Hydraulic Fracturing in Particulate Materials
For more than five decades, hydraulic fracturing has been widely used to enhance oil and gas production. Hydraulic fracturing in solid materials (e.g., rock) has been studied extensively. The main goal of this thesis is a comprehensive study of the physical mechanisms of hydraulic fracturing in cohe...
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ndltd-GATECH-oai-smartech.gatech.edu-1853-49572013-01-07T20:10:53ZHydraulic Fracturing in Particulate MaterialsChang, HongFluid leak-offFracture geometryCavity ExpansionShear bandsFluid flow localizationCohesionless materialsParticulate materialsSoft sedimentsFracture mechanicsHydraulic fracturingFor more than five decades, hydraulic fracturing has been widely used to enhance oil and gas production. Hydraulic fracturing in solid materials (e.g., rock) has been studied extensively. The main goal of this thesis is a comprehensive study of the physical mechanisms of hydraulic fracturing in cohesionless sediments. For this purpose, experimental techniques are developed to quantify the initiation and propagation of hydraulic fractures in dry particulate materials. We have conducted a comprehensive experimental series by varying such controlling parameters as the properties of particulate materials and fracturing fluids, boundary conditions, initial stress states, and injection volumes and rates. In this work, we suggest principle fundamental mechanisms of hydraulic fracturing in particulate materials and determine relevant scaling relationships (e.g., the interplay between elastic and plastic processes). The main conclusion of this work is that hydraulic fracturing in particulate materials is not only possible, but even probable if the fluid leak-off is minimized (e.g., high flow rate, high viscosity, low permeability). Another important conclusion of this work is that all parts of the particulate material are likely to be in compression. Also, the scale effect (within the range of the laboratory scales) appears to be relatively insignificant, that is, the observed features of fractures of different sizes are similar. Based on the observed fracture geometries, and injection pressures we suggested three models of hydraulic fracturing in particulate materials. In the cavity expansion or ??e driving model, the fracturing fluid is viewed as a sheet pile (blade) that disjoints the host material, and the cavity expansion occurs at the fracture (blade) front. The shear banding model is also consistent with a compressive stress state everywhere in the particulate material and explains the commonly observed beveled fracture front. The model of induced cohesion is based on the fluid leak-off ahead of the fracture front. The induced cohesion may be caused by the tensile strain near the fracture tip (where the stress state is also compressive), which, in turn, induces the cavitation of the leaked-off fluid and hence capillary forces.Georgia Institute of Technology2005-03-02T21:36:13Z2005-03-02T21:36:13Z2004-11-29Dissertation6699096 bytesapplication/pdfhttp://hdl.handle.net/1853/4957en_US |
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Fluid leak-off Fracture geometry Cavity Expansion Shear bands Fluid flow localization Cohesionless materials Particulate materials Soft sediments Fracture mechanics Hydraulic fracturing |
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Fluid leak-off Fracture geometry Cavity Expansion Shear bands Fluid flow localization Cohesionless materials Particulate materials Soft sediments Fracture mechanics Hydraulic fracturing Chang, Hong Hydraulic Fracturing in Particulate Materials |
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For more than five decades, hydraulic fracturing has been widely used to enhance oil and gas production. Hydraulic fracturing in solid materials (e.g., rock) has been studied extensively. The main goal of this thesis is a comprehensive study of the physical mechanisms of hydraulic fracturing in cohesionless sediments. For this purpose, experimental techniques are developed to quantify the initiation and propagation of hydraulic fractures in dry particulate materials. We have conducted a comprehensive experimental series by varying such controlling parameters as the properties of particulate materials and fracturing fluids, boundary conditions, initial stress states, and injection volumes and rates. In this work, we suggest principle fundamental mechanisms of hydraulic fracturing in particulate materials and determine relevant scaling relationships (e.g., the interplay between elastic and plastic processes).
The main conclusion of this work is that hydraulic fracturing in particulate materials is not only possible, but even probable if the fluid leak-off is minimized (e.g., high flow rate, high viscosity, low permeability). Another important conclusion of this work is that all parts of the particulate material are likely to be in compression. Also, the scale effect (within the range of the laboratory scales) appears to be relatively insignificant, that is, the observed features of fractures of different sizes are similar.
Based on the observed fracture geometries, and injection pressures we suggested three models of hydraulic fracturing in particulate materials. In the cavity expansion or ??e driving model, the fracturing fluid is viewed as a sheet pile (blade) that disjoints the host material, and the cavity expansion occurs at the fracture (blade) front. The shear banding model is also consistent with a compressive stress state everywhere in the particulate material and explains the commonly observed beveled fracture front. The model of induced cohesion is based on the fluid leak-off ahead of the fracture front. The induced cohesion may be caused by the tensile strain near the fracture tip (where the stress state is also compressive), which, in turn, induces the cavitation of the leaked-off fluid and hence capillary forces. |
author |
Chang, Hong |
author_facet |
Chang, Hong |
author_sort |
Chang, Hong |
title |
Hydraulic Fracturing in Particulate Materials |
title_short |
Hydraulic Fracturing in Particulate Materials |
title_full |
Hydraulic Fracturing in Particulate Materials |
title_fullStr |
Hydraulic Fracturing in Particulate Materials |
title_full_unstemmed |
Hydraulic Fracturing in Particulate Materials |
title_sort |
hydraulic fracturing in particulate materials |
publisher |
Georgia Institute of Technology |
publishDate |
2005 |
url |
http://hdl.handle.net/1853/4957 |
work_keys_str_mv |
AT changhong hydraulicfracturinginparticulatematerials |
_version_ |
1716473883953987584 |