Anisotropic Fracture Toughness Characterization of Shale Formation from Drill Cuttings

dc.contributor.advisorSakhaee-Pour, Ahmad
dc.contributor.committeeMemberFarouq Ali, S. M.
dc.contributor.committeeMemberEhlig-Economides, Christine
dc.contributor.committeeMemberWong, George K.
dc.contributor.committeeMemberSepehrnoori, Kamy
dc.creatorEsatyana, Erica 2022
dc.description.abstractShale is a sedimentary rock composed of clay minerals and silt-sized particles. Its pore throat sizes are as small as 10 nm in its matrix, which leads to ultralow permeability. It has become economically viable for hydrocarbon recovery because of hydraulic fracturing, in which the required energy is defined by fracture toughness. Shale is mechanically unstable and retrieving a suitable core size for common tests is costly and time-consuming. Thus, there is a need to develop new methods applicable to small pieces such as drill cuttings, which are often the only sources available in real-time conditions. This study proposes two methods for the geomechanical characterization of shale at the core scale based on the interpretation of small-scale measurements. Both rely on nanoindentations. The proposed conceptual models have applications in characterizing formation heterogeneity in the petroleum industry. The first determines Young’s moduli from cuttings, and the results are compared with those of the core plugs from the Wolfcamp Formation. The sensitivity of the results to sample preparation is also discussed. The second method characterizes the fracture toughness of shale based on the conceptual model proposed in accordance with the effective medium theory. The proposed model sheds light on the complexities of the induced fracture patterns in shale that differ from those observed in homogeneous materials, such as fused silica and aluminum. The conceptual model is realistic for shale because it captures the sample heterogeneity. The second method is tested at a small scale using different tip geometries. The interpreted fracture toughness values from the cube-corner and Berkovich tips are close, with less than 18% difference, which provides a partial validation for the conceptual model. The proposed model is also tested against independent data obtained from the cracked Chevron notched Brazilian disc (CCNBD) test. The difference between predicted fracture toughness values from nanoindentation and the CCNBD test is less than 13%, and this good agreement validates the proposed model. The proposed model has applications in characterizing the mechanical properties of shale using small samples from unconventional resources.
dc.description.departmentPetroleum Engineering, Department of
dc.format.digitalOriginborn digital
dc.identifier.citationPortions of this document appear in: Esatyana, Erica, A. Sakhaee-Pour, Fadhil N. Sadooni, and Hamad Al-Saad Al-Kuwari. "Nanoindentation of shale cuttings and its application to core measurements." Petrophysics-The SPWLA Journal of Formation Evaluation and Reservoir Description 61, no. 05 (2020): 404-416; and in: Esatyana, E., Alipour, M., Sakhaee-Pour, A., 2021, Characterizing Anisotropic Fracture Toughness of Shale Using Nanoindentation, SPE Reservoir Evaluation, and Engineering.
dc.rightsThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. UH Libraries has secured permission to reproduce any and all previously published materials contained in the work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).
dc.subjectShale cuttings
dc.subjectConceptual model
dc.subjectFracture toughness
dc.subjectYoung's modulus
dc.titleAnisotropic Fracture Toughness Characterization of Shale Formation from Drill Cuttings
dc.type.genreThesis College of Engineering Engineering, Department of Engineering of Houston of Philosophy


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