• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 19
  • 1
  • 1
  • Tagged with
  • 23
  • 23
  • 6
  • 6
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Observations of Soil Moisture Dynamics Associated with Hydrocarbon Affected and Layered Coarse Textured Soils

2016 February 1900 (has links)
The Aurora Soil Capping study, located in northern Alberta, was constructed to evaluate reclamation practices on lean oil sands dumps. The challenges relating to its success includes determining the appropriate soil cover design(s) for the coarse textured reclamation soil, while utilizing available salvaged natural soils, some of which contain residual bitumen in the form of aggregate oil sand material (AOSM). Limited research on this material raises key questions as to the impact it will play on transport and retention processes, along with potential contamination from hydrocarbon leaching. The research conducted sought to answer these questions. This thesis describes laboratory studies conducted on four soils; the upper organic LFH layer, Bm, BC and subsoil material while varying the amount of AOSM and implementing layering schemes. Material characterization through organic carbon and particle size analysis as well as hydrophobicity studies on AOSM through contact angle analysis were performed. A tension table and pressure plates, along with columns equipped with Time Domain Reflectometry probes, were used for water retention studies. Hydraulic conductivity was measured through constant head methods. To address hydrocarbon leaching concerns, chloride tracer studies were performed and the column outflow was analyzed using Gas Chromatography to detect the hydrocarbon type and concentration. Results from water retention and hydraulic conductivity studies indicated that although the AOSM was hydrophobic, its placement at varying concentrations and forms did not create consistent significant differences in the amount of moisture retained or transported. Results from the column studies showed that under steady state and transient conditions AOSM could result in decreasing infiltration rates and increasing chloride retention. The integration of soil layers further slowed the infiltration rate and delayed chloride transport. Under saturated conditions the presence of higher concentrations of AOSM appeared to increase the rate of water movement. Although these differences were minimal, further studies are required to explore this behavior. Overall, it can be concluded that with appropriate material placement, the addition of layering schemes and hydrocarbon material, the potential exists to increase soil water content in the upper layers of the soil, thereby increasing soil water storage for plant use.
22

The techno-economics of bitumen recovery from oil and tar sands as a complement to oil exploration in Nigeria / E. Orire

Orire, Endurance January 2009 (has links)
The Nigeria economy is wholly dependent on revenue from oil. However, bitumen has been discovered in the country since 1903 and has remained untapped over the years. The need for the country to complement oil exploration with the huge bitumen deposit cannot be overemphasized. This will help to improve the country's gross domestic product (GDP) and revenue available to government. Bitumen is classifled as heavy crude with API (American petroleum Institute) number ranging between 50 and 110 and occurs in Nigeria, Canada, Saudi Arabia, Venezuela etc from which petroleum products could be derived. This dissertation looked at the Canadian experience by comparing the oil and tar sand deposit found in Canada with particular reference to Athabasca (Grosmont, Wabiskaw McMurray and Nsiku) with that in Nigeria with a view of transferring process technology from Canada to Nigeria. The Nigeria and Athabasca tar sands occur in the same type of environment. These are the deltaic, fluvial marine deposit in an incised valley with similar reservoir, chemical and physical properties. However, the Nigeria tar sand is more asphaltenic and also contains more resin and as such will yield more product volume during hydro cracking albeit more acidic. The differences in the components (viscosity, resin and asphaltenes contents, sulphur and heavy metal contents) of the tar sands is within the limit of technology adaptation. Any of the technologies used in Athabasca, Canada is adaptable to Nigeria according to the findings of this research. The techno-economics of some of the process technologies are. x-rayed using the PTAC (petroleum technology alliance Canada) technology recovery model in order to obtain their unit cost for Nigeria bitumen. The unit cost of processed bitumen adopting steam assisted gravity drainage (SAGD), in situ combustion (ISC) and cyclic steam stimulation (CSS) process technology is 40.59, 25.00 and 44.14 Canadian dollars respectively. The unit cost in Canada using the same process technology is 57.27, 25.00 and 61.33 Canadian dollars respectively. The unit cost in Nigeria is substantively lesser than in Canada. A trade off is thereafter done using life cycle costing so as to select the best process technology for the Nigeria oil/tar sands. The net present value/internal rate of return is found to be B$3,062/36.35% for steam assisted gravity drainage, B$I,570124.51 % for cyclic steam stimulation and B$3,503/39.64% for in situ combustion. Though in situ combustion returned the highest net present value and internal rate of return, it proved not to be the best option for Nigeria due to environmental concern and response time to production. The best viable option for the Nigeria tar sand was then deemed to be steam assisted gravity drainage. An integrated oil strategy coupled with cogeneration using MSAR was also seen to considerably amplify the benefits accruable from bitumen exploration; therefore, an investment in bitumen exploration in Nigeria is a wise economic decision. / Thesis (M.Ing. (Development and Management))--North-West University, Potchefstroom Campus, 2010.
23

The techno-economics of bitumen recovery from oil and tar sands as a complement to oil exploration in Nigeria / E. Orire

Orire, Endurance January 2009 (has links)
The Nigeria economy is wholly dependent on revenue from oil. However, bitumen has been discovered in the country since 1903 and has remained untapped over the years. The need for the country to complement oil exploration with the huge bitumen deposit cannot be overemphasized. This will help to improve the country's gross domestic product (GDP) and revenue available to government. Bitumen is classifled as heavy crude with API (American petroleum Institute) number ranging between 50 and 110 and occurs in Nigeria, Canada, Saudi Arabia, Venezuela etc from which petroleum products could be derived. This dissertation looked at the Canadian experience by comparing the oil and tar sand deposit found in Canada with particular reference to Athabasca (Grosmont, Wabiskaw McMurray and Nsiku) with that in Nigeria with a view of transferring process technology from Canada to Nigeria. The Nigeria and Athabasca tar sands occur in the same type of environment. These are the deltaic, fluvial marine deposit in an incised valley with similar reservoir, chemical and physical properties. However, the Nigeria tar sand is more asphaltenic and also contains more resin and as such will yield more product volume during hydro cracking albeit more acidic. The differences in the components (viscosity, resin and asphaltenes contents, sulphur and heavy metal contents) of the tar sands is within the limit of technology adaptation. Any of the technologies used in Athabasca, Canada is adaptable to Nigeria according to the findings of this research. The techno-economics of some of the process technologies are. x-rayed using the PTAC (petroleum technology alliance Canada) technology recovery model in order to obtain their unit cost for Nigeria bitumen. The unit cost of processed bitumen adopting steam assisted gravity drainage (SAGD), in situ combustion (ISC) and cyclic steam stimulation (CSS) process technology is 40.59, 25.00 and 44.14 Canadian dollars respectively. The unit cost in Canada using the same process technology is 57.27, 25.00 and 61.33 Canadian dollars respectively. The unit cost in Nigeria is substantively lesser than in Canada. A trade off is thereafter done using life cycle costing so as to select the best process technology for the Nigeria oil/tar sands. The net present value/internal rate of return is found to be B$3,062/36.35% for steam assisted gravity drainage, B$I,570124.51 % for cyclic steam stimulation and B$3,503/39.64% for in situ combustion. Though in situ combustion returned the highest net present value and internal rate of return, it proved not to be the best option for Nigeria due to environmental concern and response time to production. The best viable option for the Nigeria tar sand was then deemed to be steam assisted gravity drainage. An integrated oil strategy coupled with cogeneration using MSAR was also seen to considerably amplify the benefits accruable from bitumen exploration; therefore, an investment in bitumen exploration in Nigeria is a wise economic decision. / Thesis (M.Ing. (Development and Management))--North-West University, Potchefstroom Campus, 2010.

Page generated in 0.0483 seconds