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Toward Better Understandings of Unconventional Reservoirs - Rock Mechanical Properties and Hydraulic Fracture Perspectives

Gong, Yiwen
http://rave.ohiolink.edu/etdc/view?acc_num=osu1605633687308252

Abstract Details

2020, Doctor of Philosophy, Ohio State University, Chemical Engineering.
The advancements of hydraulic fracturing techniques ensure the improved fracture surface areas that are open to fluids flow. The induced microcracks accelerate the fluid communications between fractures and the fracture adjacent rock matrix at fracture surface. In brittle rocks, the generated fracture network puzzles engineers since the induced hydraulic fractures and activated pre-existing fractures challenge the stimulated reservoir volume (SRV) characterizations. Furthermore, the necessary engineered justifications of each stage due to lateral heterogeneity of the reservoir and the stress shadow effect (in-situ stress increase along the wellbore) even introduce another level of complexity of the effective fracture drainage complexity. Simultaneous fracture growth becomes difficult, resulting in variations of fracture half lengths, within a stage, and among stages. The failure planes of the rock, from mode I, mode II and the combination of them, are not smooth and parallel; instead, they are usually associated with certain surface roughness and non-planar morphology, which in turn inhibit the ideal Poiseuille flow in the fracture. As a result, the fundamental studies of non-planar and rough complex fracture paths to the proppant transport are essentially inevitable. To gain better understanding of the fracture network and the geomechanical aspects that form the complex fracture network, the objective of this work is firstly to quantitatively measure the rock damage from the induced microcracks at the adjacent matrix of the hydraulic fracture; we will then investigate the rock geomechanical properties which essentially dominant the fracture generation using machine learning approaches with cross-disciplinary data sources, including well logs, petrophysical properties, and rock microstructures information. Lastly, we will probe proppant transport characteristics in bifurcated fracture system. To achieve the aforementioned adjectives, this dissertation is structured into two major parts: the microstructure diagnosis of fractured tight rocks and geomechanical rock property estimations beyond the traditional approach as the first part and the proppant transport considering the induced microfracture/bifurcated fractures as the second part. To be more specific, the microstructure analysis is achieved by SEM image analysis while the geomechanical study is conducted optimizing the data usage from machine learning techniques. The second major part is to build the complex fracture network modeling by including non-planarity, and secondary fractures and tertiary fractures in the computational fluid dynamics modeling frame (Eulerian-Eulerian) in the field scale as well as computational fluid dynamics – discrete element method coupling frame (Eulerian- Lagrangian) in the flow-unit scale, respectively. The proppant transport loss passing the bifurcated fractures are evaluated.
Ilham El-Monier (Advisor)
David Tomasko (Committee Co-Chair)
Liang-Shih Fan (Committee Member)
Yang Shang-Tian (Committee Member)
Chemical Engineering; Petroleum Engineering
Proppant transport; machine learning; rock geomechanical properties; CFD; CFD-DEM

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Citations

  • Gong, Y. (2020). Toward Better Understandings of Unconventional Reservoirs - Rock Mechanical Properties and Hydraulic Fracture Perspectives [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1605633687308252

    APA Style (7th edition)

  • Gong, Yiwen. Toward Better Understandings of Unconventional Reservoirs - Rock Mechanical Properties and Hydraulic Fracture Perspectives. 2020. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1605633687308252.

    MLA Style (8th edition)

  • Gong, Yiwen. "Toward Better Understandings of Unconventional Reservoirs - Rock Mechanical Properties and Hydraulic Fracture Perspectives." Doctoral dissertation, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1605633687308252

    Chicago Manual of Style (17th edition)

osu1605633687308252
168
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