Viscosity Reduction WAG: An Effective EOR Process for North Slope Viscous Oils

McGuire, P.L.; Redman, R.S.; Jhaveri, Bharat S.; Yancey, Katrina E.; Ning, Samson

doi:10.2118/93914-ms

Cited by 30 publications

(8 citation statements)

References 13 publications

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“…The compositional simulation shows that the oil saturation near to injector will be as low (nearly to zero) as predicted by equation of state, but laboratory core flood observation indicates nonzero residual oil saturation (S orm ). Hence, miscible gas injection overestimates oil recovery from simulation even though miscible core flood tests show rarely 100% recovery as well as field observations show bypassed oil in miscible gas injection process (McGuire et al 2005;Stalkup, 1983). One example is shown in cross-sectional view of oil saturation in Fig.…”

Section: Permeability Heterogeneity Impact On Un-contacted Oil Saturation (S Orm ) In Wag Displacementmentioning

confidence: 84%

The impact of permeability heterogeneity on water-alternating-gas displacement in highly stratified heterogeneous reservoirs

Khan

Mandal

2021

J Petrol Explor Prod Technol

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Availability of gases at the field level makes attractive to water-alternating-gas (WAG) process for low viscosity and light oils carbonate reservoir. However, impact of reservoir heterogeneity on WAG performance is crucial before field application. In general, ramp carbonates have heterogeneity due to variation of permeability and porosity. However, WAG performance significantly affected by permeability variations. This article investigates merits and demerits of WAG displacement due to permeability heterogeneities such as permeability anisotropy, high permeability streaks (HKS), matrix permeability, dolomite and thin dense stylolite layers. High-resolution compositional simulations with tuned equation of state (EoS) were carried out using 2D and 3D sector models. The study focuses on WAG performance in terms of oil recovery, vertical sweep, solvent utilization, gas oil ratio (GOR), water cut (WCT), WAG response time, gravity override, hysteresis, un-contacted oil saturation and economics. The results of simulation show that the heterogeneous reservoir provides initially faster WAG response, lower expected ultimate recovery (EUR), faster gas breakthrough, higher GOR and WCT production compared to homogeneous reservoir. The gas gravity override at smaller wells spacing is less in homogeneous reservoir as compared to heterogeneous reservoir, but it is reverse in case of larger well spacing. In heterogeneous reservoir, the HKS shows significant gas override resulting in poor vertical sweep due to capillary holding, and the high permeability dolomite layer shows early water breakthrough. This reservoir has higher solvent utilization in initial stage, and then, it becomes nearly equal to homogeneous reservoir. Simulation in both reservoirs overestimates incremental recovery of 2–3% OOIP at one pore volume injection because of not involving un-contacted oil saturation as predicted in core flood. The findings of this study will help to understand WAG performance and design in highly heterogeneous reservoirs for field applications. Graphical abstract

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Section: Permeability Heterogeneity Impact On Un-contacted Oil Saturation (S Orm ) In Wag Displacementmentioning

confidence: 84%

The impact of permeability heterogeneity on water-alternating-gas displacement in highly stratified heterogeneous reservoirs

Khan

Mandal

2021

J Petrol Explor Prod Technol

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“…In the heavier oil, the mechanism is condensing/vaporizing VR-WAG; the viscosity is reduced by a factor of 10. Laboratory and simulation studies show that oil recovery is increased by ~12% OIIP across the range of initial viscosities, despite the change in mechanism from miscible WAG (<20 cp) to VR-WAG (≥20 cp) (McGuire et al, 2005).…”

Section: Export Of Prudhoe Bay MI To the Orion And Polaris Fields (Scmentioning

confidence: 95%

“…Viscosity-reducing WAG is a technique for enhancing recovery of moderately-viscous oil (15 -150 cp) by injecting submiscible 'viscosity-reducing injectant' (VRI) (McGuire et al, 2005). When VRI is injected into a viscous oil reservoir, the oil viscosity can be reduced by up to 90% and the water-flood oil recovery can be improved by up to 15% -20%.…”

Section: Viscosity-reducing Wag (Vr-wag)mentioning

confidence: 99%

Review of Gas Injection Projects in BP

Brodie

Jhaveri

Moulds

2012

SPE Improved Oil Recovery Symposium

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BP has developed a range of innovative techniques to maximize economic oil recovery from its global miscible gas floods and the results have been reported in a series of publications over the past three decades. The purpose of this paper is to provide an overview of BP's experience of establishing, managing and optimizing a miscible gas flood.Prudhoe Bay (Alaska) is the world's largest miscible gas project. Conventional and unconventional methods have been applied in a variety of different settings. An extensive surveillance program has facilitated a good understanding of the processes operating at field scale and surveillance data are used to optimize the flood. In 2000, a large-scale gas cap water injection project was implemented to slow the decline in field pressure. This project has made the vaporization process more efficient at higher pressure, resulting in additional recovery. Miscible gas injection has been extended to numerous other fields on the North Slope of Alaska.BP has two active miscible gas projects in the North Sea: Magnus and Ula. Tertiary miscible water-alternating-gas (WAG) flooding in Magnus field started in 2002 and its impact on reservoir performance is significant and well understood. Tertiary miscible WAG injection in Ula field started in 1998 and has played a key role in arresting production decline. The WAG scheme in Ula is currently being expanded. In addition to these projects, BP operates a CO 2 injection and storage project at In Salah, Algeria, where more than 3.2 million tonnes of CO 2 have been stored since 2004.Miscible gas injection has generated considerable benefits for BP over the past three decades and will continue to do so. The potential availability of large sources of CO 2 in the future, supplied by carbon capture, could help maintain a leading role for miscible gas injection for years to come. IntroductionMiscible flooding is a proven method for enhancing oil recovery. The principle is to reduce the interfacial tension between the displacing solvent and displaced oil and thereby achieve a significant reduction in the residual oil saturation compared to immiscible water flooding and primary depletion. Under ideal conditions, miscible flooding can recover almost 100% of the oil originally in place. Under field conditions, this limit is seldom achieved owing to imperfect volumetric sweep, incomplete displacement of oil in rock that is swept and inadequate capture of displaced oil (Stalkup, 1983). In addition, commercial factors may limit the amount of miscible gas that is available. Despite these limitations, there are many successful miscible gas projects around the world and the prospects for miscible flooding in the future look bright if new sources of CO 2 become available for enhanced oil recovery.

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“…Flow of oil, gas, and water is typically observed in oil bearing formations, both at the reservoir and basin scales. Commonly applied methods for Enhanced Oil Recovery (McGuire et al 2005) require the injection of gaseous phases, such as natural gas, CO 2 or nitrogen, in two-phase (oil-water) environments. The use of three immiscible fluids is also considered in microfluidics experiments and industrial applications, to prevent coalescence of microfluidic plugs (Chen et al 2007) and to screen a small volume of solution from the effect of a large number of reagents (Zheng and Ismagilov 2005).…”

Section: Introductionmentioning

confidence: 99%

Three-Phase Permeabilities: Upscaling, Analytical Solutions and Uncertainty Analysis in Elementary Pore Structures

2014

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Viscosity Reduction WAG: An Effective EOR Process for North Slope Viscous Oils

Abstract: TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractA novel EOR method, Viscosity

Cited by 30 publications

References 13 publications

The impact of permeability heterogeneity on water-alternating-gas displacement in highly stratified heterogeneous reservoirs

The impact of permeability heterogeneity on water-alternating-gas displacement in highly stratified heterogeneous reservoirs

Review of Gas Injection Projects in BP

Three-Phase Permeabilities: Upscaling, Analytical Solutions and Uncertainty Analysis in Elementary Pore Structures

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