A Novel Approach for Resolving Reverse Emulsions in SAGD Production Systems

Bosch, Ron; Axcell, Eric; Little, Virgil; Cleary, Robert W.; Wang, Sanyi; Gabel, Robert A.; Moreland, Bill

doi:10.1002/cjce.5450820424

Cited by 19 publications

(7 citation statements)

References 3 publications

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“…Arguably, o/w emulsions are favored during pre-production in the reservoir; however, in post-production they can potentially pose some operational problems requiring specific chemical treatments [70].…”

Section: Factors Affecting Sagd Performancementioning

confidence: 99%

Interfacial Chemistry in Steam-Based Thermal Recovery of Oil Sands Bitumen with Emphasis on Steam-Assisted Gravity Drainage and the Role of Chemical Additives

Taylor

2018

Colloids and Interfaces

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In this article, the importance of colloids and interfaces in thermal heavy oil or bitumen extraction methods is reviewed, with particular relevance to oil sands. It begins with a brief introduction to the chemical composition and surface chemistry of oil sands, as well as steam-based thermal recovery methods. This is followed by the specific consideration of steam-assisted gravity drainage (SAGD) from the perspective of the interfacial chemistry involved and factors responsible for the displacement of bitumen from reservoir mineral surfaces. Finally, the roles of the different chemical additives proposed to improve thermal recovery are considered in terms of their contributions to recovery mechanisms from interfacial and colloidal perspectives. Where appropriate, unpublished results from the author's laboratory have been used to illustrate the discussions.

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Section: Factors Affecting Sagd Performancementioning

confidence: 99%

Interfacial Chemistry in Steam-Based Thermal Recovery of Oil Sands Bitumen with Emphasis on Steam-Assisted Gravity Drainage and the Role of Chemical Additives

Taylor

2018

Colloids and Interfaces

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“…11,34−36 The addition of REBs is aimed to enhance the quality of the produced water from the SAGD emulsions through the removal of dispersed oil droplets. 12,37,38 It has been widely accepted that the extraordinary stability of the SAGD emulsions is caused by the presence of interface-active species (e.g., asphaltenes, resins, and natural surfactants). 33,39−42 These interface-active species are adsorbed at the oil/water interface and form a rigid and irreversible interfacial film.…”

Section: Introductionmentioning

confidence: 99%

“…Chemical additives in conjunction with a high temperature separator (HTS) have been extensively applied to the demulsification process in the SAGD production. − Two major types of the chemical additives, i.e., emulsion breakers (EBs) and reverse emulsion breakers (REBs), are synergistically used to achieve desirable demulsification and separation efficiency. The objective of adding EBs is to improve the dryness of produced oil by treating water-in-oil (W/O) emulsions. , A variety of EBs have been explored and commercially used in conventional demulsification technologies (e.g., surface mining process of oil sands) for decades, such as propylene oxide (PO)-polymeric ethylene oxide (EO) block copolymers, − ethylcellulose, , alkylphenol resin alkoxylates, and nanoparticles. , Correspondingly, systematic studies have been conducted on the influencing factors − ,− and demulsification mechanisms ,− of EBs for destabilizing the W/O emulsions, which significantly improves their development and applications in the SAGD production.…”

Section: Introductionmentioning

confidence: 99%

“…Unlike the widespread applications of EBs in the petroleum industry, REBs are relatively new due to the emergence of enhanced oil recovery technologies (e.g., SAGD technology) for oil sands deposits in recent years. ,− The addition of REBs is aimed to enhance the quality of the produced water from the SAGD emulsions through the removal of dispersed oil droplets. ,, It has been widely accepted that the extraordinary stability of the SAGD emulsions is caused by the presence of interface-active species (e.g., asphaltenes, resins, and natural surfactants). ,− These interface-active species are adsorbed at the oil/water interface and form a rigid and irreversible interfacial film. − Consequently, electrical double layer (EDL) repulsion between the oil droplets in the aqueous phase is remarkably enhanced, which together with an additional steric hindrance by the interface-active species contributes significantly to the stability of oil-in-water (O/W) emulsions. , REBs are introduced to neutralize the surface charge of the dispersed oil droplets in the O/W emulsions, allowing the oil droplets to approach and coalesce driven by attractive interactions (e.g., van der Waals forces). , In this regard, the superior capability of REBs to neutralize the surface charge of the oil droplets, which is primarily reflected by their charge density, is crucial to their demulsification performance . Nevertheless, to the best of our knowledge, very limited studies are reported on an in-depth understanding of the influence of the charge density of the REBs and the underlying demulsification mechanisms.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Charge Density of Reverse Emulsion Breaker on Demulsification Performance for Steam-Assisted Gravity Drainage (SAGD) Emulsions under High Temperature and High Pressure

et al. 2020

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Reverse emulsion breakers (REBs) play a crucial role in the demulsification of complex water-in-oil-in-water (W/O/ W) emulsions in steam-assisted gravity drainage (SAGD) production of oil sands. Developing effective REBs remains challenging due to the poor understanding of influencing factors and demulsification mechanisms. In particular, despite the recognition of the vital role of charge density of the REBs in their demulsification performance, the available literature is limited. Herein, we investigated the correlation between the charge density of commercial REBs and their demulsification performance for complex emulsions under simulated SAGD operation conditions (100−200 °C and 0.3−1.4 MPa) by employing an in-house-built bottle test system. It is demonstrated that a high charge density of the REBs not only promotes the qualities of produced water and oil but also significantly accelerates the speed of oil/water phase separation. At the microscale, the REB with a high charge density is capable of reducing the amount and size of residual oil droplets in produced water. The interactions of the species involved during the demulsification process were investigated by employing multiple techniques including optical microscopy imaging, ζ potential measurement, and dynamic light scattering. The results suggest that the cationic REBs are adsorbed at the oil/water interface, neutralize negative surface charge of oil droplets, and replace interface-active species originally present at the oil/water interface. Multilayer adsorption of REBs may be generated after demulsification, and the adsorbed REBs could partially desorb from the surface of oil droplets with increasing temperature. This work has delineated the influence of the charge density of REBs on their demulsification performance and improved the fundamental understanding of the interactions of the constituent species in SAGD emulsions and REBs, which provides useful information on the development and applications of efficient and cost-effective chemicals in oil sands exploitation and emulsion treatment.

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“…Field reports mostly focus on the impact of emulsion on separation and transportation of produced liquid. It has in some instances been reported that the production of oil-in-water (reverse) emulsion is common in SAGD (Bosch et al, 2004). Experimental investigations however suggest that produced liquid during SAGD is predominantly water-in-oil type emulsion (Mohammadzadeh and Chatzis, 2009;Noik et al, 2005;Sasaki et al, 2001A, 2001B;Chung and Butler, 1987).…”

Section: Introductionmentioning

confidence: 99%

Investigation of Emulsion Flow in SAGD and ES-SAGD

2012

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Expanding Solvent-Steam Assisted Gravity Drainage (ES-SAGD) was invented to enhance SAGD performance by reducing energy use while increasing oil production rates and recovery factor. ES-SAGD involves co-injection of solvent and steam. The majority of energy losses occur between the steam generator and sandface and at the top of the depletion chamber (to the overburden). ES-SAGD performance improvement is traditionally ascribed to oil phase dilution which in turn leads to oil phase viscosity reduction. However, the amounts of solvent added to the process are typically very small (< 5-6% by volume) thus it remains unclear how the solvent can lead to significant lowering of the steam-to-oil ratio (~25-50%) and large enhancements of the oil rate (~25 to 100%). Here, we report on how SAGD and ES-SAGD (hexane, heptane and octane solvents) can potentially perform in the presence of in-situ emulsification at steam chamber edge. We present a numerical approach which allows incorporation of emulsion modeling into SAGD and ES-SAGD simulations with commercial reservoir simulators via a two-stage pseudo chemical reaction. Numerical simulation results show excellent agreement with experimental data for low-pressure SAGD and ES-SAGD. Accounting for viscosity alteration, multiphase effect and enthalpy of emulsification appear sufficient for effective representation of in-situ emulsion physics during SAGD and ES-SAGD in very high permeability systems. Results also show that, in-situ emulsification may play a vital role within the reservoir during SAGD; increasing bitumen mobility thereby decreasing cSOR. It was concluded that traditional approach to numerical ES-SAGD simulation can significantly over-predict incremental oil recovery. Results from this work extend understanding of ES-SAGD by examining its performance improvement over traditional SAGD in terms of multiphase behavior at the edge of the chamber, thermal efficiency and incremental recovery. Results reveal that dynamics at the edge of the chamber is more complex than simple solvent dilution model.

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A Novel Approach for Resolving Reverse Emulsions in SAGD Production Systems

Cited by 19 publications

References 3 publications

Interfacial Chemistry in Steam-Based Thermal Recovery of Oil Sands Bitumen with Emphasis on Steam-Assisted Gravity Drainage and the Role of Chemical Additives

Interfacial Chemistry in Steam-Based Thermal Recovery of Oil Sands Bitumen with Emphasis on Steam-Assisted Gravity Drainage and the Role of Chemical Additives

Effect of Charge Density of Reverse Emulsion Breaker on Demulsification Performance for Steam-Assisted Gravity Drainage (SAGD) Emulsions under High Temperature and High Pressure

Investigation of Emulsion Flow in SAGD and ES-SAGD

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