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作者 Daigle, Hugh Callahan
書名 Pore-Scale Controls on Permeability, Fluid Flow, and Methane Hydrate Distribution in Fine-Grained Sediments
國際標準書號 9781124774886
book jacket
說明 225 p
附註 Source: Dissertation Abstracts International, Volume: 72-10, Section: B, page:
Adviser: Brandon Dugan
Thesis (Ph.D.)--Rice University, 2011
Permeability in fine-grained sediments is governed by the surface area exposed to fluid flow and tortuosity of the pore network. I modify an existing technique of computing permeability from nuclear magnetic resonance (NMR) data to extend its applicability beyond reservoir-quality rocks to the fine-grained sediments that comprise the majority of the sedimentary column. This modification involves correcting the NMR data to account for the large surface areas and disparate mineralogies typically exhibited by fine-grained sediments. Through measurements on resedimented samples composed of controlled mineralogies, I show that this modified NMR permeability algorithm accurately predicts permeability over 5 orders of magnitude. This work highlights the importance of pore system surface area and geometry in determining transport properties of porous media
I use these insights to probe the pore-scale controls on methane hydrate distribution and hydraulic fracturing behavior, both of which are controlled by flux and permeability. To do this I employ coupled poromechanical models of hydrate formation in marine sediments. Fracture-hosted methane hydrate deposits are found at many sites worldwide, and I investigate whether pore occlusion and permeability reduction due to hydrate formation can drive port fluid pressures to the point at which the sediments fracture hydraulically. I find that hydraulic fractures may form in systems with high flux and/or low permeability; that low-permeability layers can influence the location of fracture initiation if they are thicker than a critical value that is a function of flux and layer permeability; that capillary-driven depression of the triple point of methane in fine-gained sediments causes hydrate to form preferentially in coarse-grained layers; that the relative fluxes of gas and water in multiphase systems controls hydrate distribution and the location of fracture initiation; and that methane hydrate systems are dynamic systems in which methane flux and hydrate formation cause changes in fluid flow on time scales of hundreds to thousands of years. My results illustrate how pore-scale processes affect macroscale properties of methane hydrate systems and generally affect fluid flow and transport from pore to basin scale
School code: 0187
Host Item Dissertation Abstracts International 72-10B
主題 Geophysics
Marine Geology
Petroleum Geology
0373
0556
0583
Alt Author Rice University
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