Additional Injector Research Articles

A modified vertical-horizontal well pattern for enhancing in-situ combustion performance in extra-heavy oil reservoirs

A proper well pattern is critical for the efficient and economical exploitation of heavy oil and bitumen during the in-situ combustion (ISC). This paper brings a modified vertical-horizontal well pattern named the modified THAI process using additional injectors in staggered line drive with auxiliary gas producer wells and investigates its ISC performance using a 3D experimental simulation. The burning stability, spatial distribution of coke zone, pressure difference, and extension features of combustion chamber are studied and analyzed. Results show that a better burning state and stable propagation for the combustion front can be achieved in this modified well pattern. Spatial distribution of coke zone structure manifests a larger sweep volume of combustion chamber and a lower extent of combustion override. Combustion chamber extension characteristics are intuitively displayed by the variation of 350 °C isothermal surfaces, and its sweep volume finally enlarges to 53032.55 cm3 with a volumetric sweep coefficient of 47.95%. The production well intermittent shutdown (PWIS) method can improve unfavorable expansion behaviors of combustion chamber with little impact on the burning state and pressure difference. The oil displacement efficiency eventually reaches 85.6%. This well pattern exhibits significant potential for enhancing in-situ combustion performance, contributing to the economic and efficient exploitation of oil in commercial ISC application.

A computational parametric study of ducted fuel injection implementation in a heavy-duty diesel engine

Experiments have shown that ducted fuel injection (DFI) effectively reduces soot emissions from direct-injection diesel engines. Although many computational studies have evaluated DFI’s spray development and soot reduction mechanisms in constant volume chambers, only limited computational work on internal combustion engines exists. The DFI duct assembly changes the engine’s in-cylinder flow, spray, and combustion development. Therefore, current production engine designs might not be optimal for achieving the best engine performance with DFI. This work conducted an extensive numerical study to evaluate how parameter changes affect DFI performance. The parameters include swirl ratio, piston geometry, compression ratio (CR), number of injector orifices, split injection strategy, and exhaust gas recirculation (EGR) in a heavy-duty diesel engine utilizing DFI. The combustion and soot emission data from the Sandia compression ignition optical research engine were used for model validation. Simulations showed that an increased swirl ratio resulted in more intense jet flame-piston interaction, slowing down the combustion heat release during the late combustion stage and leading to lower indicated thermal efficiency (ITE) due to higher exhaust losses. A piston-bowl design with a reentrant inner piston edge yielded the highest thermal efficiency, due to the reduced cylinder head heat transfer loss. Additional injector orifices led to higher efficiency owing to a more advanced combustion phasing. Nevertheless, the maximum pressure rise rate (MPRR) and oxides of nitrogen (NOx) emissions also increased with the number of injector orifices due to more rapid heat release and higher combustion temperature. Implementation of a split injection strategy combined with a higher EGR rate effectively inhibited the excessive MPRR and NOx formation. In general, the study concluded that DFI is not sensitive to most parameter changes but will benefit from future parameter optimization.

On-site measurements of the dynamic behaviour of Pelton turbines in the context of predictive maintenance

The operating modes of pumped storage power plants, such as that of the Forces Motrices Hongrin-Léman (FMHL) in Switzerland, have drastically changed over the past decades due to the emergence of new renewable energies. The number of starts and stops experienced by machines increased significantly leading to broader fatigue cycles on the different parts of the machine. Therefore, the development of predictive maintenance tools is paramount to increase the availability and reinforce operational safety of the power plant. In this context, vibration measurements were performed on a 60 MW Pelton turbine of one of the ternary units of the FMHL power plant during dynamic and steady state operations. Non intrusive instrumentation has been deployed including accelerometers on the bearing. Comparing the ramp-up and ramp-down of the Pelton turbine, a hysteresis of the vibration level for a similar power has been observed. A reduction of the vibration levels when an additional injector is engaged during the ramp-up is observed. This reduction correlates strongly with the load reduction on the buckets when the total flow rate is distributed over more injectors, leading to a smaller flow rate per injector.

Improving performance and reducing emissions from a gasoline and liquefied petroleum gas bi-fuel system based on a motorcycle engine fuel injection system

Motorcycles are popular vehicles in Vietnam, and their numbers are increasing. According to forecasts, there will be about 75 million in circulation by 2025, which is the year Vietnam will start implementing exhaust gas testing for motorcycles by Vietnamese National Standards “TCVN 643:2018”. This is the maximum permitted limit of exhaust gases for road vehicles in Vietnam. It is difficult for older motorcycles to meet this requirement, so alternative fuels need to be considered. LPG has the advantage of being a clean fuel in abundant supply, and so has the potential to provide a solution. This study was conducted on an old motorcycle of a type that is very common in Vietnam. A bi-fuel LPG and gasoline system was built from the fuel injection system on the motorcycle, with only the need to calculate, design and install two additional injectors for the LPG. The engine was run on a test platform using GT-POWER simulation software, which optimized the primary ignition angle for the LPG. The performance and pollution data were compared between gasoline and LPG, both by experiment and simulation. The results show that the performance of the LPG declines. However, the exhaust emission and fuel economy improve. The system studied does not require a change to the fuel injection system or the engine, manufacturing costs are low, and it is easy to apply in the actual situation of motorcycles in Vietnam today.

A particle-capturing and -separating, sheathless chip in series with microfilters and planar interdigital electrodes

Research on microfluidic chips is becoming more and more important in life sciences, medical testing, and chemical reactions. In the process of separating particles by dielectrophoresis (DEP), focusing of mixed particles is essential. The commonly used focusing method is sheath flow which dilutes the particle samples. However, it requires an additional injector which precludes development of an integrated system for chemical analysis and biological detection. In this paper, we propose a novel sheathless, shunt-focusing approach using microfilters (MFs) and interdigital electrodes to achieve particle capture and separation. By passing through a shrinking channel, most of the flowing small particles pass through the MFs, generating an artificial sheath flow in the channels to achieve focusing. Subsequently, interdigital electrodes provide DEP force to separate the particles. Separation efficiency was assessed by collecting polystyrene (20 μm diameter) from silica (4 μm diameter) at various flow rates. From the experimental results, the efficiency of capture reached 71%–86% and that of separation was over 98.6%. This chip is expected to be applied to the separation of circulating tumor cells in blood samples.

Computer Technologies of 3D Modeling by Combustion Processes to Create Effective Methods of Burning Solid Fuel and Reduce Harmful Dust and Gas Emissions into the Atmosphere

Using numerical methods, studies have been carried out to determine the effect of the introduction of the technology of two-stage combustion of high-ash Karaganda coal on the main characteristics of heat and mass transfer processes in the furnace of the BKZ-75 boiler at Shakhtinskaya TPP (Kazakhstan). Various regimes of supplying additional air into the combustion space, the volume of which varied from 0% (traditional basic version) to 30% of the total volume of air required for fuel combustion, have been investigated using 3D computer modeling methods. The performed computational experiments made it possible to obtain the distributions of the total velocity vector, temperature fields, concentration fields of carbon monoxide CO and nitrogen dioxide NO2 over the entire volume of the furnace and at the outlet from it. The introduction of the two-stage combustion technology made it possible to optimize the combustion of high-ash coal, since in this case there is an increase in the temperature in the torch core and a decrease in it at the outlet from the furnace, which has a significant effect on the chemical processes of the formation of combustion products. Based on the results obtained, it can be concluded that an increase in the percentage of air supplied through additional injectors to 18% leads to a decrease in the concentrations of carbon monoxide CO by about 36%, and nitrogen dioxide NO2 by 25% compared to the base case. A further increase in the volume of additional air leads to a deterioration in these indicators. The results obtained will make it possible to optimize the combustion of low-grade fuel in the furnace of the BKZ-75 boiler, increase the efficiency of fuel burnout, reduce harmful emissions into the atmosphere, and introduce a two-stage combustion technology at other coal-fired TPPs.

ИСПОЛЬЗОВАНИЕ ТЕХНОЛОГИИ ДВУХСТУПЕНЧАТОГО СЖИГАНИЯ ТОПЛИВА ДЛЯ МИНИМИЗАЦИИ ВРЕДНЫХ ВЫБРОСОВ НА КАЗАХСТАНСКИХ ТЭЦ

Studies have been carried out using numerical modeling methods to determine the effect of the introduction of a two-stage combustion technology (OFA technology) of high-ash Karaganda coal on the characteristics of combustion processes: aerodynamics of flows, temperature and concentration (COх, NOх) fields throughout the entire volume of the combustion chamber of the BKZ-75 boiler at Shakhtinskaya TPP and at the outlet from it. Comparison with the basic regime of combustion of pulverized coal fuel, when there is no air supply through additional injectors (OFA = 0%). To implement the technology of two-stage combustion, various regimes of additional air supply through injectors were chosen: OFA equals 0% (basic version, conventional combustion), 5%, 10%, 15%, 18%, 20%, 25% and 30% of total air volume required for fuel combustion. A comparative analysis of the main characteristics of the heat and mass transfer process in the combustion chamber for the investigated modes is carried out. It is shown that an increase in the volume of additional air supplied through the injectors up to 18% leads to a decrease in the concentration of nitrogen oxide NO by 25% in comparison with traditional combustion. A further increase in the volume of additional air leads to a deterioration in these indicators. The results obtained will make it possible to optimize the combustion of low-grade fuel in the combustion chamber of the BKZ-75 boiler, increase the efficiency of fuel burnout, reduce harmful emissions and introduce a two-stage combustion technology at other coal-fired TPPs.

ИСПОЛЬЗОВАНИЕ ТЕХНОЛОГИИ ДВУХСТУПЕНЧАТОГО СЖИГАНИЯ ТОПЛИВА ДЛЯ МИНИМИЗАЦИИ ВРЕДНЫХ ВЫБРОСОВ НА КАЗАХСТАНСКИХ ТЭЦ

Studies have been carried out using numerical modeling methods to determine the effect of the introduction of a two-stage combustion technology (OFA technology) of high-ash Karaganda coal on the characteristics of combustion processes: aerodynamics of flows, temperature and concentration (COх, NOх) fields throughout the entire volume of the combustion chamber of the BKZ-75 boiler at Shakhtinskaya TPP and at the outlet from it. Comparison with the basic regime of combustion of pulverized coal fuel, when there is no air supply through additional injectors (OFA = 0%). To implement the technology of two-stage combustion, various regimes of additional air supply through injectors were chosen: OFA equals 0% (basic version, conventional combustion), 5%, 10%, 15%, 18%, 20%, 25% and 30% of total air volume required for fuel combustion. A comparative analysis of the main characteristics of the heat and mass transfer process in the combustion chamber for the investigated modes is carried out. It is shown that an increase in the volume of additional air supplied through the injectors up to 18% leads to a decrease in the concentration of nitrogen oxide NO by 25% in comparison with traditional combustion. A further increase in the volume of additional air leads to a deterioration in these indicators. The results obtained will make it possible to optimize the combustion of low-grade fuel in the combustion chamber of the BKZ-75 boiler, increase the efficiency of fuel burnout, reduce harmful emissions and introduce a two-stage combustion technology at other coal-fired TPPs.

Analysis of the impact of using additional injectors in the intake manifold on utility and ecological parameters enforced ignition engine

The article presents the results of comparative research on the utility and ecological parameters of the FSO 1.6 GSi engine, which are the effect of using additional injectors in the intake manifold. In the future, these injectors will be responsible for supplying the engine with alternative fuels. Engine parameters such as: cylinder filling factor, torque, unit fuel consumption and exhaust composition were analyzed. The tests were carried out with both standard and modified collector, in which additional injectors were installed.

Influence of water droplets on propagating detonations

In order to mitigate flame acceleration and detonation in hydrogen-air mixtures, which can lead to the release of harmful radionuclides in severe nuclear plant accidents, water spray systems are being considered. A series of experiments were conducted in a detonation tube filled with hydrogen-air mixtures. It was found that for a water droplet curtain with 215 μm droplets the detonation speed deficit was increasing with increasing size and density of the water droplet cloud, decreasing the speed below the speed of the detonation products. Moreover, as the initial pressure and equivalence ratio decreased, the speed deficit increased and, for the conditions tested, reached up to 16%. For most cases, 215 μm droplets quenched the detonation temporarily but the flow rapidly accelerated back to the initial detonation speed. It was concluded that the quenching effect for 215 μm droplets was limited by relatively fast evaporation time. However, this limitation was found to be partially overcome by the usage of additional injectors to reduce to injection time for a given injected mass of water. In contrast, nozzles giving water droplet diameters of 500 μm enabled complete detonation quenching.

Application of Alcohols to Dual - Fuel Feeding the Spark-Ignition and Self-Ignition Engines

Abstract This paper concerns analysis of possible use of alcohols for the feeding of self - ignition and spark-ignition engines operating in a dual- fuel mode, i.e. simultaneously combusting alcohol and diesel oil or alcohol and petrol. Issues associated with the requirements for application of bio-fuels were presented with taking into account National Index Targets, bio-ethanol production methods and dynamics of its production worldwide and in Poland. Te considerations are illustrated by results of the tests on spark- ignition and self- ignition engines fed with two fuels: petrol and methanol or diesel oil and methanol, respectively. Te tests were carried out on a 1100 MPI Fiat four- cylinder engine with multi-point injection and a prototype collector fitted with additional injectors in each cylinder. Te other tested engine was a SW 680 six- cylinder direct- injection diesel engine. Influence of a methanol addition on basic operational parameters of the engines and exhaust gas toxicity were analyzed. Te tests showed a favourable influence of methanol on combustion process of traditional fuels and on some operational parameters of engines. An addition of methanol resulted in a distinct rise of total efficiency of both types of engines at maintained output parameters (maximum power and torque). In the same time a radical drop in content of hydrocarbons and nitrogen oxides in exhaust gas was observed at high shares of methanol in feeding dose of ZI (petrol) engine, and 2-3 fold lower smokiness in case of ZS (diesel) engine. Among unfavourable phenomena, a rather insignificant rise of CO and NOx content for ZI engine, and THC and NOx - for ZS engine, should be numbered. It requires to carry out further research on optimum control parameters of the engines. Conclusions drawn from this work may be used for implementation of bio-fuels to feeding the combustion engines.

Characterization of a Set of ECN Spray A Injectors: Nozzle to Nozzle Variations and Effect on Spray Characteristics

The Engine Combustion Network (ECN) is becoming a leading group concerning the experimental and computational analysis of Engine combustion. In order to establish a coherent database for model validation, all the institutions participating to the experimental effort carry out experiments at well-defined standard conditions (in particular at Spray A conditions: 22.8kg/m3, 900K, 0% and 15% O2) and with Diesel injectors having the same specifications. Due to the rising number of ECN participants and also to unavoidable damages, additional injectors are required. This raises the question of injector's characteristics reproducibility and of the appropriate method to introduce such new injectors in the ECN network. In order to investigate this issue, a set of 8 new injectors with identical nominal Spray A specification were purchased and 4 of them were characterized using ECN standard diagnostics. In particular, the measurements include the nozzle hole diameter, the rate of injection, the liquid and vapor penetrations, the auto-ignition delay and the lift-off length. Variations of ambient temperature, oxygen concentration and density have also been performed. In general the results show similar behavior to ECN standard injectors, confirming that this set of new injectors can be integrated into the pool of ECN injectors. However, discrepancies between spray characteristics were observed, although the injector specifications and the boundary conditions were sensibly the same. The sources of variations from injector to injector are analyzed in order to provide new information on the reproducibility of injectors characteristics, and improve the comparison methodology between experimental data and simulation.

Исследование асимптотических свойств модели гидродинамической стадии эволюции процесса классификации в аппаратах циклонного типа

The practical application features of probabilistic and statistical model related to hydrodynamic stage of classification process evolution in the cylinder-conic hydroclones with additional injector are considered in this paper. Expression for the distribution function of firm disperse phase particles in the qualifier is given over time of their stay in the device, as well as depending on its constructive and technical characteristics. The stationary solutions of Fokker-Plank-Kolmogorov kinetic equation have been got for considered process of classification within reasonable assumptions. At the description related to the change of characteristics of division of suspensions in qualifiers the application of three-parametrical curves family which parameters depend not only on hydrodynamic features of streams in the device, but also are defined by relative values of classification influence intensity and centrifugal forces in comparison with intensity of casual influences is offered.

Numerical Investigation of Potential Injection Strategies To Reduce Shale Barrier Impacts on SAGD Process

Summary It is well known that shale barriers significantly reduce steam-assisted gravity drainage (SAGD) performance in Athabasca fields. An extensive 2D simulation study shows that the flow resistance at the end of shale barriers and the extra heat absorbed by the residual water inside the unproductive shale barrier are the main reasons for the shale barrier effects. Long continuous shale barriers located vertically above or near the wellbore delay production performance significantly. We investigated potential strategies, including solvent coinjection, top injector application, or a combination of both, to reduce the shale barrier impacts. Solvent in the vapour phase can pass through the narrow flow path at the end of a shale barrier. Meanwhile, because the phase condenses from vapour to liquid, solvent efficiently reduces the flow resistance of the shale barrier. Liquid solvent coinjection can accelerate the near-wellbore flow and reduce the residual oil saturation at the wellbore vicinity. Coinjecting a multicomponent solvent can flush out the oil at different areas with different drainage mechanisms from vaporized and liquid components. Additional injector application at the top of the reservoir results in only marginal improvement.

CO2 plume management in saline reservoir sequestration

Abstract A significant difference between injecting CO 2 into saline aquifers for sequestration and injecting fluids into oil reservoirs or natural gas into aquifer storage reservoirs is the availability and use of other production and injection wells surrounding the primary injection well(s). Of major concern for CO 2 sequestration using a single well is the distribution of pressure and CO 2 saturation within the injection zone. Pressure is of concern with regards to caprock integrity and potential migration of brine or CO 2 outside of the injection zone, while CO 2 saturation is of interest for storage rights and displacement efficiency. For oil reservoirs, the presence of additional wells is intended to maximize oil recovery by injecting CO 2 into the same hydraulic flow units from which the producing wells are withdrawing fluids. Completing injectors and producers in the same flow unit increases CO 2 throughput, maximizes oil displacement efficiency, and controls pressure buildup. Additional injectors may surround the CO 2 injection well and oil production wells in order to provide external pressure to these wells to prevent the injected CO 2 from migrating from the pattern between two of the producing wells. Natural gas storage practices are similar in that to reduce the amount of “cushion” gas and increase the amount of cycled or working gas, edge wells may be used for withdrawal of gas and center wells used for gas injection. This reduces loss of gas to the formation via residual trapping far from the injection well. Moreover, this maximizes the natural gas storage efficiency between the injection and production wells and reduces the areal extent of the natural gas plume. Proposed U.S. EPA regulations include monitoring pressure and suggest the “plume” may be defined by pressure in addition to the CO 2 saturated area. For pressure monitoring, it seems that this can only be accomplished by injection zone monitoring wells. For pressure, these wells would not need to be very close to the injection well, compared to monitoring wells intended to measure CO 2 saturation via fluid sampling or cased-hole well logs. If pressure monitoring wells become mandated, these wells could be used for managing the CO 2 saturation and aquifer pressure distribution. To understand the relevance and effectiveness of producing and injecting brine to improve storage efficiency, direct the plume to specific pore space, and redistribute the pressure, numerical models of CO 2 injection into aquifers are used. Simulated cases include various aquifer properties at a single well site and varying the number and location of surrounding wells for plume management. Strategies in terms of completion intervals can be developed to effectively contact more vertical pore space in relatively thicker geologic formations. Inter-site plume management (or cooperative) wells for the purpose of pressure monitoring and plume management may become the responsibility of a consortium of operators or a government entity, not individual sequestration site operators.

Have We Overestimated Saline Aquifer CO2Storage Capacities?

During future, large scale CO2 geological storage in saline aquifers, fluid pressure is expected to rise as a consequence of CO2 injection, but the pressure build up will have to stay below specified values to ensure a safe and long term containment of the CO2 in the storage site. The pressure build up is the result of two different effects. The first effect is a local overpressure around the injectors, which is due to the high CO2 velocities around the injectors, and which can be mitigated by adding CO2 injectors. The second effect is a regional scale pressure build up that will take place if the storage aquifer is closed or if the formation water that flows away from the pressurised area is not large enough to compensate volumetrically the CO2 injection. This second effect cannot be mitigated by adding additional injectors. In the first section of this paper, we review some major global and regional assessments of CO2 storage capacities in deep saline aquifers, in term of mass and storage efficiency. These storage capacities are primarily based on a volumetric approach: storage capacity is the volumetric sum of the CO2 that can be stored through various trapping mechanisms. We then discuss in Section 2 storage efficiencies derived from a pressure build up approach, as stated in the CO2STORE final report (Chadwick A. et al. (eds) (2008) Best Practice for the Storage of CO2 in Saline Aquifers, Observations and Guidelines from the SACS and CO2STORE Projects, Keyworth, Nottingham, BGS Occasional Publication No. 14) and detailed by Van der Meer and Egberts (van der Meer L.G.H., Egberts P.J.P. (2008) A General Method for Calculating Subsurface CO2 Storage Capacity, OTC Paper 19309, presented at the OTC Conference held in Houston, Texas, USA, 5-8 May). A quantitative range of such storage efficiency is presented, based on a review of orders of magnitudes of pore and water compressibilities and allowable pressure increase. To illustrate the relevance of this approach, it is applied to the Utsira aquifer in the North Sea. In Sections 3 and 4, we discuss possible effects that may lead to higher or lower CO2 storage efficiencies. Water production appears to be an attractive strategy in order to address regional scale pressure build up and, consequently, to increase the storage capacity.Following these quantitative applications, we recommend to evaluate the CO2 storage capacities of an aquifer, during a screening study for ranking purposes, using a pressure and compressibility formula rather than a volumetric approach, in order to avoid large overestimation of the aquifer storage capacity. Further studies are naturally required to validate the storage capacities at a qualification stage.

Inferring interwell connectivity using multiwell productivity index (MPI)

The multiwell productivity index (MPI) concept can be used to predict the performance of a homogenous reservoir under various operational conditions. In this paper, based on the MPI approach, we develop a semi-analytical method to evaluate interwell connectivity in waterflood projects. At first, we rearrange the MPI formula to predict waterflood performance in a homogeneous reservoir. For such cases, we can predict the liquid rates, average reservoir pressures and injectors' bottomhole pressures (BHP) accurately, in fractions of a second. For the case of an actual heterogeneous formation, we use the injection and production data to estimate the proper influence matrix by minimizing the misfit between predicted and actual reservoir performance. Defining the heterogeneity matrix as the difference between the estimated influence matrix and the one obtained as the analytical solution for the homogenous formation, we depict the normalized interwell connectivity indices. By decoupling the effect of well locations and the changes in injection rate, producer's BHP and individual skin factors from the apparent connectivity, the connectivity indices obtained by this method solely represent the reservoir heterogeneity and possible anisotropy and hence allow improved information exchange with the geologist. Comparing to the other connectivity evaluation models, the connectivity indices obtained by this method are independent of operational conditions, such as possible shutting-in existing or adding additional injectors or producers, or converting one to the other — and hence are more suitable for decision making. A further advantage of the new method is the flexibility to incorporate additional information, e.g. injectors' BHP, into the analysis process.

Role of Operating Practices on Performance of Waterfloods in Heavy Oil Reservoirs

Abstract Identification of operating conditions that have been beneficial or injurious to overall performance of past waterfloods in heavy oil reservoirs is the first essential step towards optimization of similar projects in the future. Comparative analyses of performance of various waterfloods in a given region (deposited under similar conditions) can be very instructive to identify such conditions. Insights on performance of waterfloods in heavy oil reservoirs were derived from a comparative evaluation of recent performance history of three selected waterfloods. These waterfloods involved increasing, decreasing and steady water injection rates. It was seen that aggressive injection rates lead to increased oil rates, but at rapidly increasing water cuts. Decreasing water injection rates, on the other hand, lead to low oil rates, but with water cuts increasing relatively more gradually. There is, therefore, an economically optimal water injection rate strategy for each specific situation. Introduction In the current environment of volatile oil prices and economic uncertainties, there is a heightened need for reviewing the cost-effectiveness of ongoing waterflood and improved oil recovery (IOR) operations within the constraints of low incremental costs and risks. Some of the options being pursued include enhanced surveillance, benchmarking of performance against other successful projects in analogous reservoirs, intense characterization and simulation, upgrades to facilities, improvement in injection water quality and selective placement of additional injectors and producers. In viscous fingering-dominated waterfloods, aggressive water injection aggravates water channelling. High injection rates (sub-fracture) lead to high initial oil rates in the short-term, but they subsequently give rise to excessive water channelling which may result in loss of cost-effectiveness of the waterflood and, in some cases, premature abandonment. On the other hand, low injection-production rates (processing rates) in heavy oil waterfloods lead to relatively low oil rates, long payout periods and a long project life. There is, therefore, an optimal processing rate/strategy for each specific situation (based on technical and economic considerations) and, clearly, there is a need for systematically identifying it. Since the 1980s, over 70 waterfloods have been operated in the medium and heavy oil reservoirs of Alberta and Saskatchewan in Western Canada. Waterflooding in these reservoirs involves adverse mobility ratio and viscous fingering/water channelling leading to relatively early water breakthrough. Resulting requirements for handling large amounts of water poses formidable problems. This study was undertaken to explore whether a judicious scheduling of injection and production rates could improve cost-effectiveness of similar operations in the short- and long-term. We examined performance histories of several ongoing waterfloods, and three selected waterfloods are reviewed here. We did not have access to many details on these projects. We believe there is a persuasive case for our hypothesis. It is understood that the field data examined were, by no means, 'controlled' (i.e. there may possibly exist factors other than the ones we focused on in this review, and all cases may not strictly be comparable). Methodology We compared the performance of three selected waterfloods in the heavy oil reservoirs of Southern Alberta; namely, Jenner Upper Mannville O, Jenner Upper Mannville JJJ and Retlaw Mannville D8D.

Large eddy simulation of piloting effects on turbulent swirling flames

Pilot flames, created by additional injectors of pure fuel, are often used in turbulent burners to enhance flame stabilization and reduce combustion instabilities. The exact mechanisms through which these additional rich zones modify the flame anchoring location and the combustion dynamics are often difficult to identify, especially when they include unsteady hydrodynamic motion. This study presents Large Eddy Simulations (LES) of the reacting flow within a large-scale gas turbine burner for two different cases of piloting, where either 2 or 6% of the total methane used in the burner is injected through additional pilot flame lines. For each case, LES shows how the pilot fuel injection affects both flame stabilization and flame stability. The 6% case leads to a stable flame and limited hydrodynamic perturbations in the initial flame zone. The 2% case is less stable, with a small-lift-off of the flame and a Precessing Vortex Core (PVC) in the cold stabilization zone. This PVC traps some of the lean cold gases issuing from the pilot passage stream, changes the flame stabilization point and induces instability.

Amount-dependent isotopic fractionation during compound-specific isotope analysis.

The performance of a gas chromatography-combustion-isotope ratio mass spectrometry system (GC-C-IRMS) with respect to the dependence of delta(13)C values on the amount of sample is presented. Particular attention is paid to the localization of the amount-dependent isotopic fractionation within the system. Injection experiments with varying amounts of gases (CO(2), n-hexane, and toluene) revealed that neither the detector unit nor the combustion reactor, but rather the conditions in the split/splitless injector, contributed to this effect. Although optimization of injector parameters was performed and a reduction of this adverse effect from 3 to 1 per thousand was achieved, it was not possible to eliminate isotopic fractionation completely. Consequently, additional injector parameters have to be considered and adjusted to achieve injection conditions free of fractionation. For routine analysis of the compound-specific delta(13)C analysis of different biomarkers in many environmental samples, perfect optimization may not always be reached. Therefore, in order to prevent systematic errors in the measured delta(13)C values due to different sample concentrations, it is suggested that correction for the remaining unknown amount-dependent fractionation can be made by means of co-analyzing standards of varying analyte concentrations and known delta(13)C values. Residual overall amount-dependent isotope-fractionation can thus be corrected mathematically.