Pedersen, Per KentMacKay, Paul A.Komaromi, Bram Alexander2020-05-062020-05-062020-05-05Komaromi, B. A. (2020). Advances in Natural Fracture Characterization in Heterogeneous and Anisotropic Reservoirs (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.http://hdl.handle.net/1880/111992Natural fractures are the most common geologic structure in the Earth’s upper crust and have significant influence in a variety of geologic processes that affect many fields in geoscience and engineering related to hydrocarbon, geothermal, groundwater, and mineral resource exploration and production, carbon dioxide sequestration, waste disposal, and contaminant transport. This thesis addresses a number of problems involving natural fracture networks developed in anisotropic and heterogeneous unconventional reservoirs including: the controls on fracture stratigraphy, the relative timing and mode of natural fracturing, the variation in aperture along subsurface opening-mode fractures, and the scaling behavior of orientation dispersion. In order to address these challenges, a wide range of natural fracture datasets were collected and integrated from the subsurface and outcrop. Novel approaches to characterizing and quantifying fracture geometry are significant contributions of this thesis. Fracture characterization conducted in an organic-rich unconventional reservoir analog outcropping in the southern Alberta fold-and-thrust belt reveal that fracture stratigraphy is more strongly controlled by lithofacies characteristics than structural position, and that commonly applied scaling relationships are insufficient in describing fracture geometry. Detailed petrographic observation of the fracture-filling cements and fluid inclusion populations within the fractures reveal a complex geochemical and kinematic history among the different fracture sets. Textural evidence indicates differences in failure mode depending on lithofacies while fluid inclusion petrography and microthermometry indicate the fractures formed at depth and experienced a complex fluid migration history. Aperture measurements collected along opening-mode fractures exposed in a high-quality core of an unconventional reservoir correlate with lithology and show that previously established relationships between size and aperture are unreliable. Using a newly developed methodology, the scaling of orientation dispersion was quantified. High-resolution observations of fracture orientation, like those derived from well data, possess a large degree of variability that over-estimates the connectivity of fracture networks in reservoir-scale models. The research presented throughout this thesis serves to further the current understanding of natural fracture geometry in reservoirs characterized by heterogeneity and anisotropy. Furthermore, this thesis presents novel descriptions of natural fracture geometry and demonstrates newly developed approaches to quantifying the complexity of fracture geometry.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Natural fracturesGeologydoctoral thesis10.11575/PRISM/37802