Modified seawater as a smart EOR fluid in chalk

Puntervold, Tina; Strand, Skule; Ellouz, Raed; Austad, Tor

doi:10.1016/j.petrol.2015.06.034

Cited by 89 publications

(56 citation statements)

References 15 publications

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“…One proposed mechanism of improving waterflood performance is to displace asphaltic carboxylates tightly bound to the rock surface by ion complexing and bridging by tailored solution ions (Lager et al 2006(Lager et al , 2007(Lager et al , 2008aStrand et al 2006;Zhang and Austad 2006;Zhang et al 2007b;Sorbie and Collins 2010;Zahid et al 2012;Austad et al 2015;Puntervold et al 2015;Qiao et al 2016). MIE is strongly coupled to rock/brine-surface chemistry.…”

Section: Resultsmentioning

confidence: 99%

“…In particular, sodium and chloride ions are dominant species at high brine concentrations and may participate in ion-exchange equilibria. It is commonly accepted, however, that sodium and chloride ions are inactive at the calcite/water interface (Somasundaran and Agar 1967;Möller and Werr 1972;Siffert and Fimbel 1984;Thompson and Pownall 1989;Van Cappellen et al 1993;Pokrovsky et al 2000;Nystrom 2001;Wolthers et al 2008;Hiorth et al 2010;Alotaibi et al 2011;Heberling et al 2011;Austad et al 2015;Puntervold et al 2015). Unfortunately, no direct evidence is available to confirm or refute this view.…”

Section: Methodsmentioning

confidence: 99%

“…The surface charge of the mineral interfaces appears to play a critical role. This last observation engendered a large number of ancillary studies on silica, clay, and calcite/water interfaces and their ion-exchange behavior, especially recently (Lager et al 2008a;Sorbie and Collins 2010;Nasralla and Nasr-El-Din 2012;Alotaibi et al 2011;Alotaibi and Yousef 2015;Alshakhs and Kovscek 2015;Brady Myint and Firoozabadi 2015;Puntervold et al 2015;Qiao et al 2016). Fundamental studies (Ricci et al 2013;Alshakhs and Kovscek 2015;Brady et al 2015;Lashkarbolooki et al 2016;Mugele et al 2016) of the calcite/water interface, including molecular simulation (Kerisit and Parker 2004;Sakuma et al 2014;Qiao et al 2016), also garnered attention.…”

mentioning

confidence: 97%

“…Precise definition of LSW is lacking. In principle, spiking injection water with specific anions and/or cations has the potential to improve recovery (Strand et al 2006;Zhang et al 2007b;Sorbie and Collins 2010;Alshakhs and Kovscek 2015;Austad et al 2015;Puntervold et al 2015) without need for lower salinity.Starting in the middle 1990s, the pioneering work of Morrow and colleagues popularized LSW of sandstones. Fines release was highlighted as one of several proposed recovery mechanisms (Jadhunandan and…”

mentioning

confidence: 99%

“…Austad and coworkers, however, showed a positive response of carbonate rocks to LSW (Zhang and Austad 2006;Strand et al 2006;Zhang et al 2007a;Rezaeidoust et al 2009;Fathi et al 2010;Puntervold et al 2015). These authors also promulgated a version of MIE as an LSW oil-recovery mechanism.…”

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confidence: 99%

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Bulk and Surface Aqueous Speciation of Calcite: Implications for Low-Salinity Waterflooding of Carbonate Reservoirs

et al. 2017

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SummaryLow-salinity waterflooding (LSW) is ineffective when reservoir rock is strongly water-wet or when crude oil is not asphaltenic. Success of LSW relies heavily on the ability of injected brine to alter surface chemistry of reservoir crude-oil brine/rock (COBR) interfaces. Implementation of LSW in carbonate reservoirs is especially challenging because of high reservoir-brine salinity and, more importantly, because of high reactivity of the rock minerals. Both features complicate understanding of the COBR surface chemistries pertinent to successful LSW. Here, we tackle the complex physicochemical processes in chemically active carbonates flooded with diluted brine that is saturated with atmospheric carbon dioxide (CO 2 ) and possibly supplemented with additional ionic species, such as sulfates or phosphates.When waterflooding carbonate reservoirs, rock equilibrates with the injected brine over short distances. Injected-brine ion speciation is shifted substantially in the presence of reactive carbonate rock. Our new calculations demonstrate that rock-equilibrated aqueous pH is slightly alkaline quite independent of injected-brine pH. We establish, for the first time, that CO 2 content of a carbonate reservoir, originating from CO 2 -rich crude oil and gas, plays a dominant role in setting aqueous pH and rock-surface speciation.A simple ion-complexing model predicts the calcite-surface charge as a function of composition of reservoir brine. The surface charge of calcite may be positive or negative, depending on speciation of reservoir brine in contact with the calcite. There is no single point of zero charge; all dissolved aqueous species are charge determining. Rock-equilibrated aqueous composition controls the calcitesurface ion-exchange behavior, not the injected-brine composition. At high ionic strength, the electrical double layer collapses and is no longer diffuse. All surface charges are located directly in the inner and outer Helmholtz planes.Our evaluation of calcite bulk and surface equilibria draws several important inferences about the proposed LSW oil-recovery mechanisms. Diffuse double-layer expansion (DLE) is impossible for brine ionic strength greater than 0.1 molar. Because of rapid rock/brine equilibration, the dissolution mechanism for releasing adhered oil is eliminated. Also, fines mobilization and concomitant oil release cannot occur because there are few loose fines and clays in a majority of carbonates. LSW cannot be a low-interfacial-tension alkaline flood because carbonate dissolution exhausts all injected base near the wellbore and lowers pH to that set by the rock and by formation CO 2 . In spite of diffuse double-layer collapse in carbonate reservoirs, surface ion-exchange oil release remains feasible, but unproved.Introduction LSW refers to improved oil recovery achieved by waterflooding a reservoir with brine of lower salinity than that of the field brine. The process is alluring because of simplicity, favorable economics, and large potential. In some applications, seawater is inj...

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 97%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Bulk and Surface Aqueous Speciation of Calcite: Implications for Low-Salinity Waterflooding of Carbonate Reservoirs

et al. 2017

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Investigation of Interfacial Tension Reduction, Wettability Alteration, and Oil Recovery Using a New Non‐ionic Oil‐Based Surfactant from Gemini Surfactants Family Coupled with Low‐Salinity Water: Experimental Study on Oil‐Wet Carbonate Rock

Dabiri

Honarvar

2020

J Surfact & Detergents

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Low‐salinity surfactant (LSS) flooding is a combined enhanced oil recovery (EOR) technique that increases oil recovery (OR) by altering the rock surface wettability and reducing oil–water interfacial tension (IFT). In this study, optimum concentrations of several types of salt in distilled water were obtained on the basis of IFT experiments for the preparation of low‐salinity water (LSW). Then, a new oil‐based natural surfactant (Gemini surfactant, GS) was combined with LSW to investigate their effects on IFT, wettability, and OR. Experimental results showed that LSW is capable of reducing IFT and contact angle, but the synergy of GS and the active ions Mg2+, Ca2+, and SO42− in LSW was more effective on IFT reduction and wettability alteration. The combination of 1000 ppm MgSO4 and 3000 ppm GS led to a decrease in contact angle from 134.82° to 36.98° (oil‐wet to water‐wet). Based on core flooding tests, LSW injection can increase OR up to 71.46% (for LSW with 1000 ppm MgSO4), while the combination of GS and LSW, as LSS flooding, can improve OR up to 84.23% (for LSS with 1000 ppm MgSO4 and 3000 ppm GS). Therefore GS has great potential to be used as a surfactant for EOR.

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Synergic Impacts of Two Non-ionic Natural Surfactants and Low Salinity Water on Interfacial Tension Reduction, Wettability Alteration and Oil Recovery: Experimental Study on Oil Wet Carbonate Core Samples

Dabiri

Honarvar

2020

Nat Resour Res

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Modified seawater as a smart EOR fluid in chalk

Cited by 89 publications

References 15 publications

Bulk and Surface Aqueous Speciation of Calcite: Implications for Low-Salinity Waterflooding of Carbonate Reservoirs

Bulk and Surface Aqueous Speciation of Calcite: Implications for Low-Salinity Waterflooding of Carbonate Reservoirs

Investigation of Interfacial Tension Reduction, Wettability Alteration, and Oil Recovery Using a New Non‐ionic Oil‐Based Surfactant from Gemini Surfactants Family Coupled with Low‐Salinity Water: Experimental Study on Oil‐Wet Carbonate Rock

Synergic Impacts of Two Non-ionic Natural Surfactants and Low Salinity Water on Interfacial Tension Reduction, Wettability Alteration and Oil Recovery: Experimental Study on Oil Wet Carbonate Core Samples

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