Browsing by Subject "Heavy Oil"
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Item Enhanced Heavy Oil Recovery by Emulsification With Injected Nanoparticles(2013-11-26) Martinez Cedillo, Arturo ReyIn-situ oil-in-water emulsion generation, using modified silica hydrophilic nanoparticles as emulsifier, has been proposed as an enhanced oil recovery process. The nanoparticles are injected as an aqueous dispersion; its hydrophilic character allows emulsifying the immobile heavy oil, and transports it out of the reservoir as a low viscosity fluid. Generating the emulsions in the reservoir was suggested because it offers numerous advantages. The first advantage is low injectivity pressures due to the low dispersion viscosity. Also, the size of nanoparticles (5 nm) yields a better emulsion stability. Furthermore, complex injection facilities are not required, which reduces operational costs. In this research, 12 nanoparticle dispersions were created using nanoparticle concentrations of 0.5, 2.0 and 5.0 wt%, deionized water or brine made with 0.5 wt% of Sodium Chloride. These dispersions were tested to investigate their ability to generate oil-in-water emulsions. Emulsion generation experiments included interfacial tension measurements between heavy oil and nanoparticle dispersions, microscopy analysis to determine the amount of emulsion generated, and emulsion viscosity measurements. Results obtained from these experiments indicated that the nanoparticles lead to a reduction of the interfacial tension of the heavy oil and the dispersion. In addition, the presence of Sodium Chloride in the dispersion reduced still more of that interfacial tension, generating the largest amount of emulsions. Six core flooding experiments were conducted to study the effect of the nanoparticle dispersion flooding on the final recovery under different settings. Two types of core plugs with permeabilities of 150 mD and 2,300 mD, and two heavy oils with viscosities of 600 cP and 3500 cP were combined to establish the original experiment conditions. Tertiary heavy oil recoveries ranged from 20% to 64 % of OOIP were obtained. The results throughout these experiments suggest that if the reservoir conditions (e.g. permeability, porosity and oil viscosity) are adequate, the nanoparticle dispersion flooding may be a reliable alternative to the thermal recovery processes.Item Enhanced Oil Recovery of Viscous Oil by Injection of Water-in-Oil Emulsion Made with Used Engine Oil(2012-08-20) Fu, XuebingSolids-stabilized water-in-oil emulsions have been suggested as a drive fluid to recover viscous oil through a piston-like displacement pattern. While crude heavy oil was initially suggested as the base oil, an alternative oil ? used engine oil was proposed for emulsion generation because of several key advantages: more favorable viscosity that results in better emulsion injectivity, soot particles within the oil that readily promote stable emulsions, almost no cost of the oil itself and relatively large supply, and potential solution of used engine oil disposal. In this research, different types of used engine oil (mineral based, synthetic) were tested to make W/O emulsions simply by blending in brine. A series of stable emulsions was prepared with varied water contents from 40~70%. Viscosities of these emulsions were measured, ranging from 102~104 cp at low shear rates and ambient temperature. Then an emulsion made of 40% used engine oil and 60% brine was chosen for a series of coreflood experiments, to test the stability of this emulsion while flowing through porous media. Limited breakdown of the effluent was observed at ambient injection rates, indicating a stability of the emulsion in porous media. Pressure drops leveled off and remained constant at constant rate of injection, indicating steady-state flows under the experimental conditions. No plug off effect was observed after a large volume of emulsion passed through the cores. Reservoir scale simulations were conducted for the emulsion flooding process based on the emulsion properties tested from the experiments. Results showed significant improvement in both displacement pattern and oil recovery especially compared to water flooding. Economics calculations of emulsion flooding were also performed, suggesting this process to be highly profitable.Item Experimental and analytical modeling studies of steam injection with hydrocarbon additives to enhance recovery of San Ardo heavy oil(Texas A&M University, 2006-10-30) Simangunsong, RolyExperimental and analytical studies have been carried out to better understand production mechanisms of heavy oil under steam injection with propane and petroleum distillate as steam additives. The studies have been conducted for heavy oil from San Ardo field (12oAPI, 2800 cp at 53.3oC), under current reservoir conditions. The experiments consist of injecting pure steam, steam-propane, and steampetroleum distillate into a vertical cell containing a mixture of sand, water and San Ardo oil. The injection cell (68.58 cm long with an ID of 7.376 cm) is placed inside a vacuum jacket, set at the reservoir temperature of 53.3oC. Superheated steam at 230oC is injected at 5.5 ml/min (cold-water equivalent) simultaneously with propane or a petroleum distillate slug. The cell outlet pressure is maintained at 260 psig. Six runs were performed, two runs using pure steam, two steam-propane runs using 5:100 propane:steam mass ratio, and two steam-petroleum distillate runs using 5:100 petroleum distillate:steam mass ratio. We develop a simplified analytical model that describes steam front advancement and oil production for the 1D displacement experiments. The model incorporates heat and material balance, fillup time and Darcy??????s law pertaining to the injection cell. The analytical model results are compared against the experimental data to verify the validity of the model. The main results of the study are as follows. First, experimental results indicate that compared to pure steam injection, oil production was accelerated by 30% for 5:100 propane:steam injection and 38% for 5:100 petroleum distillate:steam injection respectively. Second, steam injectivity with steam-propane and steam-petroleum distillate increases to 1.4 and 1.9 times respectively, compared with pure steam injection. Third, steam front advancement and oil production data are in good agreement with results based on the new analytical model. The analytical model indicates that the oil production acceleration observed is due to oil viscosity reduction resulting from the addition of propane and petroleum distillate to the steam. Oil viscosity at the initial temperature with pure steam injection is 2281 cp, which is reduced to 261 cp with steam-propane injection and 227 cp with steam-petroleum distillate injection.Item Experimental and analytical studies of hydrocarbon yields under dry-, steam-, and steam-with-propane distillation(Texas A&M University, 2007-09-17) Jaiswal, NamitSimulation study has shown oil production is accelerated when propane is used as an additive during steam injection. To better understand this phenomenon, distillation experiments were performed using San Ardo crude oil (12oAPI). For comparison purposes, three distillation processes were investigated: dry-, steam-, and steam-propanedistillation, the latter at the propane-to-steam mass ratio of 0.05 at steam injection rate 0.5 g/min. Two sets of the distillation experiments were carried out. In the first set of experiments, the distillation temperatures ranged from 115????C to 300????C. Distillation pressures ranged from 0 psig to 998 psig for steam- and steam-propane distillation. The temperature-pressure combination used represented 15????C superheated steam conditions. In the second set of experiments, the distillation temperatures ranged from 220oC to 300oC at 260 psig. The temperature pressure combination used represented field conditions for crude oil. For both conditions, the cell was kept at each temperature plateau (cut) until no increase occurs in distillation yields. Distillation yields were collected at each cut, and the volume and weight of water and hydrocarbon measured. Based on these experiments, a thermodynamic modeling framework was developed that describes distillation effect and oil production for steam distillation experiments. The model is based on composition of crude oil, molecular weight of heavy fraction. The analytical model results are compared against the experimental data for synthetic crude and crude oil to verify the validity of the model. Main results of the study may be summarized as follows. The yields for steam distillation for saturated conditions of Tsat+15 o C and Psat is 10 % and with addition of 5% of propane to steam no significant increase occurs in distillation yields. The yields for steam distillation for field conditions of 260 psig and temperature range (220 ~300oC) is 18 % and with addition of 5% of propane to steam no significant increase in distillation yields. The results indicate that propane has minimal distillation effect on the heavy oil. This occurs possibly because of lesser amount of light fractions in the heavy oil that enhance the separation of components in the oil caused by the concentration gradient.Item Experimental Study of Solvent Based Emulsion Injection to Enhance Heavy Oil Recovery(2011-08-08) Qiu, FangdaThis study presents the results of nano-particle and surfactant-stabilized solvent-based emulsion core flooding studies under laboratory conditions that investigate the recovery mechanisms of chemical flooding in a heavy oil reservoir. In the study, bench tests, including the phase behavior test, rheology studies and interfacial tension measurement are performed and reported for the optimum selecting method for the nano-emulsion. Specifically, nano-emulsion systems with high viscosity have been injected into sandstone cores containing Alaska North Slope West Sak heavy oil with 16 API, which was dewatered in the laboratory condition. The experiment results suggest that the potential application of this kind of emulsion flooding is a promising EOR (enhanced oil recovery) process for some heavy oil reservoirs in Alaska, Canada and Venezuela after primary production. Heavy oil lacks mobility under reservoir conditions and is not suitable for the application of the thermal recovery method because of environmental issues or technical problems. Core flooding experiments were performed on cores with varied permeabilities. Comparisons between direct injection of nano-emulsion systems and nano-emulsion injections after water flooding were conducted. Oil recovery information is obtained by material balance calculation. In this study, we try to combine the advantages of solvent, surfactant, and nano-particles together. As we know, pure miscible solvent used as an injection fluid in developing the heavy oil reservoir does have the desirable recovery feature, however it is not economical. The idea of nano-particle application in an EOR area has been recently raised by researchers who are interested in its feature-reaction catalysis-which could reduce in situ oil viscosity and generate emulsion without surfactant. Also, the nano-particle stabilized emulsions can long-distance drive oil in the reservoir, since the nano-particle size is 2-4 times smaller than the pore throat. In conclusion, the nano-emulsion flooding can be an effective enhancement for an oil recovery method for a heavy oil reservoir which is technically sensitive to the thermal recovery method.Item Heavy Oil Upgrading from Electron Beam (E-Beam) Irradiation(2011-02-22) Yang, DaegilSociety's growing demands for energy results in rapid increase in oil consumption and motivates us to make unconventional resources conventional resources. There are enormous amounts of heavy oil reserves in the world but the lack of cost effective technologies either for extraction, transportation, or refinery upgrading hinders the development of heavy oil reserves. One of the critical problems with heavy oil and bitumen is that they require large amounts of thermal energy and expensive catalysts to upgrade. This thesis demonstrates that electron beam (E-Beam) heavy oil upgrading, which uses unique features of E-Beam irradiation, may be used to improve conventional heavy oil upgrading. E-Beam processing lowers the thermal energy requirements and could sharply reduce the investment in catalysts. The design of the facilities can be simpler and will contribute to lowering the costs of transporting and processing heavy oil and bitumen. E-Beam technology uses the high kinetic energy of fast electrons, which not only transfer their energy but also interact with hydrocarbons to break the heavy molecules with lower thermal energy. In this work, we conducted three major stages to evaluate the applicability of E-Beam for heavy oil upgrading. First, we conducted laboratory experiments to investigate the effects of E-Beam on hydrocarbons. To do so, we used a Van de Graff accelerator, which generates the high kinetic energy of electrons, and a laboratory scale apparatus to investigate extensively how radiation effects hydrocarbons. Second, we studied the energy transfer mechanism of E-Beam upgrading to optimize the process. Third, we conducted a preliminary economic analysis based on energy consumption and compared the economics of E-Beam upgrading with conventional upgrading. The results of our study are very encouraging. From the experiments we found that E-Beam effect on hydrocarbon is significant. We used less thermal energy for distillation of n-hexadecane (n-C16) and naphtha with E-Beam. The results of experiments with asphaltene indicate that E-Beam enhances the decomposition of heavy hydrocarbon molecules and improves the quality of upgraded hydrocarbon. From the study of energy transfer mechanism, we estimated heat loss, fluid movement, and radiation energy distribution during the reaction. The results of our economic evaluation show that E-Beam upgrading appears to be economically feasible in petroleum industry applications. These results indicate significant potential for the application of E-Beam technology throughout the petroleum industry, particularly near production facilities, transportation pipelines, and refining industry.Item Investigation of Hybrid Steam/Solvent Injection to Improve the Efficiency of the SAGD Process(2013-05-09) Ardali, MojtabaSteam assisted gravity drainage (SAGD) has been demonstrated as a proven technology to unlock heavy oil and bitumen in Canadian reservoirs. Given the large energy requirements and volumes of emitted greenhouse gases from SAGD processes, there is a strong motivation to develop enhanced oil recovery processes with lower energy and emission intensities. In this study, the addition of solvents to steam has been examined to reduce the energy intensity of the SAGD process. Higher oil recovery, accelerated oil production rate, reduced steam-to-oil ratio, and more favorable economics are expected from the addition of suitable hydrocarbon additives to steam. A systematic approach was used to develop an effective hybrid steam/solvent injection to improve the SAGD process. Initially, an extensive parametric simulation study was carried out to find the suitable hydrocarbon additives and injection strategies. Simulation studies aim to narrow down hybrid steam/solvent processes, design suitable solvent type and concentration, and explain the mechanism of solvent addition to steam. In the experimental phase, the most promising solvents (n-hexane and n-heptane) were used with different injection strategies. Steam and hydrocarbon additives were injected in continuous or alternating schemes. The results of the integrated experimental and simulation study were used to better understand the mechanism of hybrid steam/solvent processes. Experimental and simulation results show that solvent co-injection with steam leads to a process with higher oil production, better oil recovery, and less energy intensity with more favorable economy. Solvent choice for hybrid steam/solvent injection is not solely dependent on the mobility improvement capability of the solvents but also reservoir properties and operational conditions such as operating pressure and injection strategy. Pure heated solvent injection requires significant quantities. A vaporized solvent chamber is not sustainable due to low latent heat of the solvents. Alternating steam and solvent injection provides heat for the solvent cycles and increases oil recovery. Co-injection of small volumes (5-15% by volume) of suitable solvents at the early times of the SAGD operation considerably improves the economics of the SAGD process.Item Post Production Heavy Oil Operations: A Case for Partial Upgrading(2012-12-05) Lokhandwala, TaherThe transportation of heavy oil is a pressing problem. Various methods have been devised to mitigate the reluctance to flow of these highly dense and viscous oils. This study is focused on evaluating a case for post-production partial upgrading of heavy oil. Specifically, we analyze the impact of visbreaking, a mild thermal cracking method, on the economic and energy demands of the post-production process. Using conservative modeling techniques and principles we find significant cost and energy savings can potentially result out of visbreaking. Cost savings result as a consequence of reduced diluent usage. Even the most conservative modeling scenario under consideration exhibits significant cost savings in the form of reduced diluent usage; these savings not only offset operational costs but provide short payback periods on capital expenditures. Additionally, the lower gravity blend resulting from visbreaking can also bring about energy and cost savings in pipeline transportation and positively impact the heavy oil value chain from the producer to a refinery or regional upgrading facility. From this basic analysis of the potential of visbreaking, we can recommend investing resources to study its viability in the field. Using this analysis as a tipping off point and with a detailed look at the chemistry of the oil in question it is possible to make a very viable case for visbreaking. In a similar vein, this analysis can serve as a guide in making a case for other partial upgrading methods as well.