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You searched for subject:(Local capillary trapping). Showing records 1 – 2 of 2 total matches.

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University of Texas – Austin

1. Ren, Bo. Local capillary trapping and permeability-retarded accumulation during geologic carbon sequestration.

Degree: PhD, Petroleum Engineering, 2017, University of Texas – Austin

Safe storage of CO2 in saline aquifers depends on CO2 migration rate, accumulation, and trapping inside saline aquifers that have intrinsic heterogeneity. This heterogeneity can be in both capillary entry pressure and permeability. The former heterogeneity causes local capillary trapping while the latter results in permeability-retarded accumulation. A main objective of this dissertation is to understand how both local capillary trapping and permeability-retarded accumulation secure CO2 storage. We establish a fast simulation technique to model local capillary trapping during CO2 injection into saline aquifers. In this technique, modeling efforts are decoupled into two parts: identifying trapping in a capillary entry pressure field and simulating CO2 flow in a permeability field. The former fields are correlated with the latter using the Leverett j-function. The first part describes an extended use of a geologic criterion originally proposed by Saadatpoor (2012). This criterion refers to a single value of ‘critical capillary entry pressure’ that is used to indicate barrier or local traps cells during buoyant flow. Three issues with the criterion are the unknown physical critical value, the massive overestimation of trapping, and boundary barriers. The first two issues are resolved through incorporating viscous flow of CO2. The last issue is resolved through creating periodic boundaries. This creation enables us to study both the amount and clusters of local capillary traps in infinite systems, and meanwhile the effects of reservoir heterogeneity, system size, aspect ratio, and boundary types are examined. In the second part, we adapt a connectivity analysis to assess CO2 plume dynamics. This analysis is then integrated into the geologic criterion to evaluate how injection strategies affect local capillary trapping in reservoirs. We demonstrate that reservoir heterogeneity affects the optimal injection strategies in terms of maximizing this trapping. We conduct analytical and numerical modeling of CO2 accumulations caused by both permeability hindrances and capillary barriers. The analytical model describes CO2 buoyant migration and accumulation at a low permeability region above a high-permeability region. In the limiting case of zero capillary pressure, the model equation is solved using the method of characteristics. The permeability-retarded accumulation is illustrated through CO2 saturation profiles and time-distance diagrams. Capillary trapping is subsequently accounted for by graphically incorporating the capillary pressure curve and capillary threshold effect. The relative importance of these two types of accumulations is examined under various buoyant source fluxes and porous media properties. Results demonstrate that accumulation estimate that account for only capillary trapping understates the amount of CO2 accumulated beneath low permeability structures during significant periods of a sequestration operation. Advisors/Committee Members: Lake, Larry W. (advisor), Bryant, Steven L. (advisor), DiCarlo, David A (committee member), Daigle, Hugh C (committee member), Meckel, Timothy A (committee member).

Subjects/Keywords: Local capillary trapping; Permeability-retarded accumulation; Geologic carbon sequestration; Buoyant flow

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Ren, B. (2017). Local capillary trapping and permeability-retarded accumulation during geologic carbon sequestration. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/62236

Chicago Manual of Style (16th Edition):

Ren, Bo. “Local capillary trapping and permeability-retarded accumulation during geologic carbon sequestration.” 2017. Doctoral Dissertation, University of Texas – Austin. Accessed September 24, 2020. http://hdl.handle.net/2152/62236.

MLA Handbook (7th Edition):

Ren, Bo. “Local capillary trapping and permeability-retarded accumulation during geologic carbon sequestration.” 2017. Web. 24 Sep 2020.

Vancouver:

Ren B. Local capillary trapping and permeability-retarded accumulation during geologic carbon sequestration. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2017. [cited 2020 Sep 24]. Available from: http://hdl.handle.net/2152/62236.

Council of Science Editors:

Ren B. Local capillary trapping and permeability-retarded accumulation during geologic carbon sequestration. [Doctoral Dissertation]. University of Texas – Austin; 2017. Available from: http://hdl.handle.net/2152/62236

2. Sun, Yuhao. Investigation of buoyant plumes in a quasi-2D domain : characterizing the influence of local capillary trapping and heterogeneity on sequestered CO₂ – : a bench scale experiment.

Degree: MSin Engineering, Petroleum Engineering, 2014, University of Texas – Austin

Leakage of stored bulk phase CO₂ is one risk for sequestration in deep saline aquifers. As the less dense CO₂ migrates upward within a storage formation or in layers above the formation, the security of its storage depends upon the trapping mechanisms that counteract the migration. The trapping mechanism motivating this research is local capillary trapping (LCT), which occurs during buoyancy-driven migration of bulk phase CO₂ within a saline aquifer with spatially heterogeneous petrophysical properties. When a CO₂ plume rising by buoyancy encounters a region where capillary entry pressure is locally larger than average, CO₂ accumulates beneath the region. One benefit of LCT, applied specifically to CO₂ sequestration and storage, is that saturation of stored CO₂ phase is larger than the saturation for other permanent trapping mechanisms. Another potential benefit is security: CO₂ that occupies local capillary traps remains there, even if the overlying formation that provides primary containment were to be compromised and allow leakage. Most work on LCT has involved numerical simulation (Saadatpoor 2010, Ganesh 2012); the research work presented here is a step toward understanding local capillary trapping at the bench scale. An apparatus and set of fluids are described which allow examining the extent of local capillary trapping, i.e. buoyant nonwetting phase immobilization beneath small-scale capillary barriers, which can be expected in typical heterogeneous storage formation. The bench scale environment analogous to CO₂ and brine in a saline aquifer is created in a quasi-two dimensional experimental apparatus with dimension of 63 cm by 63 cm by 5 cm, which allows for observation of plume migration with physically representative properties but at experimentally convenient ambient conditions. A surrogate fluid pair is developed to mimic the density, viscosity and interfacial tension relationship found at pressure and temperature typical of storage aquifers. Porous media heterogeneity, pressure boundary conditions, migration modes of uprising nonwetting phase, and presence of fracture/breach in the capillary barrier are studied in series of experiments for their influences on LCT. A variety of heterogeneous porous media made of a range of sizes of loosely packed silica beads are used to validate and test the persistence of local capillary trapping mechanism. By adjusting the boundary conditions (fluid levels in reservoirs attached to top and to bottom ports of the apparatus), the capillary pressure gradient across the domain was manipulated. Experiments were conducted with and without the presence of fracture/potential leakage pathway in the capillary seal. The trapped buoyant phase remained secure beneath the local capillary barriers, as long as the effective capillary pressure exerted by the trapped phase (proportional to column height of the phase) is smaller than the capillary entry pressure of the barrier. The local capillary trapping mechanism remained persistent even under forced imbibition, in which a… Advisors/Committee Members: Bryant, Steven L. (advisor).

Subjects/Keywords: CO₂ geologic sequestration; Local capillary trapping

…19 2.1.2 Local capillary trapping .…. .…21 2.1.3 Local capillary trapping at… …storage .. 31 2.5 Persistence of local capillary trapping to CO2 storage safety… …Experimental plan for influence of bead size distribution on local capillary trapping… …the local capillary trapping volume with normalized critical capillary entry pressure for… …local capillary trapping volume with normalized critical capillary entry pressure for base… 

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Sun, Y. (2014). Investigation of buoyant plumes in a quasi-2D domain : characterizing the influence of local capillary trapping and heterogeneity on sequestered CO₂ – : a bench scale experiment. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/26451

Chicago Manual of Style (16th Edition):

Sun, Yuhao. “Investigation of buoyant plumes in a quasi-2D domain : characterizing the influence of local capillary trapping and heterogeneity on sequestered CO₂ – : a bench scale experiment.” 2014. Masters Thesis, University of Texas – Austin. Accessed September 24, 2020. http://hdl.handle.net/2152/26451.

MLA Handbook (7th Edition):

Sun, Yuhao. “Investigation of buoyant plumes in a quasi-2D domain : characterizing the influence of local capillary trapping and heterogeneity on sequestered CO₂ – : a bench scale experiment.” 2014. Web. 24 Sep 2020.

Vancouver:

Sun Y. Investigation of buoyant plumes in a quasi-2D domain : characterizing the influence of local capillary trapping and heterogeneity on sequestered CO₂ – : a bench scale experiment. [Internet] [Masters thesis]. University of Texas – Austin; 2014. [cited 2020 Sep 24]. Available from: http://hdl.handle.net/2152/26451.

Council of Science Editors:

Sun Y. Investigation of buoyant plumes in a quasi-2D domain : characterizing the influence of local capillary trapping and heterogeneity on sequestered CO₂ – : a bench scale experiment. [Masters Thesis]. University of Texas – Austin; 2014. Available from: http://hdl.handle.net/2152/26451

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