PRISM :: Browsing by Author "Gates, Ian Donald"

Browsing by Author "Gates, Ian Donald"

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Open Access
A Triple-Bottom Line Decision-Analysis Framework Using Life Cycle Sustainability Assessment: The Case of Large Greenhouse Gas Emitters in Alberta, Canada
(2018-08-28) Hannouf, Marwa Bassam; Assefa, Getachew; Keough, Noel; Herremans, Irene M.; Gates, Ian Donald; Ugaya, Cassia Maria Lie
In light of the increased environmental awareness and stringent environmental regulations, there is need to guide businesses to stay competitive while meeting environmental compliance. Sustainability strategies will reduce the environmental burden of companies while increasing their economic and social benefits. However, integrating the three dimensions of sustainability in companies’ decision-making (DM) to develop sustainability strategies is associated with complexity. This thesis takes the context of large greenhouse gas (GHG) emitters given the urgency of the climate change problem and the awareness of reducing GHG emissions to fulfill expectations from global climate change agreements such as the Paris Agreement. Using case studies among large GHG emitters in Alberta, Canada, the objective of this research was to examine the potential utility of the life cycle sustainability assessment (LCSA) approach to guide companies’ DM in developing sustainability strategies that can reduce their environmental impacts while achieving the remaining of sustainability goals. As LCSA approach is still an emerging field, the first part of this thesis has focused on the method of LCSA following UNEP/SETAC guidelines by addressing some of its challenges. The research has applied two LCSA case studies among large GHG emitters in Alberta, where a new subcategory assessment method for social life cycle assessment approach is developed and starting holistic analysis of LCSA results is presented. The second part has focused on the application of LCSA to support sustainability-oriented DM, where an LCSA-based decision-analysis framework is developed to guide decision-makers in systematic and structured way to analyze the interrelationships between LCSA results and propose potential sustainability solutions. The thesis contributes to the advancement of scientific knowledge in the development of LCSA approach by addressing some of its challenges. The evaluation conducted in this research for LCSA-based decision-analysis framework has indicated that LCSA with its systematic and life cycle perspective has the potential to provide improved information on the sustainability problems in product systems, which is going to increase the potential to develop sustainability solutions. The framework presents different advantages, but is as well associated with challenges especially regarding its application in real world.
Open Access
Acoustic Properties of Oil sands
(2017) Patel, Gaurav Jayeshbhai; Gates, Ian Donald; Chen, Shengnan; De la Hoz Siegler, Hector
A well-known, efficient and economical method to recover bitumen from oil sand reservoirs is the Steam-Assisted Gravity Drainage (SAGD) process. To monitor this recovery process, each year, operators conduct seismic shoots of the formation and from the interpretation of the data, they estimate the vertical and areal extents of the steam chambers around the SAGD well pairs within the reservoir. One of the important property that is required to process seismic data is the speed of sound in oil sands and bitumen. A lot of laboratory data is available on velocity in oil sands at different pressure and temperature but nearly all are measured at ultrasonic frequencies which is in the hundreds of thousands of Hz. However, seismic shoots are conducted at between 10 and 100 Hz and it has been shown that there is a significant difference of the speed of sound at ultrasonic and seismic frequencies. In the research, a novel large scale (2.3 m long, 2 5/8 inch diameter) high pressure core holder apparatus has been designed and constructed to measure the speed of sound versus pressure and temperature at seismic frequencies. The data obtained from the new experimental apparatus compares well with data from published literature. The same apparatus has been used to study the audible frequency effects on oil sand as a result of viscous dissipation and on bitumen viscosity.
Open Access
Advanced Control and Optimization for the SAGD Process and Bitumen Upgrading
(2018-09-07) Purkayastha, Sagar Neel; Trifkovic, Milana; Gates, Ian Donald; Plaksina, Tatyana; Shor, Roman J.
Thermal recovery techniques, like Steam-Assisted Gravity Drainage (SAGD), are used to produce the majority of the crude bitumen, in Canada. However, suboptimal production techniques have led to the use of automatic control techniques for production, in recent times. Concurrently, while Proportional Integral Derivative and single variable Model Predictive Control (MPC) strategies have proven to be superior to manual control, they have resulted in comparable performance. Consequently, for improved performance, a novel Multi Input Multi Output (MIMO) MPC is presented in this thesis and compared with a Multi Input Single Output (MISO) MPC. The results indicated a 171% improvement in oil recovery for the novel MIMO MPC over the MISO MPC. This thesis also presents an optimization strategy for integrated design and schedule of a partial bitumen upgrader. The key consideration is in identifying that the design and operation problems are not mutually exclusive, but instead, synergistic in nature. Consequently, the research documented in this thesis, elucidates two formulations; maximizing proﬁt and minimizing energy usage to highlight this concept. The results highlighted that both the design and scheduling decision variables change as per the medium term forecasts of the volatile commodity and energy pricing markets. Therefore, a design independent of the scheduling constraints or a schedule based on a ﬁxed design may lead to suboptimal results in the design and/or schedule decision space(s). Finally, the last part of the thesis focuses on the optimal power management of a microgrid on a depleted SAGD facility, comprising of an Organic Rankine Cycle based turbine to convert the geothermal SAGD waste heat into electricity, a Gas Turbine, a Battery Storage System, the central grid, and the facility itself. Furthermore, this work also introduces a Kelly Criterion (KC) based microgrid scheduling technique, which is based on maximizing information gain and is independent of supply-demand relationships. Moreover, for this study, a wavelet network based forecasting technique is used to capture the electricity market volatility. The case study presented corroborated the hypothesis that the KC approach is independent of demand and supply forecasts, and is able to perform optimally in a highly volatile energy market.
Open Access
Analysis of Flow and Heat Transfer in OTSGs and Injection Wells
(2023-04-21) Sivagnanam, Mohan; Gates, Ian Donald; Mehrotra, Anil Kumar; Hejazi, Hossein; Ponnurangam, Sathish; Mwesigye, Aggrey; Sanders, Sean R.
Steam for enhanced oil recovery, generated by using once-through steam generators (OTSGs), is injected into extra heavy oil (bitumen) bearing formations to raise the temperature of the oil within. At elevated temperatures, the oil mobility is raised enabling it to be produced to surface. To improve the performance of steam-based processes, the research documented here focuses on two components of the process. The first component is steam generation in OTSGs and the second is injection of steam into the reservoir. More specifically, in the first component, the impact of foulant is examined and how a deliberate flow perturbation can be used to delay the onset of foulant. In the second component, steam flows through slotted liners and flow control devices are investigated. The results show that the thicker the foulant, the higher the outer tube wall temperature and the lower is the water temperature – the foulant acts as an insulator on the inner wall of the tube. Flow perturbations are demonstrated to yield benefits for lowering the outer tube wall temperature. An examination of thermocouples used to measure the temperature of the tube surface in OTSGs is also presented. Simulation results for a thermocouple welded on an OTSG tube showed a discrepancy between the actual temperature and the thermocouple measurement. The use of a radiation shield is shown to provide a better estimate of the bare tube temperature. The analysis of a slotted liner shows that the slot area plays a crucial role in flow distribution within the well and reservoir. Supersonic flow in flow control devices is strongly dependent on steam quality and some of the systems examined exhibited a condensation shock and shock diamonds with exit velocity greater than the inlet. A longer diffuser is shown to minimize the impact of shock waves on the exit velocity.
Open Access
Analytical and numerical modeling of the Cyclic ES-SAGD process
(2019-04-25) Manfre Jaimes, Diego; Clarke, Matthew A.; Gates, Ian Donald; Maini, B. B.
The world is still highly dependable on the energy that comes from oil. The current demand for energy has given importance to oil reservoirs that were normally overlooked in the past due to its properties. One example is found in the Canadian heavy oil sands. The amount of oil that is accumulated in these reservoirs represents the third largest accumulation of oil in the world. In these reservoirs, thermal processes such as Steam Assisted Gravity Drainage (SAGD), are used extensively as a production method. In SAGD, the injection of the steam into the reservoir reduces the viscosity of the oil, which moves downward by the effect of gravity until it reaches a production well. This research presents an alternative way of using SAGD in an efficient and profitable manner. One of the possible variations of SAGD that has shown positive results is the co-injection of a solvent in the injected stream. The idea behind this is to improve the effect of the reduction in the oil viscosity by the diffusion of this solvent in the oil. The amount and type of solvent injected as well as the amount that is recovered are key parameters in the performance of this process, particularly because these solvents are generally more expensive than oil. This work studied the co-injection of the solvent with the steam periodically. This means that in this case the solvent is co-injected through cycles instead of continuously. Some of the aspects that were evaluated are the type of solvent, its concentration and the duration of each of the solvent injection cycles. This study includes the derivation of an analytical model that is able to estimate the oil rate than comes from a cyclic solvent co-injection SAGD process and the use of numerical reservoir simulation to determine the principal recovery mechanisms of the process. One of the principal conclusions is that a similar positive result of the solvent co-injection could be achieved with less amount of solvent usage. This would considerably benefit the profitability of the process and the general performance of SAGD.
Open Access
Analytical Modeling of Steam Injection and Steam-Solvent Co-Injection for Bitumen and Heavy Oil Recovery with Parallel Horizontal Wells
(2019-04-30) Keshavarz, Mohsen; Chen, Zhangxin; Harding, Thomas Grant; Chen, Zhangxin; Harding, Thomas Grant; Gates, Ian Donald; Maini, B. B.; Lines, Larry R.; Das, Swapan K.
Steam-assisted gravity drainage (SAGD) is recognized as one of the most promising techniques for the commercial in situ recovery of bitumen reserves. The process, however, is energy intensive and is economically challenged in thin and low-quality reservoirs. Years of small-scale testing have shown that adding small amounts of hydrocarbon solvents to steam can yield large gains in oil output and reduced emissions over the conventional SAGD (Rassenfoss, 2012). The process has been referred to with different names in industry and academia such as expanding solvent-SAGD (ES-SAGD), solvent aided/assisted-SAGD (SA-SAGD), SAGD+TM, solvent aided process (SAP) and so on. High costs of solvents compared to bitumen requires their optimized use. The numerical simulation complexities and run times can make the filed-scale optimization exercise extremely costly. Therefore, analytical models can play an important role for such a purpose and to increase the confidence in performance forecasting. This dissertation starts with a review of the primary analytical models available for SAGD and co-injection and discussion on their limitations. Then, a new universal modelling approach is proposed that is applicable to the both processes. The breakthrough in the modelling approach is the robust coupling of mass balance, energy balance and fluid flow in porous media. This approach solves the heat and mass transfer problems at the stationary base of the steam chamber where the drainage to the producer happens. Combining material balance and Darcy’s Law, it then estimates the bitumen production rate and chamber shape. Then, energy balance is incorporated to estimate the steam requirements. In addition, the new modeling approach closes the material balance on all the components which allows for the estimation of solvent requirements for a particular set of key performance indicators. The developed model is intended to be simple enough for practical applications. After validation against numerical simulation results, its application to history-matching, forward prediction, pre-screening and uncertainty analysis is demonstrated through a number of field case studies.
Open Access
Capacitance-Resistance Model Connectivity Evaluation Based on Empirical and Heat Transfer Analogy Approaches in Conventional and Heavy Oil Waterfloods
(2023-12-05) Morales German, Gabriela; Johnston, Kimberly Adriane; Hejazi, Hossein; Jonhston, Kimberly Adriane; Hejazi, Hossein; Gates, Ian Donald; Jensen, Jerry Lee; Clarkson, Christopher; Camacho-Velazquez, Rodolfo
Inter-well connectivity (IWC) is a key factor for the successful design and operation of waterflooding projects. Thus, connectivity estimation methods such as the Capacitance-Resistance Model (CRM) are continually being improved and developed. The CRM utilizes the injection and production data as input to quantify IWC information through a connectivity parameter (λ). Proposed in 2006, the CRM has been adapted several times to better perform in challenging exploitation projects such as heavy oil waterflooding. Nonetheless, CRM analysis in heavy oil reservoirs yields highly variable λ values during early times. Such a variation and inconsistency make it difficult to readily determine IWC. This research work proposes two novel approaches to improve the CRM analysis by evaluating the uncertainty in the IWC estimates, especially at the early production stage. In the first approach, data generated from reservoir simulations provide input for the CRM to estimate IWC for each injection-production well pair. The objective is to define an equation relating production data and λ behavior patterns for different high mobility ratio cases. The proposed formulation yields acceptable IWC results in homogeneous reservoir cases and provides insight into heterogeneous reservoir evaluations. For the second approach, the analogous behavior of heat conduction and pressure transients is used to complement the CRM analysis. Previous studies suggest that, besides inter-well distance (IWD), IWC estimation might be influenced by injection rate frequency (ω_a) and medium hydraulic diffusivity (D). Sensitivities of those parameters were carried out to determine their effect on IWC. As a result, applying the periodic line source solution (PLSS) for heat conduction, ω_a, D and IWD can all be considered for IWC estimation, and their effects quantified. The PLSS analysis also offered an improvement on a previously proposed method to estimate CRM connectivity prediction errors. The modification includes the effects of ω_a and IWD to provide a better error predictor. A field-case example of the modified method shows the impact of IWD and ω_a in the deviation of CRM- λs. A relevant benefit of this method is its applicability to a wide range of reservoir conditions and fluid types, at any field development stage.
Open Access
Comparative Techno economic Analysis of Ammonia Electrosynthesis
(2020-01) Wang, Miao; Kibria, Md Golam; Gates, Ian Donald; McCoy, Sean; Roberts, Edward P. L.
Ammonia (NH3) is a valuable chemical that is used as fertilizer, antimicrobial agent, and household cleaner and is among the largest chemicals produced globally. Currently, the Haber-Bosch (H-B) process, which requires elevated pressure (~100 bar) and temperature (~450C), is used to produce the majority of NH3. The H-B generates large quantities (1500 kg-CO2/ton-NH3) of greenhouse gases (GHG), especially during the steam methane reforming process to produce hydrogen (H2) feedstock. There has been growing interest in alternative electrochemical processes for NH3 synthesis due to their modular design, reduced capital cost, and potential to reduce GHG emissions over that of the H-B process. In this thesis, six alternative NH3 electrosynthesis routes are analyzed from both economic and environmental aspects. Among the six routes, electrosynthesis of NH3 from N2 and H2O at room temperature is found to be the most economically compelling process (levelized cost ~$414/ton-NH3). Compared to a conventional H-B plant, electrosynthesis using electricity from clean sources could reduce CO2 emissions by 75-90%. Based on this analysis, we have estimated the target performance metrics that need to be achieved at scale to make the electrochemical NH3 synthesis route economically and environmentally viable. This analysis reveals that electrochemical processes have merit and potential to replace the H-B process if target performance parameters (current density higher than 400 mA/cm2, selectivity higher than 60%, energy efficiency higher than 50%, and overpotential lower than 1.5 V) are achieved. This analysis gives an early indication for the electrosynthesis route to be economically viable and environmentally sustainable as compared to the century-old H-B process.
Open Access
Development of a New Parallel Thermal Reservoir Simulator
(2016-01-08) Zhong, He; Chen, Zhangxing (John); Liang, Dong; Azaiez, Jalel; Gates, Ian Donald; Liao, Wenyuan
Thermal reservoir simulation is the most complex of all reservoir simulators and thus the most computationally intensive. With the advent of computer science, today's commodity PC clusters consist of a large number of discrete computer processors distributed across a network. Improving robustness and performance of parallel reservoir simulators on new high performance computing architectures remains a key issue to address. New numerical difficulties and performance problems appear because computing architecture is very sensible to memory distribution and load balance. This project proposes a new domain partition algorithm based on a fully-distributed graph framework. A reservoir is divided into multiple subregions, where connections, defined by geometry and well perforation information, are weighted by transmissibility and well indices. The continuity of fluxes and better load balance are guaranteed. Different strategies with different message passing frequency and accuracy are proposed for high performance computation. The subregion coupling effects are released or distracted into a linear system according to the physical principles. Subregions are coupled dramatically at flooding fronts and high frequency phase-changing regions, which enhances messages passing through processors. An analytical Jacobian calculation method and a variable alignment scheme are developed in this thesis. They have the ability to simulate three-dimensional multi-component three-phase thermal processes, and are capable of determining different property estimation approaches, such as correlations or table interpolations. An automatic time step algorithm, different variable-ordering algorithms and a Gauss elimination technique are implemented to reduce the intensive computation of linear iterations and to speedup the simulation process. The simulator is validated by analytical and numerical experiments, which include the Buckley-Leverett problem and the fourth SPE comparative solution project. The capability of this simulator is demonstrated through cyclic steam stimulation, steam flooding and steam-assisted gravity drainage processes. Three different parallelism strategies are tested in this thesis. A highly scalability implementation is achieved. This efficient, accurate, and parallel thermal simulator is applicable to highly complex reservoir systems.
Open Access
Directly Deposited Solid Polymer Electrolyte for Enhanced Electrochemical Carbon Conversion
(2023-12-05) Adnan, Muflih Arisa; Kibria, Md Golam; Gates, Ian Donald; Mahinpey, Nader; Trudel, Simon; Guay, Daniel
It has become evident in recent years that we need to accelerate our transition to a net-zero future. The dwindling price of low-carbon renewable electricity has been an enabler to develop technologies that relies on low-carbon electrons. Electrochemical carbon conversion (i.e., CO2 electroreduction i.e., CO2R or CO electroreduction i.e., COR) is one of such emerging technologies that allows converting CO2 or CO into various chemical and fuel using low-carbon electricity and water. I begin this thesis with a comprehensive technoeconomic and life cycle analysis for the production of methanol using electrochemical route and the conventional one. This study showed that under current market conditions, the levelized cost of methanol from electrolysis routes is 2 to 4 folds higher than the market price due to the low performance of electrochemical CO2 conversion to methanol. I showed that to achieve market competitiveness, some key performance metrics has to be achieved for the CO2R approach, including energy efficiency >40%, stability >8000 hours, and current density >130 mA/cm2 (CO2-to-CH3OH) or >360 mA/cm2 (CO2-to-CO). I then performed experimental analysis to investigate the key challenges in CO2R using membrane electrode assembly (MEA). The key challenge on CO2R comes from the competing carbonate formation reaction in the cathode which directly depletes the CO2 utilization for CO2R. Furthermore, the carbonate crosses over to the anodes when using the anion exchange membrane (AEM). Alternatively, cation exchange membrane (CEM) or bipolar membrane (BPM) can suppress carbonate crossover. However, CEM or BPM leads to either cation crossover and excessive water transport (promotes salt formation) or proton flooding (promotes Hydrogen Evolution Reaction (HER)) to the cathode, respectively. To overcome the challenge in commercial pre-made standalone AEM and CEM, I developed a direct membrane deposition approach using a simple spray-based coating approach. This direct deposition approach eliminates the need for a pre-made standalone membrane and offer improved stability of the catalyst and cathode. Using this patent-pending approach, I then designed a thin (~3 μm as opposed to over 50 μm commercial membrane) cation infused solid polymer electrolyte (CISPE) which enables bidirectional ion transport mechanism. The use of thin CISPE substitutes the use of standalone membrane and consequently suppresses salt formation and cathode flooding. I found that this approach enables high full cell energy efficiency of 28% at 100 mA/cm2 for one step CO2R to C2H4, which results in a record low overall energy cost (i.e., CO2 capture, electrolysis, CO2 separation and carbonate regeneration) for C2H4 production of 290 GJ per ton C2H4. The use of CISPE also allowed 160 hours of stable operation for continuous production of C2H4. While the direct CO2 electrolysis to C2+ products require further development due to carbonate formation, a CO2-to-carbon monoxide (CO) electrolysis has been commercially deployed. Taking advantage of the high technology maturity of CO2-to-CO electrolysis, I investigated the possibility of CO electrolysis (COR) as an intermediate step for converting CO2 into hydrocarbon. While the salt formation issue is absent in COR, the cation crossover still hinders the COR selectivity as it diminishes the CO availability at the cathode surface. To suppress the cation crossover via both electromigration and water diffusion (diffusion of hydrated cation), I implemented and optimized the direct deposition of a thin (~0.7 μm) CISPE on the surface of the Cu cathode catalyst. This thin CISPE suppressed K+ transport to the cathode, which led to improved CO availability and partial current density to ethylene. This approach enables stable operation at 100 mA/cm2 for over 200 hours with an energy efficiency toward C2H4 of 21%, which can be translated into an overall energy consumption of 218 GJ per ton C2H4. I also reported a high energy efficiency toward ethanol (C2H5OH) production of 17%. Another reason for the low CO availability is the low solubility of CO in the aqueous electrolytes. Then, I carried out a theoretical investigation of CO mass transport at different temperatures. I found that low operating temperature facilitates high CO availability on the catalyst surface due to high CO solubility and less cathode flooding which enhances the current density toward COR product. From the experimental studies on COR at different temperatures (10 to 50oC), I observed that the low-temperature (10oC) COR enables high partial current density towards the C2+ products (657 mA/cm2). The combination of CuNP and NiFe layered double hydroxide (LDH) anode showed excellent Faradaic efficiency of ~87% at 450 mA/cm2 towards C2+ products with a CO single pass conversion of ~90% for 150 hours of stable operation. From the brief technoeconomic analysis, I found that the pressurized electrolysis system (e.g., 10 atm) requires 2.4 folds higher capital cost and 1.5 higher operating cost than the ambient pressure electrolysis cell at low temperature (e.g., 10oC). I concluded this thesis with key findings and recommended future works to address the remaining challenges in electrochemical carbon conversion, including carbonate cross-over, stability etc. Successful demonstration of this technology will enable electrification of chemical industries to produce sustainable chemicals and fuels.
Open Access
Dynamics of Colloids at Liquid-liquid Interface: Insights from Mesoscale and Microscale Simulations
(2022-05-09) Hossain, Mohammad Tanvir; Natale, Giovanniantonio; Gates, Ian Donald; Benneke, Anne Maria; Hejazi, Hossein
The dynamics of a colloidal particle at a liquid-liquid interface play an important role in several processessuch as microrheology, Pickering emulsion, encapsulation, biofilm formation. Their behaviour at the interfaceis completely different from the bulk. Moreover, due to complexity of hydrodynamics and the effectof contact lines make this study more challenging. In addition to that Janus type colloids which have multiplesurface characteristics and shapes introduce another degree of complexity. For example, amphiphilicJanus nanoparticles exhibit higher interfacial activity and adsorb more strongly to fluid interfaces than homogeneousnanoparticles of similar sizes. Both shape and chemical anisotropy on the same particle, Janusparticles offer rich self-assembly possibilities for nanotechnology. Despite their strong interest, the interfacialbehaviour of colloid nanoparticles is not fully exposed.In this thesis, a detailed analysis of dynamics for homogeneous and Janus particle varying their size andlocation at the interface has been provided. To perform that two different approaches have been considerednamed Langevin dynamics(LD) and Dissipative Particle Dynamic (DPD). In LD where the surface force andcontact line fluctuation are considered through an analytical solution where DPD is solved only based onthe interaction between particles.Finally, by using dissipative particle dynamics simulation, the translational diffusion of Janus nanorods atthe interface between two immiscible fluids is investigated. The particle aspect ratio affects both particle’stranslational thermal motion and the average orientation of the particle with respect to the interface atequilibrium. This behaviour is also linked to the interfacial tension of the system.Findings from this research will provide fundamental insights into the dynamics and self-assembly of isotropicand anisotropic Brownian particles at interfaces.
Open Access
Electrokinetic Control of Interfacial Instabilities
(2023-05-17) Nwani, Benedicta Nkenchor; Benneker, Anne Maria; Gates, Ian Donald; Hassanzadeh, Hassan; Hejazi, Hossein; Bryant, Steven; Docoslis, Aristides
Interfacial instabilities have significant impact on the efficiency of various processes that are present in our surroundings. These instabilities occur due to fluid-fluid interfacial perturbations which could be driven electrically, magnetically, via pressure, surface tension, etc. One of the most frequent occurrences of interfacial instabilities is the displacement of a more viscous fluid by a less viscous one which results in an instability known as ‘viscous fingering’. Controlling viscous fingering is challenging since it occurs at the onset of the displacement and affects the overall displacement pattern observed. Nevertheless, researchers have proposed passive and active control methods to address this issue. The objective of this thesis is to extensively explore the use of electric fields for actively controlling viscous fingering in both miscible and immiscible fluid systems. A combination of experimental and numerical techniques are employed to investigate this phenomenon. The first fluid system examined is immiscible, in which the resident fluid is a perfect dielectric fluid with a preferential wetting on the substrate and no notable fluid-fluid and fluid-wall interfacial charges. The second fluid system involves both miscible and conducting fluids with electro-neutral fluid-fluid interface. The immiscible third fluid system has significant interfacial charges between fluids due to added ionic surfactants in the invading brine, leading to preferential substrate wetting. The results of the first study conducted experimentally, indicated that viscous fingering can be effectively controlled even when one of the fluids is completely non-conductive. Regardless of the magnitude of the applied electric field, positive values stabilized the displacement, while negative values destabilized it. For the miscible fluid system, numerical simulations revealed that the effect of positive or negative electric fields on the displacement (de)-stabilization depended on whether the resident fluid experienced a higher or lower electroosmotic flow under the influence of an electric field. The third study’s experimental results revealed that the presence of the combination of electric field and ionic surfactants dramatically altered the system’s behavior, due to the presence of fluid-fluid interfacial charges that induced electro-Marangoni stresses at the interface when acted upon by an external electric field, which ultimately destabilized the displacement in most cases.
Open Access
Energy and Emissions of Unconventional Resources
(2019-01-02) Umeozor, Evar Chinedu; Gates, Ian Donald; Kumar, Amit; Assefa, Getachew; De La Hoz Siegler, H.; Shor, Roman J.
Unconventional petroleum resources constitute an increasing frontier of reserves additions as conventional production declines globally. In this era of environmental conservation and sustainability concerns, new resource development efforts confront energy, emissions, and economic intensities. Clearer understanding of resource development choices and their implications can be gained by quantifying these intensities through a systematic approach which allows effective comparisons of alternative energy systems to be drawn in the context of policy and/or business decision-making. Yet, existing assessment studies often lack transparency or do not furnish detailed methodological descriptions of the approach needed for transferability or validation of results in subsequent studies which evaluate impacts of our existing and emerging energy systems design decisions. The combination of analytical and semi-analytical modelling holds great potential to address current methodological challenges in assessing impacts of unconventional resources development. Focusing on shale gas and oil sands resources, this thesis presents new modelling tools and assessment frameworks to quantify and compare impacts of operations and technologies needed during development and recovery of these energy resources. The first part of the contributions evaluated potential environmental impacts of flowback methane in the U.S. and Canada to be 2347 and 1859 Mg CO2e per completion, respectively. The second part assessed contributions of all preproduction activities to overall energy and environmental intensities, highlighting drilling and flowback intensities as major sources. The third and fourth contribution chapters investigated the role of innovation to improve oil sands production and demonstrated the application of carbon dioxide utilization to mitigate impacts of unconventional oil and gas production, respectively.
Open Access
Energy Recovery from Oil Sands Reservoirs
(2021-01-04) Wang, Jingyi; Gates, Ian Donald; Chen, Shengnan; Hu, Jinguang; Hubbard, Stephen M.; Zeng, Fanhua
Alberta's oil sands are the third largest proven crude oil reserve in the world, after Saudi Arabia and Venezuela. The proven reserve is ~165.4 billion barrels. At original reservoir conditions, for in-situ methods, the bitumen is too viscous to extract directly with viscosities of the order of hundreds of thousands to millions of centipoise. To extract bitumen via in-situ recovery processes, the bitumen's viscosity must be lowered to less than 20 cP. In all current commercial oil sands recovery processes, this is done by injected high pressure and temperature saturated steam into the reservoir. One such process, Steam-Assisted Gravity Drainage (SAGD), has been proven to produce bitumen, but due to steam generation has high emissions intensity with large energy requirements. The research presented here studied the SAGD process from multiple angles. The first study is focused on the edge of steam chamber where both SAGD and Steam and Gas Push (SAGP) processes were compared to understand the impact of non-condensable gas on heat transport at the edge of the chamber. The second approach uses a detailed compositional model to exam the time scales for steam and bitumen flow within the depletion chamber. The approach used for multiple steam and multiple bitumen components is novel. The third study examined the instantaneous steam-to-oil ratio behavior when the steam chamber was exposed to different reservoir features. The last study explored the recovery of heat energy from post-SAGD chambers. The analysis reveals the following results. 1. non-condensable gas does improve the thermal efficiency of SAGD, but it changes the behaviour of the edge of the chamber by creating a more extensive depletion zone at the edge of the chamber. 2. the time scales for steam flow and bitumen mobilization, drainage, and production can be weeks to months to years depending on the stage of the process. This speaks to the 'thermal momentum' that is established in the reservoir during the process. 3. The SOR, in particular, the instantaneous SOR provides a signal that can be used to identify reservoir features. This could be used with multiple SAGD well pairs to determine reservoir features across pads. 4. A large fraction of the injected heat energy in the reservoir remains in the reservoir rock (sand grains) and the overburden and understrata. However, it is possible to extract a significant fraction of the energy remaining in the reservoir after SAGD operations have finished. This should be explored in the field since this provides a means to raise the overall energy efficiency of SAGD.
Open Access
Enhancing Steam-Assisted Gravity Drainage Applications in Challenging and Non-Challenging Oil Sands Reservoirs
(2018-08-13) Austin-Adigio, Maureen Emakpor; Gates, Ian Donald; Hejazi, Seyed Hossein; Shor, Roman J.; Trad, Daniel O.; Trivedi, Japan J.
Unlike the relatively clean or non-challenging ones, difficult-to-produce oil sands reservoirs with respect to Steam-Assisted Gravity Drainage (SAGD) are so named because of adverse geological features present in them, e.g. lean zones, inclined heterolithic strata (IHS), breccia/mud clasts. The presence of one or more of these features creates a challenge for SAGD since they harm the growth of the steam chamber leading to poor thermal efficiency, increased water use and high greenhouse gas (GHG) emissions. In the research documented here, five research questions are posed: (1) How well do we understand heat and fluid flow dynamics of steam propagation in bitumen reservoirs? (2) What occurs in the reservoir when steam interacts with co-injected non-condensable gas (NCG)? Is there an optimum time to start NCG co-injection? (3) How does an overlying top water reservoir with a thick IHS layer affect SAGD performance? How can the operation be altered to raise SAGD performance in this system? (4) What can be done to improve SAGD performance in heterogeneous oil sands reservoirs? (5) Can automated control, using seismic data, improve SAGD performance both with respect to steam conformance and steam-to-oil ratio (SOR)? To answer these questions, thermal reservoir simulation was used to model SAGD in oil sands reservoirs. The results reveal that: 1) Heat transfer is enhanced by warm mobilized bitumen fingering into cold bitumen as SAGD evolves. 2) The benefit of NCG co-injection is best seen in the mid or late life of SAGD. 3) In a reservoir with an IHS interval and overlying top water zone, the IHS, though a resistance to steam chamber growth, slows top water drainage into the basal sand and may benefit SAGD and depending on the injection pressure applied, the impact of top water can be delayed. 4) Steam can be optimally allocated in a strongly heterogeneous reservoir by varying steam injection rate by using a new allocation algorithm based on seismic interpretation which automates steam injection in SAGD fitted with outflow control devices (OCDs). By using the new algorithm, the rate-controlled case (i.e. OCDs with control) yields an increase of cumulative oil of 10.7% and 6.16% and decrease of cumulative SOR of 11.7% and 6.5% when compared to the base and OICDs without control cases, respectively, after 6 years of operation. This translates to a significant reduction of water usage and GHG emissions.
Open Access
Fracture Height Propagation in Tight Reservoirs Using the Finite Element Method
(2021-01-26) Cai, Jiujie; Chen, Shengnan; Chen, Zhangxin; Gates, Ian Donald; Wong, Ron Chik Kwong; Zhang, Yin
In recent years, multi-stage hydraulic fracturing technology is widely applied in oil/gas industry all over the world as a successful treatment, especially in tight and shale reservoirs. The induced fracture geometries directly affect the post-stimulation production and economic profitability of the project and accurately predicting the fracture properties is quite important. In addition to fracture length and conductivity, fracture height is another critical parameter of the hydraulic fracturing treatments in the unconventional tight/shale formations. Multiple transverse fractures are usually created along the horizontal wells, where the mechanisms of fracture-height-containment can be complicated under conditions such as interactions with the natural fractures, as well as adjacent hydraulic fractures. In addition, the directions of the bounding layers may not be parallel with that of horizontal wells. Traditional fracture propagation models applied in industry do not include all the aforementioned factors comprehensively. This research targets to study the mechanisms of hydraulic fracture propagation, focusing on the fracture-height-containment in the scenarios of multiple fractures along the horizontal wells. Firstly, a two-dimensional numerical model is proposed to analyze the methodology of single fracture height propagation via the finite element method. Then, an analytical model is built to understand the mechanisms of the fracture height containment considering inclined bounding layers. Modeling results suggested that for the closely spaced multiple fractures which are growing simultaneously, the critical fluid pressure becomes larger, implying that the fracture height propagation is more difficult under such scenario. Fracture height propagates more easily when bounding layer inclination angle increases. Thirdly, a three-dimensional numerical model with cohesive method on the fracture height propagation is used to analyze the multiple fracture interactions and the effective fracture height and width in tight reservoirs. The influence of stress shadow and stress difference on effective fracture height has been investigated and results show that the interaction from adjacent fracture becomes more significant when fracture spacing is small. Fluid injection rate is also an important influencing factor on the hydraulic fracture width especially when flow rate is low. When stress shadow effect is strong, the interior fractures can hardly propagate, and the majority of the fluid volume goes into the exterior fractures.
Open Access
Geochemical Modeling of Oil-Brine-Rock Interactions during Brine-Dependent and Brine-CO2 Recovery Technique in Carbonate Petroleum Reservoirs
(2019-04-24) Awolayo, Adedapo Noah; Sarma, Helmanta Kumar; Nghiem, Long X.; Gates, Ian Donald; Dong, Mingzhe; Lines, Larry R.; Chen, Zhangxin; Kam, Seungihl
The brine-dependent recovery process involves the tweaking of the ionic composition and strength of the injected water compared to the initial in-situ brine to improve oil production. The recovery process has seen much global research efforts in the past two decades because of its benefits over other oil recovery methods. In recent years, several studies, ranging from laboratory coreflood experiments to field trials, admit to the potential of recovering additional oil in sandstone and carbonate reservoirs and has been well-explored on two frontlines, namely, brine dilution and compositional variation. However, many challenges have saddled the recovery process, such as disputes over the fundamental chemical mechanisms; difficulty with construction of a representative model to give reliable interpretation and prediction of the process, and these necessitate applicable solution. Therefore, this study explores the formulation of theory based on experimentally-observed behavior to couple equations of multicomponent transport and geochemical reactions. Mechanisms such as dispersion/diffusion, advection, instantaneous equilibrium reactions, and non-equilibrium rate-controlled reactions are captured in the construction of the numerical models. The DLVO theory of surface forces was also applied to rationalize potential determining ion interactions and to evaluate the contribution of each force component to the wettability change in the oil-brine-rock system and the characteristic oil recovery improvement. The model was applied to interpret recently-published results on the different approaches that have been explored in the application of brine-dependent recovery process in carbonate reservoir rocks. The focus being that identifying the dominant mechanisms responsible for the observed improved recovery will help substantiate the field application of the process. The study demonstrates that injected brines, containing potential determining ions depleted in NaCl, are more effective at improving recovery when it, and wettability alteration is much more pronounced at high temperatures. It was also illustrated that potential determining ion concentrations play a more significant role as compared to brine salinity reduction. The magnitude of the contribution of the electrostatic force to sustaining a stable water film increases with decreasing ionic strength, either through reduction of NaCl, Ca2+ or brine dilution, or increasing SO42- concentration. Mineral dissolution/precipitation is necessary for the pursuit of re-establishing equilibrium and should not be ignored in modelling different mineralogical carbonate rocks. The derived optimized thermodynamic parameters are demonstrated to be widely applicable. Although chalk and limestone differ by surface area and reactivity, the same thermodynamic parameters are applicable in modeling the recovery process in their respective reservoir rocks. There is a significant increase in relative injectivity for brine-CO2 recovery mainly due to more exposure to a higher amount of CO2-saturated-brine
Open Access
Geothermal Energy and Carbon Dioxide Sequestration
(2023-04-26) Shi, Guangyu; Gates, Ian Donald; Chen, Shengnan (Nancy); Hu, Jinguang; Innanen, Kristopher A.H.; Zhao, Gang
Under the climate change crisis evolving from excessive greenhouse gas emissions, society is seeking ways to answer the call to produce clean energy. Carbon capture, utilization, and storage (CCUS) and geothermal energy are two major options to reach carbon neutrality. The research documented here examined four ways to lower emissions. In the first study, an enhanced geothermal system (EGS) in the Basal Cambrian Sandstone Unit in Alberta, Canada is explored. The second study examines the potential to combine underground CO2 sequestration and geothermal energy harvesting. The third study explores CO2-Enhanced Gas Recovery (CO2-EGR) in an offshore natural gas field located in the South China Sea. In the last study, the first China offshore CO2 sequestration operation in a shallow subsea feldspar-quartz sandstone formation is examined. The results demonstrate that open-loop EGS realizes an energy produced to energy invested ratio from 4 to 9 depending on operating rate and suggest that hydraulic fracturing accelerates energy harvesting and energy efficiency over the early process stages but the greater the injection rate, the smaller is the benefit of hydraulic fracturing. Second, combining both CO2 sequestration and geothermal operations is possible with commercial value and environmental benefits. Third, CO2-EGR demonstrates greater natural gas production together with CO2 sequestration and that there is potential that the process could be carbon neutral or negative. Fourth, offshore CO2 sequestration in a feldspar-quartz sandstone formation is possible and showcases that a dynamic behaviour occurs at the CO2 plume front where a relatively small amount of carbonate mineral precipitates which is subsequently dissolved when the acidified water in the plume passes the prior front location. The results showcase contributions for both CCUS and geothermal energy towards carbon emissions reduction.
Open Access
Heat Transfer During the Formation of Solid Oil
(2023-04-04) Sim, Kellie; Gates, Ian Donald; Kibria, Md Golam; Hu, Jinguang
Over the past decade, the transportation of heavy oil and bitumen has experienced constraints due to insufficient pipeline capacity. An alternative is transportation via rail, but this presents safety and logistical challenges due to the heat required to reduce the viscosity of the bitumen and heavy oil for loading. A novel approach is transporting bitumen as solid phase oil, which can be treated as a cold solid similar to grain or sulfur pellets, requiring no heating or special containment. One solid oil formation process extrudes a fixed-length cylinder of molten oil which is then cooled to the point that it becomes solid. The key unknown is the behaviour of the cylinder with respect to heat transfer and the time required to reach a target temperature within the cylinder where it would be considered solid enough for material handling and transport. A heat transfer model for bitumen cylinder cooling surrounded by an outer cylinder of a cooling medium was solved using CMG STARS™. The diameter of the bitumen cylinder (2 mm, 5 mm, 10 mm), the cooling fluid (air, water), the cooling fluid temperature (air at 5°C, air at 21°C, water at 21°C), and the cooling fluid flow rates (11.6 ml/s, 23.2 ml/s) were varied to determine the fastest cooling rate. The 2 mm diameter bitumen in water at 23.2 ml/s resulted in the fastest cooling. It is recommended to update the model to solve for the cooling of multiple bitumen cylinders.
Open Access
History Matching of a SAGD Well Pair Circulation Phase and Wellbore Completion Design Comparison Using a Discretized Thermal Wellbore Modelling Simulator
(2017-12-15) Ayala Rivas, Daniel Alexis; Gates, Ian Donald; De la Hoz Siegler, Hector; Shor, Roman J
Steam circulation in the early stages of Steam-Assisted Gravity Drainage (SAGD) is crucial for establishing hydraulic communication between the injector and producer well and the future development of the steam chamber. Steam is the carrier of enthalpy to the reservoir and thus, the evolution of pressure, temperature, and steam quality is important for heat transfer efficiency. In the research reported here, the steam circulation phase of a SAGD well pair is examined in detail taking into account heat loss around the wellbore in the vertical/build section and heat transfer and fluid losses in the lateral section of the well pair. In the model developed, well bore hydraulics is also accounted for by using a discretized wellbore model within a fully implicit coupled thermal reservoir simulator. Field data from the circulation phase was history-matched to calibrate the model and subsequently, five different completion designs were examined to evaluate their thermal efficiency. The results show that completion design impact heat transfer and thermal efficiency of the circulation process.