Thesis (M. S.)--Texas A&M University, 2006. / "Major Subject: Petroleum Engineering" Title from author supplied metadata (automated record created on Feb. 23, 2007.) Vita. Abstract. Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 1976. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

Thesis (Ph. D.)--Texas A&M University, 2006. / "Major Subject: Petroleum Engineering" Title from author supplied metadata (automated record created on Feb. 23, 2007.) Vita. Abstract. Includes bibliographical references.

This Master Thesis work aims to find a model system combining the positive effects of surfactant and polymer flooding to enhance oil recovery. This report presents the results of 12 core floors performed to enhance recovery of waterflood residual oil. The recovery is enhanced by a visous surfactant flood consistent of one polymer to increase the viscosity, one surfactant for interfacial tension reduction, and one di-alcohol to function as co-surfactant and for salinity control. The chemical treatment that gave the best result, gave an additional oil production normalized on OOIP of 20%, improving the oil recovery from 45 to 66% mostly by the means of mobility control. Pure viscosity floods gave an additional recovery of 12 to 13% of OOIP. Novel technology is used to investigate environmental friendly enhanced oil recovery. A biopolymer made out of microfibrils from wooden material was for the first time ever to my knowledge, attempted used in a core flood to enhance oil recovery. A viscous surfactant tertiary recovery process may help improve oil recoveries from many marginal oil fields or those that face shut-down due to uneconomic operating costs, but still contain significant amounts of oil.

The Canada-wide Standards for Petroleum Hydrocarbons (PHC CWS) in soils are remedial standards based on four petroleum distillates (Fraction 1 [F1; ECN C6-C10], Fraction 2 [F2; ECN >C10-C16], Fraction 3 [F3; ECN >C16-C34], and Fraction 4 [F4; ECN >C34-C50]). Knowledge gaps regarding petroleum toxicity to soil organisms were identified including concerns that the ecological values for F3 were overly conservative, possibly due to differences in toxicity between the low and high boiling point constituents of this distillate, and unexpected less-than-concentration-additive toxicity of binary mixtures of distillates to earthworms. An understanding of petroleum toxicokinetics with soil organisms was also needed to interpret toxicity results. Toxicity studies with one plant and two invertebrate (earthworm and collembolan) species were conducted with F3 and two subfractions of F3, F3a (ECN >C16-C22) and F3b (ECN >C22-C34), to determine if the toxicities of F3a and F3b were sufficiently different to recommend regulating the two separately. The difference in toxicities between the two was generally within the range of variability noted for the toxicity tests and thus it was not recommended to regulate the two separately. The toxicity data indicated that the exposure duration of standard test methods may be insufficient for determining the toxicity of higher distillate ranges. Toxicokinetic studies conducted with earthworms and F2, F3a, and F3b confirmed that standard test durations generally were not of sufficient duration to attain maximum body residues with F3b and sometimes F3a. Internal exposure scenarios also differed among distillates, with various accumulation curves noted and attributed to differences in loss of distillate from the soil and changes in bioavailability. Aromatics were disproportionally accumulated by earthworms relative to the ratio of aromatics to aliphatics in soil, suggesting that aromatics were the main contributors to earthworm toxicity. Toxicity and toxicokinetic studies with binary combinations of F2, F3a, and/or F3b and earthworms demonstrated that, on a soil concentration basis, toxicity was less-than-additive. Toxicokinetics indicated that this was due to a decrease in the bioavailability of distillates when a second distillate was present presumably as a non-aqueous phase liquid. However, on an internal tissue concentration basis, results were closer in agreement with concentration-addition.

Quantifying the effects of hydrocarbon contamination on hybrid poplar fine root dynamics provides information about how well these trees tolerate the adverse conditions imposed by the presence of petroleum in the soil. Infection by ectomycorrhizal (ECM) fungi may benefit hybrid poplar growing in contaminated soils by providing greater access to water and nutrients and possibly inducing greater contaminant degradation. The overall objectives of this research were to: 1) investigate the relationship between the varying concentrations of total petroleum hydrocarbons (TPH) and nutrients across a hydrocarbon-contaminated site, as well as interactions between these contaminants and physical and chemical soil properties; 2) quantify the effects of these properties on the spatial and temporal patterns of fine root production for Griffin hybrid poplar (<i>P. deltoids </i> x <i>P. petrowskyana</i> c.v. Griffin); and (3) quantify the effect of ectomycorrhizal colonization on hybrid poplar fine root dynamics and N and P uptake when grown in diesel contaminated soil under controlled conditions. A minirhizotron camera provides a nondestructive approach for viewing roots in situ. This camera was used in both the field and growth chamber experiments to provide the data necessary for estimating fine root production. The field study was conducted at Hendon, SK, Canada. Twelve minirhizotron tubes were distributed across the field site and facilitated quantification of fine root production in areas of varying contamination levels. Residual hydrocarbon contamination was positively correlated with soil total C and N, which may suggest that the hydrocarbons remaining in the soil are associated with organic forms of these nutrients or increased microbial biomass. Total fine root production at the site was greater in the 0- to 20-cm depth (1.27 Mg/ha) than the 20- to 40-cm depth (0.51 Mg/ha) in 2004. Fine root production was stimulated by small amounts of hydrocarbon contamination at the field site. Nonlinear regression described fine root production as increasing linearly up to approximately 500 mg/kg TPH, then remaining constant as contamination increased. This trend was most pronounced in the 0- to 20-cm soil layer, with a (r&178; = 0.915). Stimulation of fine root production in the presence of hydrocarbons has significant implications for phytoremediation. If hybrid poplar can maintain increased root production in hydrocarbon contaminated soils, the rhizosphere effect will be exaggerated and increased degradation of contaminants is likely to occur. Under controlled conditions, colonization of hybrid poplar roots by the ectomycorrhizal fungus <i>Pisolithus tinctorius</i>increased fine root production in a diesel contaminated soil (5000 mg diesel fuel/kg soil) compared to non-colonized trees growing in the same soil. Fine root production was 56.6 g/m&178; in the colonized treatment and 22.6 g/m&178; in the non-colonized treatment. In diesel contaminated/ECM colonized treatment, hybrid poplar leaf N and P concentrations after 12 wk were 23.1 and 3.6 g/kg, respectively. In diesel contaminated/non-colonized treatment, N and P concentrations were 15.7 and 2.7 g/kg, respectively. After 12 wk, 5.0&37; of the initial concentration of diesel fuel remained in the soil of the non-colonized treatment and 6.7&37; remained in the colonized treatment. Both treatments removed more contaminants from the soil than an unplanted control, which contained 8.9&37; of the initial diesel fuel concentration after 12 wk. Significantly more hydrocarbons were found sequestered in hybrid poplar roots from the colonized treatment (354.1 mg/kg) than in the non-colonized treatment (102.2 mg/kg). The results of this study indicate that hybrid poplar may be good candidates for use in phytoremediation of petroleum hydrocarbons because of the stimulation of fine root production at low levels of hydrocarbon contamination. However, colonization of hybrid poplar growing in diesel contaminated soil by <i>P. tinctorius</i> inhibited remediation of diesel fuel.

This study proposes and validates computationally the effectiveness of a novel, hemiwedge model for a sub-surface safety valve (SSSV). With the growing needs in the oil industry and new finds of ultra-deepwater reservoirs in the Gulf of Mexico (GOM), this SSSV will provide a small but necessary advancement to harvest these new oil reserves from extreme high-pressure/high-temperature (XHPHT) environments. Computational fluid dynamics (CFD) in the Ansys RTM CFX flow solver is used to study the flow properties of crude oil through the valve, while both AnsysRTM and SolidWorks RTM Simulation are used to perform stress and fatigue analyses and other solid mechanics studies. Analysis has shown this model to be effective in successfully and safely operating at high pressures (30,000 psi ) and high temperatures (450&deg;F) over the desired life of the SSSV, providing a viable option for helping to recover new oil reserves found in the GOM and other XHPHT environments.

The potential problem produced by asphaltene deposition during oil production has motivated the development of several experimental techniques and theoretical models, trying to understand and predict the asphaltene behavior. Despite the work devoted to understanding this subject, asphaltene deposition still represents a challenging unresolved problem. Predicting asphaltene flow assurance issues requires the ability to model phase behavior of asphaltenes as a function of temperature, pressure, and composition. It has been previously shown that the Perturbed Chain form of the Statistical Associating Fluid Theory equation of state (PC-SAFT EOS) accurately predicts crude oil bubble point and density as well as asphaltene precipitation conditions. This approach has been used to examine the effects of gas injection, oil based mud contamination, and asphaltene polydispersity on the phase behavior of asphaltenes. In this work, a new application of the PC-SAFT EOS in studying the effect of carbon dioxide injection reveals an interesting dual effect of this compound in inducing or preventing asphaltene precipitation, depending on the operating conditions. Novel tools for understanding and predicting properties of hydrocarbon and crude oil systems are also presented and discussed. These tools include the One-Third Rule---a correlation between refractive index and mass density---, a revised solubility parameter modeling approach that includes an improved mixing rule for solubility parameters, and the development of a general method for modeling asphaltene stability. The development of a simulation tool that simultaneously accounts for asphaltene precipitation, aggregation and deposition is also presented and discussed. The thermodynamic modeling using the PC-SAFT EOS is coupled with kinetic models and transport equations. The mechanism for asphaltene precipitation and deposition proposed in this work has been found to be consistent with various experiments and field observations. Furthermore, it also provides an explanation to some paradoxes, such as why some asphaltene precipitation inhibitors worsen asphaltene deposition or why strong asphaltene precipitants, such as propane, produce less amount of deposit. The work presented in this dissertation will contribute in the development of a foundation for oil sample analysis and simulations that can predict the likelihood of asphaltene deposition in the newly found oil fields worldwide.

This thesis summarizes the preliminary design work of a new subsurface safety valve (SSSV) for extreme high pressure (30,000 psi) and high temperature (450&deg;F) (XHPHT) applications. Current SSSV designs are not reliable in current production environments and certainly will not be qualified to fail-safe under XHPHT conditions. In this design stage, a quasi-static study on the fluid structure interactions of a flapper SSSV is conducted. A parametric 3D CAD model of a flapper SSSV is built in Solidworks. Then computational fluid dynamics (CFD) analysis is conducted in AnsysRTM CFX. CFD results and the water hammer pressure surge calculated are successfully imported into AnsysRTM Workbench followed by a finite element analysis (FEA) of the stresses. Flappers with different sealing types are compared and summarized. This study is a necessary step for the next design stage, which supplies information that might result in a technical step change in the SSSV design.

This thesis proposes modeling phase behavior, including the solid phase, during gas processing. Failure to accurately predict solid phase formation or freezing of CO2, hydrates, and water ice causes plugging and equipment failure. Vapor-liquid-solid phase behaviors of hydrocarbons are modeled using the Perturbed Chain-SAFT (PC-SAFT) equation of state in the presence of carbon dioxide at cryogenic temperatures. PC-SAFT does an excellent job predicting vapor-liquid equilibria (VLE), vapor-solid equilibria (VSE), and liquid-solid equilibria (LSE) using binary interaction parameters fit to the vapor-liquid equilibria data. Using these parameters produces excellent results for LSE and VSE for hydrocarbon + carbon dioxide systems over the entire range of measured temperatures and pressures. Predicting accurate solid phase behavior will help in design and optimization of processes for cryogenic systems especially when data are lacking at process conditions. Further, modeling at extreme high temperatures and pressures demonstrates the usefulness of PC-SAFT for deepwater reservoirs.