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dc.contributor.authorAnyanwu, Okechukwu Ndubuisi
dc.date.accessioned2015-08-21T00:00:29Z
dc.date.available2015-08-21T00:00:29Z
dc.date.issued2007-08
dc.identifier.urihttp://hdl.handle.net/11122/5837
dc.descriptionThesis (M.S.) University of Alaska Fairbanks, 2007en_US
dc.description.abstractWax deposition during crude oil production is a major problem that has plagued the oil industry for decades especially in cold environments such as Alaska North Slope (ANS) fields, with adverse consequences in huge mitigation cost and lost production. It is therefore imperative to adequately and accurately identify the conditions for wax precipitation and deposition in order to optimize operation of the production systems of ANS. In order to assess ANS crude's potential for wax precipitation, Viscometry and Cross Polarization Microscopy (CPM) are used to determine the temperature at which paraffins begin to precipitate from ANS dead oils. Wax dissolution temperatures (WDT) are also determined by CPM. Results show that wax precipitation is possible at temperatures as high as 41°C (106°F) while it takes up to 50°C (122°F) to get all waxes back into solution. The CPM technique was more sensitive while Viscometry results did not provide a high level of certainty in some samples and therefore appear over-estimated relative to CPM results. Previous thermal history was observed to influence test results. Pour point, viscosity, density and specific gravity have also been measured. Pour point results indicate that oil could form gel in the temperature range 12°C (53.6°C) to less than -31°C ( -23.8°F).en_US
dc.description.tableofcontents1. Introduction -- 1.1. Alaska North Slope background -- 1.2. Crude oil wax -- 1.3. Concern for wax deposition -- 1.4. Objective of study -- 2. Literature review -- 2.1. Introduction -- 2.2. Nature and chemistry of waxes -- 2.3. Wax crystallization and deposition -- 2.3.1. Wax crystallization -- 2.3.2. Wax deposition -- 2.3.3. Factors leading to wax precipitation and deposition -- 2.3.4. Wax appearance temperature measurement techniques -- 3. Sample Preparation -- 3.1. Sample preparation -- 4. Wax appearance and wax dissolution temperatures -- 4.1. Wax crystallization point -- 4.2. Wax deposition mechanisms -- 4.3. WAT and WDT measurement apparatus (CPM) -- 4.3.1. CPM test procedure -- 4.4. WAT and WDT results and discussion -- 4.4.1. WAT by cross polarization microscopy -- 4.4.2. WAT by viscometry -- 4.4.3. Wax dissolution temperature by CPM -- 4.4.4. Comparison between viscometry and CPM WAT results -- 4.4.5. Effect of thermal and shear history -- 4.4.6. Effect of cooling rate on WAT -- 5. Measurement of other oil properties -- 5.1. Viscosity measurement -- 5.1.1. Viscosity measurement procedure -- 5.1.2. Viscosity results -- 5.2. Density measurement -- 5.2.1. Density measurement procedure -- 5.2.2. Density results -- 5.3. Pour point measurement -- 5.3.1. Pour point measurement procedure -- 5.3.2. Pour point results -- 6. Conclusions and recommendations -- 6.1. Conclusions -- 6.2. Recommendations -- References -- Appendices.en_US
dc.language.isoen_USen_US
dc.titleCharacterization of Alaska North Slope oils for wax depositionen_US
dc.typeThesisen_US
dc.type.degreemsen_US
dc.identifier.departmentDepartment of Petroleum Engineeringen_US
dc.contributor.chairZhu, Tao
dc.contributor.committeeChukwu, Godwin A.
dc.contributor.committeeDandekar, Abhijit
dc.contributor.committeeZhou, Wendy
refterms.dateFOA2020-03-05T14:40:46Z


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