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dc.contributor.advisorBilstad, Torleiv
dc.contributor.authorNair, Remya Ravindran
dc.date.accessioned2019-04-05T13:02:14Z
dc.date.available2019-04-05T13:02:14Z
dc.date.issued2019-03
dc.identifier.citationSmart Water for Enhanced Oil Recovery from Seawater and Produced Water by Membranes by Remya Ravindran Nair, Stavanger : University of Stavanger, 2019 (PhD thesis UiS, no. 442)nb_NO
dc.identifier.isbn978-82-7644-828-3
dc.identifier.issn1890-1387
dc.identifier.urihttp://hdl.handle.net/11250/2593558
dc.description.abstractSustainable use of scarce water resources and stringent environmental regulations are currently moving the focus towards environmentally friendly and cost-effective injection methods in the offshore oil industry. Water injection is used for most oil reservoirs as pressure support and improved displacement of oil. Most water-based enhanced oil recovery (EOR) techniques consist of chemical injection into reservoirs resulting in hazardous flow back of chemicals and produced water (PW). Smart water injection is an alternative and simultaneously represents a sustainable environmental and economic EOR flooding technique. The optimized ionic composition of injection water improves the initial wetting towards more water-wet conditions, which improves displacement efficiency due to increased capillary forces. Smart water improves oil recovery by wettability alteration in both carbonate and sandstone reservoirs. Seawater is the main injection brine offshore and when enriched in divalent ions such as SO4 2- and Ca2+ and depleted in Na+ and Cl- is considered smart water in carbonates. Injection brine with salinity below 5,000 mg/L and low in divalent cations are considered suitable as smart water in sandstone reservoirs. Nanofiltration membranes (NF) are efficient in performing partial desalination of seawater and PW at low feed pressures resulting in high flux and low power consumption. The main focus of this research was to determine appropriate technical conditions and limitations of NF membranes for producing smart water from seawater and PW. Special focus was on exploring NF membrane performance in terms of flux and rejection under varying feed compositions, pressures, pH and recoveries of polyamide and sulfonated polyethersulfone membranes. Both permeate and retentate streams from NF membranes are used for producing smart water. The divalent ion rich retentate could be used in carbonate reservoirs, whereas the permeate with low divalent ion concentrations is optimal for sandstone reservoirs with seawater as membrane feed. Produced water re-injection (PWRI) as smart water was evaluated as an alternative to PW discharge in terms of environmental and economic advantages. One of the main concerns in membrane treatment of PW is the presence of organics that cause membrane fouling. De-oiling of synthetic PW by media filtration upstream NF membranes eliminated fouling during short-term membrane experiments. Additionally, the presence of barium and strontium ions in PW cause scaling if mixed with seawater. Membrane removal of Ba2+ and Sr2+ was optimized by increasing the concentration of scaling ions in the feed which resulted in efficient removal of Ba2+ and Sr2+ during NF experiments. However, the main challenge in reusing PW as smart water is low flux through NF membranes. Experiments with altering pH of seawater were performed within pH limitations of the membrane materials to determine the effect of pH on membrane performance. A comparison between pH tolerance on polyamide and sulfonated polyethersulfone membranes were conducted during the experiments. A significant change in ion rejection was observed even with small changes in pH. Another limitation with NF membrane separation with PW is the high total dissolved solids (TDS) in PW yielding high osmotic and operating pressures. Dilution of PW with NF permeate with seawater as feed reduces TDS. Artificial neural network (ANN) was used to predict ion rejection based on multiple variable experimental data for feed pH, pressure and flux. […]nb_NO
dc.language.isoengnb_NO
dc.publisherStavanger: University of Stavangernb_NO
dc.relation.ispartofseriesPhD thesis UiS;442
dc.relation.haspartPaper 1: Membrane Performance Analysis for Smart Water Production for Enhanced Oil Recovery in Carbonate and Sandstone Reservoirs Remya R. Nair, Evgenia Protasova, Skule Strand and Torleiv Bilstad Energy & Fuels, 2018, 32 (4), pp 4988-4995 DOI: 10.1021/acs.energyfuels.8b00447nb_NO
dc.relation.haspartPaper 2: Evaluation of Nanofiltration Membrane Process for Smart Water Production in Carbonate Reservoirs from Deoiled Produced Water and Seawater Remya R. Nair, Evgenia Protasova, Skule Strand and Torleiv Bilstad SPE Productions and Operations (In press)nb_NO
dc.relation.haspartPaper 3: Effect of pH on Produced Water Treatment Using Nanofiltration Membranes: Artificial Neural Network for Performance Assessment and Steric Hindrance Pore Model for Flux Variation Evaluation Remya R. Nair, Evgenia Protasova, Skule Strand and Torleiv Bilstad Desalination and Water Treatment (In press)nb_NO
dc.relation.haspartPaper 4: Implementation of Spiegler - Kedem and Steric Hindrance Pore Models for Analyzing Nanofiltration Membrane Performance for Smart Water Production Remya R. Nair, Evgenia Protasova, Skule Strand and Torleiv Bilstad Membranes, 2018, 8 (3), 78 DOI:org/10.3390/membranes8030078nb_NO
dc.subjectpetroleumsteknologinb_NO
dc.subjectenhanced oil recoverynb_NO
dc.subjectEORnb_NO
dc.subjectproduced waternb_NO
dc.titleSmart Water for Enhanced Oil Recovery from Seawater and Produced Water by Membranesnb_NO
dc.typeDoctoral thesisnb_NO
dc.rights.holder© 2019 Remya Ravindran Nairnb_NO
dc.subject.nsiVDP::Technology: 500::Rock and petroleum disciplines: 510::Petroleum engineering: 512nb_NO


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