Selecting EOR Polymers through Combined Approaches—A Case for Flooding in a Heterogenous Reservoir

Borovina, Ante; Hincapie, Rafael E.; Clemens, Torsten; Hoffmann, Eugen; Wegner, Jonas

doi:10.3390/polym14245514

Cited by 3 publications

(1 citation statement)

References 47 publications

(59 reference statements)

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“…In this study, we designed and fabricated a micromodel with dimensions of 120 × 45 mm (refer to Figure 2 ). While the experimental setup remained the same, the design presented here differs from the microchips typically employed in previous studies by Schumi et al [ 14 ], Borovina et al [ 30 ], and Hincapie et al [ 15 ]. Notably, our setup incorporates an automated scheduling feature, enabling the programming of experiment sequences to mitigate human error and ensure hardware reproducibility.…”

Section: Methodsmentioning

confidence: 99%

Alkali Polymer Flooding of a Romanian Field Containing Viscous Reactive Oil

Hoffmann,

Hincapie,

Borovina

et al. 2024

Polymers

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The study demonstrates the significant enhancement in oil production from a Romanian oil field using alkali–polymer (AP) flooding for reactive viscous oil. We conducted comprehensive interfacial tension (IFT) measurements across various alkali and AP concentrations, along with phase behavior assessments. Micromodel flooding experiments were used to examine pore-scale effects and select appropriate chemical concentrations. We tested displacement efficiency at the core level and experimented with different sequences and concentrations of alkali and polymers to minimize costs while maximizing the additional recovery of reactive viscous oil. The IFT analysis revealed that saponification at the oil–alkali interface significantly lowers IFT, but IFT gradually increases as soap diffuses away from the interface. Micromodels indicated that polymer or alkali injection alone achieve only minimal incremental recovery beyond waterflooding. However, AP flooding significantly enhanced incremental oil recovery by efficiently moving the mobilized oil with the viscous fluid and increasing exposure of more oil to the alkali solution. Coreflood experiments corroborated these findings. We also explored how divalent cations influence polymer concentration selection, finding that softening the injection brine significantly increased the viscosity of the AP slug.

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Section: Methodsmentioning

confidence: 99%

Alkali Polymer Flooding of a Romanian Field Containing Viscous Reactive Oil

Hoffmann,

Hincapie,

Borovina

et al. 2024

Polymers

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Flow of Viscoelastic Polymer Solutions in Porous Media: Influence of Molecular Weight and Dispersity

Langanke

Leblanc²,

Fadili

et al. 2023

Day 4 Thu, June 08, 2023

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The properties of polymeric materials are commonly modified by adjusting the dispersity of the molecular weight distribution, since polymer properties are dominated by intermolecular interactions. We utilized this approach to alter the rheological behavior of polymer solutions for application sub-surface and other porous media flow. We correlate the molecular weight distributions with screen factor measurements and in-situ rheological behavior. Aqueous solutions were prepared using mixtures of partially hydrolyzed polyacrylamide (HPAM) having different molecular weights. The behaviour of the solutions was studied in single-phase flooding experiments using Bentheimer and Berea outcrops, as well as a glass-silicon-glass microfluidic device that mimics porous media. The in-situ rheological behavior determined from flooding experiments was monitored by differential pressure measurements. To improve data accuracy, the core flooding experimental set-up was equipped with multiple pressure sensors along the core. Polymer solutions of same shear viscosity but significantly different dispersities were utilized for the investigation. Elongational viscosities were determined by screen factor measurements. We show that the apparent viscosity during polymer injection is significantly altered for polymer solutions of same average molecular weight but different dispersity. Namely, the onset of shear thickening occurs at lower equivalent shear rates when dispersity is high. Furthermore, the flow of polymer solutions in porous media was correlated to screen factor measurements. This effect of the dispersity of the molecular weight distribution can be used to optimize polymer solution applications in porous materials.

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Alkali Polymer Flooding: Tackling Risks and Challenges from Feasibility Study to Pilot

Janczak,

Hincapie,

Grottendorfer

et al. 2023

Day 3 Wed, October 04, 2023

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Alkali Polymer (AP) is considered as enhanced oil recovery (EOR) technique for a mature field in Austria. To achieve technology qualification, different workflows have been implemented that supports risks definition and mitigations. We therefore present here the necessary steps utilized for the AP technology development and qualification. We evaluate challenges including laboratory assessments, subsurface and surface elements, aiming at demonstrating the effectiveness of AP to produce additional oil and to enable a field pilot. Multidisciplinary work packages allowed creating a holistic understanding of the benefits and challenges of AP injection and mitigate these challenges to enable a field pilot. Laboratory experiments were performed to determine an effective recipe to mobilize oil without detrimental reservoir interaction (rheology measurements, phase behavior tests, core floods etc.). The design of the pilot facilities built on water softening technologies tests. Finally key producers were identified based on previous tracer and polymer breakthrough results, and workovers were planned to allow implementing scaling mitigation solutions. A partitioning tracer test was also carried out to measure the remaining oil before AP pilot. The selected recipe showed significant residual oil mobilization, recovery factor increases and low polymer adsorption. Aging experiments showed that polymer hydrolysis in the reservoir in alkaline conditions allowed using lower polymer concentration and facilitate injectivity. Facilities design centered around keeping pilot costs as low as possible, by reusing existing polymer dosing and mixing facilities, and designing an additional alkali dosing and mixing plant. To mitigate the risk of precipitation at the injector, the water treatment was upgraded to remove divalent ions before mixing with alkali. Pre-qualification tests under field conditions allowed developing and optimizing a weak acid cation exchanger unit meeting operational requirements. This process was then engineered at the pilot scale and implemented in the AP pilot project. Finally, wells were evaluated to ensure material compatibility with AP fluids, and 3 producers with high expected alkaline back-produced concentration were selected for a workover allowing retrofitting a scale inhibition string. The scale inhibitor was selected using a dynamic scale loop. In conclusion, all work packages performed enable carrying out a field pilot with reduced risk. Starting Q2 2023, the pilot will focus on gaining operational experience with the new facilities, as well as scaling and emulsions mitigation solutions. While the industry saw multiple Alkaline, Surfactant and Polymer floods, Alkali and Polymer has only limited literature. However, by avoiding costs linked to surfactant, AP appears as an attractive EOR technique for highly reactive oils. This work presents the steps carried out to obtain understanding of the potential oil gains, and evaluate injectivity, scaling and emulsions risks. The methodology allowed de-risking the technology and bringing it from the laboratory to the field with a pilot.

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Selecting EOR Polymers through Combined Approaches—A Case for Flooding in a Heterogenous Reservoir

Cited by 3 publications

References 47 publications

Alkali Polymer Flooding of a Romanian Field Containing Viscous Reactive Oil

Alkali Polymer Flooding of a Romanian Field Containing Viscous Reactive Oil

Flow of Viscoelastic Polymer Solutions in Porous Media: Influence of Molecular Weight and Dispersity

Alkali Polymer Flooding: Tackling Risks and Challenges from Feasibility Study to Pilot

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