Browsing by Author "Aguilera, Roberto F."
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Item Open Access Application of In-situ Upgrading in Naturally Fractured Reservoirs(2021-01-22) Duran Armas, Jose Luis; Pereira-Almao, Pedro R.; Maini, B. B.; Aguilera, Roberto F.; Chen, Zhangxin; Mehta, Sudarshan A. Raj; Oldenburg, Thomas B. P.; Dalaï, Ajaỳ KumarThe persisting low oil price and the need for more environmentally-friendly energy sources have driven the latest development of new technologies for the sector and, in particular, for heavy oil exploitation. Among those technologies, In-Situ Upgrading Technology (ISUT) offers downhole processing, leaving undesired products underground, enhanced oil recovery and reducing the upgrading cost. ISUT is a thermal recovery process that uses hot fluid to transport catalytic nanoparticles, creating a reactor around the wellbore. Supporting the pilot test of ISUT, planned for the Aguacate field at the central Gulf Coast region of Mexico, this thesis focus on reinforcing many technical aspects for that pilot test. A kinetic model was developed for the Aguacate heavy oil and its vacuum residue at reservoir conditions. Ten sets of temperature and residence time, similar to those used for mild hydrocracking processes but in the presence of a carbonate rock core. Moreover, five pseudo components were assigned to model the reaction inside the porous carbonate medium. These results were all utilized to create the kinetic model specific for this pilot test. The products' characterization showed moderate temperatures and longer residence times improve product quality, translating into preferred temperatures below 350 oC with longer residence times. The used set-up for the kinetic analysis replicated the reservoir environment, using a matrix and a fracture where the fluid could flow. This work confirmed the catalytic hydrogenation process in ISUT by measuring molecular markers' conversion into other organic products, indicating limits of catalyst concentration to avoid adverse effects that may result in excess paraffinic compounds, eventually risking their precipitation subsequent operating instabilities in the media. Lastly, the hydrogen consumption in the ISUT process was studied using ten experimental conditions to create a statistical model to predict the hydrogen consumed in the process. The model showed that hydrogen consumption is linear vs. temperature and reaction time.Item Open Access Assessment of Tight Rock Wettability by Spontaneous Imbibition at Elevated Pressures(2019-01-23) Sánchez Martinez, John Jairo; Kantzas, Apostolos K.; Yarranton, Harvey W.; Aguilera, Roberto F.Wettability is an important reservoir property and must be well-understood as it gives an indication of how fluids are distributed through the porous media. In tight reservoirs, which generally have been produced using hydraulic fracturing, the wettability evaluation becomes even more important for enhancing oil recovery, as it is a reference point for understanding the interaction between the fracturing fluids and the reservoir, to then be able to alter the rock wettability tendency into a more water-wet system by using appropriate fracturing fluids that would displace the oil into the matrix to the fractures by spontaneous imbibition. It is known that the wettability evaluation of a reservoir is affected by multiple factors (core preservation state, fluid properties, temperature and pressure), and that the most representative results are obtained by using conditions as similar to the reservoir as possible. However, different than conventional reservoirs, in tight media reservoirs the measurement of wettability and its alteration become even more challenging, basically due to its low porosity and permeability, and also due to its mineralogical heterogeneity. As a first approach for evaluating the wettability tendency of tight media reservoirs as close as possible to the reservoir conditions, a novel apparatus and methodology were designed in this thesis for assessing the wettability tendency of tight media samples by spontaneous imbibition tests at elevated pressures. Furthermore, the wettability tendency of four tight media core plugs from the Lower Shaunavon reservoir were evaluated by multiple spontaneous imbibition tests at atmospheric and elevated pressures.Item Open Access Characterizing Supercritical Methane Adsorption on Shale by a Multi-site Model(2018-12-13) Wu, Zhe; Chen, Zhangxin; Azaiez, Jalel; Aguilera, Roberto F.Shale gas, mainly consisting of adsorbed gas and free gas, has served a critical role of supplying the growing global natural gas demand in the past decades. Considering that the adsorbed methane has contributed up to 80% of the total gas in place (GIP), understanding the methane adsorption behaviours is imperative to an accurate estimation of total GIP. Historically, the single-site Langmuir-Gibbs model, with the assumption of a homogeneous surface, is commonly applied to estimate the adsorbed gas amount. However, this assumption cannot depict the methane adsorption characteristics due to various compositions and pore sizes of shales. In this work, a multi-site model integrating the energetic heterogeneity in adsorption is derived, which is also successfully validated with a series of measured adsorption isotherms in experimental conditions. Applying the proposed multi-site model for estimating GIP in shales can achieve more accurate results compared with using the traditionally single-site model. Furthermore, shale reservoir properties, such as reservoir porosity, a geothermal gradient, as well as a pressure gradient have been investigated and shown to affect the GIP.Item Open Access Effect of Grain Irregularity on Rock Petrophysical Parameters: A Numerical Pore-level Study(2018-05-08) Rahmanian Shahri, Meysam; Kantzas, Apostolos K.; Aguilera, Roberto F.; Clarkson, Christopher R.A good evaluation of transport properties in reservoir rocks plays a major role in the design of recovery process and prediction of recovery performance. Permeability, thermal and electrical conductivity, are important physical properties affecting fluid flow and fluid distribution. Numerical techniques based on image analysis can be considered as reliable alternative approaches to either experimental methods or empirical correlations to estimate petrophysical properties. There are various numerical approaches to directly simulate fluid flow through a virtual porous medium. For instance, Computational Fluid Dynamics (CFD) and Lattice-Boltzmann as dynamic methods, and pore morphological as quasi-static approaches are the most popular techniques to simulate flow through porous materials. A virtual porous medium can be provided by binarizing either the real CT scan images of porous media or even the synthetic images generated by statistical approaches. In this regard, the virtual porous media have to properly mimic the physical features of real sands. As providing real CT scan images with high-resolution of rock samples is expensive and time consuming, utilizing statistical approaches to generating synthetic porous media based on Particle Size Distribution (PSD) and porosity of real sands could be considered as an alternative to reconstruct virtual porous media. To generate a virtual porous medium statistically, an innovative algorithm is proposed in this research generating irregular grains based on a given porosity and particle size distribution (PSD). The proposed procedure is inspired from the crystallization concept. In this method, the shape, orientation and structure of the grains can be readily controlled by the user. This provides the opportunity to investigate the effect of some geometrical parameters such as grain irregularity on rock and flow properties. In this study, several virtual porous media with different porosities, sphericities and PSD are constructed using the proposed approach. Based on the simulation results on these media the effect of grain irregularity on transport properties and onset of non-Darcy flow is investigated.Item Open Access Experimental Study of Heavy Oil Recovery Mechanisms during Cyclic Solvent Injection Processes(2019-03-22) Plata Sanchez, Maria Alejandra; Kantzas, Apostolos K.; Bryan, Jonathan Luke; Maini, B. B.; Aguilera, Roberto F.In recent years, the Cyclic Solvent Injection (CSI) process has shown to be a promising method for enhanced heavy oil recovery in Canada. CSI laboratory studies work for only 2 to 3 cycles due to low incremental oil in subsequent cycles whereas field pilots continue for years over multiple cycles This experimental study is intended to capture the production mechanisms responsible for heavy oil production in CSI. Primary production and CSI tests were conducted using physical sandpack models saturated with live heavy oil of 9,530 mPa.s viscosity. The experiments were conducted in horizontal and vertical mode injection at high- and low-pressure depletion rates using two solvent mixtures of CH4 and C3H8. The sandpack was Computed Tomography scanned after every cycle to analyze the evolution of gas and oil saturations. Three cores were used to study the effect of gravity forces, depletion rate, solvent composition, and initial oil saturation (dead/live oil systems) on the performance of CSI processes. CSI after primary in horizontal systems produced negligible incremental oil for both slow and fast drawdown rates due to the large void space and high free gas saturation inhibiting the pressure build up to push the solvent-diluted oil. These CSI experiments were only successful in dead oil systems, where the initial oil saturation was high and pressure gradient was generated through fast depletion rates until conditions of high void space and gas channels were reached. When the sandpack was flipped vertically, CSI cycles exhibited higher incremental oil recovery per cycle. Slow depletion cycles were more efficient in terms of pressure and incremental recovery per cycle, however, faster depletion cycles performed better as a function of time. The higher C3H8 content solvent mixture exhibited better performance in comparison to the lower C3H8 content as higher volume of diluted oil was drained out of the core. These results demonstrate the importance of gravity drainage in the CSI process and its significance on successful oil recovery rates. This study illustrates the limitations of previous horizontal laboratory tests and shows an improved test configuration for modelling and prediction of the improved response observed in CSI pilotsItem Open Access Experimental Study of Heavy Oil Recovery Mechanisms in a 2D System(2019-01-17) Guerrero Zabala, Francy Viviana; Kantzas, Apostolos K.; Bryan, Jonathan Luke; Aguilera, Roberto F.; Bryant, Steven L.The aim of this study was to evaluate the macro-displacement mechanisms associated with heavy oil recovery by water and chemical flooding in a 2D Model. To evaluate the effect of sweep efficiency improvements with and without local pore level trapping of fluids, a 2D Hele-Shaw cell and a 2D Glass-bead model were used to visualize the dominant mechanisms of water, surfactant, polymer, and SP to enhance heavy oil recovery. Mineral oil displacements were conducted as a base line and compared to real crude oil displacements. Pressure drop was monitored and post-breakthrough oil recovery during the water flood and chemical flood was assessed through material balance and image sequences which showed the distribution of the fluids in the model and cell. The results demonstrated that displacements performance is highly-correlated to the viscosity or mobility ratio between the fluids. The synergy between polymer and surfactant lead to a slightly better sweep efficiency in the 2D system compared to surfactant or polymer alone, however the displacement of heavy oil is greatly controlled by polymer effects. The findings from these non-linear systems provided insights into fluid flow behavior in diverging flow paths, as opposed to linear core floods that have limited flow pathways.Item Open Access Geomaterial-Functionalized Microfluidic Devices for Multiphase Flow in Porous Media(2020-03-23) Zhang, Yaqi; Hejazi, Seyed Hossein; Hejazi, Seyed Hossein; Aguilera, Roberto F.; Sanati-Nezhad, Amir; Oldenburg, Thomas B. P.; Torabi, FarshidFluid flow, species transport, and chemical reactions in geological formations abound in the exploitation of fossil fuels and geothermal energy, the geological storage of carbon dioxide (CO2), and the disposal of hazardous materials. Reservoir rocks are made of grains, with an extensive surface area, where the physicochemical fluid-solid interactions greatly influence the multiphase flow behavior. The success of the design, implementation, and prediction of engineering activities related to subsurface systems depends on the understanding of the flowing fluids’ properties and their interactions with the surrounding rock surfaces. Microfluidics, which performs laboratory tests in miniaturized flow cells, has exhibited numerous functionalities and potentials to assess subsurface processes. However, a key constraint in the application of microfluidics to flow in porous rocks is the surface discrepancy between microfluidic chips and the actual rocks/soils. This research develops novel microfluidic devices (e.g., ‘surface-mimetic micro-reservoirs’ (SMMRs) functionalized with reflective rock surfaces), which represent multiscale and multi-type of natural rocks/soils. The advanced surface-functionalized microfluidic chips are applied to address the physics of fluids in porous media, which includes rock-fluid interactions. The novel layer-by-layer (LbL) assembly for surface modification is employed to produce rock-forming mineral coatings on microfluidic chip surfaces. Substrates of glass, quartz, and polydimethylsiloxane (PDMS), and the actual microscale flow channels made of glass and PDMS are successfully functionalized with geomaterials of clays and quartz. We characterize the coating stability, nanoscale structures, and wettability of the functionalized substrates and microfluidic chips using dynamic flooding experiments, scanning electron microscope (SEM), optical microscopy, profilometer, atomic force microscopy (AFM), and contact angle measurements. The surface modification technique generates a stable coated surface with tunable hydrophilicity in microfluidic chips and is shown to be universal, reliable, and material-independent. The microfluidic chips functionalized by clay particles are used in two-phase flow experiments, which illustrate the role of the coated clays on flow patterns. Functionalized microfluidic chips enable the real-time and multi-scale evaluation of transport processes in reservoir-mimetic visual models, thus unravelling the intricate interactions between the flowing fluids and rock minerals. The present study provides a path in the development of microfluidic technology-based applications for subsurface energy and environmental research.Item Open Access Heat of Combustion Analysis of Residual Hydrocarbon Following In Situ Combustion Tests(2018-09-21) Kamisaki, Marta Hiromi; Mehta, Sudarshan A.; Moore, Robert Gordon Gord; Mehta, Sudarshan A.; Moore, Robert Gordon Gord; Pereira Almao, Pedro R.; Aguilera, Roberto F.Production of Athabasca Oil Sands has always been a challenge due to its high viscosity. To produce the subsurface oil, enhanced oil recovery (EOR) is necessary. In Situ Combustion (ISC) is an EOR technique with high recovery factor but, due to the high number of reactions occurring simultaneously during application of the method, the use of computational simulators is still a challenge. Therefore, laboratory physical simulations are necessary to evaluate the viability of ISC in a specific field. These simulations are normally conducted using core samples in one-dimensional combustion tube tests to analyze the temperature profiles, pressure drops, product gas compositions and fluid production. A new 3-D physical laboratory simulator has been developed by the In Situ Combustion Research Group at the University of Calgary. The model consists of a 3-D box to evaluate ISC as a hybrid process with steam. The advantage of the 3-D model is that it provides better visualization of the process since multiple dimensional data are obtained. Post-test core samples that exhibited a significant coke bank or wall were selected from two 3-D tests which had been previously performed using cores from Athabasca Oil Sands reservoirs. Both of the 3-D tests evaluated in this research simulated a pre-production by SAGD (Steam Assisted Gravity Drainage). The 3-D boxes were packed with two distinct oil zones: Rich Zone (with a higher oil concentration) and Lean Zone (with a lower oil concentration). Lean Zone represented the area pre-produced by SAGD. After packing, the ISC process was performed with dry air (21% oxygen) injection during 3-D Test #1 and with enriched air (95% oxygen) and super-heated steam co-injection during 3-D Test #2. This current study analyzes selected samples of the post-test residual that are associated with the coke bank or coke wall in terms of the heats of combustion of residual hydrocarbon in contact with the sand, the toluene extractable oil, its fractions (maltenes and asphaltenes), as well as the toluene insoluble coke fraction remaining on the extracted core matrix. The higher O2 concentration on the injected fluid used during 3-D Test #2 might have increased the oxidation of the hydrocarbons. As a result, the heat of combustion of coke from 3-D Test #2 was found to be lower than from Test #1 (with normal air injection). Therefore, it was not possible to obtain a generalized value for the heat of combustion of coke for Athabasca Oil Sands. Coke showed to have a lower contribution to the total heat of combustion when compared to other hydrocarbon components tested (oil, maltenes and asphaltenes). For this reason, coke appears to not be the main fraction used as fuel used during In Situ combustion process. A significant finding from this study is that the residual hydrocarbon which is visually identified as the coke bank or coke wall is a mixture of maltenes, asphaltenes and toluene insoluble coke fractions. It was also observed when measuring the heat of combustion of samples that involved residual hydrocarbon plus sand that either gelatin capsules or benzoic acid was required to achieve complete combustion of the samples.Item Open Access Laboratory Investigation of High Pressure Air Injection (HPAI) in a Dolomite Reservoir Core(2020-01-17) Ruteaga-Romero, Selene; Mehta, Sudarshan A. Raj; Moore, Robert Gordon Gord; Mehta, Sudarshan A. Raj; Moore, Robert Gordon Gord; Aguilera, Roberto F.; Hassanzadeh, HassanIn this thesis an Enhanced Oil Recovery (EOR) process is presented, using thermal recovery by High Pressure Air Injection (HPAI) on a Mexican light oil reservoir. The main difference between HPAI and In Situ Combustion (ISC) is that the latter term is used to refer to air injection-based processes in heavy oil reservoirs, which require operation in the high temperature range (+350°C), for successful displacement of the oil by the oxidation zone. HPAI implies air injection into deep, light oil reservoirs, for which bond scission or combustion reactions are dominant in the 150 to 300°C or Low Temperature Range (LTR). Two combustion tube tests were performed and analyzed, with the goal to evaluate the physical, chemical (kinetics) and fluid flow process behavior, as well as the rock and oil system’s combustion characteristics, in a way to determine if this type of EOR would be suitable for the target reservoir, which is a Naturally Fractured Reservoir (NFR). The combustion tube tests were operated at the actual reservoir conditions of 2,213 psia (15.26 MPa) pressure and at the native temperature of 149°C with an air injection flux of 30 m3(ST)/m2h. For both tests, dolomite core plugs pre-saturated with dead oil were placed at specific intervals in the recombined core pack. Currently, Mexico is starting to consider HPAI as an EOR in some of its reservoirs. Combustion tube tests are a method measuring the oil recovery, air requirement, fuel requirement and oxygen consumption. Such information is needed to design a field project and to estimate the economic parameter. Based on the overall velocity of the combustion front, and produced gas composition history, there did not seen to be a strong effect on the burning performance between Test one which was initially fully saturated with liquids and Test two which had three different saturation regimes. The overall oil recovery based on the Original Oil in Place (OOIP) was 91.7% for Test one and 79.5% for Test two. For both tests, the oil saturation remaining in the core plugs was essentially zero.Item Open Access Microseismic Based Reservoir Characterization (SBRC): Stimulated Reservoir Volume, Diffusivity, Geomechanics and Probabilistic Modeling(2018-04-27) LI, QI; Aguilera, Roberto F.; Aminzadeh, Fred; Lines, Laurence R.; Mehta, Sudarshan A. Raj; Moore, Robert Gordon; Wong, Ron Chik-KwongMicroseismic monitoring is a technique that allows examining the 3D growth of a microseismic event cloud stemming from a hydraulic fracturing job. The prevalence of microseismic monitoring has given rise to a new research area referred to as Microseismic Based Reservoir Characterization (SBRC). The primary objective of this thesis is to develop new microseismic interpretation methods with a view to advance practical petroleum engineering aspects of SBRC particularly in tight and shale reservoirs. The major original contributions of this dissertation include: 1. Development of an analytical solution to calculate the relative seismicity rate occurring during a hydraulic fracturing job. Current methods require the use of numerical solutions. 2. Development of a diffusion-based method for calculating the stimulated reservoir volume (SRV) in anisotropic, asymmetric, nonuniform shale petroleum reservoirs. The analytical solution satisfies the requirements of fast implementation, robust application and analytical tractability. Current methods to handle these complexities require the use of numerical solutions. 3. Development of a correlation for calculating Biot coefficient with an emphasis on shale petroleum reservoirs based on knowledge of porosity and permeability. The easy-to-use correlation provides good agreement with previously published direct experimental measurements. This is important as Biot coefficient plays a very important role on stress coupling in microseismicity modeling. 4. Development of a method for calculating large-scale permeability using Mogi’s (1967) empirical rock failure relationship. Large scale permeability plays a very important role on the success or failure of a hydraulic fracturing job. 5. Development of a probabilistic model that combines stochastic process, seismicity rate and statistical learning approach for predicting real time microseismicity occur- rences. This is important in evaluating the ongoing process of a hydraulic fracturing job. 6. Development of a geostatistical simulation algorithm, TopoSim, which integrates topological preserving algorithms and utilizes unsupervised machine learning pro- tocol. The algorithm can be used, for example, in the evaluation of paleochannels in reservoirs of continental origin, and to generate multiple natural fractures network realizations, which can be fed into reservoir and geomechanical simulators. It is concluded that the above original contributions will enhance the SBRC particularly in the case of shale petroleum reservoirs.Item Open Access Pore Level Modeling of Immiscible Displacements in Heterogeneous Media(2019-08-01) Flores de Dios Mosqueda, Tania; Kantzas, Apostolos K.; Hejazi, Seyed Hossein; Aguilera, Roberto F.; Hassanzadeh, HassanIn the petroleum industry, Reservoir Simulation plays an important role to forecast production behaviour. In this field it is essential to know the reservoir production performance under different types of exploitation. This is a key in choosing the accurate production process for a reservoir. To aim this, the main tool used for a reservoir engineer is reservoir simulation. Nowadays reservoir simulations still have some gaps such as the simulation at different scales. Commercial simulators cannot reproduce precisely the reservoir behaviour and the physics at the microscopic scale. If a reservoir simulator could be able to replicate pore scale events, they could have a more realistic representation of the reservoir physics. This thesis tries to emulate drainage in three different 2-D heterogeneous porous media patterns with a porous plate at the production end, which restricts oil flow, but it conducts water; water being the wetting fluid and oil the non-wetting fluid. The porous medium was inserted in an open source software for computational fluid dynamics (CFD) called OpenFOAM capable of making simulations on a micro scale and capable of reproducing pore events such as snap-off, Haines-jumps, disconnected ganglia of oil and the simultaneous filling of neighboring pores. In this thesis, graphs of the variation in fluid saturations versus time are presented in order to compare drainage process in different porous media.Item Open Access Reliability Analysis on Thermal Equipment Operating Under Steam-Assisted Gravity Drainage (SAGD) Operations in Alberta(2019-04-05) Rodriguez, Heidy Patricia; Mehta, Sudarshan A.; Moore, Robert Gordon Gord; Shor, Roman J.; Aguilera, Roberto F.The thermal industry needs to find ways of managing various financial risks and the high standards to account for the harsh conditions of the Steam-Assisted Gravity Drainage (SAGD) operations, resulting from high temperatures, mechanical loads, geomechanical disturbance, exposure to caustic and corrosive environments and therefore the challenges to intermediate casing designs that lead to failures. An exploratory and a frequency analysis of 2,270 reported thermal failures from the Oil Sands in Alberta, Canada, together with a review of their evolution and the relationship between the failure modes, rates, field/well conditions and equipment specifications helped as foundation of the proposed step-by-step guidance to a high-robust reliability model called Reliability-Based Design Assessment (RBDA). To tackle uncertainty and variability, the model includes the identification of the top influential parameters that affect the structural adequacy of the intermediate casing applied to a case study that encompasses connection fatigue as a failure mechanism.Item Open Access Study of Oxidation Reactions in A Light Oil Carbonate Reservoir for High-Pressure Air Injection Process(2020-09-03) Hernández Hernández, Thalia Iveth; Mehta, Sudarshan A.; Moore, Robert Gordon Gord; Aguilera, Roberto F.; Hassanzadeh, HassanAir injection-based processes have drawn attention over the years as an enhanced oil recovery (EOR) technique due to the high thermal efficiency and the unlimited availability and low cost of the air. A key challenge for the application of the process is the poor understanding of the reaction kinetics. Without reliable knowledge about the mechanics of the kinetic reaction, the performance of the air injection-based EOR process cannot be accurately predicted. Experimental studies are necessary to understand various aspects of the mechanisms of the process. This study focuses on the study of chemical reactions and their kinetics in a light oil carbonate reservoir in Mexico. Two air injection thermal analysis techniques were used: Accelerating Rate Calorimeter (ARC) and Ramped Temperature Oxidation (RTO). Five ARC tests and three RTO tests were performed on oil and core samples from the target reservoir to analyze the behaviour of a dolomite core and fluid system while injecting air. Based on the analysis of the experimental data, it was concluded that the studied reservoir is suitable for the application of the High-Pressure Air Injection process. ARC tests demonstrated that the oil and core system was reactive and the reactivity of the oil during isoage tests suggested the reservoir was a candidate for self-ignition. RTO tests evaluated the oxidation characteristics of the oil. The temperature range where the oil and core reacted with air in all the experiments corresponded to bond-scission reactions for light oils. Calculations of kinetic parameters are discussed in this study.