Effects of Thermally-Induced Secondary Cracks on Hydraulic Fractures

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atmire.migration.oldid1050
dc.contributor.advisorSettari, Antonin
dc.contributor.authorTran, David Viet Dang
dc.date.accessioned2013-06-17T16:56:15Z
dc.date.available2014-01-16T08:00:19Z
dc.date.issued2013-06-17
dc.date.submitted2013en
dc.description.abstractThe purpose of this research is to investigate the change in geometry of a hydraulic fracture aperture over time when cold frac fluid is injected into a hot reservoir. Secondary cracks may occur around the surface of a hydraulic fracture if there is large difference between frac fluid and the formation temperature. The study is organized as follows: 1. Literature review and development of fundamental equations (Chapter 1 & 2): Literature related to hydraulic fracture stimulation is reviewed, to support this study’s importance and explain how it will enrich the research in the field of hydraulic fracturing. Fundamental equations of flow and deformation, which form the basis of this this research, are developed. 2. Initiation and propagation of secondary cracks (Chapter 3): Using the finite element method, initiation and propagation of secondary cracks in porous media is calculated under varying combinations of pore pressure, temperature, Young’s modulus, initial effective stress, pressure and thermal diffusivity, leakoff conditions and crack spacing. The initiation time and growth of the length and width of the secondary cracks are computed. 3. Growth and decay of a hydraulic fracture (Chapter 4): Aperture formulae, based on the continuum thermo-poroelasticity for a KGD (Khristianovic-Geerstma-de Klerk) fracture model under 2D plane strain and plane stress conditions, are developed. These new, simple formulae consider the effects of poroelasticity and thermo-elasticity, as well as the distances the pressure and temperature propagate into the medium (penetration depth). The aperture formulae are validated by comparing their results with the results of the finite element method. The comparison shows that the simplified formulae provide excellent results with significant reduction in computation time. 4. Effects of secondary cracks on the aperture of hydraulic fracture (Chapter 5): This phenomenon is quite new in the hydraulic fracturing stimulation. Under given boundary conditions, secondary cracks will appear on the fracture surface and propagate into the formation. When the secondary cracks occur, fracture aperture magnitude and shape change. Therefore, the presence of secondary cracks will significantly influence the fracturing stimulation process. Discussion and recommendations for further studies are provided at the end of the dissertation in Chapter 6. The results emphasize the important role that geomechanics plays in the simulation of hydraulic fracturing.en_US
dc.description.embargoterms6 monthsen_US
dc.identifier.citationTran, D. V. (2013). Effects of Thermally-Induced Secondary Cracks on Hydraulic Fractures (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/25834en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/25834
dc.identifier.urihttp://hdl.handle.net/11023/757
dc.language.isoeng
dc.publisher.facultyGraduate Studies
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.rightsUniversity 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.
dc.subjectEngineering--Civil
dc.subjectEngineering--Mechanical
dc.subjectEngineering--Petroleum
dc.subject.classificationHydraulic fractureen_US
dc.subject.classificationSecondary cracksen_US
dc.subject.classificationJumps in aperture profilesen_US
dc.subject.classificationPenetration depthen_US
dc.subject.classificationCrack interactionen_US
dc.subject.classificationCrack clustersen_US
dc.subject.classificationCrack lengthen_US
dc.subject.classificationCrack widthen_US
dc.subject.classificationPressurizationen_US
dc.subject.classificationLeakoffen_US
dc.subject.classificationPorous mediumen_US
dc.titleEffects of Thermally-Induced Secondary Cracks on Hydraulic Fractures
dc.typedoctoral thesis
thesis.degree.disciplineChemical and Petroleum Engineering
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameDoctor of Philosophy (PhD)
ucalgary.item.requestcopytrue
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