The Role of Immiscible Fingering on the Mechanism of Secondary and Tertiary Polymer Flooding of Viscous Oil

Beteta, Alan; Sorbie, Kenneth Stuart; McIver, Katherine; Johnson, G.; Gasimov, Rustam Rauf; Zeil, W. van

doi:10.1007/s11242-022-01774-8

Cited by 17 publications

(13 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given the low frontal advance rate in these experiments ~0.005 m/day, it is expected that there will not be sufficient variance in shear rate to significantly impact the in situ viscosity. A low sensitivity to injected viscosity was noted by Beteta et al (2022) [ 31 ] in similar permeability Bentheimer cores during displacement of oil and direct simulation matches of the experiments were obtained using the methodology from Sorbie et al (2020) [ 16 ] assuming a Newtonian fluid.…”

Section: Methodsmentioning

confidence: 80%

See 1 more Smart Citation

Immiscible Viscous Fingering: The Simulation of Tertiary Polymer Displacements of Viscous Oils in 2D Slab Floods

Beteta

Skauge

2022

Polymers

Self Cite

View full text Add to dashboard Cite

Immiscible viscous fingering in porous media occurs when a high viscosity fluid is displaced by an immiscible low viscosity fluid. This paper extends a recent development in the modelling of immiscible viscous fingering to directly simulate experimental floods where the viscosity of the aqueous displacing fluid was increased (by the addition of aqueous polymer) after a period of low viscosity water injection. This is referred to as tertiary polymer flooding, and the objective of this process is to increase the displacement of oil from the system. Experimental results from the literature showed the very surprising observation that the tertiary injection of a modest polymer viscosity could give astonishingly high incremental oil recoveries (IR) of ≥100% even for viscous oils of 7000 mPa.s. This work seeks to both explain and predict these results using recent modelling developments. For the 4 cases (µo/µw of 474 to 7000) simulated in this paper, finger patterns are in line with those observed using X-ray imaging of the sandstone slab floods. In particular, the formation of an oil bank on tertiary polymer injection is very well reproduced and the incremental oil response and water cut drops induced by the polymer are very well predicted. The simulations strongly support our earlier claim that this increase in incremental oil displacement cannot be explained solely by a viscous “extended Buckley-Leverett” (BL) linear displacement effect; referred to in the literature simply as “mobility control”. This large response is the combination of this effect (BL) along with a viscous crossflow (VX) mechanism, with the latter VX effect being the major contributor to the recovery mechanism.

show abstract

Section: Methodsmentioning

confidence: 80%

“…Permeability distribution ranges from 0.01 to 10 D with an average of ~3 D. The effect of this permeability range of (k max /k min ) is examined below. Sensitivities to grid resolution and correlation length have been previously presented, and as such are not repeated here [ 15 , 16 , 31 ].…”

Section: Methodsmentioning

confidence: 99%

Immiscible Viscous Fingering: The Simulation of Tertiary Polymer Displacements of Viscous Oils in 2D Slab Floods

Beteta

Skauge

2022

Polymers

Self Cite

View full text Add to dashboard Cite

show abstract

“…Following this work the methodology has been shown to be capable of directly matching both core and slab scale experiments across a wide range of oil viscosities (µ o /µ w 100-7,000) (Beteta et al, 2022a, b). Furthermore, (Beteta et al, 2022a) showed the methodology could predict the impact of reducing the injection uid viscosity and veri ed this with further core ooding experiments.…”

Section: Introductionmentioning

confidence: 77%

“…The rst step in the numerical modelling of viscous ngering systems, determining factional ow and generation of relative permeability curves from laboratory data, has been presented in a previous publication (Beteta et al, 2022a). This work utilised the methodology proposed by Sorbie et al (2020) for simulating two phase immiscible viscous ngering.…”

Section: Simulation Backgroundmentioning

confidence: 99%

“…Here, the methodology developed by Sorbie et al (2020) is applied to a series of eld scale simulations, utilising the experimental data and 2D simulations presented previously (Beteta et al, 2022a). The eld scale simulations are based upon the Captain eld in the North Sea which has been undergoing polymer ooding since 2011 (Johnson et al, 2022;Osterloh & Law, 1998;Poulsen et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Immiscible Viscous Fingering at the Field Scale: Numerical Simulation of the Captain Polymer Flood

Beteta¹,

Sorbie²,

Johnson³

2023

Preprint

Self Cite

View full text Add to dashboard Cite

Immiscible fingering in reservoirs results from the displacement of a resident high viscosity oil by a significantly less viscous immiscible fluid, usually water. During oil recovery processes, where water is often injected for sweep improvement and pressure support, the viscosity ratio between oil and water (µo/µw) can lead to poor oil recovery due to formation of immiscible viscous fingers resulting in oil bypassing. Polymer flooding, where the injection water is viscosified by the addition of high molecular weight polymers, is designed to reduce the impact of viscous fingering by reducing the µo/µw ratio. A considerable effort has been made in the past decade to improve the mechanistic understanding of polymer flooding as well as in developing the numerical simulation methodologies required to model it reliably. Two key developments have been (i) the understanding of the viscous crossflow mechanism by which polymer flooding operates in the displacement of viscous oil; and (ii) the simulation methodology put forward by Sorbie et al. (2020), whereby immiscible fingering and viscous crossflow can be simply matched in conventional reservoir simulators. This publication extends the work ofBeteta et al. (2022) to conceptual models of a field case currently undergoing polymer flooding – the Captain field in the North Sea. The simulation methodology is essentially “upscaled” in a straightforward manner using some simple scaling assumptions. The effects of polymer viscosity and slug size are considered in a range of both 2D and 3D models designed to elucidate the role of polymer in systems both with and without “water slumping”. Slumping is governed by the density contrast between oil and water, the vertical communication of the reservoir and the fluid velocity and, when it occurs, the injection water channels along the bottom of the reservoir directly to the production well(s). It is shown that polymer flooding is very applicable to a wide range of reservoirs, with only modest injection viscosities and bank sizes return significant volumes of incremental oil. Indeed, oil incremental recoveries (IR) of between 29–89% are predicted in the simulations of the various 2D and 3D cases, depending on the slug design for both non-slumping and slumping cases. When strong water slumping is present the performance of the polymer flood is significantly more sensitive to slug design, as alongside the viscous crossflow mechanism of recovery, a further role of the polymer is introduced – sweep of the ‘attic’ oil by the viscous polymer flood, which is able to overcome the gravity driven slumping and we also identify this mechanism as a slightly different form of viscous crossflow. In slumping systems, it is critical to avoid disrupting the polymer bank before sweeping of the attic oil has been performed. However, as with the non-slumping system, modest injection viscosities and bank sizes still have a very significant impact on recovery. The conceptual models used here have been found to be qualitatively very similar to real field results. Our simulations indicate that there are few cases of viscous oil recovery where polymer flooding would not be of benefit.

show abstract

Immiscible Viscous Fingering: Modelling Unstable Water–Oil Displacement Experiments in Porous Media

et al. 2022

View full text Add to dashboard Cite

Viscous fingering in porous media occurs when the (miscible or immiscible) displacing fluid has a lower viscosity than the displaced fluid. For example, immiscible fingering is observed in experiments where water displaces a much more viscous oil. Modelling the observed fingering patterns in immiscible viscous fingering has proven to be very challenging, which has often been identified as being due to numerical issues. However, in a recent paper (Sorbie et al. in Transp. Porous Media 133:331–359, 2020) suggested that the modelling issues are more closely related to the physics and formulation of the problem. They proposed an approach based on the fractional flow curve, $${f}_{w}^{*}$$ f w ∗ , as the principal input, and then derived relative permeabilities which give the maximum total mobility. Sorbie et al. were then able to produce complex, well-resolves immiscible finger patterns using elementary numerical methods. In this paper, this new approach to modelling immiscible viscous fingering is tested by performing direct numerical simulations of previously published experimental water/oil displacements in 2D sandstone porous media. Experiments were modelled at adverse viscosity ratios ($${\mu }_{o}/{\mu }_{w}$$ μ o / μ w ), with oil viscosities ranging from μo = 412 to 7000 cP, i.e. for a viscosity ratio range, ($${\mu }_{o}/{\mu }_{w}$$ μ o / μ w ) $$\sim$$ ∼ 400–7000. These experiments have extensive production data as well as in situ 2D immiscible fingering images, measured by X-ray scanning. In all cases, very good quantitative agreement between experiment and modelling results is found, providing a strong validation of the new modelling approach. The underlying parameters used in the modelling of these unstable immiscible floods, the $${f}_{w}^{*}$$ f w ∗ functions, show very consistent and understandable variation with the viscosity ratio, ($${\mu }_{o}/{\mu }_{w}$$ μ o / μ w ).

show abstract

The Role of Immiscible Fingering on the Mechanism of Secondary and Tertiary Polymer Flooding of Viscous Oil

Cited by 17 publications

References 31 publications

Immiscible Viscous Fingering: The Simulation of Tertiary Polymer Displacements of Viscous Oils in 2D Slab Floods

Immiscible Viscous Fingering: The Simulation of Tertiary Polymer Displacements of Viscous Oils in 2D Slab Floods

Immiscible Viscous Fingering at the Field Scale: Numerical Simulation of the Captain Polymer Flood

Immiscible Viscous Fingering: Modelling Unstable Water–Oil Displacement Experiments in Porous Media

Contact Info

Product

Resources

About