Browsing by Author "Li, Huazhou"
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Item Open Access Improved Bitumen Recovery Using Urea Solutions(2021-12) BinDahbag, Mabkhot; Hassanzadeh, Hassan; Sarma, Hemanta; Dong, Mingzhe; Du, Ke; Li, HuazhouThis work presents experimental and simulation studies to design and optimize urea solutions to improve bitumen recovery. Initially, the solubility of ammonia in Athabasca bitumen was measured at vapor-liquid equilibrium (VLE) condition at different temperatures and pressures ranging from 348 to 463 K (75 to 190 ℃) and 1 to 4 MPa, respectively. The liquid phase density of ammonia-saturated bitumen was measured. The experimental solubility and density data were modeled using the Peng-Robinson equation of state (PR-EoS) by tuning the binary interaction coefficient and volume shift parameters of ammonia, respectively. The modeling results revealed that PR-EoS gives an acceptable prediction of ammonia solubility in bitumen and density of ammonia saturated-bitumen. Additionally, 1-D sand pack flooding experiments were conducted to recover heated bitumen at 423 K and 3.447 MPa pore pressure by injecting two different concentrations of urea solutions (5 and 10 wt %) at 1 cm3/min injection rate. Another flooding experiment was conducted by flooding sand pack with fresh water at the same flooding condition to be used as a baseline of urea solution flooding experiments. Supplementary experiments such as interfacial tension (IFT) measurements, emulsion viscosity measurements, total acid number (TAN) measurements, and Fourier-transform infrared (FTIR) measurements were conducted to prove the generation of in situ surfactants through the flooding process. The results of these flooding experiments (at 423 K) showed that flooding with urea solutions improves the oil recovery efficiency, highlighting the synergy between the reduction in viscosity of bitumen and the generation of in situ surfactants. Besides the reduction in viscosity of bitumen resulting from the heat, the generated in situ surfactants emulsify the oleic phase leading to the generation of W/O emulsion at the displacement front. This emulsion makes the displacement front more stable due to the attenuation of the viscous fingering. The supplementary experiments confirmed the generation of in situ surfactants, as evidenced by the reduction in the interfacial tension and total acid number measurements, and confirmed the results with FTIR analysis. Along with flooding experiments, a fine grid numerical simulation was conducted to model the experimental oil recovery data to obtain relative permeability curves through history matching technique. The history matching results revealed the efficiency of urea solutions to change the rock wettability toward more water-wet and suppress viscous fingering phenomenon. After confirming the mechanism of urea solutions in recovering bitumen, several 1-D sand pack flooding experiments were conducted by injecting hot urea solutions into cold sand packs at room temperature to optimize the injection rate, injection temperature, and urea solution concentration. Three injection rates (4, 8, and 12 cm3/min), four injection temperatures (453, 473, 493, and 513 K), and three urea solution concentrations (5, 10, and 15 wt %) were investigated in these flooding experiments. The flooding experiments of cold sand packs revealed an optimum flow rate that leads to more efficient displacement of oil by urea solutions. The optimum flow rate is attributed to the balance between the retention time and heat delivered to the oil sands through the flooding process. The results show higher oil recovery at higher concentrations of urea. Furthermore, the results reveal that while higher injection temperature accelerates the oil recovery initially, it reduces the ultimate oil recovery.Item Open Access Improvement of Carbon Dioxide EOR in Water-Wet Reservoirs by Using Active Carbonated Water(2016) Shu, Guanli; Dong, Mingzhe; Chen, Shengnan; Li, Huazhou; Hassanzadeh, Hassan; Mahinpey, Nader; Wong, Ron Chik-KwongCO2 injection for enhanced oil recovery has been widely and successfully used in many oil fields. The drawbacks of conventional CO2 injection are high mobility and gravity segregation, which lead to low sweep efficiency in the reservoir. Particularly in strongly water-wet reservoirs, a significant trapping of oil by water occurs after CO2 flood due to water blocking effect. To overcome the effect of water blocking, carbonated water flood is considered. In this thesis, a new injection strategy is proposed to recover the trapped residual oil in water-wet reservoirs. After waterflood, a slug of carbonated water is pre-flushed before CO2 flood, followed by an extended waterflood. A series of parallel tests are performed to compare the recovery efficiencies of tertiary floods. Additionally, the slug size of carbonated water is investigated and optimized to achieve the maximum economic value. In accordance with experimental results from parallel tests, it is recognized that molecular diffusion plays important role in recovering the trapped oil. In order to study the mass transfer process of dissolved CO2 from carbonated water into oil phases, a theoretical model is developed. The diffusion process is governed by diffusion coefficients of CO2 in water and oil phases. To determine these two diffusivities, an experimental method is proposed. In the experiment, two phases are placed in a closed diffusion cell immersed in a water bath at a constant temperature. To avoid natural convection, the water phase locates at the bottom and oil phase lies at the top. Combined with a developed theoretical model, pressure changes that occur in the cell are recorded and analyzed to investigate the mass transfer process. By means of the theoretical model and experimental method, effects of operational parameters on diffusion coefficients are studied. To explain the reasons for enhanced oil recovery by pre-flushing carbonated water before the CO2 flood, three types of experiments are involved in investigating the mechanisms. The derived theoretical model and experimental method can be applied to study the mass transfer process and to determine diffusion coefficients for any liquid-liquid system.Item Open Access Mathematical Modeling of Heavy Oil Recovery Using Electromagnetic Heating Combined with Solvent Injection(2019-01-11) Sadeghi, Asghar; Hassanzadeh, Hassan; Harding, Thomas Grant; Abedi, Jalal; Okoniewski, Michal M.; Vyas, Rushi J.; Li, HuazhouEfficient heating of oil sands is a challenge in thermal recovery of bitumen. Currently, a standard computational platform for modeling electromagnetic heating combined with solvent injection is lacking and a coupled approach is used. In this approach, a thermal reservoir simulator and an electromagnetic (EM) simulator are coupled to model electromagnetic heating (EMH) combined with solvent injection. This study presents first effort to model the recovery process by developing a standalone electromagnetic heating thermal simulator to simulate the recovery process. The work described in this thesis has two main contributions including development of analytical and numerical models. The analytical contribution includes development of solutions for electromagnetic heating of lossy geological media with applications to bitumen extraction from oil sands. Analytical models are presented for the start-up period of a SAGD-type well-pair for three different scenarios including steam circulation, electrical heating (EH), and EMH-EH. These analytical solutions are then combined with the Duhamel’s theorem to predict the temperature distribution around the horizontal wellbores. The energy efficiency of each scenario is evaluated. The results show that EMH-EH results in a shorter preheating period and is more energy efficient than the current practice of steam circulation. A semi-analytical model was also developed to predict the bitumen production rate, steam chamber growth, and energy efficiency of the process during the vapor chamber development period. The results showed that electromagnetic assisted gravity drainage is less energy intensive than the SAGD. The numerical contribution includes development of standalone two-dimensional, multi-component and multi-phase thermal simulator with an integrated electromagnetic EM component to simulate EM-based bitumen recovery processes. This numerical model integrates full Maxwell’s equation in the frequency domain with variable electrical properties based on temperature and water saturation, coupled with heat and mass transfer in the reservoir. Coupled equations are solved in a fully implicit scheme. The aim of developing a numerical model was to investigate the applicability of high-frequency waves coupled with the solvent as a viable method for bitumen extraction at the field scale. A case study demonstrates the physics of the various phases of the recovery process. The results of the EM-solvent process are compared with the commonly-used conventional thermal recovery method (SAGD) to assess production performance of the two processes in terms of energy efficiency, solvent usage and oil rate. The results reveal that EM-solvent recovery process has potential to eliminate water usage, reduce energy intensity, while recover more oil. These findings reveal that electromagnetic heating is a promising water-free recovery technology for future developments of oil sands resources.