Correlations of NMR relaxation time with viscosity/temperature, diffusion coefficient and gas/oil ratio of methane-hydrocarbon mixtures

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dc.contributor.advisorHirasaki, George J.en_US
dc.contributor.advisorKobayashi, Rikien_US
dc.creatorLo, Sho-Weien_US
dc.date.accessioned2009-06-04T08:22:57Zen_US
dc.date.available2009-06-04T08:22:57Zen_US
dc.date.issued2000en_US
dc.description.abstractA 90 MHz NMR Spectrometer equipped with a high pressure probe was used to study relationship between NMR relaxation time and temperature, viscosity, diffusivity and gas/oil ratio of methane-hydrocarbon mixtures. This research project involves three parts: (1) modifications of the existing NMR apparatus. (2) Measurements of relaxation times and diffusion coefficients of methane-hydrocarbon mixtures. (3) Development of generalized correlations between transport properties and temperature and relaxation times. The NMR apparatus was modified in order to make elevated temperature and pressure measurements. The modifications included calibration of pressure transducers, addition of temperature measuring devices, connection to the high pressure sample probe of a sapphire sample cell and leak detection of the system. After the modifications, the apparatus was capable of measurements from 20 to 60°C at pressure up to 6000 psia. NMR relaxation measurements of three mixtures, methane-n-hexane, methane-n-decane and methane-n-hexadecane, were made. The log mean relaxation times were plotted against viscosity/temperature and it was found that unlike stock tank oils, they do not depend linearly on viscosity/temperature on a log-log scale. Each of the mixtures forms a different curve on the plot of relaxation time vs. viscosity/temperature. Diffusivity measurements were also made for these three mixtures, as well as pure hexane, decane and hexadecane. The log mean diffusion coefficients were calculated. The relationship between diffusion coefficients and relaxation times were studied, and it was found that diffusion coefficients depend linearly on T1 for pure hydrocarbons, but the dependence does not hold for methane-hydrocarbon mixtures. Correlations between transport properties and NMR relaxation times were developed. First, a relaxation time mixing rule was developed by studying the theory of NMR relaxation mechanism. From the mixing rule, it was found that departure of relaxation times of methane-n-alkane mixtures from linear correlation on a log-log scale can be correlated with proton fractions of methane, which can be expressed as gas/oil ratio. Thus, correlation between relaxation time, viscosity/temperature and gas/oil ratio was developed. Correlation between relaxation time, diffusivity and gas/oil ratio was also developed. From these correlations, viscosity and gas/oil ratio can be estimated just from NMR relaxation time and diffusion coefficient.en_US
dc.format.extent124 p.en_US
dc.format.mimetypeapplication/pdfen_US
dc.identifier.callnoTHESIS CH.E. 2000 LOen_US
dc.identifier.citationLo, Sho-Wei. "Correlations of NMR relaxation time with viscosity/temperature, diffusion coefficient and gas/oil ratio of methane-hydrocarbon mixtures." (2000) Diss., Rice University. <a href="https://hdl.handle.net/1911/19530">https://hdl.handle.net/1911/19530</a>.en_US
dc.identifier.urihttps://hdl.handle.net/1911/19530en_US
dc.language.isoengen_US
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.en_US
dc.subjectChemical engineeringen_US
dc.subjectPetroleum engineeringen_US
dc.titleCorrelations of NMR relaxation time with viscosity/temperature, diffusion coefficient and gas/oil ratio of methane-hydrocarbon mixturesen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentChemical Engineeringen_US
thesis.degree.disciplineEngineeringen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US
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