ORCID Identifier(s)

0000-0001-8072-7098

Graduation Semester and Year

2022

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Earth and Environmental Science

Department

Earth and Environmental Sciences

First Advisor

Qinhong Hu

Abstract

Understanding geomechanical properties of shales, such as stiffness properties and fracture toughness, is important in different areas of petroleum industry-related activities including fracturing efficiency, petroleum flow to the wellbores, and induced seismicity. Nanoscale to microscale experiments on shale samples require a much smaller sample compared to macroscale experiments. This is a major advantage because irregularly-shaped drill cuttings from shales can be used for experimental analyses, such as nanoindentation or atomic force microscopy (AFM). However, a characterization of mechanical properties at the nano- to micro-scale is a relatively new addition to classical geomechanical experiments on shales, and there is still lack of both fundamental knowledge and standard procedures for conducting experiments at this scale. The frictional behavior is one of the important mechanical properties of organic matter (OM) which is still not investigated. The first half of this dissertation is focused on understanding the standard procedures for conducting the experiments in nanoscale and investigating the frictional properties. For this research, I examine the mineralogy of the surface of shale samples using scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and measuring the friction force and Young's modulus of OM using AFM. Samples from Bakken shale formation has been used for this project. The second half of this dissertation is focused on understanding the structure and geometry of pore spaces. Because hydrocarbon is accumulated mainly in the pore spaces of shale, coal, and tight sandstone reservoirs, it is highly crucial to understand the morphology of the pore spaces. For this research, I applied SEM imaging and image processing and compared their results with these from AFM imaging of the pore structure. Samples from Bossier shale and Haynesville shale formation has been used for this project. Overall, this dissertation will help to understand the standard procedures of mechanical characterization and the frictional behavior of OM in nanoscale, and determine the 3D structure of pore spaces, of organic-rich shales.

Keywords

AFM, Organic-rich shale, Nanotribology, Friction, Young's modulus, Pore structure

Disciplines

Earth Sciences | Physical Sciences and Mathematics

Comments

Degree granted by The University of Texas at Arlington

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