The Vault

Permanent URI for this community

http://hdl.handle.net/1880/116113

Browse

Now showing 1 - 20 of 955

Open Access
2-D up-scaling of naturally fractured reservoirs
(2002) Xie, Jin; Pooladi-Darvish, Mehran
Open Access
3d modeling and experimental studies of ni/ysz anodes in an sofc with internal reforming of methane
(2007) Nikooyeh, Kasra; Hill, Josephine M.
Open Access
A (w/o) microemulsion approach for in-situ preparation of high concentrations of colloidal metal oxide nanoparticles
(2007) Nassar, Nashaat; Husein, Maen
Control over nanopa1ticle size 1s a key factor which labels a given nanoparticle preparation technique successful. When organic reactions are mediated by ultradispersed catalysts the concentration of the colloidal nanocatalysts and their stability become key factors as well. Ultradispersed metal oxide nanoparticles have applications as heterogeneous catalysts for organic reactions, and were recently demonstrated as effective H2S(gl absorbents. The catalytic activity and absorption effectiveness of metal oxide nanoparticles depend primarily on their surface area, which in turn, is dictated by their size, colloidal concentration and stability. This work presents a water-in-oil (w/o) microemulsion approach for in-situ preparation of ultradispersed metal oxide/hydroxide nanoparticles, namely: iron and copper and discusses the effect of different (w/o) microemulsion variables on their stability and highest possible time-invariant colloidal concentration (nanoparticle uptake). The concentration of the stabilized metal oxides corresponded to the nanoparticle uptake. In-situ preparation of colloidal catalysts and absorbents minimizes aggregation associated with storage and transportation. Much higher surface area per unit mass of nanoparticles and per unit volume of the colloidal suspension than reported in the literature was obtained. The following trends in the colloidal concentration were common for the (w/o) microemulsion system and the heavy oil matrix. An optimum water to surfactant mole ratio, R, was found for which a maximum nanoparticle uptake was obtained. Nanoparticle uptake increased linearly with the surfactant concentration and displayed a power function with the precursor salt concentration. A mathematical model based on correlations for water uptake by Winsor type II microemulsions accurately accounted for the effect of the aforementioned variables on the nanoparticle uptake by the microemulsions. Furthermore, the in-situ microemulsion approach developed in the first part was applied for in-situ preparation of effective H2Scgl colloidal absorbents within heavy oil matrix. H2 Scgl is a by-product of insitu heavy oil upgrading with potential negative impact on underground water. In this work, preliminarily evaluations of the effectiveness of the in-situ prepared colloidal iron oxide/hydroxide in heavy oil matrix for the absorption of H2 S(gJ was conducted successfully.
Open Access
A bifurcation study of natural convection in porous media with internal heat sources
(1994) Choi, Eungsoo; Chakma, Amit
Open Access
A chemical reaction kinetic study into the low severity pyrolysis of Athabasca bitumen
(1998) Wilcott, Heather R.; Behie, Leo A.
Embargo
A comparison of a forward in situ combustion correlation with results of a simulator
(1982) Diaz, Noe Damian; Aziz, Khalid
Open Access
A Comparison of Mean Estimators
(2014-01-31) Moghadasi, Maryam; Jensen, Jerry Lee
The mean values of reservoir parameters such as permeability, porosity, and hydrocarbon reserves are widely used to evaluate a formation for potential development and perform reservoir simulations. Among different mean estimators, the arithmetic average and Swanson’s rule are commonly used within the petroleum industry. In the petroleum literature, Swanson’s rule has been promoted as a superior alternative to the arithmetic average. A few researchers have evaluated its performance for the case of a log-normal distribution with a limited range of variability but they have overlooked its performance for other types of distribution, which may describe the distributions of reservoir parameters. Prior studies only concentrated on evaluating the bias of Swanson’s rule whereas an optimum mean estimator should simultaneously have zero bias, small uncertainty, consistency, and high efficiency. In addition to bias, this research study, thus, evaluates the performance of mean estimators based on these toher properties. This research study also compares the performance of Swanson’s rule with some well-known mean estimators: the arithmetic average, maximum likelihood estimator, and Pearson-Tukey’s rule for log normal and the power-normal and bimodal distributions. The mean estimators’ properties are analytically derived and numerically validated via Monte Carlo simulation. We find that none of these mean estimators simultaneously satisfies all conditions of an optimum mean estimator for all ranges of variability and sample size. In other words, each mean estimator can be an optimum mean estimator depending on sample size, variability, and distribution type. Being unbiased is a desirable property, but it is not necessarily the most important property because a mean estimator can be de-biased. We propose a de-biased version of Swanson’s rule and find it is an appropriate alternative for approximating the mean value, particularly for a data set with large standard deviation and small sample size. Moreover, we evaluate the performance of the mean estimators when data follow a first-order auto-regressive model to illustrate that the auto-correlation causes the mean estimators to behave differently compared to the uncorrelated case.
Open Access
A comparison of pressure flow solvers for dynamic process simulation
(2006) Mohajer, Mahyar; Svrcek, William Y.
Embargo
A computational procedure for simulating crude towers
(1985) Zibdawi, Mohamad A. (Mohamad Ahmad), 1958-; Bishnoi, Prithwi R.
Open Access
A Confocal Rheology Study of Network Stabilized Bicontinuous Emulsion Gels
(2018-08-24) Malone, Rachel Alexis; Trifkovic, Milana; Karan, Kunal; Bryant, Steven L.
In this thesis, a new bicontinuous soft material was discovered. Bicontinuous intraphase jammed emulsion gels (bipjels) were formed from critical mixtures of water and 2,6-lutidine and were stabilized with commercially produced alumina coated silica nanoparticles. Using a novel confocal rheology platform, the microstructure and rheological properties of the bipjels were simultaneously studied and provided key insights into the morphology and stability of the new materials during their formation, aging, and cooling. Through varying the concentration of the nanoparticles and the initial mixing energy delivered to the bipjel mixtures, the final morphologies could be tuned. A curvature analysis was performed over the aging of the different biPjel samples showing traits of optimal hyperbolic surfaces. The bipjels did not lose their strength upon cooling and liquids remixing which bodes well for their future development as an advanced material. Bipjels represent a new gateway for understanding the role non-interfacially localized particles play in stabilizing non-equilibrium morphologies.
Open Access
A Field Application of Nanoparticles For Improved Downhole Losses in Invert Emulsion Drilling Fluids
(2015-05-25) Borisov, Alexey; Husein, Maen; Hareland, Geir
Invasion of drilling fluids filtrate and solids into porous, permeable, fractured or vuggy zones can cause formation damage and presents a major source of drilling problems. Furthermore, downhole mud losses also increase environmental and financial risks associated with drilling operations, costing over $1B annually. This thesis investigates the use of in situ prepared calcium carbonate nanoparticles (CNP) for fluid loss prevention in invert emulsion drilling fluids. CNP at 5 wt% concentration were synthesized within a custom ‘carrier’ emulsion using a modified microemulsion approach. Subsequently, the carrier emulsion was used to deliver target concentration of NPs to a host drilling fluid of interest via volumetric dilution. High pressure, high temperature (HPHT) fluid loss experiments on commercial invert emulsion drilling fluids showed that CNP at concentration of 0.5 wt% provided a 20–50% improvement over conventional lost circulation materials (LCM). In addition, basic properties of mud samples were not affected significantly in the presence of the carrier emulsion. In order to evaluate performance of CNP under real-life conditions, six full-scale field tests were conducted in horizontal wells in Alberta, Canada. Industry-scale synthesis of CNP followed the lab-bench process and was implemented at a specialized mixing facility. The results suggested that the scale-up from 3×10-4 m3 (300 mL) to 20 m3 did not affect average particle size or final properties of the carrier emulsion. Furthermore, field HPHT data showed good agreement with the lab experiments, where the average fluid loss in the test wells was reduced by 20–30% compared to the control wells using conventional drilling fluids. Finally, analysis of mud losses revealed that the cumulative losses while drilling were on average 20–30% lower in the presence of 0.5 wt% CNP, which suggested that NPs help to reduce downhole losses.
Open Access
A field scale reservoir simulation of a hybrid isc-sagd technology applicable to the Athabasca oil sands
(2010) Forero Rodriguez, Cesar Augusto; Moore, R. Gordon; Mehta, S. A. (Raj)
Open Access
A Genetic Algorithm Optimizer with Applications to the SAGD Process
(2013-07-12) Chen, Zhen; Chen, Zhangxing (John)
Steam-assisted gravity drainage (SAGD) using parallel pairs of horizontal wells, one drilled for steam injection and the other for oil recovery, is the most widely used and effective in-situ method for recovering the Canadian oil sands. An optimization task is used to identify the parameters that will produce either a maximum or minimum value for objective functions the user specifies. In the area of reservoir simulation, the parameters can be well spacing to identify optimal field development plan, or a steam injection pressure/rate and a liquid production rate in the SAGD process for optimal operating conditions. The objective functions may be physical quantities, such as cumulative oil produced, the recovery factor, and the cumulative steam-oil ratio, or an economic index like net present value (NPV) dependent on those physical quantities. They can also be a function independent on the physical quantities, e.g., a history match data error if the optimization task is history match. The objective of this thesis is to develop an optimizer using a genetic algorithm that can be used to optimize a variety of tasks in reservoir simulation, including the history match error minimization, the optimal field development plan, production optimization and process optimization. In this work, the genetic algorithm using both binary and continuous encoding is designed and developed, which can be coupled with a reservoir simulator to study optimization tasks in reservoir simulations. This genetic algorithm is benchmarked with the traditional gradient based optimization algorithm. The genetic algorithm optimizer coupled with a reservoir simulator is used to optimize the steam injection rates over the life of a steam-assisted gravity drainage process in a reservoir with gas cap. The parameter sensitivities of the genetic algorithm are studied.
Open Access
A GMRES Solver with ILU(k) Preconditioner for Large-Scale Sparse Linear Systems on Multiple GPUs
(2015-09-28) Yang, Bo; Chen, Zhangxing (John)
Most time of reservoir simulation is spent on the solution of large-scale sparse linear systems. The Krylov subspace solvers and the ILU preconditioners are the most commonly used methods for solving such systems. Based on excellent parallel computing performance, GPUs have been a promising hardware architecture. The work of developing preconditioned Krylov solvers on GPUs is necessary and challengeable. We devote our efforts into the development of the GMRES and the ILU(k) preconditioner on a multiple-GPU architecture and achieve favorable speedup effects. Our GPU computation includes the algorithms such as SPMV, nested RAS, decoupled ILU(k) and parallel triangular solver, etc. The numerical experiments prove that our preconditioned GMRES algorithm is feasible and works well on a multiple-GPU workstation.
Open Access
A kinetic model of the hydrocarbon fraction reactions during the low-and high-temperature oxidation of Athabasca bitumen
(1999) Stipanov, Josko; Moore, R. Gordon
Embargo
A kinetic study of gas hydrates
(1981) Ourfali, Mounir; Bishnoi, Prithwi R.
Embargo
A Kinetic study of methane hydrate decomposition
(1985) Kim, Hyo Chee; Bishnoi, Prithwi R.
Gas hydrates are examples of a group of molecular compounds known as clathrates. Clathrates are characterized by nonstoichiometric compound with hydrogen bonds. Gas hydrates are formed when the gas is enclosed in the cavities of water molecules. There have been some basic studies in the kinetics of formation for simple and mixed hydrates of some major components of natural gas. However, no study has been reported on the kinetics of hydrate decomposition. The primary objective of this study was to obtain experimental data and to formulate a model to describe the kinetics of decomposition of methane gas hydrates. The experiments were designed to collect kinetic data and experiments were conducted under isothermal and isobaric conditions. Experiments were performed at temperatures ranging from 273 to 283 K, and pressures ranging from 1.93 to 6.97 MPa. The experimental results indicate that the reaction rate of the decomposition of the methane gas hydrate is function of the reaction temperature, pressures, and the amount of methane remaining in the hydrate. The proposed model reveals that the rate of reaction is dependent on the surface area available on the hydrate particles and also that the order of reaction is two-thirds with respect to the moles of methane in the hydrate.
Embargo
A kinetic study of methane hydrate formation
(1980) Vysniauskas, Anthony; Bishnoi, Prithwi R.
Gas hydrates are crystalline compounds of gas and water molecules which are thermodynamically stable at elevated pressures and low temperatures. Their formation is the result of the hydrogen bonding properties of water molecules combined with the van der Waals forces of interaction between "guest" solute and "host" water molecules. Interests in gas hydrates, in the past, were focused mainly on establishing the thermodynamic conditions for their formation with very little attention being given to the kinetics of their formation. In the present investigation, the kinetics of methane hydrate formation are studied using a semibatch stirred tank reactor. The temperatures studied in the experiments are 274.2, 276.5, 278.7, 281.0, and 284.0 Kover a pressure ranging from 3 MPa to 10 MPa. The results reveal that the formation kinetics are a function of the surface area of the gas-water interface, temperature, pressure and degree of supercooling. A plausible mechanism describing the formation of gas hydrates is proposed. The controlling mechanism is suggested to involve the interaction of molecules of water monomers with the parent water cluster and the hydrate forming gas molecules. On the basis of the proposed mechanism, a semi-empirical reaction rate model is formulated and correlated with respect to the obtained experimental data. The resultant expression shows a good fit with the data over the entire range studied. The form of the rate expression is anticipated to apply for other gas hydrates as well.
Open Access
A laboratory program for data interpretation of core analysis
(2002) Zhao, Feng (Kevin); Kantzas, Apostolos
Open Access
A method for converting aqueous demetallization products into dispersed metal oxide nanocatalysts in heavy oil
(2012) Abdrabo, Amr Abdelrazek Elgeuoshy Meghawry; Husein, Maen
Metallic heteroatoms deactivate expensive catalyst and, thus, should be removed at early stages during crude oil processing. Electro and biological demetallization are examples of two emerging techniques which remove the metallic heteroatoms; mainly nickel and vanadium, into ions or ionic complexes ultimately residing in the aqueous phase of a two phase water/oil system. This work investigates the conversion of the aqueous metallic species into metal oxide nanoparticles, which are effective upgrading catalysts, dispersed in the oil phase. The conversion step commenced in-situ within a water-in-oil emulsion structure, and the resultant nanoparticles remain very well dispersed in the heavy oil phase. The product nanoparticles were characterized, after successful collection from the oil phase, using X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-Ray spectroscopy (EDX). Despite the complexity of the heavy oil system, results confirmed the in-situ formation of NiO and V2 05 nanoparticles with mean sizes of 20 and 15 nm, respectively. Some aggregates have, nevertheless, formed, due to the relatively high temperature requirement of the method. Investigating the catalytic role of the as-prepared nanoparticles was limited to the NiO nanoparticles, since only low concentrations of V20s could be prepared. An attempt to increase the concentration of dispersed V2 05 by using precursors with higher solubility in water was not successful. A semi-batch reactor setup was employed to investigate the catalytic hydrocracking of heavy oil in the presence of dispersed NiO nanoparticles. On the other hand, batch reactor arrangement was employed to study the thermalcracking of heavy oil in the presence of dispersed NiO nanoparticles.