Browsing by Author "Bentley, Laurence Robert"

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    A geophysical study of alpine groundwater processes and their geologic controls in the southeastern Canadian Rocky Mountains
    (2017) Christensen, Craig William; Hayashi, Masaki; Hayashi, Masaki; Bentley, Laurence Robert; Diiwu, John
    Groundwater storage is essential for maintaining steady stream flows and temperatures in mountain watersheds, yet catchment-scale hydrogeological processes remain poorly understood. This study characterizes the hydrogeology of a new site in Kananaskis Valley of southeastern Canadian Rocky Mountains. Three different geophysical methods (electrical resistivity tomography, seismic refraction tomography, and ground penetrating radar) imaged structures such as thick, heterogenous talus, permafrost, and a buried overdeepening. Bedrock topography, overburden heterogeneity, and overburden thickness are the most important controls on groundwater flow paths and storage, and may explain anomalously high winter base flows at the site. Comparing the talus deposits to those at a contrasting site in Yoho National Park points to a causal link between hydrogeological characteristics and physiographic variables, hinting at possible spatial patterns in groundwater storage potential. These results will help water resource and ecosystem managers in adapting to stream flow changes resulting from climate change.
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    Characterization and Construction of 3D Numerical Simulators for Oil and Liquids-Rich Multi-Porosity Shale Reservoirs
    (2017) Lopez Jimenez, Bruno Armando; Aguilera, Roberto; Mehta, Sudarshan A.; Moore, Robert Gordon; Harding, Thomas Grant; Bentley, Laurence Robert; Camacho-Velazquez, Rodolfo
    Production from oil and shale gas-condensate reservoirs in the United States and Canada has increased during the past few years. However, an understanding of shale rocks and fluid flow through them is still limited. Thus, the objective of this research is to develop methodologies for characterizing multi-porosities in shale petroleum reservoirs and for simulating fluid flow of oil and condensates through these types of rocks. The characterization part is carried out with the use of (1) an original petrophysical model built for quantification of total organic carbon (TOC), Knudsen number, water saturation, and multiple porosities in shales, (2) measurement of gas permeability from shale samples in the laboratory using commercial equipment, and (3) an original laboratory-based correlation for estimating stress-dependent permeability, porosity and compressibility of tight rocks. The simulation part is carried out with the use of (1) an original radial numerical model developed for calculating sorption-dependent permeability of shales, (2) a commercial 3D model for investigating pore size-dependency of pressure-temperature envelopes in shale gas-condensate reservoirs, and (3) an original fully-implicit 3D-3phase pseudo-compositional model for oil and condensate shale reservoirs developed with capabilities to handle multiple porosities and stress-dependent properties of natural and hydraulic fractures. Key challenges include the handling of (1) adsorbed porosity, (2) organic porosity, (3) inorganic porosity, (4) natural fracture porosity, (5) hydraulic fracture porosity, (6) diffusion from solid kerogen, and (7) fluid transport in the small pores of shales, which deviate significantly from the behavior in conventional reservoirs. It is concluded that the methods developed in this thesis provide important foundation for the characterization and simulation of shale petroleum reservoirs.
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    Modeling Storage and Flow of Fluids in Shale Reservoirs
    (2017) Haghshenas, Behjat; Chen, Shengnan; Clarkson, Christopher R.; Hill, Josephine; Marriott, Robert; Bentley, Laurence Robert; Plaksina, Tatyana; Javadpour, Farzam
    Recent development of shale gas reservoirs has led to a revolution in the global energy market. The shale gas industry has expanded rapidly through the application of new drilling and completion technologies, particularly horizontal wells completed in multiple hydraulic fracture stages. While these technologies play a critical role enabling economical production from these resources, uncertainty in the understanding of basic shale gas reservoir properties, and methods used to characterize them, has led to inefficiencies in shale gas resource development. This thesis addresses uncertainties in the characterization of fluid storage and transport mechanisms in shales, and uses new methods for characterization in exploring enhanced recovery options for shale-hosted hydrocarbons. The primary gas storage mechanisms in organic-rich shales are free gas storage and adsorption; however, there is a significant amount of uncertainty in modeling these storage mechanisms in shale. Of the adsorption models tested, the simplified local density (SLD) model was found to be the most useful for shale gas storage estimation. The model was used not only for adsorption modeling, but also to rigorously correct free gas storage calculations for the presence of adsorbed phase volume. Further, the SLD model was used to predict changes in fluid behaviour within the confined pore space of shale reservoirs. An important contribution of this thesis is the estimation of gas storage and transport parameters from shale reservoir drill cuttings. Low-pressure (N2 and CO2) adsorption data was collected on “artificial” (crushed rock) shale cuttings, and used, in combination with the SLD model to predict high-pressure/high-temperature adsorption of hydrocarbons. Further, adsorption rate data, collected on small masses of artificial cuttings, combined with sophisticated numerical modeling which takes into account the physics of gas storage and transport through shale, was used to estimate shale gas diffusivity/permeability. Finally, the importance of hydrocarbon adsorption and diffusivity for predicting hydrocarbon liquid recovery after CO2 injection was investigated. A history-matched (flowback data) multi-fractured horizontal well completed in a tight liquid-rich reservoir was used as a starting point for sensitivities using CO2 injection. Unique to this study, fluid compositions as a function of depth in the reservoir were available. Simulation of CO2 huff-n-puff schemes using this calibrated model demonstrated that inclusion of adsorption/diffusion effects has an important impact on hydrocarbon liquid recovery.