A 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.

Drainage of a mobile, symmetric, plane-parallel thin liquid film between two gas bubbles (foam film) is studied. An analytical solution for the rate of thinning of such a liquid film with an insoluble surfactant and having both film elasticity and surface viscosity is presented for the first time. Analysis is extended to the more general case of a soluble surfactant and compared with previous analyses. Surfactant material parameters affecting the rate of thinning are identified and grouped into a single dimensionless parameter, the surfactant number which describes the transition from a mobile to an immobile film. Significant deviation from the Reynolds velocity is found when this dimensionless parameter is small. Since draining foam or emulsion films are generally of nonuniform thickness with a thick region or 'dimple' as the central part and separated from the Plateau border by a thinner 'barrier ring', an analytical solution is not possible. Hence a numerical model was developed. This model simulates the hydrodynamics associated with the drainage of an axisymmetric, dimpled, mobile foam film with an insoluble surfactant. This extends the work of Joye (1994) which was limited to immobile films. Results of the parametric study indicate that the rate of drainage of these films is dependent on surfactant properties viz. elasticity, surface dilatational viscosity, surface shear viscosity and surface diffusivity. These properties are grouped into a single dimensionless parameter which is the same as obtained by our analytical solution for a plane parallel film and which correlates with the rate of drainage of the foam film. This parameter describes the transition from a mobile film to an immobile film. The simulations indicate considerable motion of the interface for draining mobile foam films. Foam texture in a porous medium is governed by the hydrodynamics of individual foam films (lamellae) flowing through pores of varying size. The stability of foam in a particular application depends upon the stability of a lamella in the porous medium, especially as the lamella expands in translating from a small pore (pore throat) to a larger pore (pore body). The numerical simulator developed above is extended to translating foam films to model the effect of various parameters on foam stability. The model predicts that the travelling lamella is unstable only for certain ranges of surfactant properties, porous media geometry and flow conditions, for e.g. gas flow rate and capillary pressure. Simulations show that mobile foam films stretch in going from a pore throat to a pore body and may thin down to the critical thickness and break, under certain conditions. In contrast immobile foam films are very stable due to an entrainment effect which occurs as the film expands in going from a pore throat to a pore body. The critical capillary pressure at which a moving lamella will break is determined as a function of film and porous medium properties. Further the concept of asymmetric drainage of foam films in porous media has been explored.

Through isobaric temperature ramping experiments, the solubility of pure methane, ethane, propane, carbon dioxide gases and a methane-propane gas mixture in pure liquid water has been measured. The experiments are conducted at low temperatures and pressures corresponding to the clathrate hydrate formation and decomposition region. The inhibitory effect of a 10 weight percent methanol aqueous solution and a 0.5 weight percent polyvinylpyrrolidone aqueous solution on the hydrate formation and decomposition conditions has been estimated. A study of the pH-induced change in the hydrate stability has also been performed. The isobaric solubility data obtained show a significant divergence from Henry's law prior to and during hydrate formation. A molecular mechanism of hydrate nucleation is hypothesized, based on an analysis of the gas supersaturation observed and the current knowledge on the structure of liquid water.

Experiments and numerical simulations were carried out to improve the understanding of foam flow in underground porous media, especially three-dimensional foam flow, and to develop a numerical model for the design of the foam hydrogen sparging process for aquifer remediation. Injection of hydrogen is a promising method to enhance in situ anaerobic biodegradation of chlorinated solvents. The use of foam formed in situ by injection of hydrogen and a suitable surfactant solution greatly extends the horizontal migration of hydrogen in the subsurface, especially near the bottom of the aquifer where chlorinated solvents normally reside. The number of hydrogen injection wells required is thereby reduced. Experiments were conducted in a 2x2x2 foot glass tank filled with sand and instrumented to permit sampling or measurement of local pressure differences as a function of time at 36 points located at 9 lateral positions and four elevations. After the tank was filled with surfactant solution, gas was injected at constant pressure from one corner near the bottom of the tank. In some experiments the packing of the sand was homogeneous; in others it was layered. The experiments confirmed that foam greatly increases lateral gas distribution along the bottom as well as average gas saturation in the tank. A model was developed to simulate three-dimensional foam flow in porous media and was incorporated into the existing reservoir simulator UTCHEM. The model changes the gas relative permeability curve and gas viscosity from those of ordinary two-phase flow to represent the reduced gas mobility when foam is present. All except one parameter of the model can be obtained from foam experiments in one-dimensional sand columns. This parameter is a geometric factor, which accounts for the greater mobility of foam in three dimensions than in one dimension for similar conditions, presumably the result of the greater number of possible flow paths in three dimensions. A history match of several of the above tank experiments showed that if foam mobility in the tank was taken to be about five times greater than in a column, simulated average gas saturation, gas injection rate, gas distribution and pressure profile six inches above the bottom of the tank were in good agreement with experimental results for the homogeneous packing. For the layered packing it was also necessary to fit another parameter to the data to account for generation of additional foam by flow, of gas from lower to higher permeability regions. The simulator was used to design a foam hydrogen sparging process for a hypothetical aquifer. Results showed that with foam well spacing could be increased by 80% for a particular homogeneous aquifer while maintaining about the same sweep efficiency near the bottom of the aquifer.

This thesis addresses several key issues in the design of foam for mobility control in alkaline-surfactant enhanced oil recovery processes. First, foam flow in fracture systems was studied. A theory for foam flow in a uniform fracture was developed and verified by experiment. The apparent viscosity was found to be the sum of contributions arising from liquid between bubbles and the resistance to deformation of the interfaces of bubbles passing through the fracture. Apparent viscosity increases with gas fractional flow and is greater for thicker fractures (for a given bubble size), indicating that foam can divert flow from thicker to thinner fractures. The diversion effect was confirmed experimentally and modeled using the above theory for individual fractures. The amount of surfactant solution required to sweep a heterogeneous fracture system decreases greatly with increasing gas fractional flow owing to the diversion effect and to the need for less liquid to occupy a given volume when foam is used. The sweep efficiency's sensitivity to bubble size was investigated theoretically in a heterogeneous fracture system with log-normal distributed apertures. Second, the foam application in forced convection of alkaline-surfactant enhanced oil recovery processes was studied. From sand pack experiments for the alkaline-surfactant-polymer process, a 0.3 PV slug of the surfactant blend studied can recover almost all the waterflood residual crude oil when followed by a polymer solution as mobility control agent. But this blend is a weak foamer near its optimum salinity while one of its components, IOS, is a good foamer. Two types of processes were tested in sand packs to study possible process improvements and cost savings from replacing some polymer by foam for mobility control. The first used IOS foam as drive after the surfactant slug, while the second, which is preferred, involved injecting gas with the surfactant slug containing polymer followed by IOS foam. It was found that foam has higher apparent viscosity in high than in low permeability region. Thus, use of foam should be more attractive in heterogeneous system to get better sweep efficiency.

Surface mining in the Athabasca oil sands region of Northern Alberta, Canada, results in the disturbance of significant areas of boreal forest landscape. The Aurora Soil Capping Study is a reclamation research project that aims to find the optimal soil capping (cover) material and thickness to re-establish a boreal forest ecosystem above a lean oil sands (LOS) disposal area at Syncrude's Aurora North mine. The objectives of this laboratory and field-based study are to (1) characterize the in-situ hydrocarbon composition of the LOS material, (2) determine the effect of temperature on rates of gas flux and the biodegradation potential of petroleum hydrocarbons (PHC) as a result of microbial activity and (3) determine the potential for PHC to leach into the groundwater system. The results of the laboratory-study show that temperature has a significant effect on the rate of PHC degradation as indicated by the linear relationship observed between temperature and CO2 gas flux rates. The respiratory results from the laboratory-based study were consistent and relatively comparable with data from the field study, which indicates that the column study could be useful in estimating in situ PHC degradation.

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We use a MARAN-2 laboratory NMR spectrometer for making measurements using the CPMG pulse sequence for estimating the spin-spin or T$\sb2$ relaxation time distribution. Algorithms are developed for estimating the relaxation time distribution. Guidelines are given for designing the measurements to reduce measurement artifacts. The measured R-X channels data are transformed to the signal-plus-noise channel and the noise channel before using in the estimation of the relaxation time distribution. The reduction of the number of data by sampling and averaging decreases significantly the computational time. The optimum $\alpha$ (regularization parameter) depends on the corresponding slope of the plot of log$\rm\sb{10\chi A}$ versus log$\sb{10}\alpha.$ Further, this optimum slope in log-log scale is inversely proportional to the number of data. A systematic parametric study reveals that the broadening of the estimated relaxation time distribution can be reduced by decreasing the noise level, decreasing the echo spacing, or using a sufficient range of data.

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