Browsing by Subject "Hydrocarbons"
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Item A study of improved recovery by vaporization/condensation process due to elevating temperatures in hydrocarbon reservoirs(Texas Tech University, 1998-05) Jain, Vishok K.A simulation of vaporization/condensation process was conducted to study the effect of the process on the gas enrichment and overall recovery of a low density crude oil. The simulation begins with the identification of the most suitable equation of state model to characterize vaporization/condensation process. This was accomplished by simulating the constant volume depletion test and constant composition expansion test using three equation of state models and comparing the simulation results with the available experimental data. The equation of model, which predicted the constant volume depletion data most accurately, was selected to be used further in the study. The Peng-Robinson equation of state was found to be most accurate in predicting the experimental data. The vaporization/condensation process was characterized by employing a combination of constant volume depletion test simulation and flash calculations using the selected equation of state. The entire characterization of vaporization/condensation process was performed on WinProp, a phase property program. The vaporization/condensation process was found to be feasible as it was resulting in gas enrichment and increase in liquid saturation. These results were much more pronounced when conducted the vaporization/condensation at the high pressure and high vaporization temperature. Therefore, it was concluded that the vaporization/condensation may result in additional recovery if carried out at high reservoir pressure and high vaporization temperature.Item An analysis of volcaniclastic sediments, Pacific offshore, Guatemala(Texas Tech University, 1980-05) Gonzales, EduardoThis thesis describes extensive experimental implementations of multiplex holography for use in representing two-dimensional spacevariant optical systems. Diffusers are used to encode the reference beams for effective crosstalk suppression. The problem of hologramto-hologram crosstalk is both analytically and experimentally examined, and various methods for its suppression are discussed. The merits of using ground glass diffusers for crosstalk suppression are experimentally investigated, and the superiority of chirped-wave diffuser illumination over plane-wave illumination in crosstalk suppression is demonstrated. The first implementations of binary-coded diffuser masks for crosstalk suppression in multiplex holography are shown. The experimental proof of coherent addition in overlapping holographic outputs is presented, and the first holographic representation of an extremely space-variant optical system is shown. The holographic representation of an optical system using a large (10 x 10) array of input sampling points is also shown. With a working 2-D space-variant holographic processor thus available, a variety of space-variant processing operations for future investigations are suggested.Item Characterization of hydrocarbon pollutant burdens in petrochemical and refinery process streams(Texas Tech University, 1978-08) Cheng, Shangta WalterNot availableItem Deposition and diagenesis of the Gilmer Limestone (Jurassic), Leon and Freestone counties, Texas(Texas Tech University, 1983-12) Mayfield, Ricky LNot availableItem Emission spectra of simple hydrocarbons excited in a radio-frequency plasma(Texas Tech University, 1965-08) Mercer, Howard NicholasBeginning with an elementary discussion of the theory of atomic and molecular spectra and continuing with a discussion of the plasma state and other methods of excitation, a description of the apparatus used as well as the procedure followed in obtaining the results is given. The results of the analysis of the spectra will be introduced In tabular form. Generally, these results will be discussed In terms of the various methods of excitation.Item Hydrocarbons of pest aphids and their detection by a braconid parasitoid(Texas Tech University, 2003-05) Borth, Leahann MarieThe research here reported describes the presence and semiochemical functions of cuticular hydrocarbons of cotton aphids {Aphis gossypii Glover), corn leaf aphids (Rhopalosiphum maidis Fitch), and greenbugs (Schizaphis graminum Rondani) Potential ecological pressures that may influence the production of hydrocarbons in geographically separated cotton aphid populations were considered. Both the alarm pheromone, (E)-^- farnesene, and a total of 14 n-alkane hydrocarbons from hexane extracts of cotton aphids collected from Lubbock and Brazos Counties, Texas, and Kern County, California, were identified by GC/MS analysis. The alkanes were common to both color varieties, but the relative proportions of the compounds differed significantly within each population. Among populations, however, hydrocarbons differed significantly not only in relative concentrations, but also in their types. Next, the potential of using the hydrocarbon profiles of different aphid species in systematics was investigated. GC/MS analysis revealed 4, 5 and 14 «-alkane hydrocarbons, respectively, from the hexane extracts of corn leaf aphids, greenbugs, and both green and yellow varieties of cotton aphids collected from Lubbock and Hale Counties in Texas. Unlike the shorter chain compounds, the longer chain compounds between C25 and C29 were common to all three species, and were the most abundant hydrocarbons of each species. There were clear differences in the hydrocarbon profiles of apterous females among species and between color varieties of the cotton aphid, demonstrating that although the pests each produce many of the same compounds, when viewed as a whole, their hydrocarbon profiles are species-specific. Lastly, the attractiveness of naive female parasitic wasps (Lysiphlebus teastaceipes) to various host-associated chemical cues was measured via a series of Y-tube olfactometer bioassays to investigate the foraging strategies of Z. testaceipes as influenced by the host-associated chemical cues. Semiochemicals of cotton aphids elicited stronger responses from Z. testaceipes than semiochemicals produced by the cotton plant. All the bioassays resulting in significant preferences by the wasps were aphid-related. Finally, separating the aphid extract into smaller fractions did not elicit a response from Z. testaceipes, indicating that this wasp only responded to the entire extract profile of the aphid.Item Microwave-induced plasma destruction of trichloroethylene(Texas Tech University, 1993-12) LaDue, Douglas EugenePublic concern over environmental problems has forced the government to pass regulations controlling the safe disposal of chemical wastes. One particular class of hazardous waste that requires a safe disposal method is chlorinated hydrocarbons (CHCs). The US Environmental Protection Agency regards incineration as the best available method to destroy CHCs. However, there are several technical difficulties associated with the use of incineration to destroy CHCs. Therefore, there is considerable interest in developing alternative methods to destroy CHCs. This work investigated the destruction of CHCs in a microwave-induced plasma reactor as an alternative to incineration of CHCs. Trichloroethylene (TCE) was selected as a surrogate to represent the general class of CHC wastes. TCE was reacted with oxygen and water in a microwave-induced plasma in an air environment at atmospheric pressure. The first part of the experimental work was directed at identifying the range of operating conditions where a plasma could be sustained. Three operating parameters were investigated: microwave input power, and the air, argon and water feed concentrations in the feed. Based on the results of this part, "maps" showing the operating conditions where a plasma could be sustained were prepared. It was found that sustaining a plasma in an air environment at atmospheric pressure while introducing the reactants TCE and water required an input microwave power greater than 600 W. Unfortunately, it was also found that operating the experimental system at an input microwave power greater than 600 W resulted in the mechanical failure of the reactor. Therefore, in order to lower the power requirements of the reaction medium, an argon and air mixture was used as the carrier gas for the TCE destruction experiments. The second part of the experimental work was the investigation of the reaction of TCE with oxygen and water in a microwave-induced plasma at atmospheric pressure. It was found that the plasma could be sustained, the TCE conversion was greater than 98%. The products of the TCE destruction were mainly carbon dioxide, carbon monoxide and hydrochloric acid. A small amount of nitric oxide was produced firom the reaction of air in the microwave-induced plasma.Item NMR relaxation in crude oils at elevated temperatures(Texas Tech University, 1999-08) Jacob, JamesUntil recently, most nuclear magnetic resonance (NMR) measurements in support of lab petrophysics and well logging were conducted at room temperature. However, the T2 relaxation of bulk crude oils strongly depends on temperature. Measurement of the crude oil relaxation response at reservoir temperatures is needed for optimal interpretation of log data. This work used a Can-Purcell-Meiboom-Gill (CPMG) pulse sequence to measure the NMR T2 relaxation at 2 MHz. Four stock tank crude oils were studied over the temperature range 30-100°C at a constant pressure of 300 psig. For comparison, the T2 temperature response of five viscosity standards was measured over the same temperature range and compared to the crude oil data. A two component exponential decay described all the T2 data. As expected from the temperature dependence of translational diffusion, there is not a universal curve that fits all hydrocarbon mixtures. The standards and the crude oils did not fit a single curve. The observed T2 varied directly with absolute temperature and inversely with the viscosity. For the crude oils, the log mean T2 was related to a viscosity value calculated from the stock tank oil viscosity conelation as developed by Beggs and Robinson and modified by Egbogah. This T2 relation did not agree with a widely accepted T2 conelation developed at room temperature from oil samples of differing viscosity (0.7 to 1000 cp). When the viscosity of one of the crude oils was measured as a function of temperature, that data then fit the room temperature T2 conelation. Viscosity values derived from correlations based only on API gravity are evidently insufficient to make close estimates of crude oil T2 relaxation at elevated temperatures. In the T2-viscosity plot, one of the crudes was a distinct outlier from the others. The composition of this sample suggests further investigations into the T2 relaxation of oil-based mud filtrate and mixtures of crude and oil-based mud filtrate.Item An on-board distillation system to reduce cold-start hydrocarbon emissions from gasoline internal combustion engines(2004-05) Ashford, Marcus Demetris, 1972-; Matthews, Ronald D.Item Sensitivity of AVA reflectivity to fluid hydrocarbon properties in porous media(2007-05) Bain, Kevin Alan, 1977-; Tatham, R.H. (Robert H.), 1943-The sensitivity of transmission and reflection coefficients to varying physical parameters of a hydrocarbon fluid is examined. In particular, earlier work on generalized fluid properties is extended to consider realistic hydrocarbon properties at in-situ conditions. I also expand previous studies of P-P reflectivity, including Biot theory fluid effects, to include P-Sv mode-converted reflections. The goal is to understand how the reflection coefficients change as individual fluid parameters, such as density or viscosity, are varied, which fluid parameters have the greatest affect on the transmission and reflection coefficients, and what actual hydrocarbon and reservoir properties are involved. There is no sensitivity to a fluid or hydrocarbon parameter if the transmission and reflection coefficients do not change as that parameter is varied. The sensitivity analysis is further refined by calculating partial derivates of the reflection coefficients with respect to fluid viscosity. Special attention is given to viscosity because viscosity may act as a proxy for permeability as well as partial gas-saturation in common reservoir sands. To this end I am able to quantitatively describe the degree of gas-saturation and its influence on reflection coefficients. This might provide a technique to lessen the uncertainty encountered in the fizz-gas risk phenomenon. In the gas-oil interfaces, I find that the changes in the P-P reflectivity to be as much as 1.3% for a decrease in oil viscosity corresponding to a change from 1 to 99% gassaturation. In the oil-brine interfaces, the changes in the P-P reflectivity are estimated to be a maximum of 2.6% for a decrease in oil viscosity corresponding to a change from 1 to 99% gas-saturation. Changes in P-SV reflectivity are negligible (<1%) for both models at typical seismic frequencies (~100 Hz).Item Structural model and fracture analyses for a major gas emplacement in Devonian sandstones of the Subandes(2009-12) Iñigo, Juan Francisco Pedro, 1980-; Laubach, Stephen E. (Stephen Ernest), 1955-; Cloos, Mark; Horton, Brian K.The fold and thrust belt of the Subandean Ranges (central and southern Bolivia, and northern Argentina) contains both gas and condensate production and reserves in Devonian quartzose sandstones within deep structures. Reservoir sandstones present values of permeability close to 0.01 mD, implying that reservoir drainage must be controlled by a fracture system that enhances permeability. Hydrocarbon production in naturally fractured reservoirs is affected by fracture quality (degree of openness), spatial arrangement, size distribution (including aperture, height and length), fracture abundance, and arrangement with respect to stratigraphic and macro-structural features. Systematic study of fractures in the subsurface is complicated by the small probability that a well will intersect sufficient fractures for direct analysis of their attributes. Because of this fracture data obtained from logging and coring must be complemented with alternative methodologies. In my study I performed a workflow that includes geologic mapping of outcrop analogs of subsurface units, fracture characterization in outcrops and thin sections, the construction of kinematic structural model using algorithms for 3D analysis, petrographic description of composition and diagenesis, and statistical multivariate analyses in order to define how structural, lithologic and diagenetic features affect fracture distribution. From the construction of a structural model and the analyses of its properties, I generated semi-quantitative models of fracture attributes based on classic fold-related fracture concepts. This model was tested with direct fracture observations from core and outcrop, coupled with microstructural imaging using SEM-CL, to document fracture attributes. The models all show high curvature and strain values homogeneously distributed along the azimuth and close to the hinge of the anticline, which implies this domain should be most fractured. On the other hand, microfracture studies reveal that although highest strain values are found in the hinge, low strains also are found along the hinge even for samples with similar lithologies. The study of macro and microfractures in outcrop and core samples allowed me to clearly identify two opening mode fracture sets for the Devonian sandstones. These present an orthogonal arrangement and variable cross cutting relations. The dominant set (defined as Set I) has a WNW strike and is perpendicular to the structural trend of the Subandean Ranges; the subordinate set (defines as Set II) has a NNE strike, and is parallel to the previously mentioned structural trend. Set I has higher strain accumulation, log-normal spacing distribution, and is strongly controlled by the primary quartz content of the rocks. Set II also has a log-normal spacing distribution, and presents structural control.Item Substitution reactions of 5[alpha]-Cholestan-6[alpha]-ols(Texas Tech University, 1976-05) Lundberg, Robert DwightThe primary objective of the present study was to reexamine the original reaction of 5a-cholestan-6a-ol with phosphorus pentachloride using modern techniques to determine whether 6a-chloro-5a-cholestane is the sole product, or whether the epimeric 63-chloro-5a-cholestane is also formed and, if so, to what extent. A secondary objective was the synthesis of 3a-halogen substitued 5a-cholestan-6a-ols, the 3a-substituent of which might be capable by steric interaction with the 6a-halophosphonate moiety thus influencing the steric course of the reaction. The 3a,6a-distance is ca. 5A, and for suitably sized 3a-substituents is capable of being spanned by the large phosphorus atom of a 6a-halophosphonate.Item Tectonostratigraphic and subsidence history of the northern Llanos foreland basin of Colombia(2011-08) Campos, Henry Miguel; Mann, Paul, 1956-; Horton, Brian K.; Steel, Ronald J.; Cardozo, NestorThe Llanos foreland basin of Colombia is located along the eastern margin of the northern Andes. The Llanos basin is bounded to the north by the Mérida Andes, to the east by the Guiana shield, to the south by the Serrania de la Macarena, and to the west by the frontal foothills thrust system of the Andes (the Cordillera Oriental). The Llanos foreland basin originated in the Maastrichtian, after a post-rift period during the Mesozoic, and recorded an abrupt pulse of middle Miocene subsidence possibly in response to subduction and collision events along the Pacific margin of northwestern South America. Regional east-west shortening, driven in part by collision of the Panama arc along the Pacific margin of Colombia, has built the widest part of the northern Andes. This wide area (~600 km) includes a prominent arcuate thrust salient, the Cordillera Oriental, which overthrusts the Llanos foreland along a broad V-shaped salient that projects 40 km over the northern Llanos foreland basin. In this study, I interpret 1200 km of 2D seismic data tied to 18 wells and regional potential fields (gravity and magnetic) data. Interpreted seismic data are organized into four regional (300 to 400-km-long) transects spanning the thrust salient area of the northern Llanos basin. I performed 2D flexural modeling on the four transects in order to understand the relative contributions of flexural subsidence due to tectonic and sedimentary loading. Sedimentary backstripping was applied to the observed structure maps of six Eocene to Pleistocene interpreted horizons in the foreland basin in order to remove the effects of sedimentary and water loading. Regional subsidence curves show an increase in the rate of tectonic subsidence in the thrust salient sector of the foreland basin during the middle to late Miocene. The flexural models predict changes in the middle Miocene to recent position of the eastern limit of foreland basin sediments as well as the changing location and vertical relief of the flexurally controlled forebulge. Production areas of light oil in the thrust belt and foreland basin are located either south of the thrust salient (Cusiana, Castilla, Rubiales oilfields) or north of the salient (Guafita-Caño Limon, Arauca oilfields) but not directly adjacent to the salient apex where subsidence, source rock thicknesses, and fracturing were predicted by a previous study to be most favorable for hydrocarbons. There are no reported light oil accumulations focused on the predicted present or past positions of the forebulge, but detailed comparisons of seismic reflection data with model predictions may reveal stratigraphic onlap and/or wedging relationships that could provide possible traps for hydrocarbons.Item Transient Behavior of Mass Transfer Through Liquid Membranes(Texas Tech University, 1977-08) Shen, Sidney YihNot Available.Item Wavelet transform analysis of seismic data(Texas Tech University, 2004-12) Phillips, Griffin CNot available