Low Salinity Effect at Pore Scale: Probing Wettability Changes in Middle East Limestone

Pedersen, Nina Ritter; Hassenkam, Tue; Ceccato, Marcel; Dalby, Kim N.; Mogensen, Kristian; Stipp, S. L. S.

doi:10.1021/acs.energyfuels.5b02562

Cited by 35 publications

(35 citation statements)

References 56 publications

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“…In the biological community and in recent literature related to reservoir fluids, researchers have studied adhesion at the nanoscale to understand the effects of overall salinity on nanomaterial adhesions, mineral dissolution, molecular adhesion related to protein-protein interactions, and even wettability of reservoir surfaces 35 , 51 , 56 , 59 , 64 – 89 . In such studies, increasing overall salinity increases adhesion, which then plateaus 36 , 38 , 73 , 74 , 77 , 79 – 81 . In addition, changes in the interaction forces can be used to link more adhesive areas to mineralogical composition and with changes in wettability 76 , 81 , 84 , 85 .…”

Section: Introductionmentioning

confidence: 99%

Calcium-Mediated Adhesion of Nanomaterials in Reservoir Fluids

Eichmann

Burnham

2017

Sci Rep

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Globally, a small percentage of oil is recovered from reservoirs using primary and secondary recovery mechanisms, and thus a major focus of the oil industry is toward developing new technologies to increase recovery. Many new technologies utilize surfactants, macromolecules, and even nanoparticles, which are difficult to deploy in harsh reservoir conditions and where failures cause material aggregation and sticking to rock surfaces. To combat these issues, typically material properties are adjusted, but recent studies show that adjusting the dispersing fluid chemistry could have significant impact on material survivability. Herein, the effect of injection fluid salinity and composition on nanomaterial fate is explored using atomic force microscopy (AFM). The results show that the calcium content in reservoir fluids affects the interactions of an AFM tip with a calcite surface, as surrogates for nanomaterials interacting with carbonate reservoir rock. The extreme force sensitivity of AFM provides the ability to elucidate small differences in adhesion at the pico-Newton (pN) level and provides direct information about material survivability. Increasing the calcium content mitigates adhesion at the pN-scale, a possible means to increase nanomaterial survivability in oil reservoirs or to control nanomaterial fate in other aqueous environments.

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Section: Introductionmentioning

confidence: 99%

Calcium-Mediated Adhesion of Nanomaterials in Reservoir Fluids

Eichmann

Burnham

2017

Sci Rep

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“…Recent work, for example, has demonstrated that adsorbed organic compounds, which are associated with all natural surfaces, change wetting properties 13,14 . Although crude oil is a complex mixture of many organic compounds, it is primarily the functional groups that deter- mine which adhere on the pore surfaces.…”

Section: Introductionmentioning

confidence: 99%

A pH-Resolved View of the Low Salinity Effect in Sandstone Reservoirs

et al. 2016

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Core plug and field tests have shown that significantly more oil can be produced from sandstone reservoirs when the water that is injected to maintain pressure in the reservoir has lower salinity than regular seawater. We investigated the adhesion between functional groups known to dominate in crude oil and grains from reservoir sandstone as a function of pH and salinity. We used atomic force microscopy (AFM) in chemical force mapping mode, and we functionalized the AFM tips both with −CH 3 , to model adhesion of hydrophobic molecules, and with −COO(H), to model polar compounds. As the pH increased, the adhesion force decreased. The behavior was similar for the two types of tips, but adhesion was higher for the polar tip. The average adhesion at pH 4.5 for the −COO(H) tip in artificial seawater (ASW) was close to 300 pN, and 200 pN in ASW diluted by a factor of 20. For the −CH 3 tip, adhesion was ∼200 pN in high salinity and 140 pN in low salinity. Regardless of the salinity, adhesion decreased as pH increased. To gain understanding about the controlling processes, we examined our data in light of the Dejarguin−Landau−Verwey−Overbeek (DLVO) theory and the Henderson−Hasselbalch expression. The commonly used form of the DLVO relationship could not account for the pH dependence. It predicts adhesion to be independent of pH in high-salinity solution and strongly dependent on pH in low salinity, opposite to the experimental evidence. Although DLVO theory cannot be expected to quantitatively represent real systems, it is unlikely that DLVO would predict reversed behavior. Our results indicate that the extended double layer, which is one of the prevailing explanations for the low salinity effect, is not the full explanation. Decrease in surface charge density at low salinity plays an important role. The change in adhesion as pH increases above 5.5, which is the typical pH of sandstone reservoirs, to the neutral range could enhance oil recovery. This is probably a factor in the effectiveness of alkaline flooding and might be an inherent factor in the production that results from flooding with seawater, which is typically pH 8.3. However, the buffering effect in sandstone reservoirs, which maintains pH at ∼5.5, suggests that benefits from controlling pH for EOR could be marginal.

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“…Precisely controlling the effective wetting properties of droplets in immiscible two-phase flows is desirable in many applications, from fabricating microfluidic devices [1][2][3] and electronic displays [4][5][6][7] to understanding the microscopic dynamics of enhanced oil recovery, which has field-scale consequences [8][9][10][11][12]. Lippmann already in the 19th century [13,14] laid the groundwork for the field of electrowetting, by making the observation that applying an electric field indeed can change the wetting behaviour of conductive liquid-liquid systems.…”

Section: Introductionmentioning

confidence: 99%

Controlling wetting with electrolytic solutions: Phase-field simulations of a droplet-conductor system

2018

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The wetting properties of immiscible two-phase systems are crucial in applications ranging from laboratory-on-a-chip devices to field-scale oil recovery. It has long been known that effective wetting properties can be altered by the application of an electric field; a phenomenon coined as electrowetting. Here, we consider theoretically and numerically a single droplet sitting on an (insulated) conductor, i.e., within a capacitor. The droplet consists of a pure phase without solutes, while the surrounding fluid contains a symmetric monovalent electrolyte, and the interface between them is impermeable. Using nonlinear Poisson-Boltzmann theory, we present a theoretical prediction of the dependency of the apparent contact angle on the applied electric potential. We then present well-resolved dynamic simulations of electrowetting using a phase-field model, where the entire two-phase electrokinetic problem, including the electric double layers (EDLs), is resolved. The simulations show that, while the contact angle on scales smaller than the EDL is unaffected by the application of an electric field, an apparent contact angle forms on scales beyond the EDL. This contact angle relaxes in time towards a saturated apparent contact angle. The dependency of the contact angle upon applied electric potential is in good agreement with the theoretical prediction. The only phenomenological parameter in the prediction is shown to depend on the permeability ratio between the two phases. Based on the resulting unified description, we obtain an effective expression of the contact angle which can be used in more macroscopic numerical simulations, i.e. where the electrokinetic problem is not fully resolved.

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Low Salinity Effect at Pore Scale: Probing Wettability Changes in Middle East Limestone

Cited by 35 publications

References 56 publications

Calcium-Mediated Adhesion of Nanomaterials in Reservoir Fluids

Calcium-Mediated Adhesion of Nanomaterials in Reservoir Fluids

A pH-Resolved View of the Low Salinity Effect in Sandstone Reservoirs

Controlling wetting with electrolytic solutions: Phase-field simulations of a droplet-conductor system

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