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Please use this identifier to cite or link to this item: http://hdl.handle.net/1956/2355

Title:	Effects of initial anaerobic biodegradation on crude oil and formation water composition
Authors:	Skaare, Bent Barman
Issue Date:	4-Apr-2007
Publisher:	The University of Bergen
Abstract:	The e ect of initial biodegradation on oil and formation water was studied using both laboratory degradation schemes and biodegraded oils from the reservoir comprising Troll C. The e ects of biodegradation on the molecular level of oil may be heteroge- neous even in systems that ought to have the same starting point. This is true for both laboratory incubations and for biodegradation processes inside model reservoirs. Simultaneous depletion in di erent oil constituents and compound groups occurs at di erent relative rates, as a result of di erences in the bacterial activity. The dependence of the molecular e ects on the active microbial com- munity is also valid in reservoirs. This makes assessing biodegradation di cult on a molecular level because the e ects may vary according to the prevailing bacterial community in each reservoir. As a result of these di erences using multivariate analysis, e.g. principal component analysis, may provide valuable information that would not have been apparent using univariate ratios. The composition of organic acids in the water phase of the model reservoirs studied are highly dependent on the biodegradation processes it has encoun- tered, as it oods through the system. The identi cation of metabolites speci c for anaerobic biodegradation of naphthalene, 2-methylnaphthalene and tetralin in the formation water from Troll C indicates that the composition of such wa- ter might be dependent on the ongoing biodegradation in the reservoirs as well as in the model reservoirs. The water solubility of such metabolites, along with the assumption that biodegradation occurs at or near the oil water contact, can make identi cation of the metabolites easier in formation water than in the corresponding oils. Hence, the composition of formation waters may contribute information which is not available from the water composition. This was thecase in the samples from Troll C.
URI:	http://hdl.handle.net/1956/2355
ISBN:	978-82-308-0360-8 (print version)
Appears in Collections:	Department of Chemistry (Various)

Files in This Item: File Description Size Format Main_Thesis_Bent_Barman_Skaare.pdf Main Thesis 606.85 kB Adobe PDF View/Open Paper_I_Bent_Barman_Skaare.pdf Barman Skaare, B., Barth, T., Torsvik, T., Heterogeneity of biodegra-dation in long-term model petroleum reservoirs { Implications for in-reservoir biodegradation. Preprint. Submitted for publication in Organic Geochemistry. Published by Elsevier. Abstract only. 113.38 kB Adobe PDF View/Open Paper_II_Bent_Barman_Skaare.pdf Barman Skaare, B., Ommedal, H., Barth, T., Torsvik, T., Simultaneous depletion of oil components during initial biodegradation of crude oil by sulfate-reducing bacteria. Preprint. Submitted for publication in Organic Geochemistry. Published by Elsevier. Abstract only. 113.54 kB Adobe PDF View/Open Paper_III_Bent_Barman_Skaare.pdf Barman Skaare, B., Wilkes, H., Vieth, A., Rein, E., Barth, T., Alteration of crude oil from the Troll area by biodegradation: Analysis of oil and water samples. Preprint. Submitted for publication in Organic Geochemistry. Published by Elsevier. 770.19 kB Adobe PDF View/Open Paper_IV_Bent_Barman_Skaare.pdf Barman Skaare, B., Nodland, E., Ommedal, H., Barth, T., Unraveling initial petroleum biodegradation processes by multivariate modeling { comparison of incubation schemes, reservoir model studies and in-reservoir biodegradation. Preprint. Prepared for publication in Organic Geochemistry. Published by Elsevier. Abstract only. 105.69 kB Adobe PDF View/Open

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