Dynamic PET data analysis.

The spray impulse and injection pressure of each hole of the 4-hole injector of F186 engine were tested by using the transient test system for flow coefficient and injection rate of each hole of the injector, and the injection rate, fuel injection quantity and flow coefficient of each hole were obtained. According to the measured injection rate of each hole and cycle fuel injection quantity, a 3D model of the diesel engine was established with the FIRE software, and the uniform injection rate and uneven injection rate of each hole were made as the injection setting for the combustion simulation to comparatively analyze the influence of the uneven injection rate of each hole on the combustion process of diesel engine. As the injection of each hole is uneven, some holes with high injection rate have long fuel spray penetration distance and the fuel spray is fully mixed with the air, and the ignition starting point is moved ahead. When compared with the case of uniform injection rate, the phase corresponding to the heat release rate in the case of uneven injection rate is moved forwards, the maximum cylinder pressure and temperature rise fast, the maximum cylinder pressure and maximum average temperature in cylinder are higher, the NO generation is larger, and the Soot generation is slightly larger. In the case of uneven injection rate from four holes, as the utilization of air in the hole-located cylinder space by the fuel spray is uneven, the hole with a large quantity of injection makes the oxygen in the hole-located cylinder space relatively low, the wall collision of the hole with high injection rate is more, and the diffusion combustion is incomplete and insufficient.

Nuclear-decay data: The statement of uncertainties

At the annual general meeting of the International Committee for Radionuclide Metrology (ICRM) held last June at the Physikalisch-Technische Bundesanstalt, it was suggested that letters should be sent to the editors of journals that publish nucleardecay data, drawing attention to the need for specific statements of the uncertainties that are associated with such data. Authors frequently fail to state clearly the nature of their estimates of uncertainty, and not all editors insist on such clarity, so that evaluators of nuclear-decay data often f'md that it is necessary to consult with the individual authors to arrive at the weighting factors appropriate to their data. If uncertainties could be dearly characterized in the abstracts or in the text of papers reporthag values of nuclear parameters, there would be a corresponding shortening of the time required for the data to be evaluated and tabulated. There are many methods of stating estimates of conventional random and systematic uncertainties that are acceptable, provided that the methods used are described. Thus random error may be stated as: (i) the estimate of the standard deviation (or the square root of the variance), which is in the same units as the observed data and indicates the order of magnitude of the spread of the data: (ii) the standard error (or the estimated standard deviation of the mean of the distribution); and (ri) the estimated limits for the mean at stated levels of confidence (C1) (e.g. limits at the 99-percent CI define the range within which there is a 99:percent probability of ineluding the mean of a population). Provided that the author states the number of independent measurements made of the given parameter, or the number of degrees of freedom, these statements of random uncertainty are related uniquely to each other. The other component of the overall uncertainty is the estimate of possible systematic error. The significance, or meaning, of the estimate of systematic uncertainties should be dearly stated and also related to the method chosen to state the random uncertainties. Thus an estimate of maximum conceivable systematic uncertainties would logically be combined with a random uncertainty at a 99-percent confidence level. An appropriate fraction of the estimate of maximum conceivable systematic uncertainty would be chose to match smaller random confidence levels. The methods used to combine random and systematic uncertainties should also be stated by authors, and an explicit listing of all components of these uncertainties will allow an evaluator of nuclear data to unravel the statements of uncertainty and to choose

Using the principles of dimensionless ratios, the data from a Higgins-Leighton method at constant pressure may be easily and quickly usedto predict the pressure may be easily and quickly usedto predict the highest constant rate of injection of water that is possible without fracturing the reservoir rock at the possible without fracturing the reservoir rock at the wellbore,to predict quickly the performance to the ultimate life of a waterflood with a constant rate of injection,to predict the life of a waterflood using a high constant rate early in the flood when the pressure at the wellhead may be low and then, later, a pressure at the wellhead may be low and then, later, a reduced rate to avoid fracture, andto estimate, after the flooding is started, the time at which the kick (first increase in oil rate) will occur and the relative size of the kick. These are all useful in making an economic analysis of a potential waterflood. With the method presented we can quickly process the predictions using relative permeabilities that appreciably influence recovery of oil. The method includes the use of layers to determine the effect of vertical permeability variations. All of this information is useful in designing the constant-rate pumps used to inject water into reservoirs. With these features, we can use the predicted performance at a constant pressure to obtain the predicted performance history at a constant injection rate during the entire life of the flood. Also, we can quickly predict the performance of a flood at different constant rates performance of a flood at different constant rates during the life of the flood; that is, at a very high rate for the short initial period when the well may be operating under nearly vacuum conditions at the wellhead, then at decreasing sets of constant rates or even at continuously changing rates. The economics of a flood is affected by the size and cost of constant-rate pumps and the rate of return of the investment during the life of a flood. With the performance data vs the rate of injection, the performance data vs the rate of injection, the economic feasibility can be easily determined. The relationships among time, rates and volumes have been checked by computer runs. They were tested on the individual layers and on combinations of layers of different absolute permeability. The ratio relationship was found to reproduce exactly the produced volumes and other data. At the time of this produced volumes and other data. At the time of this writing, it has not been tested on combinations of layers of different relative permeability-saturation curves. But, in principle, it should hold for these combinations also. The highest constant injection rate that will require a pressure just less than would be expected to fracture the formation can be determined with a model computer run at constant pressure. When the mobility ratio is greater than one, the injection rate for the model will decrease, pass through a minimum, and then increase. This minimum injection rate is the maximum permissible constant injection rate. Any constant rate in excess of this would require a pressure that would probably fracture the formation at pressure that would probably fracture the formation at some time during the flood. This highest permissible pressure is used in the Higgins-Leighton prediction method. The printout of the results of the calculations using the Higgins-Leighton method at constant pressure or a plot of the results will show lowest injection rate. P. 1246

Summary Hydrophobically modified polyacylamides (HMPAMs), also known as associative polymers, have high potential as EOR chemicals due to their specific chemical properties. However, the strength of hydrophobic interactions also leads to more complex flow behavior. Mostly, polymer injectivity is studied in linear coreflood experiments. However, in reality the polymer injection occurs in radial flow. The main difference is that linear flow has constant pressure gradient and thereby constant shear rate, while radial flow has a position dependent pressure gradient and therefore a shear gradient in the near-well region. For complex non-Newtonian polymers like HMPAMs this may have large implications for injectivity. The influence of relatively weak hydrophobic interactions on flow properties was studied by radial injection of a semi-dilute solution of associative polymer under high injection rates. Radial flow was achieved by injection in a well placed in the center of a 30 cm diameter, 3 cm thick disc cut from Bentheimer outcrop sandstone. Bentheimer was chosen due to the high homogeneity of the rock. Pressure ports were positioned between the injection well and the rim to allow determination of the pressure decay curve during flow. Effluent was collected and analyzed for mechanical degradation. The radial injection of the associative polymer showed shear thinning behavior at all rates, including at near-well equivalent rates. This means that this polymer can be injected with relatively low pressures and will gain viscosity as it propagates further from the well. Interestingly, this is different from the observations in linear core floods. Disruption and regeneration of weak hydrophobic interactions appears to be the main cause of the change in rheological behavior between linear and radial flow. The associative polymer showed excellent shear stability with only moderate viscosity reduction at extreme injection rates. The results confirm the need for in-situ measurements of polymer rheology not only in linear but also radial flow as input data for injectivity modeling. The experiments reveal that the associative polymer has different rheological behavior in bulk, linear and radial flow. The near-Newtonian behavior at near-well injection rates combined with building of viscosity at lower rates further from the well is beneficial for application in polymer flooding. This is to our knowledge the first systematic investigation of an associative polymer in radial flow. The results have major implications for polymer flood modeling and flood design, particularly for injections in vertical wells where injectivity is critical.

256.05 million tonnes of carbon dioxide (CO 2 ) have been released into the atmosphere of Malaysia as of 2021. If no steps are done to limit Malaysia's CO 2 emissions, it is projected that this scenario could go on for relatively many years to come. The feasibility of CO 2 geological sequestration has been taken into consideration as a viable method of minimizing CO 2 emission in Malaysia, considering the anticipated rise in energy demand for sustainable development in this nation. The long-term fate of the captured CO 2 is, however, the primary concern of public and environment but it is not practical to do simulations in a lab or via experiments. In examining the movement of the CO 2 plume after being injected into the sandstone aquifer, computer simulation is therefore more practical to utilize in this research. Malay Basin was ranked as the most potential basin for carbon sequestration in Malaysia because it fulfils most of the criteria. Therefore, by utilizing data from previous studies, 10 km 2 of Malay Basin sandstone aquifer was simulated using COMSOL Multiphysics software in order to explore the pattern of CO 2 dispersion in sandstone aquifer and to predict its migration radius in a given period. The second goal of this research is to determine a relationship between the rate of CO 2 injection per 10 km2 and the velocity of CO 2 plume flow in sandstone aquifer. Lastly, this study aims to estimate the saturation of CO 2 per 10 km2 of the aquifer with various injection rates after a given time. Results from the numerical computation shows that CO 2 injected into the Malay Basin migrates upward and laterally, with the plume pattern expanding over time and higher injection rates. On the other hand, the velocity of plume dispersion fluctuates and decreases with distance due to pressure gradients and dissolution of CO 2 into the formation’s brine. Saturation of CO 2 was also found to be the highest at the injection point and broadens with higher injection rates. This study's findings have practical implications for optimizing design, managing injection rates, assessing caprock integrity, implementing monitoring strategies, and conducting environmental impact assessments to ensure safe and effective carbon storage for long-term CO 2 sequestration in Malay Basin. Given the size of Malaysia's geological CO 2 sequestration industry, this research is seen as a wise investment from an economic standpoint. Politically speaking, the findings of this research provide policymakers and legislators with a suitable point of reference for implementing CO 2 emission regulations in Malaysia.

ABSTRACT: Carbon geological storage is a promising technology to divert massive amounts of carbon dioxide from local emission points and the atmosphere to subsurface reservoirs. Carbon storage projects seek maximizing injection rates and storage volumes. However, the injection of any fluid in the subsurface increases the reservoir pore pressure and alters the state of stress. Hence, maximizing injection rates and storage volumes face geomechanical limitations. This paper presents a method to optimize the selection of injector location and injection rates in faulted and fully compartmentalized reservoirs by integrating coupled reservoir and geomechanics simulations, cash flow, and neural networks. Injection stops when a fault approaches the shear yield limit at a distance fixed by a safety factor. We apply the method to a reservoir geometry inspired in a faulted sand in the Gulf of Mexico Coast. Low injection rates result in the highest storage volumes but in low net present value because of the long injection period (>100 years). Excessively high injection rates result in rapid changes of stresses in proximity to faults and early injection shut-in. The use of neural networks permits spanning all possible locations and injection rates and finding an optimum solution that maximizes net present value. 1. INTRODUCTION CO2 storage in deep geologic formations is one solution to reduce CO2 emissions and CO2 atmospheric concentration (Bachu, 2008; Benson and Cole, 2008; Bickle, 2009). However, all pore space in geological formations is not readily available for storage since pore pressure increases due to injection can change the stress state and lead to fault reactivation – Fig. 1 (Cappa and Rutqvist, 2011; Faulkner et al., 2018; Tang et al., 2019; Ryu et al. 2019). Moreover, fault reactivation may induce seismic events or compromise fault sealing capacity (An et al., 2020; Rinaldi et al., 2015; Zoback and Gorelick, 2012). Compartmentalized reservoirs are more likely to develop high pressure increases with injection (Ehlig-Economides and Economides, 2013). Hence, pore pressure management is a critical activity in carbon geological storage for achieving high injection rates and volumes while averting geomechanical risks (Jung et al. 2019).

The study on the flow behaviors of oil and water two phases in porous media and their influencing factor is very important to adjust the porous carbonate reservoir development strategy and enhance the oil recovery. Based on the CT (computed tomography) scanning of real carbonate reservoir core sample, the micropore structure was reconstructed, and the effects of different factors (injection rate, oil-to-water viscosity ratio, and contact angle) and secondary development methods (higher injection rate and water displacement direction optimization) on the flow behavior of oil and water two phases were explored by numerical simulation in this paper. It is found from the study that the pores in the porous carbonate reservoirs have good structural connectivity. During the displacement process, the oil-water interface mainly resides at the pore throat junction with a large change of pore size, and the Haines jumps exist in the oil-water movement; the areal sweep efficiency of the water phase is jointly affected by the viscosity effect, interfacial tension, pore structure, and injection rate. Under the minimum injection rate and oil-to-water viscosity ratio, the maximum oil recovery can be obtained, and the oil recovery is 52.62% and 57.01%, respectively. The recovery efficiency and swept area are better in a water-wet system than oil-wet system. During the secondary development, the remaining oil is hardly displaced even with the injection rate increased by a factor of 50, and it shows improvement after 250 times of initial injection rate. Changing the position of water inlet and the produced fluid outlet results in better recovery since the remaining oil near the new inlet and outlet can be effectively produced.

In order to study the effect of fuel injection rate shaping on spray combustion, an electronically controllable fuel injection system was developed. In this system, the arbitrary injection rate shaping was obtained by controlling the movement of nozzle needle directly with piezoelectric actuator while the fuel pressure was maintained its constant injection pressure. By using this injection system, fuel was injected into the pressure chamber with three types of fuel injection rate shaping with different slope of injection rate rise. From the results of visualizations of non-evaporating spray, it was found that the slope of injection rate rise made great influences on the spatial and temporal fuel distributions and spray temporal evolution. Moreover, it was shown that, though there was no great difference in spray angle in low injection rate, spray angle by lift control injection was larger than that by pressure control injection in high injection rate.

In this paper, plastic injection molding of micro parts having dimensions in the order of micron scale was investigated through experiments. Process parameters were varied on the machine and the plastic parts obtained were characterized. It was found that the mold temperature is the most significant parameter affecting the partial filling of a cavity. Injection pressure and injection rate (volumetric flow rate) were of secondary importance. The contribution of the injection rate is not affected as the thickness of the cavity is reduced. However, injection rate becomes more important as compared to injection pressure, when the dimension of the cavity is reduced. The injection time (filling and holding times) was found to be insignificant in the filling process and can be neglected. To obtain good micro parts, high mold temperature, high injection rate, and high injection pressure are recommended for the filling process.

Trends in hydraulic fracturing over the years have closely followed an increased knowledge or better understanding of what occurs in the formation during a fracturing treatment. As more and more knowledge was gained emphasis shifted from materials to horsepower and high injection rates. Recently the shift has been back to materials and more careful planning and engineering of individual treatments. Improved technology within the past two or three years has led to the development of new, viscous fracturing fluids and more sophisticated computer programs. These developments have greatly improved results of fracturing treatments and have made it possible to successfully stimulate those wells which previously were poor candidates for hydraulic fracturing poor candidates for hydraulic fracturing treatments. The purpose of this paper is to discuss recent developments in fracture fluids and techniques and the technology involved in their use. Case histories are used to show the improvements in economy, efficiency, and increased production results. Introduction Since the introduction Hydraulic fracturing as a stimulation tool in the late 1940's, development trends have closely paralleled each fact learned concerning what actually takes place in a formation during a fracture treatment place in a formation during a fracture treatment In the early days, equipment available was capable of providing injection rates of one to two barrels per minute and screen-outs were common. It was felt that viscous fluids would suspend and transport propping agents better and development emphasis was on fracture fluids. Heavy refined oils became common frac fluids and water-in-oil emulsions, acid-in-oil emulsions, and soap-type oil gels appeared. Next, fluid loss was recognized and fluid loss agents were introduced. It was discovered that in many cases crude oil could be used as a fracture fluid with these new agents and treating economics apparently improved. The trend to crude oil with fluid loss agents, however, increased the incidence of screen-outs until a relationship between injection rates and screenouts was found. Increased injection rates reduced the probability of a screen-out and equipment was built to provide higher rates.

Effect of miscibility and injection rate on water-saturated CO2 Injection

In this paper, the effect of pre-existing discrete fracture network (DFN) connectivity on hydraulic fracturing is numerically investigated in a rock mass subjected to in-situ stress. The simulation results show that DFN connectivity has a significant influence on the hydraulic fracture (HF) & DFN interaction and hydraulic fracturing effectiveness, which can be characterized by the total interaction area, stimulated DFN length, stimulated HF length, leak-off ratio, and stimulated total length. In addition, even at the same fluid injection rate, simulation models exhibit different responses that are strongly affected by the DFN connectivity. At a low injection rate, total interaction area decreases with increasing DFN connectivity; at a high injection rate, total interaction area increases with the increase of DFN connectivity. However, for any injection rate, the stimulated DFN length increases and stimulated HF length decreases with the increase of connectivity. Generally, this work shows that the DFN connectivity plays a crucial role in the interaction between hydraulic fractures, the pre-existing natural fractures and hydraulic fracturing effectiveness; in return, these three factors affect treating pressure, created microseismicity and corresponding stimulated volume. This work strongly relates to the production technology and the evaluation of hydraulic fracturing effectiveness. It is helpful for the optimization of hydraulic fracturing simulations in naturally fractured formations.

During diagnostic cerebral angiography, the contrast bolus injected into a vessel can cause substantial changes in baseline pressures and flows. One potential, and serious complication is the re-rupture of aneurysms due to these injections. The goals of this in vitro study were to evaluate the effect of injection conditions on intraneurysmal pressure changes during angiography. A silicone replica of a complete circle of Willis model with ophthalmic, anterior communicating, and basilar tip aneurysms was connected to a physiologically accurate flow pump. Contrast injections were performed under different conditions (carotid or vertebral vessel imaging, catheter diameter, injection rate, injection time, and arterial blood flow rate) and the pressure in each aneurysm was recorded before and during each injection. The effect of injection conditions on percentage increase in aneurysm pressures was statistically assessed. Additionally, the effect of the distance between the aneurysm and the catheter-tip on aneurysmal pressures was assessed. Mean intraneurysmal pressures during injection (84.5 ± 10.8 mmHg) were significantly higher than pre-injection pressures (80.4 ± 10.6 mmHg, p < 0.0001). Only 3 of the 5 conditions - carotid injections, higher injection rates, and smaller catheter diameters - significantly increased intraneurysmal pressures. The catheter-tip distance showed no correlation to pressure increases. Increasing contrast injection rates and decreasing catheter diameters are correlated to intraneurysmal pressure increases during angiography irrespective of the distance to the catheter tip. Future in vivo studies are required to confirm these findings and determine whether the amplitude of pressure increases with commonly used injection rates can be clinically detrimental.

Novel modelling technologies that includes induced fractures in a dynamic reservoir simulator has been used to analyse subsurface aspects of an inverted 5-spot injection pilot. The techniques have allowed an accurate depiction of growing induced fractures. Simulation results indicate that induced fracture growth is limited at injection rates &amp;lt; 200 m3/d but that higher injection rates will result in fracture propagation and a risk of rapid water breakthrough. The results have been validated by field observations. A controlled and cautious increase in injection rate has resulted in a positive production response with rate increases of 50–100% in three of the four producers in the pilot. Results from the pilot have increased the current reservoir understanding and reduced subsurface uncertainties. The knowledge gained is being included in an updated Field Development Plan that will be issued in 2005. The plan will incorporate an optimised injection strategy by a careful and controlled ramp up in injection rate. This project has also advanced induced fracture research with a field verification of the predictive capabilities of the modelling technology. Introduction The Marmul Haima West sandstone reservoir in South Oman, containing heavy and viscous crude (22 ºAPI, μo = 90 cP) and on production since 1980, was initially developed on depletion/solution gas drive using vertical wells. To boost production and improve recovery, an aggressive waterflood development using horizontal wells was initiated in 1999. The development was, however, stopped prematurely in 2000 after excessive induced fracture growth resulted in water short-circuiting and poor well performances. To improve subsurface understanding and redefine a development strategy, an inverted 5-spot produced water injection pilot project was initiated in 2002 with the procurement and construction of dedicated water cleaning and injection facilities and drilling of 5 new vertical pilot wells (i.e. wells I-1, P-1, P-2, P-3 and P-4). A map of the field and the placement of the 5-spot pilot have been shown in Figure 1.