Waves and oscillations in a coupled conduit-crack system, applications in volcanoes and hydrocarbon reservoirs
Abstract/Contents
- Abstract
- Coupled conduit-crack systems are ubiquitous beneath active volcanoes and in hydrocarbon reservoirs. Understanding the geometry and fluid properties in such systems is critical to evaluating volcanic hazards and optimizing hydrocarbon recovery. However, geological barriers prevent direct observation of subsurface structures. In the oil industry, man-made sources are placed inside wells with known trajectories to excite tube waves or guided waves along a fluid-filled conduit, which are sensitive to properties of the surrounding formation and fractures intersecting the well. Resonance of guided waves along hydraulic fractures, known as Krauklis waves or crack waves, occurs at specific frequencies; these frequencies and associated attenuation of the resonant modes can be used to constrain fracture geometry. Direct measurements of pressures are available along the well but not possible inside the fractures. Therefore, rigorous treatment of fluid-filled cracks and the interactions between waves in the crack and along the conduit are necessary to better exploit the downhole measurements. At active volcanoes, perturbations, such as rockfalls, earthquakes, and explosions, excite very long period (VLP) (longer than 2 s) oscillations in the plumbing system captured by indirect measurements, such as ground deformation, seismic, and infrasound signals. However, a quantitative understanding of wave propagation and resonance in a coupled conduit-crack system is required to interpret observations. In this thesis, I investigate waves and oscillations in a coupled conduit-crack system and aspire to address challenges faced by both volcanology and oil industry. I perform numerical simulations in 2D and 3D to capture rich resonant modes in such systems, understand the oscillation physics of distinct modes, and identify general controls on their periods and decay characteristics, such as finite crack length, width, crack non-planarity, conduit geometry, fluid viscosity, buoyancy, etc. I establish the link between physical parameters in the coupled system with observable measure- ments, such as downhole pressure data and broadband seismic data on Earth's surface, and develop inversion procedure to obtain the optimal parameters that best explain observations.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2019; ©2019 |
| Publication date | 2019; 2019 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Liang, Chao |
|---|---|
| Degree supervisor | Dunham, Eric |
| Thesis advisor | Dunham, Eric |
| Thesis advisor | Mavko, Gary, 1949- |
| Thesis advisor | Segall, Paul, 1954- |
| Degree committee member | Mavko, Gary, 1949- |
| Degree committee member | Segall, Paul, 1954- |
| Associated with | Stanford University, Department of Geophysics. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Chao Liang. |
|---|---|
| Note | Submitted to the Department of Geophysics. |
| Thesis | Thesis Ph.D. Stanford University 2019. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2019 by Chao Liang
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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