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Title: Resistivity-thermal conductivity-porosity relationships for marine sediments
Author: Lovell, Michael Anthony
Awarding Body: Bangor University
Current Institution: Bangor University
Date of Award: 1984
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A laboratory examination of the electrical resistivity formation factor, thermal conductivity, and porosity properties of natural and artificial marine sediments, both in terms of their own interdependences and of their interrelationships with other geophysical and geotechnical quantities has been carried out. Marine sediments have been considered as two separate systems, sands and clays. For the sands, measurements of electrical formation factor, thermal conductivity, porosity, and permeability have been made using three cells. For the deep sea clays, an oedometer cell has been modified to enable resistivity, thermal conductivity, compressional wave and shear wave velocity measurements to be made, permeability and porosity values being derived from uniaxial consolidation theory. Formation factor (and compressional wave velocity in the clays) exhibit close interrelationships with permeability, and the capability of predicting permeability to within an order of magnitude both empirically and theoretically (using Biot's equations) is shown. Electrical formation factor is shown to help in defining a mass coupling factor for this theoretical model. Formation factor is related to porosity for both sands and clays. While any one sample is best represented by Archie's (sands) or Winsauer's (clays) empirical law, the overall trend is a 3rd degree polynomial; particle shape appears to dominate both porosity and permeability relationships with electrical resistivity. Thermal conductivity exhibits a dependence on porosity for saturated sediments. The successful prediction of thermal conductivity using a geometrical model requiring volume and thermal conductivity values has been demonstrated for up to 3 components, and for a variety of particle shapes. Using the common relation, porosity, thermal conductivity may be related to formation factor for both sands and clays. Anisotropy is shown to exist in sands and clays for some of the energy transfer processes measured. The recognition and subsequent measurement of these phenomena may improve the already good correlations described above.
Supervisor: Not available Sponsor: NERC
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available