Hydraulic impedance technique for the characterization of unsaturated fractured rock

Persistent Link:
http://hdl.handle.net/10150/192055
Title:
Hydraulic impedance technique for the characterization of unsaturated fractured rock
Author:
Tang, Jinshan,1960-
Issue Date:
1991
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
A hydraulic impedance technique was developed by using an impeding layer and conductance layer. Laboratory experiments show that the developed technique is promising for the in situ characterization of unsaturated hydraulic properties of fractured rock, such as fracture flow and effective transmissivity as a function of matrix suction. An estimated suction boundary condition at a borehole surface can be imposed using this impedance technique and flow into the fractured rock can be measured. Because the conducting properties of saturated fractures are normally much higher than the rock matrix, an estimation of saturated fracture transmissivity is possible. Then as the suction at the borehole surface is increased, the fracture transmissivity decreases, yielding information about the drainage characterization of the fracture. The suction at which fracture flow becomes insignificant is critical to understanding fracture versus matrix flow in fractured rock. C125 cellulose tubular membrane with an average conductance of 2.64x10⁻⁸ s⁻¹ was selected as the impeding membrane, the conductance of the membrane decreases when the initial saturation decreases. To minimize the variation in conductance, the membrane must be presoaked for 100 hours. 10-pound canvas was selected as the conductance layer, the transmissivity (T, cm⁻²/s) of the canvas is an exponential function of the confining pressure (P, kPa), expressed as T(P)=0.0274e⁻⁰•⁰²⁹⁶ᴾ. The canvas layer can yield a relative constant suction along the membrane/rock interface as shown by modeling. A 1-D radial analytical flow model can be used on a small scale to simulate flow if the boundary conditions can be specified for the technique and the effect of gravity is insignificant.
Type:
Thesis-Reproduction (electronic); text
LCSH Subjects:
Hydrology.; Hydraulic fracturing.; Fracture mechanics -- Technique.; Rocks -- Fracture.
Degree Name:
M.S.
Degree Level:
masters
Degree Program:
Hydrology and Water Resources; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Evans, Daniel D.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleHydraulic impedance technique for the characterization of unsaturated fractured rocken_US
dc.creatorTang, Jinshan,1960-en_US
dc.contributor.authorTang, Jinshan,1960-en_US
dc.date.issued1991en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractA hydraulic impedance technique was developed by using an impeding layer and conductance layer. Laboratory experiments show that the developed technique is promising for the in situ characterization of unsaturated hydraulic properties of fractured rock, such as fracture flow and effective transmissivity as a function of matrix suction. An estimated suction boundary condition at a borehole surface can be imposed using this impedance technique and flow into the fractured rock can be measured. Because the conducting properties of saturated fractures are normally much higher than the rock matrix, an estimation of saturated fracture transmissivity is possible. Then as the suction at the borehole surface is increased, the fracture transmissivity decreases, yielding information about the drainage characterization of the fracture. The suction at which fracture flow becomes insignificant is critical to understanding fracture versus matrix flow in fractured rock. C125 cellulose tubular membrane with an average conductance of 2.64x10⁻⁸ s⁻¹ was selected as the impeding membrane, the conductance of the membrane decreases when the initial saturation decreases. To minimize the variation in conductance, the membrane must be presoaked for 100 hours. 10-pound canvas was selected as the conductance layer, the transmissivity (T, cm⁻²/s) of the canvas is an exponential function of the confining pressure (P, kPa), expressed as T(P)=0.0274e⁻⁰•⁰²⁹⁶ᴾ. The canvas layer can yield a relative constant suction along the membrane/rock interface as shown by modeling. A 1-D radial analytical flow model can be used on a small scale to simulate flow if the boundary conditions can be specified for the technique and the effect of gravity is insignificant.en_US
dc.description.notehydrology collectionen_US
dc.typeThesis-Reproduction (electronic)en_US
dc.typetexten_US
dc.subject.lcshHydrology.en_US
dc.subject.lcshHydraulic fracturing.en_US
dc.subject.lcshFracture mechanics -- Technique.en_US
dc.subject.lcshRocks -- Fracture.en_US
thesis.degree.nameM.S.en_US
thesis.degree.levelmastersen_US
thesis.degree.disciplineHydrology and Water Resourcesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairEvans, Daniel D.en_US
dc.contributor.committeememberRasmussen, Todden_US
dc.contributor.committeememberSully, Michael J,en_US
dc.identifier.oclc220956481en_US
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