects, and complex geochemical reactions. In addition, because enormous quantities of CO2 must be injected to have any significant impact on the atmospheric carbon problem, the spatial scale of the problem becomes very large. Broad questions involving the fate of the injected CO2, including possible leakage of CO2 out of the formation, as well as the fate of displaced fluids like resident brines, lead to very challenging modeling and analysis problems. Because important leakage pathways can be very localized, and their properties can be highly uncertain, an overall analysis of the system requires resolution of multiple length scales in the context of a probabilistic approach. These requirements render standard numerical simulators ineffective due to excessive computational demands. A series of simplifying assumptions may be proposed to provide more efficient numerical calculations, even to the point of allowing for analytical or semi-analytical solutions. Such simplifications, while restrictive in their assumptions, allow for large-scale analysis of leakage in a probabilistic framework while capturing much of the essential physics of the problem. Example calculations illustrate the utility of these methods, and show the current state of leakage estimation. They also lead to a proposal for specific field experiments that can reduce the uncertainty associated with potential leakage pathways.

2010-08-12T20:14:48Z