Thesis (M.B.A)--Boston University

Investigation of forward in situ combustion have been carried out in a 7.3 cm diameter tube having a length of 0.869 m. Experiments at pressures up to 50 psig were made to study combustion characteristics and enhanced oil recovery of three different crude oils, namely North Sea Forties (36.6 °API), Maya Isthmus (32.4 °API) and Maya (22.1 °API). Sand packs were prepared with oil saturations in the range 38-44.32%. Close adiabatic control of the combustion tube was achieved for both dry and wet combustion modes. Detailed production history and overall mass balances are presented. Correlation in both graphical and tabular form is given for air-fuel ratio, oxygen utilisation and normalised combustion velocity. In this respect, the results of the present work show good agreement with those of other workers. Normal wet, partial quenched modes of combustion were produced using WARs up to 3.75 m3/Mm3 (STP). The combustion front temperature was not significantly affected by the cooling effect of the injected water. Under partially quenched conditions, high combustion-steam zone temperatures were achieved. For wet combustion, the oxygen utilisation generally improved slightly. Air requirement, air-oil ratio and fuel consumption all decreased with increased water-air ratio and increased with increased clay content. The velocity of the combustion front (normalised with respect to the air flux) increased in a linear manner as the WAR increased. Increasing the clay content, however, gave rise to a decrease in the combustion front velocity. High oil recovery, at 79.37%, was achieved during normal wet combustion of Forties oil. In sand mixtures containing amorphous silica powder, the combustion exhibited virtually 100% oxygen utilisation, with higher carbon burning rates compared with runs using clay addition. These effects are attributed to the nature and magnitude of the surface area of solid additives, which play an important role in the oxidation mechanisms.

"The objective of this study is to characterize the flammability of oil-soaked sand towards the development of technology to clean up petroleum product spills using in situ combustion. The burning rate of a sand-oil mixture is enhanced using immersed conductive objects (copper rods) which enable rapid heat-up of the flame exposed to the upper surface of the rod and transmits heat back into the sand. Consequent conduction of heat to the porous media through the lower portion of the immersed rod significantly increases vaporization and therefore the burning rate. Bench scale experiments (10cm) were performed with increasing spill content (18% and 24%) exposed to external heat fluxes (15, 20, 25 and 30kW/m^2 ) and different rod configurations (single rod, multiple rods and cases with various heights and diameters). Flammability parameters such as ignition time, mass loss rate, and temperature profiles were investigated. Experiments show that the ignition time decreases and the burn efficiency rate increases with the addition of immersed objects. A numerical model is used to further explain the controlling parameters for enhancement in burning rate and optimization of the technique."

Typescript (photocopy). / Digitized by Kansas Correctional Industries

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Oil spill accidents represent an inherent occupational, environmental, economic, and community health disaster associated with the transformation of petroleum resources into products that help meet our world’s energy need. Dispersants are applied to break the oil spill into sufficiently small droplets and mitigate oil spill impacts by reducing the possibility of shoreline impact, lessening the impact on marine life and significantly increasing the oil-water interfacial area available for remediation processes. Existing dispersants are liquid solutions of surfactant in hydrocarbon solvents. There are several concerns with the existing dispersant systems including the large volume of hydrocarbon solvents introduced into the ecosystem. / Olasehinde Gbenro Owoseni

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Growing global energy demand has prompted the exploitation of non-conventional resources such as Coal Bed Methane (CBM) and conventional resources such as gas-condensate reservoirs. Exploitation of these resources primarily depends on stimulation by hydraulic fracturing. Traditional hydraulic fracturing practices, however, are in many ways inadequate in addressing difficulties associated with these non-conventional and conventional resources. For example, complex in-situ stress distribution, large material property contrasts and unique production mechanism complicate the implementation of hydraulic fracture treatments in CBM and gas-condensate reservoirs respectively. An integrated approach to optimise hydraulic fracture treatments in reservoirs under complex conditions is developed in this thesis. The optimisation methodology integrates a fracture geometry model which predicts fracture geometry for a given set of treatment parameters, a production model which estimates reservoir productivity after stimulation and an economic model which calculates net present value. A stochastic optimisation algorithm combining features of evolutionary computations is used to search for the optimum design. Numerical techniques such as finite element analysis, iterative semi-analytical methods and evolutionary computation are also used. The following are the major contributions of this thesis: 1. A three-dimensional hydraulic fracture geometry model which accounts for poroelastic effects, in-situ stress and rock material properties, has been developed to provide a more realistic description of the hydraulic fracture geometry. This served as a tool to visualise hydraulic fracture propagation for a given in-situ stress distribution, rock material properties and treatment parameters. Furthermore, by accounting for poroelastic effects, it is possible to identify the causes of exceptionally high treatment pressures. 2. An innovative production model was formulated in this thesis to quantify the well deliverability due to hydraulic fracturing. The production model has been used for a range of production scenarios for CBM and gas-condensate reservoirs such as: multiple wells at arbitrary locations and various well types (stimulated and unstimulated wells). 3. The optimisation methodology presented in this work provides a platform for operators to assess risks and gains associated with different field development scenarios. The added feature of sub-optimal NPV contouring provided flexibility to calibrate the treatment design in real-time. The strength of the optimisation methodology lies in the flexibility to: (1) impose design constraints, (2) optimise multiple variables and (3) simulate multiple objectives.

This thesis centres on studying intricate bargaining relationships between the major actors in the highly politicised oil industry. By covering the period between 1998 and early 2007, this study focuses exclusively on contemporary bargaining in the oil industry, as it is unfeasible to cover a longer time-span. In the current decade, which unlike previous two cooperative decades, can be characterised as conflictual, and thus politicised, the structure of the oil industry can best be understood by studying bargaining between numerous actors, the main of which are the international oil companies (IOCs), oil-exporting states, oil-importing states, and the national oil companies (NOCs). The central argument is that due to their weak relative bargaining power, the IOCs have been on the losing side in their bargaining with oil exporting countries and/or their NOCs in the current decade when compared to the late 1990s, and thus, we are witnessing the return of the obsolescing bargain.

Molecular hybridization of Northern blots of single (1D) and two-dimensional polyacrylamide gels (2D-PAGE) with a ³² P-labelled full length CCCVd₂ ₄ ₆ cRNA probe demonstrated the presence of Coconut cadang - cadang viroid (CCCVd)-like RNAs in nucleic acid extracts of both symptomatic (orange spotted) and asymptomatic oil palms in commercial plantations in Malaysia. Compared with CCCVd in coconut these CCCVd-like RNAs seemed to be present at low concentration in the oil palm samples as shown by the weak hybridization signals observed in the oil palm samples even when large amounts of nucleic acid extract (leaf fresh weight equivalent of 20-100 g) were loaded onto the gel. Ribonuclease protection assay (RPA) was found to be more sensitive in detecting low concentrations of the CCCVd-like RNAs in the oil palm samples than Northern blots as shown by the higher percentage of positive samples. RPA showed that 90 % of the symptomatic and 50 % of asymptomatic palms from Malaysia had RNAs which protected the ³²P-labelled full length CCCVd antisense probe and produced a similar RPA pattern to that of CCCVd. RPA results also indicated that there were mismatches in the sequence of the CCCVd-like RNAs in the oil palms compared to CCCVd from coconut. RT-PCR amplification of CCCVd-like RNAs from an asymptomatic palm was only successful when nucleic acids were partially purified using 1D or 2D-PAGE. RNAs eluted from the circular region of 2D-gels of the asymptomatic palm were amplified to a low concentration using CCCVd-specific primers but re-amplification of these first round RT-PCR products was needed for detection of the amplicons by ethidium bromide staining. No amplified product was obtained from a symptomatic palm. Cloning and sequencing of the RT-PCR products from the asymptomatic oil palm produced 20 clones of five sizes comprising 297 nt (OP₂₉₇), 293 nt (OP₂₉₃), 270 nt (OP₂₇₀), 232 nt (OP₂₃ ₂) and 165 nt (OP₁₆₅). 71 % of the clones were OP₂₉₇. Comparison of OP₂₉₇, OP₂₉₃, and OP₂₇₀ with genome database sequences showed high sequence similarity with CCCVd₂₉₆. OP₂₉₇. OP₂₉₃, OP₂₇₀ had 98 %, 97 % and 90 % sequence similarity with CCCVd₂₉₆ respectively. OP₂₃₂ and OP₁₆₅ also had high sequence similarity with parts of CCCVd ₂₄₆ with which they were aligned. Because an arbitrary level of 90 % sequence similarity is accepted as separating viroid species from variants, OP₂₉₇ , OP₂₉₃ and OP₂₇₀ can be considered as variants of CCCVd. No variants of the ' fast ' CCCVd ₂ ₄ ₆ form were obtained. The consensus OP₂₉₇ sequence had single base substitutions or additions at 5 sites, OP₂₉₃ had substitutions, additions or deletions at 8 sites, and OP₂₇₀ had substitutions at 4 sites as well as deletion of a 26 nt repeat at the right terminus, producing a predicted branched secondary structure. Compared with CCCVd₂₉₆ , all variants substituted (C-U) at nt 31 in the pathogenicity domain and (A-C) at nt 175 in the right hand terminal domain. The presence of sequences similar to OP₂₃₂ and OP₁₆₅ has not been reported for CCCVd. Analysis of DNA extracted from both symptomatic and asymptomatic oil palms from Malaysia by nested PCR using universal primers sets to amplify the 16S rRNA operon showed the presence of phytoplasma-like DNAs in both sets of samples. They were also detected in DNA extracted from oil palm seedlings maintained at the Waite campus but not in the other palm species maintained in the glasshouse. RFLP analysis of phytoplasma-like DNAs gave a different pattern than that expected for Australian grapevine yellows phytoplasma. The phytoplasma - like DNAs were also not related to lethal yellowing phytoplasma (LYp) as PCR analysis with LYp specific primers did not produce any amplicon. No association with OS was found and so they were not characterised further. CCCVd-infected coconut leaf collected in the Philippines contained two short interfering RNAs (siRNA) approximately 20 nt and 25 nt in size. A high stringency wash of the Northern blots failed to remove the hybridisation signal suggesting that these siRNAs had sequences closely similar to CCCVd. The siRNAs were present in all stages of the cadang-cadang and also samples with the 'brooming' symptom. siRNAs are regarded as a marker for post-transcriptional gene silencing (PTGS) in plants infected by viroids but the results obtained were insufficient to determine whether PTGS regulates the accumulation of CCCVd. This is the first report that a viroid closely related to CCCVd occurs in oil palm, and in a region outside the Philippines, the country where CCCVd is thought to be contained. The implications for quarantine matters are discussed. / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture and Wine, 2005.