Experimental and Numerical Investigations of Fluid Flow for Natural Single Rock Fractures

Persistent Link:
http://hdl.handle.net/10150/194280
Title:
Experimental and Numerical Investigations of Fluid Flow for Natural Single Rock Fractures
Author:
Park, Jinyong
Issue Date:
2005
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:
To quantify the roughness of natural rock fracture surfaces, a two dimensional version of the modified divider method was adopted. The parameter Dr2d×Cx was found to be suitable to quantify the roughness of natural rock fractures. In addition to the mean aperture, a modified 3D box counting method was used to quantify aperture distributions of the same fractures. The modified 3D box counting method produced fractal dimensions in the range 2.3104 to 2.5661.The following new functional relations were developed for aperture parameters: (a) power-functionally decreasing mean aperture with increasing normal stress, (b) power-functionally decreasing 3D box fractal dimension with increasing normal stress, (c) linearly increasing mean aperture with increasing 3D box fractal dimension, (d) linearly decreasing mean aperture with increasing fracture closure, and (e) linearly decreasing 3D box fractal dimension with increasing fracture closure.Fluid flow through nine natural single rock fractures was measured at different normal stresses. The flow calculated for three out of the nine fractures according to sample scale cubic law using mean apertures overestimated the experimental flow by 2.2 ~ 235.0 times within a normal stress range of 0 ~ 8 MPa. The elementally applied cubic law (EACL) through a finite element model (FEM) also overestimated the experimental flow by 1.9 ~ 111.7 times within the same normal stress range. As the normal stress applied on a natural rock fracture increases, the overestimation increases due to increasing contact areas and increasing tortuous behavior of flow. These findings clearly show the inapplicability of the cubic law to estimate flow through natural rock fractures especially under high normal stresses. New hyperbolic functions were developed to relate mean aperture to the power n to applied normal stress at both the sample and finite element scales.The following new functional relations were developed between fluid flow rate and the aperture parameters: (a) power-functionally increasing flow rate per unit head with increasing mean aperture, (b) exponentially decreasing flow rate per unit head with increasing fracture closure, and (c) power-functionally increasing flow rate per unit head with increasing 3D box fractal dimension.
Type:
text; Electronic Dissertation
Keywords:
Mining Geological & Geophysical Engineering
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Mining Geological & Geophysical Engineering; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Kulatilake, Pinnaduwa H. S. W.
Committee Chair:
Kulatilake, Pinnaduwa H. S. W.

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleExperimental and Numerical Investigations of Fluid Flow for Natural Single Rock Fracturesen_US
dc.creatorPark, Jinyongen_US
dc.contributor.authorPark, Jinyongen_US
dc.date.issued2005en_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.abstractTo quantify the roughness of natural rock fracture surfaces, a two dimensional version of the modified divider method was adopted. The parameter Dr2d×Cx was found to be suitable to quantify the roughness of natural rock fractures. In addition to the mean aperture, a modified 3D box counting method was used to quantify aperture distributions of the same fractures. The modified 3D box counting method produced fractal dimensions in the range 2.3104 to 2.5661.The following new functional relations were developed for aperture parameters: (a) power-functionally decreasing mean aperture with increasing normal stress, (b) power-functionally decreasing 3D box fractal dimension with increasing normal stress, (c) linearly increasing mean aperture with increasing 3D box fractal dimension, (d) linearly decreasing mean aperture with increasing fracture closure, and (e) linearly decreasing 3D box fractal dimension with increasing fracture closure.Fluid flow through nine natural single rock fractures was measured at different normal stresses. The flow calculated for three out of the nine fractures according to sample scale cubic law using mean apertures overestimated the experimental flow by 2.2 ~ 235.0 times within a normal stress range of 0 ~ 8 MPa. The elementally applied cubic law (EACL) through a finite element model (FEM) also overestimated the experimental flow by 1.9 ~ 111.7 times within the same normal stress range. As the normal stress applied on a natural rock fracture increases, the overestimation increases due to increasing contact areas and increasing tortuous behavior of flow. These findings clearly show the inapplicability of the cubic law to estimate flow through natural rock fractures especially under high normal stresses. New hyperbolic functions were developed to relate mean aperture to the power n to applied normal stress at both the sample and finite element scales.The following new functional relations were developed between fluid flow rate and the aperture parameters: (a) power-functionally increasing flow rate per unit head with increasing mean aperture, (b) exponentially decreasing flow rate per unit head with increasing fracture closure, and (c) power-functionally increasing flow rate per unit head with increasing 3D box fractal dimension.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectMining Geological & Geophysical Engineeringen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineMining Geological & Geophysical Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorKulatilake, Pinnaduwa H. S. W.en_US
dc.contributor.chairKulatilake, Pinnaduwa H. S. W.en_US
dc.contributor.committeememberSternberg, Ben K.en_US
dc.contributor.committeememberWarrick, Arthur W.en_US
dc.contributor.committeememberGuertin, Phillip D.en_US
dc.identifier.proquest1385en_US
dc.identifier.oclc137355381en_US
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