Influence of Wettability and Oil Saturation on the Rheological Behavior of CO2-Foams

Beunat, Virginie; Batôt, Guillaume; Gland, N.; Pannacci, Nicolas; Chevallier, E.; Cuenca, Amandine

doi:10.3997/2214-4609.201900151

Cited by 2 publications

(3 citation statements)

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“…In their study, the residual oil saturation had limited impact on the MRF decline value. 50 Boeije et al 51 explored the foamability of different surfactant formulations in untreated (hydrophilic) and artificially treated (hydrophobic) bead packs. Independent of the presence of residual oil, MRF values were smaller in the hydrophobic bead-pack compared to the hydrophilic system, implying weaker foam under hydrophobic conditions.…”

Section: Introductionmentioning

confidence: 99%

“…Similarly, Kristiansen and Holt reported lower foam apparent viscosities with the oil-wet reservoir rocks compared to the water-wet Berea rocks, though the difference in the rock type and permeability made their findings less conclusive. Recently, Beunat et al coinjected supercritical CO 2 with a proprietary surfactant blend into sandstone cores and measured about 30% decline in the mobility reduction factor (MRF) for the “altered-wettability” cores, compared to the water-wet cores. MRF represents the foam stability, defined as the ratio of pressure drop during foam injection to that during water–gas coinjection.…”

Section: Introductionmentioning

confidence: 99%

“…MRF represents the foam stability, defined as the ratio of pressure drop during foam injection to that during water–gas coinjection. In their study, the residual oil saturation had limited impact on the MRF decline value . Boeije et al explored the foamability of different surfactant formulations in untreated (hydrophilic) and artificially treated (hydrophobic) bead packs.…”

Section: Introductionmentioning

confidence: 99%

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Distinguishing the Effect of Rock Wettability from Residual Oil on Foam Generation and Propagation in Porous Media

et al. 2021

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One of the common challenges of applying foam for enhanced oil recovery is the foam instability in the presence of crude oil and nonwater-wet surfaces. In this experimental study, we systematically distinguish the effect of rock surface wettability from that of crude oil saturation on foam rheology under reservoir conditions. Neutral-wet Berea and reservoir sandstone cores are prepared by aging with crude oil, followed by the wettability index measurements. Transient foam generation and steady-state foam quality scans are conducted in neutral-wet cores, with/without water-flood residual oil. Nuclear magnetic resonance imaging is also utilized to measure the remaining oil saturation at the end of the foam-flood. It is shown that strong foam can be generated in a neutral-wet core with no residual oil because of the solubilization of the adsorbed crude oil components and the wettability alteration toward more water-wet conditions. However, in a neutral-wet core containing residual oil, foam generation is initially hindered. Foam generation occurs after injecting several pore volumes of surfactant solution and increasing the superficial velocity to overcome the minimum pressure gradient required for in situ foam generation. The findings from this study suggest that surface wettability in the presence of bulk oil saturation significantly affects transient foam generation. The final steady-state foam strength becomes comparable to the water-wet and oil-free case once the residual oil saturation is adequately reduced.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Distinguishing the Effect of Rock Wettability from Residual Oil on Foam Generation and Propagation in Porous Media

et al. 2021

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A Modified Well Index To Account For Shear-Thinning Behaviour In Foam EOR Simulation

Soulat

Douarche

Flauraud

2019

Day 3 Thu, September 19, 2019

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An accurate evaluation of injectivity is essential to the economics of any chemical EOR process. Most commercial simulators enable non-Newtonian behaviour modelling but it is often overlooked due to inadequate grid resolution. Indeed, in cases where shearthinning fluids are injected in a reservoir, shear rates and viscosities in the vicinity of the wellbore can be poorly estimated if the spatial resolution of the well grid-blocks is too coarse. This results in biases in injectivity and economics which we discuss here in the context of foam-based displacements. We consider continuous foam injection in models of different spatial resolutions ranging from 1 to 100 m gridblock sizes and study the behaviour of injection wells obtained on the coarser grids compared with the results from a high resolution grid. This reference grid is sufficiently refined to account for near-wellbore large velocity gradients and render injectivity accurately. In this work we propose new formulations of the well index that capture shear-thinning behaviour that the conventional Peaceman calculation fails to address. We first demonstrate that a poor evaluation of near-wellbore velocity leads to erroneously degraded injectivity on the coarser grids when compared to the reference grid. In order to correct these errors our modified well index is applied and validated in various scenarios of foam displacement simulation with radial grids. It captures a more accurate injectivity than the conventional Peaceman calculation once steady-state regime is reached. The modified well index we propose, used under a simplified form as direct input in reservoir simulation, significantly enhances injectivity estimates without resorting to grid refinements or modifying the shear-thinning model of the injected foam. In most cases it yields results that are closer to those obtained using grid refinements than the Peaceman formula at a much more attractive computational cost. Additional work remains to complete our understanding of injectivity in more complex settings, especially in the context of foam injection when effects such as foam dry-out and destruction in the presence of oil are as important on sweep efficiency as its shear-thinning behaviour. Our workflow successfully corrects biases in the estimation of injectivity and yields more accurate results and avoids resorting to time-consuming methods such as grid refinements and physical input data alteration. Moreover it is simple to implement in most commercial simulators and does not require using empirical criteria. However, it bears some limitations which we also discuss.

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Influence of Wettability and Oil Saturation on the Rheological Behavior of CO2-Foams

Cited by 2 publications

References 0 publications

Distinguishing the Effect of Rock Wettability from Residual Oil on Foam Generation and Propagation in Porous Media

Distinguishing the Effect of Rock Wettability from Residual Oil on Foam Generation and Propagation in Porous Media

A Modified Well Index To Account For Shear-Thinning Behaviour In Foam EOR Simulation

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