Early Stage Of Injection Research Articles

Semi-analytical model to determine perforation interval for secure CO2 storage in saline aquifers

Abstract Due to density difference between injected CO 2 and in-situ brine, the pressure difference between wellbore and formation varies with depth in a CO 2 injection well. Consequently the flux distribution along a vertical well is not uniform during the early stages of injection. For injection rates below a certain threshold, this can lead to only a fraction of the perforations contributing to injection. Generally this reduces the efficiency of CO 2 immobilization by dissolution in brine and by residual trapping because less volume of rock and brine comes in contact with injected CO 2 . Thus for injection rates below the threshold, optimization of the length of the perforated interval is required to maximize trapping. We describe a semi-analytical algorithm that finds the optimum interval of injection for a given flow rate so that all the perforations contribute throughout the injection period. Although bottomhole pressure rises while injecting in smaller perforation interval, the greater mobility of the CO 2 phase upstream of the drying front reduces this increase and enables the use of smaller interval. In the case of a horizontal well, the length of well plays an important role in determining the CO 2 trapping. The two competing effects, trapping along the well length and along lateral direction, determine the optimum well length required. Greater well length increases the trapping in direction of well path but reduces in lateral direction because of the ratio of gravity forces to viscous forces becomes larger. Thus dominance of either of these competing effects and cost of drilling determine optimal well length. This study illustrates the effect of different injection strategies on multiple objectives of CO 2 sequestration including maximizing trapping and minimizing leakage potential. We find that the benefits of a strategy to maximize injectivity may be offset by less CO 2 entering secure modes of storage.

AN EXPERIMENTAL STUDY ON SPRAY TRANSIENT CHARACTERISTICS IN FUEL CONTAINING CO2

Spray of fuel containing CO2 is a method of twin-fluid spray that involves dissolving CO2 gas into liquid fuel before it is ejected from the injector. The technique of dissolving CO2 gas into liquid fuel is essentially different from other methods of twin-fluid spray and leads to significant improvements in performance in terms of smaller drop sizes and lower injection pressures. This paper presents an experimental study on the process of injecting a bubble jet of transient spray with fuel containing CO2 using high-speed imaging technology. Experiments were performed under atmospheric conditions with a diesel hole-type nozzle. The effect of injection pressure on the bubble jet atomization process was evaluated, especially in the early stage of injection. The transient characteristics of spray, such as spray angle and spray tip penetration, were also investigated. The images clearly display the developing process of the spray. New insight into the process of bubble jet injection of fuel containing CO2 spray was obtained, and a possible mechanism to explain the phenomena was proposed.

Experimental investigation of electrostatic effects on ethanol and ethanol-diesel blend sprays in atmospheric ambiance

An experimental investigation of electrosprays of ethanol-diesel blends and electrostatically assisted injection of ethanol and ethanol-isooctane blends was performed in order to investigate the potential of novel injection techniques for ethanol-containing fuels. An exponential dependence of liquid fuel conductivity on ethanol content was established. Simple, fundamental electrosprays of ethanol-diesel blends containing 5-15% ethanol exhibited micro-dripping atomisation and produced sprays that approached the monodispersity that has been observed for pure ethanol sprays operating in the cone-jet mode. Experiments were also performed with ethanol and ethanol?isooctane blends on a commercially available swirl-type fuel injector that was modified with a conductive cap in order to electrostatically charge the fuel emerging from it. Electrostatically charged ethanol sprays penetrated in the ambient gas significantly less at the early stage of injection, especially for lower injection pressures. In addition, the angle formed by the hollow cone of spray was larger for the charged sprays. Such effects are expectedly diminishing with decreasing alcohol content.

Analysis of diesel spray structure using a hybrid model

This study proposes a hybrid model that consists of modified Taylor Analogy Breakup (TAB) model and a Discrete Vortex Method (DVM). In this study the simulation is divided into three steps. The first step is to analyze the breakup of the injected fuel droplets by using a modified TAB model. The second step is based on Siebers’ theory of liquid length, which is an analysis of spray evaporation. The liquid length analysis for injected fuel is used to connect both the modified TAB model and the DVM. The final step is to reproduce the ambient gas flow and the inner vortex flow of the injected fuel by using the DVM. In order to examine this hybrid model, we performed an experiment involving a free evaporating fuel spray at the early injection stage within an environment similar to that found inside of an engine cylinder. The numerical results were calculated by using the present hybrid model and compared to the experimental results. The calculated results of the gas jet flow that were determined through the DVM corresponded well with the experimental results for a downstream evaporative spray. It is also confirmed that an ambient gas flow occupies the downstream region of a diesel spray.

Flow characteristics of spray impingement in PFI injection systems

The present paper addresses an experimental study of the dynamic exchanges between the impact of an intermittent spray and the liquid film formed over the target, based on detailed phase Doppler anemometry (PDA) measurements of droplet size, velocity and volume flux in the vicinity of the impact. The flow configuration is that of a pulsed injector spraying gasoline onto a flat disc to simulate the port fuel injection (PFI) of an internal combustion engine operating at cold-start conditions. The measurements evidence that the outcome of impact cannot be accurately predicted based on the characteristics of the free spray, but requires precise knowledge of the flow structure, induced by the target. The implications for spray–wall interaction modelling are then discussed based on the application of conservation equations to the mass, momentum and energy exchanged between the impinging droplets and the liquid film. The results show that the liquid film starts to form in the vicinity of the stagnation region at early stages of injection and a non-negligible proportion of droplets impinging at outer regions splash after interaction with the film. Film disruption is mainly driven by the intermittent axial momentum of impinging droplets, which enhances the vertical oscillations. The radial momentum imparted to the liquid film at the stagnation region is fed back onto secondary droplets emerging later during the injection cycle at outwards locations, where momentum of impacting droplets is much smaller. As a consequence, although the number of splashed droplets is enhanced by normal momentum, their size and ejection velocity depends more on the radial spread induced onto the liquid film and, hence, on the radial momentum at impact. The analysis further shows that existing spray–wall interaction models can be improved if the dynamic exchanges between the impacting spray and the liquid film are accounted.

Near Nozzle PIV Measurements and Droplets Size Pattern of a GDI Swirled Spray(Spray Technologies, Atomization)

The aim of the present work is to analyze the effect of the injection pressure on the flow pattern and droplets size in a gasoline hollow-cone spray generated by a swirled injector, applying Particle Image Velocimetry (PIV) and Phase Doppler Anemometry (PDA). Experiments were carried out in the range of injection pressures between 6 and 10 Mpa using a common rail injection system, a commercial swirled type injector with a nozzle diameter of 0.50 mm and a cone angle of 67°. The investigation was carried out injecting the fuel in a chamber at ambient temperature and pressure. A 2-D imaging technique was used to follow the global evolution of the spray as function of the injection time in order to estimate the jet development, the morphology of the spray, and the instantaneous velocity field of fuel droplets. PIV images were captured, firstly, aligning the light sheet to the vertical axis of the spray; then, experiments were also taken with the light sheet placed through the cross section of the spray in order to explore the structure and velocity field, at different distances from the nozzle. A PDA system was used to acquire, simultaneously, the droplets velocity as well the droplets size. The system, equipped with an argon-ion laser, was set in forward scattering mode at an off-axis of 30°. Measurements were performed at the same operative conditions as for the visualization ones, choosing different distances from the nozzle. Droplets velocity and size data set provided a minimum of 40,000 in-cycle resolved valid data that were analyzed using the ensemble averaging technique. Results provided detailed information on the spatial velocity distribution and size of droplets close to the nozzle region. Ensemble averaged velocity field of fuel droplets obtained on the vertical plane through the injector axis showed high velocity values up to 100 m/s in the early stage of injection, whereas during the transition to completely developed main spray, droplets travel at lower velocities. The velocity field obtained on the cross section of the spray, at locations close to the nozzle (5 and 10 mm) and in the early stage of injection (up to 0.6 ms), showed a symmetric radial velocity field around the spray axis. Size measurements performed near the nozzle showed a D_<10> profile constant along the stationary period of injection and not affected by the injection pressure. Results also gave a global increasing trend of the temporally averaged mean diameter along the spray axis.

Halo formation at early stage of injection in high-intensity hadron rings.

Halo formation under a nonequilibrium state for a two-dimensional Gaussian beam in a FODO lattice, which is an array of magnets where F is focusing, D is defocusing, and O is the drift space between magnets, was examined in terms of a transition of time-varying nonlinear resonances. Nonlinear resonant-interactions between individual particles and intrinsic beam-core oscillations result in a beam halo. The location of the halo is analytically tractable using canonical equations derived from an isolated resonance Hamiltonian.

Average Droplet Size Distribution of a GDI Spray by Simultaneous Fluorescence/Scattering Image Technique

The objective of this study is to investigate the average droplet size distributions of a GDI spray by simultaneous fluorescence/scattering image technique. GDI engine is recently very popular because of high engine efficiency and low emissions. However, the injectors must have good spray characteristics because the fuel is directly injected into the cylinder. The fuel mixtures used in this study were 2% of fluorobenzene, 9% of DEMA(diethyl-methyl-amine) and 89% of hexane by volume. The system for obtaining 2-D fluorescence/scattering images of fuel spray was constituted of a laser sheet, a doubling prism, optical filters, and an ICCD camera. Using the ratio of the fluorescence to the scattering intensities, SMD distributions were obtained. SMD measured by the technique was compared with that obtained by PDA. It was found that average droplet size was bigger at spray center in the early stage of injection and at the outer periphery of the spray in the late stage of injection.

Observation of the Atomization Process of an Intermittent Spray From a Diesel Nozzle in Its Very Early Stage.

The atomization behavior of an intermittent fuel spray from a diesel nozzle was clearly observed by means of shadowgraphy using an image-converting camera with the framing rate of 105 f.p.s. and an image-intensified CCD camera with high-speed gating. A rather wide range of valve-opening pressure (5 to 70 MPa) was covered, and simultaneous measurement of the injection pressure inside the nozzle sac was also attempted to clarify the atomization mechanisms at its very early stage of injection. At the beginning of injection, the emergence of a liquid column was observed. Initially, it has almost the same diameter as the nozzle hole and then spreads radially, forming the spray angle in the vicinity of the nozzle exit. The timing of this spray-angle formation becomes earlier with the increase in valve opening pressure, even if the pressure inside the nozzle sac at this moment does not vary. This pressure approximately corresponds to that of the transition region in an atomization regime of a steady jet.

Initial Breakup and Atomization of Droplets in Diesel Fuel Sprays.

Because combustion and exhaust emissions in direct injection engines are strongly influenced by fuel-air mixing during the ignition delay period, it is important to investigate the disintegration of fuel flow and droplet formation at a very early stage of injection. In this study, photographs of sprays up to 400 μs from the start of injection were taken using a Nano-spark light source and a newly developed droplet image analysis method. The results show that the contour of the spray suddenly changes into a large-scale structure at about 200 μs after the start of injection. In the sprays before this time, disintegration occurs in narrow areas near the spray tip. However, after this time, branch like structures cause the disintegration. It is observed that many small droplets remain in the vicinity of the nozzle tip in initial sprays up to at least 200 μs.

Observations of Microscopic Structures of Diesel Sprays with a Nano-spark Light Source.

To elucidate the process of fuel-air mixture formation before ignition in diesel engines, it is important ot investigate the disintegration of fuel flow and droplet formation in intermittent sprays at the very early stage of injection. In this study, the microscopic structures of nonevaporating sprays up to 0.5 ms from the start of injection are studied using photographs with high time resolution, using a nanosecond spark light source. The results show that the fuel flows have very distinctive shapes just after the start of injection. Fragments of disintegrated fuel are observed even at 50 microseconds from the commencement of injection. Ambient pressure has a great effect on the mode of disintegration.

A mechanism of catecholamine tolerance in congestive heart failure--alterations in the hormone sensitive adenylyl cyclase system of the heart.

It is well known that failing hearts show diminished responsiveness (desensitization) to catecholamines. In this study, 2 different animal models were used to investigate the alterations in the hormone sensitive cardiac adenylyl cyclase system in a congestive heart failure. In the first model, cardiomyopathic Syrian hamsters (BIO53.58), we found reduced activity of the catalytic protein of adenylyl cyclase; this reduction was more prominent in an older animals (28-week-old vs 16-week-old). At both ages, the amount of inhibitory GTP-binding protein (Gi) was markedly increased in BIO53.58 compared to control healthy hamsters. Moreover the increased Gi was shown to be fully functional in the inhibitory pathway of the adenylyl cyclase system. In the second model, chronically norepinephrine-infused rats, we found a decrease in beta-adrenergic receptor density at an early stage of injection (3 days), while the activity of catalytic protein decreased beyond 14 days of injection, and the amount of Gi increased after 7 days of injection. These results suggest that increased plasma catecholamine concentrations in the setting of congestive heart failure might be a major trigger for qualitative and quantitative alterations observed in various components of cardiac adenylyl cyclase system, and that GTP-binding proteins and catalytic protein of adenylyl cyclase are involved in the mechanism of desensitization especially after chronic in vivo stimulation of adrenergic receptors.

Atmospheric Dispersion of Ammonia During Application of Anhydrous Ammonia Fertilizer

AbstractThere is a need to develop techniques for the prediction of the aerial spread of hazardous chemicals released in agricultural operations. The dispersion of ammonia (NH3) gas during soil injection of anhydrous NH3 is one such example. In previous work we established that after injection NH3 escaped from the soil to the atmosphere at a rate that decreased exponentially with time; in our study the whole process took about 2 h. In this paper we combine the dynamics of the emission process with existing micrometeorological theory for atmospheric dispersion from line sources, to predict NH3 concentrations in the air at the downwind edge of the field. The predictions are compared with concentrations measured during an injection operation.Although the total NH3 emission during the operation was only 1.2 kg/ha, NH3 concentrations up to 213 µg/m3 were recorded at the downwind edge in the early stages of injection. Wind speed and atmospheric stability had large influences on NH3 dispersion. In light winds and stable conditions NH3 concentrations &gt; 100 µg/m3 were recorded when the applicator was &gt; 200 m upwind, and some NH3 enrichment still occurred when it was 600 m upwind.The model underestimates NH3 concentrations when the treated width is &lt;30 m, but predicts them very well at greater distances in both stable and unstable conditions. The model is used to predict NH3 concentrations downwind of the applicator for a range of wind speeds and emission strengths.The approach should prove useful not only for estimating NH3 pollution hazards but also for predicting dispersion in related agricultural operations where a time‐dependent decay and/or a line‐source analogy are appropriate.

Structural Development of the Hanover-Fierro Pluton, Southwestern New Mexico

Structures associated with the forcibly emplaced Hanover-Fierro pluton were studied to determine its mechanisms of intrusion. The pluton has been extensively examined, and good three-dimensional information is available from drill holes and mines. The funnel-shaped body plunges northward, and approximately 700 m of structural relief appears along the length of the present outcrop. At higher structural levels around the southern end, the country rocks were deformed by folding and thrusting; at deeper levels near the center and north end, the country rocks were deformed largely by rotation and tectonic thinning. Joints in the pluton indicate that maximum principal compressive stress (σ 1 ) rotated from a vertical orientation at depth to a horizontal east-west orientation near the surface, forming a pair of vertical conjugate shear (transverse) joints of moderate dihedral angle (36°). Along the main axis of the pluton, a set of vertical north-trending (longitudinal) joints formed; plumose structure on the joints indicates that they propagated upward . Apparently, upward-directed maximum principal compressive stress governed the direction of fracture propagation, and tensile stresses caused by outward rotation of σ 1 governed their orientation . The intermediate principal compressive stress (σ 2 ) rotated with σ 1 , forming a set of joints dipping gently inward toward the center of the pluton with dip progressively decreasing from the center to the margins. Structures around the pluton indicate that the early stage of injection produced arching and deformation by simple shear in the sedimentary overburden. With continued intrusion, an entire plug of overburden was uplifted, and lateral pressure of the magma locally exceeded the coefficient of friction along pre-existing regional joints causing minor shearing. Strata near the pluton were significantly thinned tectonically. During the final stage, lithostatic pressure of 200 to 640 m of overburden was no longer sufficient to prevent large-scale deformation, and folds and thrusts developed around the pluton.

Evaluation and Modification of the Means San Andres Unit Waterflood

Following detailed studies, the injection scheme of this unit was expanded to include interior injection as well as the original peripheral injection. The success of the project has borne out the peripheral injection. The success of the project has borne out the fact that a combination of engineering analysis and geological interpretation is far more effective in understanding performance than either study could be by itself. Overview Injection modifications made to the Means San Andres Unit waterflood in 1970 increased the gross unit oil production from 13,000 to more than 17,000 B/D during calendar 1970. Those modifications changed the waterflood scheme from an indirect peripheral waterflood to direct pressure support from peripheral waterflood to direct pressure support from interior injection. As a result, portions of the reservoir that previously were not effectively flooded have been brought under direct waterflood. Other portions of the reservoir that had been receiving some indirect support from the peripheral injection are now being flooded more efficiently because of the direct support from the interior injection. History The Means field is located in Andrews County, Tex.. about 15 miles northeast of the city of Andrews. Geologically, the field is on the eastern edge of the Central Basin Platform. It lies in a north-south trend of San Andres production stretching for more than 100 miles in West Texas. The trend contains several very prolific San Andres reservoirs, most of which are now under active waterflood. The means San Andres field was discovered in 1934. Early wells showed a potential exceeding 1,000 BOPD, with some as high as 5,000 BOPD. Although the center of the field was developed in the 1930's, complete definition of the field came slowly as development moved towards the relatively tight rock around the flanks of the field. The extreme southern part of the field was not developed until the part of the field was not developed until the mid-1950's after the introduction of hydraulic fracturing. The eastern part of the Means field was unitized as the Means San Andres Unit early in 1963. Water injection was started around the periphery shortly after unitization. The injection plan was designed to conform to the natural contours in the field. In an attempt to augment what was suspected to be a very weak natural water drive, the injectors were completed below the oil-water contact. Fig. 1 reflects the early response to the peripheral injection. The field had produced its allowable for several years, so the produced its allowable for several years, so the production response was not immediate. Very shortly production response was not immediate. Very shortly after the start of injection, however, the average GOR dropped significantly from 1,100 to about 350 scf/bbl only slightly greater than the solution GOR of 260 scf/bbl. The original bottom-hole pressure of about 1,800 psi had gradually declined to pressure of about 1,800 psi had gradually declined to about 950 psi at the start of water injection. During early water injection the average reservoir pressure increased to 1,150 psi, where it was maintained fairly stable during the relatively constant production times. The field produced little water during primary and early stages of injection. In fact, after production under a unit allowable commenced in 1965, the water production decreased considerably, and only recently production decreased considerably, and only recently has it increased to a significant value. After the 1967 Mid-East crisis with the attendant high market demand, the Unit reached the limit of its capacity for the first time. P. 1421

Estimating Gas-Water Contacts in Aquifer Gas Storage Fields Using Shut-In Wellhead Pressures

Abstract Continuous and accurate information on gas-water contact is desirable in the initial filling of aquifer storages to prevent possible loss of gas. Some information on the extent of the gas bubble is obtained as gas reaches observation wells completed in the storage zone and from periodic neutron logging. However, sometimes an insufficient number of wells are drilled for accurate structural control and for adequate knowledge of the gas bubble growth, particularly during the initial stages of development. This article presents two simple methods of estimating gas-water contacts in aquifer gas storage fields using unstabilized shut-in wellhead pressures. The first method involves setting up a shut-in wellhead pressure-vs-depth relationship for stabilized conditions. For unstabilized conditions an aquifer pressurization correction is applied enabling calculations to be made without the necessity of shutting in a field for the long period of time required for stabilization. The amount of pressurization of the aquifer over its original pressure can be obtained from a water observation well located near the edge of the gas bubble. This method gives the lowest point of the gas-water contact at the time the pressures are measured. In the second method, a pressure fall-off curve is extrapolated to stabilized conditions. It was found that shut-in time required to obtain a reliable extrapolation increased as the storage volume increased and pressurization of the aquifer occurred. Accordingly, the usefulness of this method is largely restricted to the early injection stage of field development or when no water observation well is available for calculations by the first method. Presented here are calculations of gas-water contacts based on pressure data from two storage fields which agree closely with other gas-water contact information. Introduction In developing gas storages in aquifers, experience indicates that initially the injected gas has a tendency to finger out rapidly through thin zones of high permeability, and often travels considerable distances horizontally and vertically. Since gas tends to move parallel to bedding planes, the gas-water contact is usually lower at the edge of the gas bubble than in the center. Often the injection pressure differential is high enough that it could force gas to spill out below the lowest closing contour between observation wells. Knowledge of the gas-water level is especially important during early stages of development. Some information on the horizontal and vertical movement of gas can be obtained as gas reaches observation wells completed in the storage formation and from neutron logs run periodically in both injection and observation wells. Katz proposed a method of calculating the horizontal distance from a water observation well to the edge of the gas bubble. However, none of these methods indicates how far the gas may extend down the structure between observation wells. when structural control is poor or unpredictable, as in the case of an erosional surface, an inherent danger exists that gas may escape at unknown spill points. During initial development, information on the movement of the gas-water contact is valuable in indicating whether operations are proceeding satisfactorily. Under normal operations the gas-water contact should progressively deepen as the volume of gas in storage is increased. If it does not, spillage or leakage is indicated. It is possible for the gas-water contact to remain constant at low rates of injection as a result of gravity drainage of water out of the gas bubble. However, periodic determinations of the gas-water contact as the reservoir is filled with gas at a uniform rate should reveal any abrupt decrease in movement which would indicate that spillage or leakage has developed. Gas-water contact data also provide a means of calculating water displacement efficiency being achieved. By determining the amount of gas stored in a unit rock volume, storage volumes at various levels of the gas-water contact can be more accurately estimated and arrival time of gas at an observation well can be predicted more closely. JPT P. 877ˆ

保存血に於ける細菌汚染の実験的研究

The growth curves of three experimentally contaminated strains of Pseudomonas and one of Aerobacter aerogenes in banked blood were shown.During first 24hrs. after inoculation, the viable number of bacteria decreased remarkably on account of bactericidal activity of serum, but surviving cells started again to grow during the following 24 to 48hrs., the growth being completed in 7 to 14 days.Seventy-one per cent of 40 strains grew abundantly in banked blood when incubated at 5-6°C, while only one strain among other water bacteria (21 strains of Achromobacter, Alcaligenes and Flavobacterium) multiplied under these conditions.Therefore, it is obvious that pseudomonas is the most dangerous contaminant among water bacteria.In order to explain the mechanism of shock syndrome developing after the transfusion of contaminated blood, the effects of intraveneous injection of washed bacterial cells into experimental animals were investigated.A remarkable depressor action was demonstrated when the cell suspension of either Aerobacter or Pseudomonas was injected. On the other hand, the action was not significant with Micrococcus. Should an accident occur, it is necessary to isolate the contaminated bacteria from the patient or after death.The author demonstrated that if the contaminant was coli-aerogenes group organism, the causative agent was easily isolated from the human materials. However, the isolation was not successful in the case of pseudomonas, because the water forms of pseudomonas were destroyed in an early stage of injection.