Philosophiae Doctor - PhD / Petrophysical evaluation of the Albian age gas bearing sandstone reservoirs of the O-M field, Offshore South Africa has been performed. The main goal of the thesis is to evaluate the reservoir potentials of the field through the integration and comparison of results from core analysis, production data and petrography studies for the evaluation and correction of key petrophysical parameters from wireline logs which could be used to generate an effective reservoir model. A total of ten wells were evaluated and twenty eight sandstone reservoirs were encountered of which twenty four are gas bearing and four are wet within the Albian age depth interval of 2800m to 3500m. Six lithofacies (A1, A2, A3, A4, A5 and A6) were grouped according to textural and structural features and grain size from the key wells (OP1, OP2 and OP3). Facies A6 was identified as non reservoir rock in terms of reservoir rock quality and facies A1 and A2 were regarded as the best reservoir rock quality. This study identifies the different rock types that comprise reservoir and non reservoirs. Porosity and permeability are the key parameters for identifying the rock types and reservoir characterization. / South Africa

Master of Science / Department of Geology / Matthew Kirk / Biodegradation of crude oil to methane has long been known to exist in shallow petroleum reservoirs. It is only in the past decade, however, in which the concept of in-reservoir petroleum biodegradation has changed from a model emphasizing aerobic crude-oil degradation (with oxygen delivered down from meteoric waters) to a more recent model in which crude-oil degradation is driven by anaerobic processes (methanogenic microorganisms). In this study, we examine controls on microbial conversion of crude oil and coal into methane in middle-Pennsylvanian strata in the Cherokee Basin, Kansas, USA and how access to oil or coal influence microbial communities. Specifically, we considered the following hypotheses: 1) microorganisms in the basin are capable of generating methane by degrading crude oil or coal and 2) potential controls on the rate of methane formation include microbial diversity, formation water chemistry, nutrient abundance, and carbon dioxide abundance. To test these hypotheses, we used three sets of laboratory experiments constructed of materials from the Cherokee basin, Kansas. One set tested environmental controls on methane generation from oil, another from coal, and a third was a control experiment that utilized methanogenic substrates rather than oil or coal. In the experiments with oil and coal, environmental factors tested ammonium/phosphate availability, feedlot wastewater injection, and carbon dioxide abundance. Our experiments also tested the influence of salinity, by including materials from a well producing water with relatively low salinity and a well producing water with relatively high salinity. The cultures were allowed to incubate from approximately 75 to 170 days, during which headspace of oil and coal bioreactors were sampled periodically and analyzed for methane concentrations. Post incubation analyses included microbial DNA sequencing. We determined that a higher concertation of methanogens existed in the lower salinity well, which has higher potential for practical stimulatory injection. Of methane produced, the only significant (Mann Whitney) treatment had access to oil in lower salinity formation water. Access to coal resulted in no significant results. Microbial diversity, in the form of methanogenic archaea abundance, formation water chemistry (salinity), and wastewater nutrient often correlated with increased, yet insignificant, rates of methane production, while carbon dioxide abundance showed no benefit. Of methanogenic substrates consumed, we determined that most Cherokee basin methanogens preferred methanol over hydrogen and acetate.

This thesis examines the prospect of structure H (sH) hydrate to be exploited for methane storage. The methane content in the hydrate, hydrate kinetics and conversion rates are areas of particular importance. Experiments and theory are employed at the macroscopic and molecular levels to study the relevant phenomena. sH hydrate was successfully synthesized from ice particles with full conversion achieved within a day when thermal ramping above the ice melting point was applied. It was found that a polar guest (tert-butyl methyl ether / TBME) wets ice more extensively compared to two hydrophobic guests (neo-hexane / NH and methyl-cyclohexane / MCH). TBME also has much higher solubility in water. Consequently, the system with TBME was found to exhibit the highest initial hydrate formation rate from ice particles or in water in a well stirred vessel. However, the rate with the hydrophobic guests was the fastest when the temperature exceeded the ice point. Thus, the applied temperature ramping compensated the slow kinetics below the ice point for the hydrophobic guests and allowed faster overall conversion than the polar guest. Structure, cage occupancy, composition and methane content in the hydrate were also determined by employing different techniques and the results were found to be consistent. It was found that the methane content in structure H hydrate with TBME was the smallest (103-125 v/v) whereas that with NH was 130-139 (v/v) and that with MCH was 132-142 (v/v). The methane content in structure II hydrate by using propane (C₃H₈) and tetrahydrofuran (THF) as the large guest molecule were also estimated. Optimal methane content was found at approximately 100 (v/v) for both C₃H₈ and THF systems with the large guest concentrations at 1% for C₃H₈ (10°C) and 1% for THF (room temperature). The gas content is of course lower than that for structure I hydrate (170 v/v) but one should consider the fact that the hydrate formation conditions are much lower (less than 1 MPa). Finally, MD simulations revealed for the first time the formation of defects in the cavities for the TBME/methane/water (sH hydrate) system which may affect hydrate stability and kinetics. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

Most natural gas fields in Saudi Arabia contain around 10 mol.% carbon dioxide. The present technology to remove carbon dioxide is performed by chemical absorption, which has many drawbacks. Alternatively, membrane-based gas separation technology has attracted great interest in recent years due to: (i) simple modular design, (ii) potential cost effectiveness, (iii) ease of scale-up, and (iv) environmental friendliness. The state-of-the-art membrane materials for natural gas sweetening are glassy cellulose acetate and polyimide, which were introduced in the 1980s. In the near future, the kingdom is planning to boost its production of natural gas for power generation and increase the feedstock for new petrochemical plants. Therefore, the kingdom and worldwide market has an urgent need for better membrane materials to remove carbon dioxide from raw natural gas. The focus of this dissertation was to design new polyimide membrane materials for CO2/CH4 separation exhibiting high permeability and high selectivity relative to the standard commercial materials tested under realistic mixed-gas feed conditions. Furthermore, this study provided a fundamental understanding of structure/gas transport property relationships of triptycene-based PIM-polyimides. Optimally designed intrinsically microporous polyimide (PIM-PIs) membranes in this work exhibited drastically increased CO2/CH4 selectivities of up to ~75. In addition, a novel triptycene-based hydroxyl-containing polyimide (TDA1-APAF) showed 5-fold higher permeabilities over benchmark commercial materials such as cellulose acetate. Furthermore, this polyimide had a N2/CH4 selectivity of 2.3, thereby making it possible to simultaneously treat CO2- and N2-contaminated natural gas. Also, TDA1-APAF showed a CO2 permeability of 21 Barrer under binary 1:1 CO2/CH4 mixed-gas feed with a selectivity of 72 at a partial CO2 pressure of 10 bar which are significantly better than cellulose triacetate. These results suggest that TDA1-APAF polyimide is an excellent candidate membrane material for removal of CO2 and N2 from natural gas. Moreover, based on the collected data for CO2/CH4 mixed-gas experiments from this work and previously published reports, a new mixed-gas 2017 CO2/CH4 permeability/selectivity upper bound curve was initiated to reflect the actual performance including plasticization phenomena at high feed pressure and 10 bar CO2 partial pressure to simulate the real conditions of the wellhead pressure.

El procesamiento del gas natural para la extracción del etano e hidrocarburos superiores es una actividad de gran impor-tancia dentro del sistema gasífero de un país. El etano constituye la materia prima fundamental de la denominada petroquímica base gas, mientras que propano, butanos, pen-tanos y superiores, se comercializan fundamentalmente como combustibles. En el caso de Argentina, la actividad de proce-samiento forma parte del sistema de transporte y distribución de gas natural, el cual se encuentra regulado para asegurar una adecuada provisión de este insumo a los consumidores industriales y domiciliarios. Por este motivo suelen existir res-tricciones sobre la cantidad de hidrocarburo que puede extraerse del gas disponible. Por otra parte, el negocio de ex-tracción se encuentra sujeto a la incertidumbre inherente a los mercados en lo que respecta a demanda y precios de los productos del procesamiento así como a la variabilidad de los gasoductos en cuanto a calidad y cantidad de gas a proce-sar. Como consecuencia, esta actividad se encuentra sometida a una gran variabilidad a lo largo del año, lo que dic-ta la necesidad de ajustar en forma permanente la operación de los complejos de extracción para optimizar el negocio.Dada la complejidad estructural de las plantas de extracción moder-nas, esta tarea puede verse beneficiada por la disponibilidad de herramientas de asistencia en la toma de decisiones basa-das en modelos matemáticos de optimización. En esta tesis se presenta un modelo matemático para optimizar la operación del complejo de extracción de hidrocarburos instalado en la localidad de Gral. Daniel Cerri próxima a la ciudad de Bahía Blanca. El modelo no-lineal mixto-entero propuesto contempla las múltiples opciones de mezclado disponibles en el complejo así como la posibilidad de operar o pasar a reserva sus cinco plantas de extracción de hidrocarburos. Dichas plantas po-seen diferentes tecnologías de extracción y por lo tanto rendi-mientos distintos en función de sus respectivas variables ope-rativas. Los resultados del modelo se comparan contra datos históricos del proceso para cinco escenarios operativos fre-cuentes a lo largo del año, con el objeto de cuantificar los potenciales beneficios de su aplicación sistemática. Se presen-tan además diversas aplicaciones con el objeto de ilustrar su uso para asistir en la toma de decisiones tanto a escala ope-rativa, como táctica y estratégica. / The processing of the natural gas for the extraction of ethane and heavier hydrocarbons is of fundamental importance within the gas system of a country. Ethane is the basic raw material of the gas based petrochemical industry, while propane, buta-nes, pentanes and heavier compounds are mainly commer-cialized as fuels. In the case of Argentina, the processing ac-tivity is a part of the natural gas transport and distribution system, which is regulated by law in order to ensure an adequate provision for home and industrial use. For this rea-son, constraints on the amount of hydrocarbons that can be extracted from the available gas frequently arise. On the other hand, the extraction business is subject to market inhe-rent uncertainty regarding demands and prices of the pro-ducts, as well as to the variability of the pipelines regarding quality and availability of raw material. As a consequence,this activity faces a high variability along the year, which dictates the necessity of tuning the operation of the extraction complexes almost permanently in order to optimize the busi-ness. Due to the structural complexity of the modern extrac-tion plants, this task could benefit from the availability of deci-sion making support tools based on mathematical optimization models. In this thesis a mathematical model is presented aimed to optimize the operation of the hydrocarbon extraction complex located in Gral. Daniel Cerri close to Bahía Blanca city. The proposed mixed-integer-nonlinear model considers all the available gas mixing options in the process as well as the possibility of turning-on and shutting-down its five hydrocar-bon extraction plants. Such plants possess different technolo-gies and therefore different extraction efficiencies as func-tions of their respective operative variables. Model results are compared against historical process data for five frequent operating scenarios along the year in order to quantify the potential benefits of its systematic application. Several appli-cations are also proposed in order to illustrate its use in decision making at operational, tactical and strategic levels.

Municipalities protect human health and environmental resources from impacts of urban natural gas drilling through setback distances; the regulation of distances between well sites and residences, freshwater wells, and other protected uses. Setback distances have increased over time, having the potential to alter the amount and geographical distribution of drillable land within a municipality, thereby having implications for future land use planning and increasing the potential for future incompatible land uses. This study geographically applies a range of setback distances to protected uses and freshwater wells in the city limits of Denton, Texas to investigate the effect on the amount of land remaining for future gas well development and production. Denton lies on the edge of a productive region of the Barnett Shale geological formation, coinciding with a large concentration of drillable land in the southwestern region of the study area. This region will have the greatest potential for impacts to future municipal development and land use planning as a result of future gas well development and higher setback standards. Given the relatively high acreage of drillable land in industrially zoned subcategory IC-G and the concern regarding gas well drilling in more populated areas, future drilling in IC-G, specifically in IC-G land cover classes mowed/grazed/agriculture and herbaceous, would have the least impact on residential uses and tree cover, as well as decreasing the potential for future incompatible land uses.

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The market for natural gas in the United States follows a yearly price pattern of high prices during the winter heating season and lows during the summer months. During the winter heating season the daily and weekly price fluctuations for natural gas are normally related to ambient air temperature and other weather related phenomenon. This paper examines a natural gas price forecasting model developed by the U.S. Department of Energy, Energy Information Agency (EIA). This paper proposes that a more accurate forecasting model can be created from the EIA model by focusing on forecasting price during only the winter heating season and by adding other variables to the EIA model. The forecasting results of the core EIA model are compared to the results of other linear regression models. / Master of Arts

A single compressor station site along a gathering line network was monitored for fugitive methane emissions to quantify long-term emissions in Appalachia Virginia. Continuous monitoring was conducted from January 2021 to April 2021. The compressor station undergoing monitoring operated two CAT3516 Tale and one CAT3516 B engines operating at 80% of max output flow. Data presented on methane emissions during this period was gathered with an eddy covariance monitoring station. This station was equipped with an LI-7700 methane analyzer, LI-7500A - CO_2/H_2 O analyzer as well as a sonic anemometer these sensors could be observed remotely through cellular connection. The data is represented in flux output ((µmol)/(s m^2 )) as well as kg CO_2 equivalence of methane outlined by the EPA greenhouse gas inventory. The average daily emissions for this compressor station are estimated to be 136 kg CO_2 equivalent emissions. This study shows that the site during the observational period the compressor station emitted on average are estimated to be 5.43 kg of CH_4 per day. / Master of Science / There has been an increased interest in quantifying and recording methane (CH_4) emissions among all sectors. A main focus of interest among methane is to understand fugitive gasses and emissions resulting from the natural gas sector. Leaks along pipelines are most likely occurring at connection points between components. This study aimed to continuously monitor a pipeline compressor station in Appalachia Virginia. Compressor stations are just one component of the pipeline network as well as the natural gas production and delivery chain attributed with CH_4 emissions. To monitor methane emissions at the site a stationary eddy covariance monitoring station was installed that was equipped with an open path methane analyzer, open path CO_2 and H_2 O analyzer, and a sonic anemometer. The data gathered was used to calculate the flux of methane which is the amount of methane being generated or absorbed by the area of interest. The goal of this study was to continuously monitor methane emissions of a natural gas compressor station. Data presented in this study was collected from January 2021 to April 2021. Data was presented in the flux output ((µmol)/(s m^2 )) as well as kg CO_2 equivalence of methane outlined by the EPA greenhouse gas inventory.