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Abstract Water injection technique is contributing millions of oil barrels on a daily basis to the global oil supply; one of the challenges faced by such an important production method is scale buildup due to the different dissolved solids and high salinity of the injected water. For produced water or effluent water, pretreatment is a critical step before the injection process to reduce the risk of scale potential and well formation damage. One of the beneficial treatments of the effluent water is to be mixed in a compatible ratio with seawater, especially for those countries with easy access to seawater. Thus, the objective is to find a compatible mix ratio with seawater as one way of solving effluent water reuse without increasing the risk of scale and formation damage during water injection operation. In this study, effluent water samples were collected from different oilfield geographical locations in Kuwait, and then the samples were analyzed in the laboratory for their physical and chemical properties to select the most compatible one for mixing with seawater. The selected effluent water was then mixed with seawater in 1:1 ratio to evaluate the compatibility of the mix in terms of sulfate formation and scale tendency. The selected North field/seawater was tested under 75 ºC and 1000 PSi in an autoclave. The filtered precipitates were characterized by energy-dispersive spectroscopy (EDS) and scanning electronic microscope (SEM) micrographs. Further, the formations of sulfate were detected by X-ray diffraction (XRD). The OLI ScaleChem software was used to investigate the composition of mineral scales that may occur in the water mix at different ratios ranging from 0 to 100% to compare it with the actual water mix finding. In the effluent waters comparison part, North field water showed low pH (4.6) and alkalinity, as well as moderate TDS (190,000 MG/L). The main constituents of the scale deposited at the selected water mixing ratio were calcium sulfate CaSO4 and silicon oxide detected by XRD. However, the amount of barium sulfate was not presented in the precipitates indicating that all of it went in the liquid phase. The study concludes that at downhole conditions, the compatible mix of North Kuwait effluent water with seawater has high risk of barium sulfate in comparison with other common scale such as calcium sulfate, calcium carbonate and strontium sulfate (SrSO4). Also the study revealed that the prediction of different seawater ratios showed that at 70% seawater concentration, the barium sulfate concentration drops and consequently the scale risk reduced.

Water injection is used as a widespread IOR/EOR method and promising formation damages (especially mechanical ones) is a crucial challenge in the near-wellbore of injection wells. The magnesium oxide (MgO) NanoParticles (NPs) considered in the article underwater flooding experiment tests to monitor the promising mechanical formation damage (size exclusion) in lab mechanistic scale include micro-scale classical deep bed filtration model, permeability, and pore size distribution. The averaged upper-scale equations were constructed on the water injection basis on the presence of NPs. The model validation to adjust the equation of state was obtained based on fluid samples from the laboratory and simulation tests. The permeability decline (up to 50% initial permeability) was important when the optimum value of capturing the probability coefficient (pa) is 0.7 mismatched on the conventional simulation results. Pore size distribution in each simulation time step based on retention concentrations determined in the sandstone samples. Formation damage analyses on the presence of NPs showed that modification of the static reservoir models has excellent potential regarding porosity and permeability maps, in large-scale simulation. This study displays an improved approach to NPs’ movement through a porous medium which will act as a benchmark for future waterflooding EOR projects in sandstone oil reservoirs or similar basins all over the world.

Abstract Surfactants are used in the process of chemical water injection to reduce interfacial tension of water and oil and consequently decrease the capillary pressure in the reservoir. However, other mechanisms such as altering the wettability of the reservoir rock, creating foam and forming a stable emulsion are also other mechanisms of the surfactants flooding. In this study, the effects of three commercially available surfactants, namely AN-120, NX-1510 and TR-880, in different concentrations on interfacial tension of water and oil, the wettability of the reservoir rock and, ultimately, the increase in oil recovery based on pendant drop experiments, contact angle and carbonate core flooding have been investigated. The effects of concentration, temperature, pressure and salinity on the performances of these surfactants have also been shown. The results, in addition to confirming the capability of the surfactants to reduce interfacial tension and altering the wettability to hydrophilicity, show that the TR-880 has the better ability to reduce interfacial tension than AN-120 and NX-1510, and in the alteration of wettability the smallest contact angle was obtained by dissolving 1000 ppm of surfactant NX-1510. Also, the results of interfacial tension tests confirm the better performances of these surfactants in formation salinity and high salinity. Additionally, a total of 72% recovery was achieved with a secondary saline water flooding and flooding with a 1000 ppm of TR-880 surfactant.

Abstract Capillary and interfacial forces are of great influences of trapping hydrocarbon in porous media after primary and secondary recovery processes. The trapped crude oil in the reservoir can be mobilized and produced by reducing these forces. Thus, surfactant flooding, as a main enhanced oil recovery (EOR) method, is usually applied to reduce the interfacial tension (IFT) of crude oil–water system in porous medium and improves the oil recovery. This study focused on the effect of [C8Py][Cl] and [C18Py][Cl] ionic liquids (ILs), as a new family of surfactant, in combination with various salts including sodium chloride, potassium chloride, magnesium sulfate and potassium sulfate on IFT reduction. EOR injection solutions were prepared from mixing the ILs at different concentrations of 100, 250, 500 and 1000 ppm with the salts ranging from 500 to 80,000 ppm. Obtained results showed that the minimum IFT value from both ILs was achieved when the concentration of the ILs was about 1000 g/mL, and the concentrations of KCl, K2SO4, MgSO4 and NaCl were 1000, 2000, 500 and 80,000 ppm, respectively. The minimum IFTs were achieved when NaCl and ILs concentrations were the maximum and MgSO4 concentration was the minimum.

Rotating Vortex Rope (RVR) resulting from flow instabilities inside draft tube affects the hydraulic turbine's efficiency and wear. Among the passive and active RVR mitigation methods, the water injection method has been widely investigated lately. The present research focuses on the dynamics of RVR mitigation using the water injection method and the optimization of exergy loss during the water injection. The numerical simulations are performed using a reduced turbine geometry consisting of one stay vane, two guide vanes, one runner passage by applying periodic boundary conditions at side boundaries, and a complete draft tube. The pressure fluctuations, velocity field, and the RVR structure are well captured using the Shear Stress Transport - Scale Adaptive Simulation (SST-SAS) turbulence model. The results of the local swirl number during the load variation show that the onset of flow instabilities and RVR formation are created due to a decrease of the axial momentum below the runner cone. The required axial momentum flux of water injection is calculated for a stable swirl number and the local minimum ratio of dimensionless loss to the pressure recovery factor. The numerical results show that the rotating and plunging components of the pressure fluctuations inside the draft tube reduce during the water injection. The pressure recovery of the draft tube improves. The dynamics of RVR mitigation are visualized using λ 2 criterion and the spectrogram of pressure probes on the draft tube wall. An optimum water flow rate and jet velocity for a fixed axial momentum are proposed. The results show that a water jet with a large radius and low velocity is more effective to mitigate the RVR and minimizing the draft tube losses. [ABSTRACT FROM AUTHOR]

Copyright of Aeronautical Science Bulletins / Repüléstudományi Közlemények is the property of National University of Public Service and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The approach of this research is to enlarge the knowledge about the methodologies to increase the maximum achievable load degree in the context of gasoline CAI engines. This work is the continuation of a previous work related to the study of the water injection effect on combustion, where this strategy was approached. The operating strategies to introduce the water and the interconnected settings were deeply analyzed in order to optimize combustion and to evaluate its potential to increase the maximum load degree when operating in CAI. During these initial tests, the engine was configured to enhance the mixture autoignition. The compression ratio was high compared to a standard gasoline engine, and suitable fuel injection strategies were selected based on previous studies from the authors to maximize the reactivity of the mixture, and get a stable CAI operation. Once water injection proved to provide encouraging results, the next step dealt in this work, was to go deeper and explore its effects when the engine configuration is more similar to a conventional gasoline engine, trying to get CAI combustion closer to production engines. This means, mainly, lower compression ratios and different fuel injection strategies, which hinders CAI operation. Finally, since all the previous works were performed at constant engine speed, the engine speed was also modified in order to see the applicability of the defined strategies to operate under CAI conditions at other operating conditions. The results obtained show that all these modifications are compatible with CAI operation: the required compression ratio can be reduced, in some cases the injection strategies can be simplified, and the increase of the engine speed leads to better conditions for CAI combustion. Thanks to the analysis of all this data, the different key parameters to manage this combustion mode are identified and shown in the paper. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An analytical solution to the problem of calculating the heating and cooling of water injected into the well is presented. The results of calculations of temperature profiles at various daily flow rates and temperature regimes for White Tigre (Vietnam) and Uzen (Kazakhstan) fields are discussed. [ABSTRACT FROM AUTHOR]

Combustion knock is a major barrier to achieving high thermal efficiency in spark ignition engines. Water injection was recently identified as a potential way of overcoming this barrier. To evaluate its general applicability, experiments were performed on a downsized three-cylinder spark ignition engine, varying the humidity of the intake air, the water injection timing, and the engine speed. The minimum quantity of injected water required to maintain a given load (and thus level of engine performance) was determined under each set of tested conditions. The knock-suppressing effects of water injection were found to be related to changes in the fuel–air mixture's specific heat ratio (kappa) rather than evaporative cooling, and to therefore depend on the total quantity of water in the cylinder rather than the relative humidity per se. The total quantity of water in the cylinder was also shown to be a key determinant of advancement in combustion phasing and particulate emissions under various conditions. [ABSTRACT FROM AUTHOR]

Port water injection (PWI) is considered one of the most promising technologies to actively control the increased knock tendency of modern gasoline direct injection (GDI) engines, which are rapidly evolving with the adoption of high compression ratios and increased brake mean effective pressure levels in the effort to improve their thermal efficiency. For PWI technology, appropriately matching the spray evolution and the intake system design along with obtaining a high spray atomization quality, are crucial tasks for promoting water evaporation so as to effectively cool down the air charge with moderate water consumption and lubricant dilution drawbacks. In the present paper, a detailed experimental analysis of a low-pressure water spray is presented, covering a lack of experimental data on automotive PWI systems. Phase doppler anemometry and fast-shutter spray imaging allowed us to investigate the influence exerted by the injection pressure level and by the water temperature on spray drop size and global shape, obtaining a complete database to be used for the optimization of PWI systems. The obtained results evidence how significant benefits in terms of atomization quality can be obtained by adopting injection pressure and water temperature levels compliant with standard low injection pressure technologies. [ABSTRACT FROM AUTHOR]

Homogeneous charge compression ignition has proven to be both highly efficient and to operate with ultra-low NOx raw emissions. However, homogeneous charge compression ignition combustion is a dynamic process due to strong cycle-to-cycle coupling effects caused mainly by the residual gas. Compared to conventional spark-ignited and diesel engines, the lack of direct mixture composition and ignition control increases the challenge of combustion instabilities, especially at boundary conditions. To stabilize the combustion process, real-time in-cylinder combustion diagnostics and control are often used. In this study, for the first time, ion current detection technology and direct water injection are combined for homogeneous charge compression ignition combustion control. By analyzing the return map of the crank angle at 50% cumulative heat release under unstable conditions, it was identified that a misfire or incomplete combustion is usually followed by knocking-like early combustion with high cylinder pressure gradients. Through the correlation analysis between ion current and combustion, a cycle-to-cycle closed-loop control strategy was developed and implemented on a rapid control prototyping engine control unit. Real-time calculated ion current parameters were used to predict the 50% cumulative heat release position of the next cycle and prevent early combustion by direct water injection. The calculation results and controller performance were validated on a single-cylinder research engine. With the controller activated, the standard deviation of 50% cumulative heat release and dynamic programming to the max could be reduced by 19% and 11%, respectively. The coefficient of variation of indicated mean effective pressure was reduced by 12%. A slight increase in indicated mean effective pressure after activating the controller also shows the potential for efficiency improvement. Moreover, not only early combustion is controlled, but also late combustion is significantly reduced. [ABSTRACT FROM AUTHOR]

Water/steam direct injection is an effective method to lower emissions and improve the power of engines by using waste heat recovery (WHR). The parameters of water injection (WI) and steam injection (SI) were analyzed at compression stroke on the effect of brake power and emissions in marine engines, including injected timing, mass, and temperature. The results demonstrated that NOx emissions were substantially reduced by using WI method. However, brake power was also decreased. The SI method not only decreased NOx emissions but also improved brake power. The NOx emissions were ascended with increasing temperature and delaying injected timing of water. Opposing trends were found for SI method. The injected mass has a large effect on power and emissions compared with the influence of temperature and timing. The NOx emissions can be reduced by 72.8% with 2.08% power loss when the 20 g of water was injected into the cylinder at −50 °CA, 15 bar and 400 K. The NOx emissions can be reduced by 38.9% with 24.7% power improvement when the same mass of superheated steam with 500 K of temperature was injected into the cylinder. It can be obvious that SI method can increase power while reducing fuel consumption and emissions. [ABSTRACT FROM AUTHOR]

Crack seepage in nature involves natural and water injection flow, causing crack morphology in nature to be varied. Using the numerical simulation method of smoothed particle hydrodynamics (SPH), the natural free flow process in a crack was analyzed. With the interference of the initial velocity of the x = 0 particles, the other terminal particles were shifted, and the particles with initial velocities were reversed. For water injection simulations, ghost particles were set to block particles from overflowing, as particles subjected to injection water were mobilized more quickly than under free flow conditions. For rough cracks, particle magnitude was affected by the boundary shape, but overall particle velocity was influenced little, and the distribution of particles was sparse and densely spaced. For the branch crack simulation, overall particle seepage velocity decreased, but particles moved faster through the wider branch than through the narrower branch. SPH can simulate the seepage through crack networks and be used to analyze the effects of different crack geometries and physical properties. [ABSTRACT FROM AUTHOR]

Compression ignition (CI) engines contribute more detrimental emissions when compared to petrol engines, especially NOx and smoke emissions. The main reason for diesel engines to emit higher NOx emissions is owing to higher excess air ratios, which promotes the NO formation chemistry and thus emitting marginally lowered HC and CO emissions. Biodiesel applications are becoming very important and gaining rapid momentum in the arena of depleting fossil fuels and increasing pollution norms. Biodiesel-fuelled CI engine gives relatively better performance and reducing emissions; however it increases the nitrogen oxides (NOx) emissions. This review paper studies on NOx emission reduction techniques such as water injection, emulsification, injection timing retardation and simultaneous technology and its effects on various operating parameters carried out in biodiesel powered CI engines. The emission characteristics of the diverse biodiesel-diesel blends have been summarised and discussed. NOx emissions can be reduced up to 37–50% by water injection method in biodiesel engines. It is also inferred that water-biodiesel emulsification reduces the NOx about 10–60% compared to conventional diesel. However, all these technologies reduce nitrogen oxides and particulate matter emissions considerably but increase HC, CO emissions and increase specific fuel consumption (BSFC) thereby reduces brake thermal efficiency (BTE). [ABSTRACT FROM AUTHOR]

Coal seam water injection is a critical measure for the prevention of coal-and-gas outbursts. However, the gas–solid–liquid coupling effect in front of the working face before and after water injection during coal mining is scarcely investigated. This issue was explored in this study by (a) numerical simulation of stress, gas pressure, and water saturability distribution as well as their coupling effect in front of the working face via the proposed multi-field coupling model run in the COMSOL software and (b) comparative analysis of the above parameters before and after water injection. During coal mining, stress in front of the working face first increased and then dropped to the initial value as the distance from the coal wall increased, while gas pressure exhibited a similar distribution pattern. After water injection, the stress distribution pattern remained almost unchanged, but the stress peak shifted forward, the stress relief zone broadened, while the gas pressure around the borehole dropped. In particular, the gas pressure in front of the borehole increased slightly at the beginning of water injection. As water was permanently injected, the gas pressure in front of the borehole decreased, while that around the borehole further decreased. Meanwhile, the water saturability of the coal seam around each borehole increased, with a ring-shaped distribution pattern. Due to the interaction of water injection among multiple boreholes, the contour lines of water saturability showed semi-circular distribution patterns around multiple boreholes. [ABSTRACT FROM AUTHOR]

Waterflooding is one of the most common secondary recovery methods in the oil and gas industry. Globally, this process sometimes suffers a technical failure and inefficiency. Therefore, a better understanding of geology, reservoir characteristics, rock typing and discrimination, hydraulic flow units, and production data is essential to analyze reasons and mechanisms of water injection failure in the injection wells. Water injection failure was reported in the Middle Miocene Hammam Faraun reservoir at El Morgan oil field in the Gulf of Suez, where two wells have been selected as injector's wells. In the first well (A1), the efficiency of injection was not good, whereas in the other analog A2 well good efficiency was assigned. Therefore, it is required to assess the injection loss in the low efficiency well, where all aspects of the geological, reservoir and production data of the studied wells were integrated to get a complete vision for the reasons of injection failure. The available data include core analysis data (vertical and horizontal permeabilities, helium porosity, bulk density, and water and oil saturations), petrographical studies injection and reservoir water chemistry, reservoir geology, production, and injection history. The quality of the data was examined and a set of reliable X–Y plots between the available data were introduced and the reservoir quality in both wells was estimated using reservoir quality index, normalized porosity index, and flow zone indicator. Integration and processing of the core and reservoir engineering data indicate that heterogeneity of the studied sequence was the main reason for the waterflooding inefficiency at the El Morgan A1 well. The best reservoir quality was assigned to the topmost part of the reservoir, which caused disturbance of the flow regime of reservoir fluids. Therefore, it is clearly indicated that rock typing and inadequate injection perforation strategy that has not been aligned with accurate hydraulic flow units are the key control parameters in the waterflooding efficiency. [ABSTRACT FROM AUTHOR]

Thin oil rim are reservoirs with hydrocarbon pay zone not more than 100 ft. Production challenges mainly water, and gas coning arises due to this trait and presence of a larger gas cap and aquifer. To safely exploit from oil rim reservoirs, the right production choices and optimization of production parameters need to be implemented before the commencement of any recovery scheme. A case study reservoir of an oil rim in the Niger-delta producing region is placed on a concurrent production via 8 horizontal producer wells after history matching and optimization of production parameters using a black oil simulator (Eclipse). Six different pattern scenarios of water and gas injection at 3 rates are considered: optimized oil recovery estimates of 5.43%, 4.51%, 5.41%, 4.93%, 5.89%, and 5.82% for inverted direct line water injection, inverted staggered water injection, inverted 4 spot injection, 5 spot water injection, inverted 7 spot water injection, and inverted 9 spot water injection respectively. The incremental oil recovery over the base case (no injection) recorded in like manner are 1.43%, 0.51%, 1.41%, 0.93%, 1.89%, and 1.82%. The results show that pattern water injection at 1000 stb/day is more suitable for optimum oil recovery for oil rims under concurrent production. [ABSTRACT FROM AUTHOR]

This study analyzed the thermal balance of a turbocharged gasoline direct injection engine with intake air humidification and studied the reason why intake air humidification improved the thermal efficiency of the basic engine. The results showed that since the evaporation of the introduced water absorbed heat in the intake port that caused the decrease of the temperature of the intake air, and the specific heat capacity of working medium increased with intake air humidification. Therefore, an apparent decrease in the in-cylinder temperature. Each energy loss can be affected by intake air humidification in different degrees, among which the exhaust loss and heat transfer loss decreased evidently, while pumping loss and friction loss increased to some extent. Furthermore, the sum of the decrease of exhaust loss and heat transfer loss was higher than the sum of the increase of pumping loss and friction loss, hence, the thermal efficiency of the basic gasoline engine increased when the benefit gained from intake air humidification was greater than the negative impact.

In high altitude and Mach number, the inflow air with the high temperature will influence on the aero-engine performance while the mass injection pre-compressor cooling (MIPCC) technology is one of the problem-solving ways to reduce high temperature. To explore the convection coupling process between droplet and inflow air, the compressible Reynolds average N-S equations in the compressor coupled with the pre-cooling section is solved by the finite volume method to analyze its performance changes at different water injection rates and droplet sizes. Results show that, in the flight of 3.5 Mach number, the larger water injection rate easily form the shock wave due to the disturbance of droplets in the pre-cooling section. Furthermore, the temperature on the pressure surface near the trailing edge of the rotor blade aggravates along the radial migration, leading to uneven temperature distribution in the radial direction. Within the water injection rates of 0-8% and the particle sizes of 10-20 µm, the inflow mass flow of air improves by 15.3-31.4%; the temperature ratio of compressor drops by 3.6-16.14%, which results in the decrease of specific compression work of the compressor and the changing trend from “increasing” to “decreasing” for the compressor efficiency.

The characterization of molten corium–concrete interaction (MCCI) has increasingly become a cause of concern because, in the case of a severe nuclear accident, the core could meltdown and release radiation into the environment. The objective of this study was to determine the thermochemical impact of metal content in the corium and analyze the effect of corium metal content on ablation depth, corium temperature, its viscosity and surface heat flux, and production of hydrogen, carbon monoxide, and carbon dioxide. The governing heat transfer equations were solved while considering the various thermochemical reactions in the existing numerical code in a comprehensive way. The developed MCCI model in CORQUENCH was validated against the data available in the literature. Our findings showed that the composition of corium, especially its metal content, has a noticeable effect on mitigating or aggravating the ablation depth and nuclear reactor integrity. We observed that during molten corium–concrete interaction, zirconium plays a significant role and its presence can increase the ablation depth exponentially from 18.5 to 139 cm in the investigated case study. It was found that the presence of zirconium in the corium instigated various thermochemical reactions continuously, and thus the injected water, instead of quenching the molten corium, enhances the temperature by facilitating exothermic reactions. Additionally, due to the presence of zirconium, the production of hydrogen and carbon monoxide increases by 45 and 52 times, respectively and the generation of carbon dioxide becomes zero because the zirconium reacts with carbon dioxide continuously, converting it to carbon monoxide.

The effect of water injection into a reservoir on oil production for Tournaisian deposits of the Sosnovskoe gas-oil field is evaluated. Statistical methods such as correlation, regression and stepwise discriminant analysis were used. Data on monthly and cumulative oil production, on amount of water injected into the reservoir from four injection and twelve production wells was used. Based on the data, studies have been performed to assess the effect of the volume of monthly water injection into the reservoir on monthly oil production, provided that each injection well affects only nearby producing wells. It was explained why there was no correlation between the parameters of monthly injection and monthly oil production. Then, in order to evaluate the efficiency of water injection into the reservoir, it was decided to use the data from the accumulated volume of water injection and the accumulated volume of oil production. It was found that there is a relationship between the parameters of the accumulated volume of water injection and the accumulated volume of oil production. The greater the accumulated volume of water injection, the greater the accumulated volume of oil production, but the gradients of increase for all wells are individual. Three areas were defined on the graphs. Relationships between the parameters have a high degree of linearity over a certain range. In order to establish the boundaries of those areas where the influence of the values of the accumulated volume of water injection on the accumulated volume of oil production is conditionally homogeneous, linear discriminant analysis was used. Results of the evaluation study show that water injection into the reservoir has a different degree of influence on the production wells. This analysis can be further applied to substantiate workovers and to identify hydrodynamic communication.

As a physiochemical property, asphaltenes are known to be one the most surface active compounds in crude oil. Due to such property, their behavior is most probably influenced by fluid-fluid interactions at the contact surface (interface). Potentially and naturally, in most cases, water is in contact with crude oil and is co-produced with it as well. Considering that asphaltene molecules are polar compounds similar to water molecules, asphaltenes are interfacially affected by water while they are absorbed to the interface. Such effects could be investigated by interfacial tension (IFT) changes when de-ionized water is used and dead-crude oil does not contain other surface active impurities like metallic compounds. In this study, extensive IFT experiments were conducted between three different oil samples and distilled water in a wide range of pressure from 2000 to 0 psia. The reversibility of asphaltene absorbance to the interface was also investigated by reversing the pressure path from 0 to 2000 psia. The results show that oil/water IFT changes with pressure, but upward/downward oscillations were detected. Such an oscillating behavior of IFT trends was related to asphaltenes surface activity as the oil samples used did not contain other impurities. Oscillations were reduced as resin to asphaltene ratio was increased, suggesting the non-absorbable behavior of the asphaltenes stabilized by resins. A microscopic surface experiment on one of the samples showed that at a certain concentration and particle size, a rigid film of absorbed asphaltenes was created at the interface instantaneously. The high rigidity of such a film gives rise to a hypothesis, which states that water affects asphaltene surface behavior possibly through strong hydrogen bonding (H-bond). Reversing the pressure path revealed that asphaltene surface absorbance is partially irreversible. The experiments were conducted three times, and each data set was presented along with an average of three sets for each sample.

Water flooding is one of the most influential methods for pressure maintenance and enhanced oil recovery. However, water flooding is likely to develop the formation of oilfield scale. Scale formation in reservoirs, due to the mixing of injection water and formation water, could cause formation damage and production limit. Therefore, it is necessary to simulate the compatibility of brine and injection water. Scale prediction is performed using many thermodynamic and/or kinetic based models. In this study, simulations with speciation (ion pairing) are studied, which is a thermodynamic based tool. The utilization of reservoir conditions, formation water analysis, and sea water analysis as the inputs in this method resulted to the accurate prediction of potential scales. In this study, the factors impacting on the scale potential such as pH, temperature, and mixing ratio were also investigated. The obtained results showed that calcite and aragonite were the major scale potential to precipitate. Finally, the results illustrated the important effect of pH and temperature on different scales formation.

Abstract In most reservoirs with oil rims, as the production begins, the gas–oil and oil–water fluid interfaces start deforming because of the imbalance between viscous and gravitational forces, leading to coning or cusping. This can be overcome using proper withdrawal rate, offset from water–oil contact and horizontal length. Further smart horizontal wells require optimization of nozzle size and compartment length also. To see the effect of these parameters on recovery, a three-dimensional geological model of a clastic reservoir from Upper Assam Basin has been used. This model was history matched for a period of 16 years on 46 wells. After successful validation of model on field scale and well level, performance prediction was carried out to see the effect of withdrawal rate, offset from water–oil contact, horizontal length, compartment length and nozzle size using vertical/horizontal and ICD completion. From the analysis, it is evident that application of advanced well completion, ICD, is suitable for such reservoir. Depending on the scenario, maximum cumulative oil production was obtained from ICD wells with 1.08 MMm3 compared to vertical well with cum oil production of 0.63 MMm3. Economic analysis has been carried out for the examined scenarios.

Abstract Water injection wells often develop casing leaks that result in crossflow between two formations. The crossflow can be upward or downward depending on the respective location of each formation and the gravitation hydrostatic column between the formations. Traditionally, crossflow rates are measured by running production logs (flowmeter); a process that require well intervention. Such intervention in a well with compromised downhole integrity is not preferred as it incur additional cost and exposes the oilfield operator to possible mechanical risks such as stuck tools. In this work, we present a numerical method to predict crossflow rates without such intervention. The method requires readily available input from the water injection that includes injection flow rates and pressures, in addition, to shut-in well data. The workflow developed in this study includes nodal analysis and well performance modeling. A water injection well (Well-XYZ) was selected to validate the developed workflow as a case study in this paper. Well-XYZ has an upward crossflow that resulted from a downhole leak. The numerical method starts with building a well performance model before the leak develops. The injection data (pressure and flow rates) before leak development are used for this model. Second, a well with the same physical dimensions of Well-XYZ is imagined and modeled as a producing well from the downhole formation to the leak point. The shut-in well data of Well-XYZ are used to build the production well model. Third, we choose the leak point as the system node and obtain its pressure either by direct measurement or through calculation. Once the system node pressure is obtained, it is inputted as the wellhead producing pressure of the imagined well and its production rate will be the crossflow rate. The results of this method were tested by running a production log on Well-XYZ. The results of the production log showed that the method was able to accurately predict the crossflow rate with a less than 2% error.

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

By considering the long history of water injection in oil fields, we used several sandstone cores with different permeability to conduct experimental tests. The damage effect of formation permeability caused by five types of injected water based on an oilfield water quality standard (SY/T 5329-2012) was investigated. A model for water quality sensitivity to permeability was proposed, and through theoretical derivation, a mathematical expression that described the attenuation law of permeability was established. This study provides a theoretical basis for the re-selection of water quality in oilfields developed through long-term water injection and improves the effectiveness of water flood development. [ABSTRACT FROM AUTHOR]

The technology of wireless intelligent injection is widely used in domestic oilfields for its easy installation and highly-effective cost. Currently, acoustic signal transmission wireless intelligent water injection has been carried out on the preliminary exploration attempt. Based on the communication characteristics of wellbore control process, the tubing of acoustic signal transmission frequency calculation and optimization, as the communication channel, is to guarantee the successful implementation of the important basis of process. The present researchers established a mathematical model of acoustic transmission, and used the numerical model to calculate acoustic signal transmission curves of amplitude and frequency distribution curve. Combined with the calculation results and the actual field test results, the accuracy of the calculation model is verified. At the same time, it is proved that the ideal acoustic signal transmission frequency through water injection zone is set to be 1 164~1 179 Hz. [ABSTRACT FROM AUTHOR]

Introduction of ever more stringent emission regulations on internal combustion engines beyond 2020 makes it necessary for original equipment manufacturers to find cost-effective solutions to improve the combustion engine efficiency and decrease its emissions. Highly efficient combustion engines can benefit from technologies such as cooled external exhaust gas recalculation and water injection. Among these technologies water injection can be used as a promising method to mitigate knock and significantly reduce the CO2 emissions. This is particularly important in highly downsized boosted engines which run under much higher intake pressures and are more prone to knocking combustion. In addition to anti-knock behaviour, water injection is also an effective method for reducing NOx emissions and exhaust gas temperature at high loads, which can protect the turbine in turbocharged engines. This study shows the influence of intake port injection of water on efficiency and emissions of a boosted downsized single-cylinder gasoline direct-injection engine in detail. Six different steady-state speed and load combinations were selected to represent the conditions that knocking combustion start to occur. Water ratio sweep tests were performed to find out the optimum water/fuel ratio at each test point and the impact on the combustion and emissions. In addition to gaseous emissions, impact of water injection on particle emissions was also investigated in this study. The results show the net indicated efficiency improved significantly (by a maximum of around 5% at medium load and around 15% at high load) up to a maximum level by increasing the injected water mass. Improvement in efficiency was mainly due to the increased heat capacity of charge and cooling effect of the injected water evaporation which reduced the in-cylinder temperature and pressure. Thus, knock sensitivity was reduced and more advanced spark timings could be used, which shifted the combustion phasing closer to the optimum point. However, increasing the water/fuel ratio further (more than 1 at medium load and more than 1.5 at high load) deteriorated the combustion efficiency, prolonged the flame development angle and combustion duration, and caused a reduction in the net integrated area of the P-V diagram. Efficiency improvements were lower at higher engine speed (3000 r/min) as the knock sensitivity was already reduced intrinsically. In terms of other, harmful, non-CO2 emissions, water injection was effective in reducing the NOx emissions significantly (by a maximum of around 60%) but increased the HC emissions as the water/fuel ratio increased. The results also show a significant reduction in particle emissions by adding water to the mixture and advancing the spark timing at medium and high loads. In addition, water injection also reduced the exhaust gas temperature by around 80°C and 180°C at medium and high loads, respectively. [ABSTRACT FROM AUTHOR]

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Enhancing hydrocarbon recovery is an ongoing practice in the petroleum industry. Multiple approaches are developed and proved their effectiveness in increasing reservoirs recovery. One of the recent approaches is the Low Salinity Water Injection which is known in the industry by "LoSal". The determination of the optimum low salinity of the injected water and the mechanism behind its ability to enhance the hydrocarbon recovery are still the subjects of interest for many researchers and industry professionals. Despite the value of the LoSal water injection, it brings with it a considerable challenge to the future formation evaluation, namely the determination of the fluids' saturation. The mixing of the low salinity injected water with the original high-salinity formation water creates variable water salinity across the reservoir. This is known in the industry by the "mixed-salinity" problem. The horizontal and the vertical heterogeneity of the permeability and porosity across the reservoir is the main factor that controls the "mixed-salinity" distribution in the injected volume. The challenge of calculating the fluids' saturation exists for both the infill drilling wells and the monitoring wells. For the infill drilling wells, the saturation calculations require accurate formation water resistivity values, Rw, which became variable due to the mixed-salinity. For the monitoring wells, the fluids saturation calculations require accurate formation water sigma absorption, Σw, which also became variable for the same reason. The inability to determine the current Rw and Σw on foot-by-foot basis results in incorrect calculations of the water and hydrocarbon saturations. This creates an economic burden on the reservoir management. The existing methods to interpret the fluids saturation in mixed-salinity reservoirs face the challenges of accuracy, effect of borehole environment and high-data acquisitions cost. A forward modeling is developed to illustrate the problem and its impact on the reservoir decisions making process. A solution to the challenges is proposed, investigated, and proved both theoretically and in the laboratory. The proposed solution is based on lowering the LoSal water resistivity, prior to injection, to be equal to the original formation water resistivity without changing its low salinity. This is achieved by mixing the LoSal water with either acid or alkaline based on the reservoir condition. The acid or alkaline will reduce the resistivity of the LoSal water while keeping its low salinity unchanged. The determination of the required volume of the acid or the alkaline is calculated using the conductivity mixing law and the solution is tested on core plugs. The possible effects of the acid on the formation lithology, specially the clay content is discussed and proved to be negligible due to the very low acid volume required. This is also supported by previously published measurements. [ABSTRACT FROM AUTHOR]

This work presents the assessment of direct water injection in spark-ignition engines using single cylinder experiments and tabulated chemistry-based simulations. In addition, direct water injection is compared with cooled low-pressure exhaust gas recirculation at full load operation. The analysis of the two knock suppressing and exhaust gas cooling methods is performed using the quasi-dimensional stochastic reactor model with a novel dual fuel tabulated chemistry model. To evaluate the characteristics of the autoignition in the end gas, the detonation diagram developed by Bradley and co-workers is applied. The single cylinder experiments with direct water injection outline the decreasing carbon monoxide emissions with increasing water content, while the nitrogen oxide emissions indicate only a minor decrease. The simulation results show that the engine can be operated at λ = 1 at full load using water--fuel ratios of up to 60% or cooled low-pressure exhaust gas recirculation rates of up to 30%. Both technologies enable the reduction of the knock probability and the decrease in the catalyst inlet temperature to protect the aftertreatment system components. The strongest exhaust temperature reduction is found with cooled low-pressure exhaust gas recirculation. With stoichiometric air-fuel ratio and water injection, the indicated efficiency is improved to 40% and the carbon monoxide emissions are reduced. The nitrogen oxide concentrations are increased compared to the fuel-rich base operating conditions and the nitrogen oxide emissions decrease with higher water content. With stoichiometric air--fuel ratio and exhaust gas recirculation, the indicated efficiency is improved to 43% and the carbon monoxide emissions are decreased. Increasing the exhaust gas recirculation rate to 30% drops the nitrogen oxide emissions below the concentrations of the fuel-rich base operating conditions. [ABSTRACT FROM AUTHOR]

The increasing need for fossil energy along with waste gases led to both the increase in the environment pollution and search for alternative energy sources. The most important criterion here is to maintain sustainability and find a zero-emission source. In this regard, since hydrogen is obtained from the water electrolysis or the digestion of hydrocarbons, it is one of the alternative clean energy sources. Despite intense usage of the hydrogen in the refineries and industries, it is also predicted to be common use of hydrogen in power systems as fuel soon. The present study analysed the change in performance of gas turbines depending on water injection into the air before the compressor. In the study, two different gas turbine systems (non-recuperative and recuperative) is designed. For the use of hydrogen as a fuel for the designed gas turbine systems, the injected water amount was increased from 0 kg-water/s to 46 kg-water/s, while the GT-Turbine inlet pressure increased from 4 bar to 20 bar. For these circumstances, the performance of the gas turbine systems investigated depending on injected water-air mass flow ratio and GT-Turbine inlet pressure. After comprehensive analyses, the maximum net power production, thermal and exergy efficiencies of the non-recuperative gas turbine were calculated as 58,459 kW, 22.33% and 23.07% at 20 bar and 0.031 injected water/air mass flow ratio. The maximum net power production, thermal and exergy efficiencies of the recuperative gas turbine system were calculated as 131,307 kW, 50.16% and 52.70% at 4 bar and 0.057 injected water/air mass flow ratio. • Analysing the effect of water injection into the air at the compressor inlet for GTs. • Evaluation of the effect of using hydrogen on the performance of the GT systems. • Comparing performances of non-recuperative and recuperative GT systems. • Obtaining the best-performing system parameters of non-recuperative/recuperative GTs. • Analysing the environmental impact of water injection and hydrogen usage as fuel. [ABSTRACT FROM AUTHOR]

In view of the dual-media characteristics of low permeability buried hill reservoirs, the fingering and tongue-feeding phenomena are serious during the flooding development process. The flooding phase breaks through prematurely, the crude oil utilization in the matrix is low, and the final oil displacement efficiency is low. In this paper, the laboratory analysis of long lithologic displacement was conducted for the XL low permeability buried hill reservoir block to evaluate the effects of fracturing, displacement media and displacement methods on the development. The experimental results show that the oil displacement efficiency value of the continuous gas injection flooding process before fracturing is 60.98%, the oil displacement efficiency value of the continuous gas injection flooding process after fracturing is 58.93%, and the oil displacement efficiency value of the continuous water injection flooding process after fracturing is 69.94%. The water injection volume during continuous water flooding after fracturing is 1.60PV, the oil displacement efficiency during pulse gas flooding after fracturing is 64.01 %, the oil flooding efficiency during pulse water flooding after fracturing is 67.63%, and the water injection volume of the pulse water flooding process after fracturing is 1.92PV. Those results show that the continuous oil flooding process after fracturing is the highest in the final oil displacement efficiency, and it requires less water injection than the pulse water flooding process after fracturing. The experimental research in this paper shows that in the process of dual-media displacement development of low permeability buried hill reservoirs, the continuous water flooding displacement development process after fracturing can communicate well with the matrix and highpermeability channels, and at the same time reduce the breakthrough time of the displacement phase to obtain better oil displacement efficiency. [ABSTRACT FROM AUTHOR]

One of the most critical pollutant emissions in spark ignition (SI) engines is hydrocarbon (HC) emissions, which are partially incomplete combustion products. In this study, the upper surface of a piston was covered with ceramic material with a high heat reserve in order to reduce HC emissions from SI engines and to increase engine performance. However, when the upper surface of the piston was coated with a high heat reserve material, NOx emissions released from the engine especially under full load conditions increased compared with the standard case, due to increased temperatures inside the cylinder. Water was injected into the intake manifold to control NOx emissions. As a result of the experimental studies carried out, it was found out that in the thermal barrier–layer engine there was a 3.5% increase in effective power and a 4.9% decrease in specific fuel consumption compared with the standard case. HC emissions decreased by 36% and NOx emissions increased by 11.1%. When water injection was applied to the engine, HC emissions decreased by 43% and NOx emissions decreased by as much as 24.8% compared with the standard engine data. Engine performance parameters improved by 3.44% compared with the standard case. [ABSTRACT FROM AUTHOR]

The objective of this work is to investigate experimentally controlling cavitating flow over NACA66 (MOD) hydrofoils by means of an active water injection along its suction surface. The continuous water vertically jets out of the chamber inside the hydrofoil through evenly distributed surface holes. Experiments were carried out in cavitation water tunnel, using high-speed visualization technology and the particle image velocimetry (PIV) system to study the sheet/cloud cavity behaviors. We studied the effects of this active control on cavity evolution with four kinds of jet flow at two different jet positions. We analyzed the effect of water injection on the mechanism of the cavitating flow control. The results were all compared with that for the original hydrofoil without jet and show that the active jet can effectively suppress the sheet/cloud cavitation characterized by shrinking the attached cavity size and breaking the large-scaled cloud shedding vortex cavity into small-scaled ones. The optimum effectiveness of cavitation suppression is affected by the jet flow rates and jet positions. The water injection at flow rate coefficient 0.0245 with the jet position of 0.45C reduces the maximum sheet cavity length by 79.4 % and the cavity shedding is diminished completely, which gives the most superior effect of sheet cavitation suppression. The jet blocks the re-entrant jet moving upstream and weakens the power of re-entrant jet and thus restrains the cavitation development effectively and stabilizes the flow field. [ABSTRACT FROM AUTHOR]

In-cylinder water injection is a promising approach for reducing NOx and soot emissions from internal combustion engines. It allows one to use a higher compression ratio by reducing engine knock; hence, higher fuel economy and power output can be achieved. However, water injection can also affect engine combustion and emission characteristics if water injection and injector parameters are not properly set. Majority of the previous studies on the water injection are done through experiments. Therefore, subtle aspects of water injection such as in-cylinder interaction of water sprays, spatial distribution of water vapor, and effect on flame propagation are not clearly understood and rarely reported in literature due to experimental limitations. Thus, in the present article, a computational fluid dynamics investigation is carried out to analyze the effects of direct water injection under various injector configurations on water evaporation, combustion, performance, and emission characteristics of a gasoline direct injection engine. The emphasis is given to analyze in-cylinder water spray interactions, flame propagation, water spray droplet size distribution, and water vapor spatial distribution inside the engine cylinder. For the study, the water-to-fuel ratio is varied from 0 to 1. Various water injector configurations using nozzle hole diameters of 0.14, 0.179, and 0.205 mm, along with nozzle holes of 4, 5, 6, and 7, are considered for comparison in addition to the case of no_water. Computational fluid dynamics models used in this study are validated with the available data in literature. From the results, it is found that the emission and performance characteristics of the engine are highly dependent on water evaporation characteristics. Also, the water-to-fuel ratio of 0.6 with 6 number of nozzle holes and the nozzle diameter of 0.14 mm results in the highest indicated mean effective pressure and the lowest NOx, soot, and CO emissions compared to other cases considered. [ABSTRACT FROM AUTHOR]

Steady-state experiments were conducted on a 12.4L, six-cylinder heavy-duty engine to investigate the influence of port-injected water and dilution via exhaust gas recirculation (EGR) on combustion and emissions for diesel and gasoline operation. Adding a diluent to the combustion process reduces peak combustion temperatures and can reduce the reactivity of the charge, thereby increasing the ignition-delay and, allowing for more time to premix air and fuel. Experiments spanned water/fuel mass ratios up to 140mass% and exhaust gas recirculation ratios up to 20vol% for gasoline and diesel operation with different injection strategies. Diluting the combustion process with either water or EGR resulted in a significant reduction in nitrogen oxide emissions along with a reduction in brake thermal efficiency. The sensitivity of brake thermal efficiency to water and EGR varied among the fuels and injection strategies investigated. An efficiency breakdown revealed that water injection considerably reduced the wall heat transfer; however, a substantial increase in exhaust enthalpy offset the reduction in wall heat transfer and led to a reduction in brake thermal efficiency. Regular diesel operation with main and post injection exhibited a brake thermal efficiency of 45.8% and a 0.3% reduction at a water/fuel ratio of 120%. The engine operation with gasoline, early pilot, and main injection strategy showed a brake thermal efficiency of 45.0% at 0% water/fuel ratio, and a 1.2% decrease in brake thermal efficiency for a water/fuel ratio of 140%. Using EGR as a diluent reduced the brake thermal efficiency by 0.3% for diesel operation, comparing ratios of 0% and 20% EGR. However, a higher impact on brake thermal efficiency was seen for gasoline operation with early pilot and main injection strategy, with a reduction of about 0.8% comparing 0% and 20% EGR. Dilution by means of EGR exhibited a reduction in nitrogen oxide emissions up to 15 g/kWh; water injection showed only up to 10 g/kWh reduction for the EGR rates and water/fuel ratio investigated. [ABSTRACT FROM AUTHOR]

The reservoirs from Chang 4 to Chang 7 of the triassic Yanchang formation in Ordos Basin are the main production strata in the Wuqi Oilfield, China. To supplement formation energy and increase reservoir diversion capacity, adjustment measurements such as water injection and hydraulic fracturing are needed urgently. Research on reservoir sensitivity is essential to reduce reservoir damage and minimize developmental impacts. Based on an analysis of the lithologic characteristics, cementation and pore structure of the Chang 4-Chang 7 reservoirs, reservoir sensitivity flow evaluation experiments were conducted according to the evaluation criteria for a clastic reservoir. Reservoir sensitivity types and sensitivity and influencing factors were analyzed. The experimental results show that the different types of reservoirs had different reservoir sensitivities. The Chang 4+5 reservoirs were moderately to weakly sensitive to velocity, weakly sensitive to water, weakly sensitive to acidity and weakly to moderately sensitive to alkalinity. The Chang 6 reservoir was weakly to moderately sensitive to velocity, weakly to moderately sensitive to water, moderately to strongly sensitive to acidity and weakly sensitive to alkalinity. The Chang 7 reservoir was weakly sensitive to velocity, not at all to weakly sensitive to water, weakly to moderately sensitive to acidity and weakly sensitive to alkalinity. Reservoir sensitivity is not only affected by the composition and distribution of sensitive minerals but also by the heterogeneity of the pore structure of the reservoir. Therefore, the sensitivity characteristics of different types of reservoirs should be adjusted accordingly during water injection and fracturing. [ABSTRACT FROM AUTHOR]

• A new blast-injection technology was proposed for coal and gas out-burst control. • The out-burst mechanism and the effect of the proposed technology were studied. • Equipment and application protocols were developed to optimize the technology. • A field experiment demonstrated a significant reduction in out-burst risk. Coal and gas out-bursts are a major risk in deep gassy coal mines. In order to minimize the out-burst potential during the mining process, we propose a novel blast-injection integrated (BII) technology. In this technology, a group of de-stress blasts are first used to de-stress the area near the active mining face and push the stress peak further away from the mining face. The cracks generated by the blasting improve the connectivity between the pre-existing fractures and promote gradual release of gas at the mining face. This is followed by water injection directly into the coal seam through the blast holes. The injection of water can greatly improve coal plasticity and reduce the initial speed of gas diffusion, ultimately reducing the potential for violent out-bursts. To implement this technology, a set of devices were developed that include hole packers and transport and safety accessories. The BII technology was subsequently tested at an active mine. It was found that the stress relief zone in front of the coal face increased longitudinally by ∼5 m, and the rate of gas emission at the mining face doubled within 30 min after the de-stress blasting. The injection water volume after the de-stress blasting also increased by 25 times compared to the un-blasted condition, and the monthly gas concentration in the return airway decreased from 0.58% to 0.36%. Additionally, the concentration of dust in the return airway was found to decrease. Based on the field test results, it was concluded that BII technology is an effective measure to limit coal and gas out-burst potential. [ABSTRACT FROM AUTHOR]

Predictions of salt solubility, brine vapor pressure and density are necessary to plan subsurface and surface operations. In this work, a comparative study was conducted to investigate prediction capabilities for salt solubility, equilibrium and volumetric properties of several minerals in "Formation" water by the Pitzer model (a commonly used industrial model) and by the ePC-SAFT equation of state (EOS). To achieve this, several validation and comparison steps were considered for reliable implementation of both models. Firstly, solubility, brine densities and vapor pressures for single-salt solutions were predicted. Afterward, the models' applications were extended to several mixtures of two salts to predict solubility compared to experimental data from available literature. ePC-SAFT shows promising accuracy. The average relative deviation for prediction of liquid density (which cannot be estimated with the Pitzer model) for single-salt solutions of NaBr, KCl, NaCl and Na2SO4 are 1.13%, 0.70%, 1.02% and 0.36%, respectively. The average relative deviation from experimental data of vapor pressure for mixtures of NaCl and KBr is 0.75% and for mixtures of NaBr and KCl is 0.74% for systems with different concentrations. Moreover, a stochastic regression procedure is presented to evaluate the ePC-SAFT parameters. This technique is used for strontium in different salt solutions. The average relative deviation for mean ionic activity coefficients calculated by ePC-SAFT from experimental data using the ePC-SAFT parameters of strontium from the work of Held et al. [1] for single-salt solutions of strontium chloride, strontium bromide, strontium iodide, strontium nitrate and strontium perchlorate are 19.73%, 19.96%, 15.15%, 14.95% and 25.70%, respectively. These values using the ePC-SAFT parameters of strontium regressed in this work are 6.98%, 10.13%, 8.33%, 9.59% and 10.08%, respectively. Finally, the solubility of different salts was studied for mixing of formation water (FW) and injection water (SW). [ABSTRACT FROM AUTHOR]

Elements of a homogeneous algorithm for numerical simulation of the thermogasdynamic parameters of a viscous two-phase nonequilibrium chemically reactive nonisobaric rocket-engine exhaust jet have been formulated within the framework of a two-velocity and two-temperature continuum model on the basis of "viscous-layer" and "narrow-channel" equations. By numerical calculation, the authors has established the basic regularities of the influence of the water feed, the mixing of the jet with air, and the afterburning of the high-temperature rocket-engine jet in the air oxygen on the flow structure and thermogasdynamic and thermophysical parameters of the jet. [ABSTRACT FROM AUTHOR]