| Design Optimization of Slotted Liner Completions in Cased and Perforated Wells: A Numerical Skin ModelVelayati, A., Roostaei, M., Fattahpour, V., Mahmoudi, M., Nouri, A., Alkouh, A., Fermaniuk, B. and Kyanpour, M., 2018, December. Design Optimization of Slotted Liner Completions in Cased and Perforated Wells: A Numerical Skin Model. In SPE International Heavy Oil Conference and Exhibition. Society of Petroleum Engineers.
Abstract
Several parameters affect the skin factor of the cased and perforated (C&P) wells completed with slotted liners. Existing skin factor models for slotted liners account for such factors as the flow convergence, pressure drop and partial production but neglect phenomena such as partial plugging of the screen or near-wellbore permeability alterations during the production. This paper discusses these factors and incorporates them into a skin model using a finite volume simulation.
The finite volume analysis evaluates the skin factor as a result of pressure drop in the gap between the casing wall and the slotted liner. This skin model accounts for: 1) the perforation density and phasing, 2) slotted liner specifications, and 3) different amount of sand accumulation in the annular space between the casing and the sand screen. A semi-analytical pressure drop model is also linked to the numerical model to incorporate the skin factor due to flow convergence behind the perforations.
The results of finite volume analysis reveal that a low perforation density would behave close to the open-hole completion for sand-free casing-liner annular space. Conversely, pressure drops were found to be significant for a partially or totally filled space. Additionally, it was found that the optimum completion design occurs if the slotted liner joints are in line with the casing joints. Besides, a partially perforated casing or a partially open sand screen increases the distance fluids have to travel in the annular space and intensifies the skin factor.
This paper provides skin models derived for vertical and perforated wells completed with slotted liner sand screens using the finite volume simulations. Each part of the model has been verified against existing numerical models in the literature. The model improves the understanding of flow performance of the sand screens and skin factor, which in turn leads to a better design of sand control completions. University of Alberta | Publication | 2018-12-10 | Arian Velayati, "Morteza Roostaei", "Vahidoddin Fattahpour", "Mahdi Mahmoudi", Nouri, A., "Ahmad Alkouh", "Brent Fermaniuk", "Mohammad Kyanpour" |
| Evaluation of the Scaling Resistance of Different Coating and Material for Thermal OperationsFattahpour, V., Mahmoudi, M., Roostaei, M., Cheung, S., Gong, L., Qiu, X., Huang, J., Velayati, A., Kyanpour, M., Alkouh, A. and Strom, R., 2018, December. Evaluation of the Scaling Resistance of Different Coating and Material for Thermal Operations. In SPE International Heavy Oil Conference and Exhibition. Society of Petroleum Engineers.
Abstract
Several alloys and coating techniques have been used by industry for their anti-corrosion and anti-fouling properties in the industry. One of the major problems in thermal operation is related to silica and calcium carbonate scale. In this study, we intend to better understanding the relative scaling resistance performance of different coatings and alloys exposed to typical formation water in thermal operations. This paper provides a study on failed samples collected from various projects in Western Canada. Moreover, a review of research work on scaling properties of different materials in thermal applications will be presented.
Different failed screens were collected from various projects in Western Canada. Thin section analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) joined with energy dispersive X-ray spectroscopy (EDX) were performed on collected failed pipeline samples to determine the composition of the scale material. Obtained results revealed that the main scaling materials are silicates and carbonates. Chert, clays and carbonates act as cement to bind sand grains (mainly quartz).
Later, a review was performed on an ongoing investigation regarding the materials and coatings for improving the anti-scaling properties. Bulk scaling tests, Atomic Force Microscopy (AFM), and in-situ field trials were used to investigate the anti-scaling properties of two RGL proprietary grade materials, proRC05, and proRS06, as well as electroless nickel (EN) coating. Carbon steel L80, carbon steel 4140 and EN30B alloy steel were used for comparison. The microstructural change of the material surface was studied using complementary techniques (e.g., XRD, SEM, and EDX). The tests have been performed under a complex chemical environment that represents the chemistry of the near screen condition in thermal operation, to assess the relative performance of different coatings. Among proRC05, proRS06, 4140 carbon steel and EN30B alloy steel, the anti-scaling performance follows the order of proRC05 > proRS06 > 4140 carbon steel > EN30B alloy steel. Comparison between EN-coated and uncoated samples shows that the EN-coated carbon steel L80 provides better anti-corrosion and fouling resistance performance with a small amount of iron oxides and silica foulants. Field trials of EN-coated technology have been also proven to be effective.
This work provides a detailed review on recent attempts on evaluating the anti-scaling properties of various materials and coatings to minimize the silica and calcium carbonate scale. Furthermore, field trials were reviewed for evaluating the scaling and corrosion properties in thermal production. The results of this study will help engineers select material for projects in which silica and calcium carbonate scaling could be a significant issue. | Publication | 2018-12-10 | "Vahidoddin Fattahpour", "Mahdi Mahmoudi", "Morteza Roostaei", "Stephen Cheung", "Lu Gong", Xiaoyong Qiu, "Jun Huang", Arian Velayati, "Mohammad Kyanpour" |
| A concise review of experimental works on proppant transport and slurry flowFinal proppant distribution inside hydraulic fractures which depends on particle properties, movement and deposition highly impact wellbore productivity and consequently is crucial in modeling and design of hydraulic fracturing. This paper presents a thorough review of laboratory scale tests performed on proppant transport related to hydraulic fracturing treatments and governing physics behind its mechanisms. University of Alberta | Publication | 2020-02-12 | "M Roostaei", Nouri, A., S A Hosseini, "M Soroush", Arian Velayati, "M Mahmoodi" |
| An Analytical Model for Hydraulic Fracture Initiation in Deviated WellboresThis paper presents an analytical model to calculate the hydraulic fracture initiation pressure from an arbitrarily oriented wellbore in an elastic medium with and without perforations and investigates the competition between axial and transverse fractures. The model predicts the location of fractures and their initiation pressures, in relation to the in-situ stress condition and wellbore azimuth and inclination. Not only has the model been applied to different states of in-situ stress and wellbore orientations, but also the results have been presented in terms of non-dimensional parameters to improve the applicability of the study. University of Alberta | Publication | 2019-06-23 | "M Roostaei", "A Sharbatian", "V Fattahpour", "M Mahmoudi", Arian Velayati, "A Ghalambor", Nouri, A. |
| How the Design Criteria for Slotted Liners in SAGD are Affected by Stress Buildup around the LinerHow the Design Criteria for Slotted Liners in SAGD are Affected by Stress Buildup around the Liner
Roostaei, M., Guo, Y., Velayati, A., Nouri, A.
Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, Canada
Fattahpour, V. and Mahmoudi, M.
RGL Reservoir Management, Leduc, Alberta, Canada
ABSTRACT: Unconsolidated sand was packed on a slotted-liner coupon in large-scale sand retention tests (SRT) and was subjected to several stress conditions, corresponding to the evolving stress conditions during the life cycle of a SAGD producer. Cumulative produced sand at the end of testing was measured as the indicator for sand control performance. Retained permeability was calculated by measuring pressure drops near the liner and was considered as the quantification of the flow performance of the liner. Experimental results indicate the liner performance is significantly affected by the stress induced compaction of the oil sand. The stress results in the sand compaction, leading to a denser sand, hence, a lower porosity and permeability. The lower porosity results in a higher porescale flow velocity, which can trigger more fines mobilization, hence, a higher skin buildup. With respect to sanding, the higher stress can stabilize the sand bridges: Increased normal forces between near-slot sand particles result in a higher inter-particle friction, hence,more stable sand bridges and less produced sand. The lower and upper bounds of slot window are governed by plugging and sandproduction, respectively. Experimental results indicate an upward shift in both the lower and upper bounds at elevated stressconditions University of Alberta | Publication | 2018-06-17 | "Morteza Roostaei", "Y. Guo", Arian Velayati, Nouri, A., "V. Fattahpour", M Mahmoudi " |
| On the sanding and flow convergence skin in cased and perforated slotted liner wellsWell completion is the process of borehole preparation for the production. Cased and perforated slotted liner completion is used extensively as the completion configuration in the wells drilled into conventional sand formation reservoirs. Such completions may exhibit lower productivity ratios compared to the open-hole condition. The reasons include perforations collapse, flow convergence in the vicinity of the slots and perforations, and the formation damage caused by perforating. These effects have compounding effects as the formation damage magnifies the flow convergence effect and the flow convergence magnifies the skin buildup by the fines migration. In this study, a Computational Fluid Dynamics (CFD) numerical finite volume model was constructed for a vertical cased and perforated completion in a sand reservoir. Results include the skin values that were compared for the different slot and perforation densities. Stability of the perforation tunnels was considered as a variable in this research, and the results were summarized and analyzed in terms of the skin formed as a result of flow convergence. It was found that sanding in perforation tunnels and the resulting change in the permeability of the collapsed tunnel magnifies flow convergence skin significantly, especially in the lower shot densities and this added pressure drop can be very troubling. Results show in lower perforation densities higher pressure drawdowns may trigger sand production due to the tensile failure. Additionally, a parametric study was carried out on the sanding possibilities
University of Alberta | Publication | 2019-06-23 | Arian Velayati, "M Roostaei", "A. Sharbatian", "V. Fattahpour", "M. Mahmoudi", C F Lange, Nouri, A. |
| Risk Assessment in Sand Control Selection: Introducing a Traffic Light System in Stand-Alone Screen Selection.Risk Assessment in Sand Control Selection: Introducing a Traffic Light
System in Stand-Alone Screen Selection
Mahdi Mahmoudi and Vahidoddin Fattahpour, RGL Reservoir Management; Arian Velayati, University of
Alberta; Morteza Roostaei and Mohammad Kyanpour, RGL Reservoir Management; Ahmad Alkouh, College of
Technological Studies; Colby Sutton and Brent Fermaniuk, RGL Reservoir Management; Alireza Nouri, University
of Alberta
Abstract
Sand control and sand management require a rigorous assessment of several contributing factors including
the sand facies variation, fluid composition, near-wellbore velocities, interaction of the sand control with
other completion tools and operational practices. A multivariate approach or risk analysis is required to
consider the relative role of each parameter in the overall design for reliable and robust sand control. This
paper introduces a qualitative risk factor model for this purpose.
In this research, a series of Sand Retention Tests (SRT) was conducted, and results were used to formulate
a set of design criteria for slotted liners. The proposed criteria specify both the slot width and density for
different operational conditions and different classes of Particle Size Distribution (PSD) for the McMurray
oil sands. The goal is to provide a qualitative rationale for choosing the best liner design that keeps the
produced sand and skin within an acceptable level. The test is performed at several flow rates to account for
different operational conditions for Steam Assisted Gravity Drainage (SAGD) and Cyclic Steam Stimulation
(CSS) wells. A Traffic Light System (TLS) is adopted for presenting the design criteria in which the red
and green colors are used to indicate, respectively, unacceptable and acceptable design concerning sanding
and plugging. Yellow color in the TLS is also used to indicate marginal design.
Testing results indicate the liner performance is affected by the near-wellbore flow velocities,
geochemical composition of the produced water, PSD of the formation sand and fines content, and
composition of formation clays. For low near-wellbore velocities and typical produced water composition,
conservatively designed narrow slots show a similar performance compared to somewhat wider slots.
However, high fluid flow velocities or unfavorable water composition results in excessive plugging of the
pore space near the screen leading to significant pressure drops for narrow slots. The new design criteria
suggest at low flow rates, slot widths up to three and half times of the mean grain size will result in minimal
sand production. At elevated flow rates, however, this range shrinks to somewhere between one and a half
to three times the mean grain size. University of Alberta | Publication | 2018-12-10 | "Mahdi Mahmoudi", "Vahidoddin Fattahpour", Arian Velayati, "Morteza Roostaei", "Ahmad Alkouh", "Colby Sutton", "Brent Fermaniuk", Nouri, A. |
| Design and Development of Experimental Facilities to Study Oil Recovery in Thermal WellsPoster presented in 2020 FES Industry Mixer
University of Alberta | Activity | 2020-02-20 | Mahmood Salimi, Nouri, A. |
| HP-HT Well Completion Testing for Digital Oil Well Technology Validation and ResearchPoster presented in 2019 FES Colloquium
University of Alberta | Activity | 2019-05-07 | Mahmood Salimi, Nouri, A. |
| HP-HT Well Completion Testing for Digital Oil Well Technology Validation and ResearchPoster presented in 2nd Annual Future Energy Systems
University of Alberta | Activity | 2018-10-03 | Mahmood Salimi, Nouri, A. |
| Introducing A Model Emulsion Replicating SAGD Reservoir Emulsion FeaturesThis thesis introduces a model emulsion that replicates the physical features of steam-assisted gravity drainage (SAGD) reservoir emulsion. Moreover, a framework was presented which enables adjusting the emulsion properties such as dynamic viscosity, size of the droplets, kinetic stability, and asphaltene precipitation to reach the target features accurately. For this purpose, the research followed two primary phases.
In the first phase, a base recipe containing water, the external oil phase, and a non-ionic surfactant (Span 83) was selected and screening and comparative tests were carried out to determine the proper homogenization settings, assess the surfactant performance, add/introduce other surfactants/components such as gilsonite and hexane to the recipe and evaluate the effect of electrolyte, phase ratio, and additives concentrations on the features of the emulsions.
The second phase of the research started once the decision on the final components of the model emulsion recipe was made. In this stage, BoxBehnken experimental design was adopted to run the experiments and establish correlations for the target features with the concentration of the additives/components. These correlations were used as objective functions in the optimization to attain the goals, which were SAGD emulsion features.
This research employs different techniques to evaluate the emulsion properties. The kinetic stability of emulsions was monitored by optical microscopy, water phase separation in the bottle tests, and interfacial tension measurements. The viscosity of emulsions was measured by a cone and plate viscometer, and the size of the droplets and asphaltene aggregates were determined by optical microscopy.
In addition to the primary objective of the research several other marginal objectives were followed. This research presents a comprehensive characterization of w/o macro-emulsions stabilized by a non-ionic surfactant (Span 83), where the effect of phase ratio, oil composition, electrolyte, and surfactant concentration on the emulsion features was investigated. Moreover, gilsonite is introduced as a new additive that can be used to mimic asphaltene precipitation in oil.
Asphaltene precipitation in different oil blends was monitored and characterized, and the effect of gilsonite concentration, oil composition, electrolyte, and phase ratio on emulsions properties was studied. Molecular dynamic simulation coupled with experimental results in terms of water phase separation, interfacial tension measurements, viscosity measurements, and micrography reveal some important aspects of the asphaltene aggregation role in the stability of w/o emulsions.
The application of the model emulsion is quite extensive. It can be used in sand pack and core flooding tests that currently neglect the emulsion flow. Utilizing model emulsion eliminates the need to run similar tests at high-pressure high-temperature conditions with bitumen, which is risky and hazardous, and can replace the difficult procedure of asphaltene extraction from bitumen. Additionally, the results presented in this research around asphaltene precipitation behavior and stability of w/o emulsions by asphaltene aggregates have important implications for solvent-SAGD operations. | Publication | 2021-01-01 | Arian Velayati |
| Near-Wellbore Permeability Damage by Fines Migration in Steam Assisted Gravity Drainage WellsThis thesis investigates the flow performance impairment or permeability damage under the fines migration process near the SAGD wellbore producers completed with sand control screens. A new sand retention testing (SRT) procedure was developed to replicate a more representative fines migration process in SAGD wellbore conditions to evaluate the flow performance of sand control screens. The investigation factors included different sand control screen specifications, flow rate, flow salinity, fines content, and sand and fine particles size distributions. The research was conducted in two experimental and numerical stages.
The first stage comprised extensive SRT experiments to investigate the hydrodynamic and chemical effects of the fines migration process, evaluate the reliability of previous testing procedures for replicating representative fines migration process in SRT experiments, and troubleshoot the set-up deficiencies. University of Alberta | Publication | 2022-11-30 | Miri, R. |
| Novel Laboratory Methodology for Fines Migration Testing for SAGD WellsThe near-wellbore permeability loss owing to the release and migration of naturally fine particles
impairs the well productivity in oil reservoirs. The damage would be intensified in the presence
of restrictions such as sand control screens used in unconsolidated formations due to retardation
and accumulation of fine particles resulting from flow convergence and high volumetric flux. In
this study, sand retention flow tests in unconsolidated sand packs with different sand screens
resulted in fines migration under salinity reduction and consequently high permeability loss near
the sand screens. The sand pack represented a high permeable oil sand reservoir around a SAGD
well producer with a relatively high content of fine clay particles. In general, sand screens with a
low open flow area and narrow aperture size caused higher permeability loss under the same flow
conditions. Higher salinity reduction yielded higher mobilized fines concentration, causing high
permeability loss of the sample.
A 3D numerical model considering the sand screen geometry simulated the fines migration
process and matched the observed pressure drops with acceptable accuracy. The initial mobile
fines concentration for the model was set upon assuming an instant fine particles release
mechanism under salinity change. The model incorporates governing equations of fluid and
species transport in porous media associated with variations in porosity and permeability by
retained fine particles. Two objective functions of dimensionless pressure drop along the whole
and top-interval of the sand pack determined the model parameters through an optimization
algorithm. The calibrated model could predict the dimensionless pressure drops for the near
screen interval with sufficient accuracy. It was confirmed that the matching parameters were
nearly independent of the sand screen. However, different values for different salinities were
obtained, confirming their dependency on flow properties along with the porous media.
Keywords: Numerical modeling, Fines migration, Unconsolidated sands, Sand control screen University of Alberta | Activity | 2021-05-01 | Miri, R., "Mohammad Haftani", Mahmood Salimi, Nouri, A. |
| Electricity Generation from Post-blowdown Steam Assisted Gravity DrainageResearchers at the University of Alberta have developed innovative systems and methods that utilize a closed-loop circuit for water circulation in post-blowdown Steam Assisted Gravity Drainage (SAGD) operations. The goal is to recover heat from reservoirs after oil extraction and convert this recovered thermal energy into mechanical power, which is then used to generate electricity. The technology leverages an Organic Rankine Cycle (ORC) engine, which efficiently converts heat into mechanical work. Notably, the estimated cost per megawatt-hour (MWh) using this approach is lower than other conventional methods1. This advancement holds promise for sustainable energy production while optimizing oil recovery processes. University of Alberta | IP Management | 2023-05-17 | Mahmood Salimi, Nouri, A., Bruce Peachey |
| Electricity Generation from Post-blowdown Steam Assisted Gravity DrainageSALIMI, M., Nouri, A. (2021) Electricity Generation from Post-blowdown Steam Assisted Gravity Drainage, United States Provisional Patent No. 63/190,367
In an aspect, the present disclosures provides methods and systems for harvesting thermal energy, including for example, harvesting thermal energy from a spent oil well having an injection well borehole (IWB), comprising disposing a conduit system within the IWB having an inner conduit within an outer conduit; connecting a first end of an inflow conduit to a proximal end of the inner conduit; connecting a second end of the inflow conduit to a cool water output of a heat exchanger (HX) system; connecting a first end of an outflow conduit to a proximal end of the outer conduit; connecting a second end of the outflow circuit to a hot water input of the HX system; circulating water in a closed loop to harvest thermal energy from an environment surrounding the closed loop; and extracting heat from the water circulating through the HX system. University of Alberta | IP Management | 2021-01-01 | Mahmood Salimi, Nouri, A. |
| SYSTEM AND METHOD FOR POST-SAGD STEAM-LESS GREEN BITUMEN RECOVERY AND CLEAN POWER GENERATIONAlireza Nouri, Mahmood Salimi, and Bruce Peachey, SYSTEM AND METHOD FOR POST-SAGD STEAM-LESS GREEN BITUMEN RECOVERY AND CLEAN POWER GENERATION, United States Provisional Patent Application Serial No. 63/659,944 University of Alberta | IP Management | 2022-01-01 | Nouri, A., Mahmood Salimi, Bruce Peachey |
| A Review of Fines Migration around Steam Assisted Gravity Drainage Wellbores University of Alberta | Publication | 2021-10-01 | Miri, R., "Mohammad Haftani", Nouri, A. |
| Emulsification and Emulsion Flow in Thermal Recovery Operations with a Focus on SAGD Operations: A Critical Review University of Alberta | Publication | 2020-05-01 | Arian Velayati, Nouri, A. |
| Formulating a model emulsion replicating SAGD in-situ emulsions University of Alberta | Publication | 2022-01-01 | Arian Velayati, Nouri, A. |
| In-situ Combustion: A Comprehensive Review of the Current State of KnowledgeThis paper is related to In Situ Combustion. ISC has some advantages compared to SAGD process including higher thermal efficiency, small heat loss and it can be applied in deeper and high-pressure reservoirs. This paper reviews the ISC and investigates the issues and possible solutions. University of Alberta | Publication | 2023-12-01 | Juan David Antolinez Jimenez, Miri, R., Nouri, A. |
| Near-Wellbore Salinity Effect on Sand Control Plugging by Fines Migration in Steam-Assisted Gravity Drainage Producer WellsThe study investigates the impact of formation water salinity on fines migration and the flow performance of sand control screens in steam-assisted gravity drainage (SAGD) wells. Researchers conducted sand retention testing (SRT) under representative rock and multiphase flow conditions. They developed a novel SRT methodology that incorporated the salinity effect in multiphase flow through sandpack and sand control screens. The results revealed that reducing salinity significantly decreased the retained permeability of the screen coupon due to fines migration. This research highlights the importance of considering salinity effects in sand retention tests for SAGD wells, especially where high saline formation water is diluted by low-saline condensate steam University of Alberta | Publication | 2024-03-04 | Hoda Dadjou, Miri, R., Mahmood Salimi, Nouri, A. |
| Permeability decline by fines migration near sand control screens in steam assisted gravity drainage: A numerical assessmentThe near-wellbore permeability loss caused by the release and migration of naturally fine particles impairs the well productivity in oil reservoirs. The damage would be intensified in the presence of restrictions such as sand control screens due to retardation and accumulation of fine particles resulting from flow convergence and high volumetric flux. University of Alberta | Publication | 2023-02-15 | Miri, R., Mahmood Salimi, Carlos Lange, Nouri, A. |
| Physical features’ characterization of the water-in-mineral oil macro emulsion stabilized by a nonionic surfactantWater-in-oil (w/o) emulsions are widely used in the food and pharmaceutical industries, among others. Moreover, the most common type of emulsion produced and handled in the oil industry processes is the w/o emulsion. This study investigates the features of a water-in-mineral oil macro-emulsion formulated with mineral oil as the continuous phase and Span 83 as the nonionic surfactant. Emulsions are prepared at room temperature according to the hydrophilic–lipophilic difference (HLD) theory and were tested for the mean droplet size and droplet size distribution, viscosity, and kinetic stability. An empirical correlation was introduced that estimates the viscosity of the water-in-mineral oil macro-emulsions and captures the non-Newtonian behavior at larger water fractions. The effect of electrolyte and internal phase concentration was specifically assessed on the emulsion flocculation and the stability of the system. Stability tests show a threshold electrolyte concentration exists after which droplets coalesce upon collision and flocculation. Salting out is most likely the responsible mechanism of phase separation in the emulsions with higher electrolyte concentrations. The results imply that sedimentation is accountable for the formation of different layers in emulsion with time. The sedimentation rate was intensified for emulsion with smaller water content (64% variation in 3 days between 10% emulsion and 40% emulsion) and concentrated emulsions were found to be more stable. Also, the size of the droplets was influenced by the NaCl concentration, surfactant concentration, and phase ratio. University of Alberta | Publication | 2020-11-30 | Arian Velayati, Nouri, A. |
| Role of Asphaltene in Stability of Water-in-Oil Model Emulsions: The Effects of Oil Composition and Size of the Aggregates and DropletsWater-in-oil (W/O) emulsions are the most common type of emulsions handled in petroleum processes. It is thought that the field emulsions are primarily stabilized by asphaltene–resin micelles, and several research studies have examined the stability mechanisms of asphaltene in crude emulsions. However, there are still plenty of research gaps and unanswered questions in this area due to the complexity of the problem and difficulty of access and crude emulsion processing. These challenges can be addressed by investigating the effect of asphaltene on model emulsions’ kinetic stability. This study introduces a model W/O emulsion prepared by a new stabilizer (gilsonite) that contains asphaltenes and resins in combination with a non-ionic surfactant (Span 83). The colloidal characterization of the asphaltene aggregates in the mineral oil and oil blend of toluene and mineral oil was carried out. The size of the asphaltene aggregates in the mineral oil was found to increase with the added gilsonite concentration because of asphaltene precipitation and the process of smaller aggregates clumping together, forming flocs. Gilsonite was also found to precipitate and stabilize the W/O emulsions with the mineral oil as the external phase where the asphaltene precipitation was the most severe. The emulsions’ least kinetic stability was measured when toluene was added in the oil blend (50% volume fraction), where 100% water phase separation was observed with 0.25% gilsonite concentration. However, the dilute emulsion (10% water content in the emulsion) samples with 25% toluene revealed higher stability in terms of water phase separation than the case with 12.5% toluene with 20.83% less water separation in a 3 day storage period. This observation contradicts the expected outcome in a thermodynamic perspective where the W/O emulsion stability is thought to be merely dependent on asphaltene precipitation. The dilute emulsion with 12.5% toluene contained asphaltene aggregates larger than the emulsion droplets, which cannot contribute to the stability process. The ratio of the mean aggregate size to the mean droplet size was 133% larger for the dilute emulsion with a smaller fraction of toluene in the oil blend for this case. Therefore, the aggregates’ size to droplet size misalignment resulted in less stability for this emulsion than for the emulsion with higher aromaticity of the oil blend despite the very high precipitation rate. This paper presents observations of the effects of the asphaltene precipitation rate, size of the aggregates, and size distribution of the emulsion droplets on the model W/O emulsions’ stability. The significance of the results is in revealing the importance of integrating the thermodynamical and colloidal viewpoints to describe the role of asphaltene in stabilizing emulsions. This approach leads to the conclusion that besides asphaltene precipitation, the aggregate size distribution in relation to the size of the emulsion droplets is a critical factor in stabilizing the emulsions. Results presented in this study can be used in the design of solvents in enhanced oil recovery, producing model emulsions, replicating oil reservoir in situ emulsion features, synthesis of demulsifiers for the emulsions stabilized with asphaltene–resin micelles, and other industrial applications. Additionally, gilsonite was introduced as a new additive that can be used to study the role of asphaltene in stabilizing model emulsions. University of Alberta | Publication | 2021-03-16 | Arian Velayati, Nouri, A. |
| Sand Control Screen Selection for Cased Dual-Annulus Gas Wells based on Scaled Laboratory Tests This paper is under preparation and related to sand control in dual annalus gas wells. University of Alberta | Publication | 2023-12-20 | "Suzanne Stewart", Miri, R., Nouri, A. |
