Laboratory Evaluation of Sodium Hydroxide, Sodium Orthosilicate, and Sodium Metasilicate as Alkaline Flooding Agents for a Western Canada Reservoir

Abstract

Laboratory Evaluation of Sodium Hydroxide, Sodium Orthosilicate, and Sodium Metasilicate as Alkaline Flooding Agents for a Western Canada Reservoir L.E. Larrondo; L.E. Larrondo Petroleum Recovery Inst. Search for other works by this author on: This Site Google Scholar C.M. Urness C.M. Urness Petroleum Recovery Inst. Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Oilfield and Geothermal Chemistry Symposium, Phoenix, Arizona, April 1985. Paper Number: SPE-13577-MS https://doi.org/10.2118/13577-MS Published: April 09 1985 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Larrondo, L.E., and C.M. Urness. "Laboratory Evaluation of Sodium Hydroxide, Sodium Orthosilicate, and Sodium Metasilicate as Alkaline Flooding Agents for a Western Canada Reservoir." Paper presented at the SPE Oilfield and Geothermal Chemistry Symposium, Phoenix, Arizona, April 1985. doi: https://doi.org/10.2118/13577-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE International Conference on Oilfield Chemistry Search Advanced Search AbstractThe performance of sodium hydroxide, sodium orthosilicate, and sodium metasilicate solutions in oil recovery was evaluated in displacement tests using core samples and fluids from a Western Canada sandstone oil reservoir. Each core plug was first waterflooded with the formation (produced) brine and then resaturated with the reservoir oil before being treated with a given alkaline solution. The latter was injected either continuously or as a slug. Up to 2 pare volumes injected (PVI) of alkaline solution, 0.3 weight percent sodium hydroxide and 1.0 weight percent sodium metasilicate recovered the largest amount of additional oil. At higher PVI, 0.3 and 1.0 weight percent sodium hydroxide solutions recovered more percent sodium hydroxide solutions recovered more additional oil than all other solutions. The oil recovery from the alkaline slugs (0.5 to 0.66 PV) was poorer, possibly because most of the alkali injected poorer, possibly because most of the alkali injected was consumed through reactions with the rock and reservoir fluids.Emulsification and interfacial tension measurements as well as alkali consumption data suggest that ail of the alkaline solutions used in the displacement tests should have had similar performance. The differences observed in the oil recoveries could be explained in terms of mineral and/or structural heterogeneity of the reservoir rack. In addition, the effects of freezing part of the sample in liquid nitrogen may have played a role in the observed performance of the alkaline solutions. performance of the alkaline solutionsIntroductionAlkaline flooding is a chemical oil recovery method characterized by the in situ formation of surface active compounds through the reaction of the alkali with acidic substances in the crude oil. These surfactants adsorb at the oil/aqueous phase interface and promote emulsification by lowering the interfacial tension. They can also adsorb onto rock surfaces and alter the wettability of the reservoir rock. According to Johnson the mechanisms responsible for improved oil recovery by alkaline flooding are:emulsification and entrainment,emulsification and entrapment,wettability reversal from oil-to-water-wet, andwettability reversal from water-to oil-wet.The chemicals most commonly used in alkaline flooding are sodium hydroxide, sodium carbonate, and soluble silicates. Due to reservoir heterogeneity and the mineral composition of the rock and reservoir fluids, the same alkali might induce different mechanisms and final oil recoveries in different reservoirs.An important number of laboratory investigations dealing with the interaction of alkaline solutions with reservoir fluids and reservoir rocks have been reported in the literature. The effects of time, pH, salinity, and hardness content on interfacial tension as well as on the formation and stability of emulsions have been studied. Alkali consumption through reversible and irreversible reactions with rock has been evaluated as a function of alkali concentration, alkali type, salinity, mineral composition, temperature and the available surface area of the rock.The laboratory studies presented in this paper were undertaken to evaluate the performance of sodium hydroxide, sodium orthosilicate, and sodium metasilicate solutions in oil recovery using core samples and fluids from a Western Canada sandstone oil reservoir. Emulsification and interfacial tensions of wellhead crude oil with alkaline solutions of varying concentration were first examined to select the most suitable alkaline solutions. Oil recoveries were then evaluated with those solutions in linear displacement tests.FLUIDS AND THEIR PROPERTIESWellhead oil and produced brine from the sandstone reservoir and synthetic source water, were used in the present study. The oil sample was centrifuged and filtered before use.p. 307 Keywords: concentration, oil recovery, sodium metasilicate, enhanced recovery, sodium hydroxide, source water, consumption, hydroxide, emulsification, displacement test Subjects: Improved and Enhanced Recovery, Waterflooding This content is only available via PDF. 1985. Society of Petroleum Engineers You can access this article if you purchase or spend a download.