Water-Based EOR in Carbonates and Sandstones

Austad, Tor

doi:10.1016/b978-0-12-386545-8.00013-0

Cited by 130 publications

(42 citation statements)

References 48 publications

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“…Various experiments conducted by researches indicated an increase in pH value of about pH 2 to pH 4 upon the injection of low-saline brine. In situ surfactant that lowers oil or water IFT is produced when organic acids in the crude oil react under high-pH conditions [46]. The formation of surfactants and reduction of IFT forms either oil-water emulsion or water-oil emulsions which results in the improvement of water sweep efficiency [33].…”

Section: Increase In Ph and Reduction In Interfacial Tensionmentioning

confidence: 99%

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Potential of Low-Salinity Waterflooding Technology to Improve Oil Recovery

Mahmud¹,

Arumugam²,

Mahmud³

2019

Enhanced Oil Recovery Processes - New Technologies

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Low-salinity waterflooding (LSWF) is a potential new method for enhanced oil recovery (EOR) in sandstone and carbonate rock formations. LSWF approach has gained an attention in the oil and gas industry due to its potential advantages over the conventional waterflooding and other chemical EOR technologies. The efficiency of waterflooding process is effected via reservoir and fluid parameters such as formation rock type, porosity, permeability, reservoir fluid saturation and distribution and optimum time of water injection. Combined effect of these factors can define the ultimate recovery of hydrocarbon. The main objective of this chapter is to review the mechanism of LSWF technique in improving oil recovery and the mechanism under which it operates. Various laboratory studies and few field applications of LSWF in recent years have been presented mainly at the lab scale. Also it will explore numerical modeling developments of this EOR approach.

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Section: Increase In Ph and Reduction In Interfacial Tensionmentioning

confidence: 99%

“…A chemical mechanism proposed by Austad [46] signifies the role of clay at low pH values. Thermodynamic chemical equilibrium that initially exists at reservoir condition at low pH increases the adsorption of anions and cations onto the clay surface.…”

Section: Enhanced Oil Recovery Processes -New Technologiesmentioning

confidence: 99%

Potential of Low-Salinity Waterflooding Technology to Improve Oil Recovery

Mahmud¹,

Arumugam²,

Mahmud³

2019

Enhanced Oil Recovery Processes - New Technologies

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“…The initial reservoir wettability is a result of the chemical equilibrium established between rocks and reservoir fluids, due to millions of years of contact. The disequilibrium of the COBR system induced by the injection of a low salinity or modified salinity brine can lead to an increase in oil recovery [10,15]. Wettability alteration from this 'initial reservoir wetting state' has been reported as the main mechanism behind enhanced oil recovery (EOR) by LSWI [15,16].…”

Section: Introductionmentioning

confidence: 99%

“…The disequilibrium of the COBR system induced by the injection of a low salinity or modified salinity brine can lead to an increase in oil recovery [10,15]. Wettability alteration from this 'initial reservoir wetting state' has been reported as the main mechanism behind enhanced oil recovery (EOR) by LSWI [15,16]. Wettability alteration itself is an effect produced by other microscale mechanisms, such as surface ion exchange [17], changes in surface charge [18], double-layer expansion [19], and mineral dissolution [20].…”

Section: Introductionmentioning

confidence: 99%

Crude Oil–Brine–Rock Interactions in Tight Chalk Reservoirs: An Experimental Study

et al. 2021

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We present a systematic study of crude oil–brine–rock interactions in tight chalk cores at reservoir conditions. Flooding experiments are performed on outcrops (Stevns Klint) as well as on reservoir core plugs from Dan field, the Ekofisk and Tor formations. These studies are carried out in core plugs with reduced pore volumes, i.e., short core samples and aged with a dynamic ageing method. The method was evaluated by three different oil compositions. A series of synthetic multicomponent brines and designed fluid injection scenarios are investigated; injection flow rates are optimized to ensure that a capillary-dominant regime is maintained. Changes in brine compositions and fluid distribution in the core plugs are characterized using ion chromatography and X-ray computed tomography, respectively. First, we show that polar components in the oil phase play a major role in wettability alteration during ageing; this controls the oil production behavior. We also show that, compared to seawater, both formation water and ten-times-diluted seawater are better candidates for enhanced oil recovery in the Dan field. Finally, we show that the modified flow zone indicator, a measure of rock quality, is likely the main variable responsible for the higher oil recoveries observed in Tor core samples.

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“…Water ionic compositional effects appear to be more complex in carbonates not only because lower salinity is important, but also because certain key ions, such as sulfates, calcium, and magnesium, play an important role in impacting oil recovery. Injection waters of lower salinity, but enriched with divalent ions and depleted in monovalents, were shown to be the mostdesired water chemistry to result in better incremental oil recovery in carbonates (Fathi et al 2011;Yousef et al 2011a;Yousef et al 2012a;Austad 2013;Chandrasekhar and Mohanty 2013).…”

Section: Introductionmentioning

confidence: 99%

A Critical Review of Alternative Desalination Technologies for Smart Waterflooding

Ayirala

Yousef

2016

Oil and Gas Facilities

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The results of this review study show that there is no commercial technology yet available to selectively remove specific ions from seawater in one step and optimally meet the desired water-chemistry requirements of smart waterflooding. As a result, different conceptual process configurations involving selected combinations of chemical precipitation, conventional/emerging desalination, and produced-water-treatment technologies are proposed. These configurations represent both approximate and improved solutions to incorporate specific key ions into the smart water selectively, besides presenting the key opportunities to treat produced-water/ membrane reject water and provide ZLD capabilities in smartwaterflooding applications. The developed configurations can provide an attractive solution to capitalize on existing huge producedwater resources available in carbonate reservoirs to generate smart water and minimize wastewater disposal during fieldwide implementation of smart waterflood.

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Water-Based EOR in Carbonates and Sandstones

Cited by 130 publications

References 48 publications

Potential of Low-Salinity Waterflooding Technology to Improve Oil Recovery

Potential of Low-Salinity Waterflooding Technology to Improve Oil Recovery

Crude Oil–Brine–Rock Interactions in Tight Chalk Reservoirs: An Experimental Study

A Critical Review of Alternative Desalination Technologies for Smart Waterflooding

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