Penetration Ratio Research Articles

Research on Optimized Penetration Ratio Fracturing Technology for Transition Zone

The geological reserves of the Sazhong transition zone are 10046×104t, accounting for 12.5% of the Sazhong development zone. The effect of fracturing stimulation in this block is of great significance for the stable production of the Sazhong oilfield. The transition zone has the characteristics of low porosity, low permeability and low oil saturation. The crude oil has three high and one low characteristics: high viscosity, high wax content, high freezing point and low sulfur content. In the transition zone, due to poor physical properties of the oil layer, unbalanced formation pressure, high proportion of low-yield and low-efficiency wells, and energy replacement of thin oil layers, it is difficult to tap the potential of the production increase measures, and the effect of the measures is getting worse year by year. According to statistics, since the transition zone has 40 fractured oil wells since 2009, the fracturing process is general pressure and multi-crack, and the average pressure is 3 layers and 1 slit. The average average sand volume of single seam is 7.1m3, the average sand ratio is 25.7%, and the penetration ratio is only 14.1%. The average initial liquid increase after fracture is 20.4t, and the average initial daily oil increase is only 2.5t. Therefore, the study of transition zone fracturing technology can improve the overall development effect of the block, which is of great significance for the sustainable high yield and stable production of the Sazhong Oilfield.

Thailand

The Thai insurance sector is a relatively small but growing part of the country’s financial services industry. Insurance sector assets have grown from 10 percent of gross domestic product (GDP) in 2006 to over 22 percent of GDP in 2016, constituting 9 percent of total financial industry assets. Similarly, between 2008 and 2017, gross premiums written have grown at an average annual rate of approximately 16.9 percent, substantially above nominal GDP growth of 9.9 percent during the same period. As a result, the insurance penetration ratio (the ratio of premiums written to GDP) has gradually increased from 3.63 percent in 2008 to 5.39 percent in 2017.

Impact of microgrid operation on performance of radial distribution system

Voltage profile and real power loss are the criteria in determining performance of Radial Distribution System (RDS). Presence of Distributed Generators in RDS is assessed by ‘Penetration Ratio’. The use of PR fails in the analysis of the implications of the presence of a Microgrid on RDS as it is zero in islanded mode and sometimes in grid-connected mode. An attempt has been made to introduce a new term ‘Relief Factor’ to overcome this lacuna. This Factor is evaluated by developing an algorithm based on power flow analysis using Backward Forward Sweep method. The developed algorithm is tested on a 34 bus RDS by integration of a two-shift industrial Microgrid. The power flow analysis is run for 24 snapshots of the day. Relief Factor is found to be suitable to analyze the impact of a Microgrid on the performance of RDS in both the modes of Microgrid operation viz. grid-connected mode and islanded mode.

Deep-Reinforcement-Learning-Based Distributed Vehicle Position Controls for Coverage Expansion in mmWave V2X

In millimeter wave (mmWave) vehicular communications, multi-hop relay disconnection by line-of-sight (LOS) blockage is a critical problem, especially in the early diffusion phase of mmWave-available vehicles, where not all the vehicles have mmWave communication devices. This paper proposes a distributed position control method for autonomous vehicles to make long relays connecting to road side units (RSUs) by avoiding blockages to communicate with each other via LOS paths. Even though vehicles with the proposed method do not use the whole information of the environments and cooperate with each other, they can decide their action (e.g., lane change and overtaking) to form long relays using only information of its surroundings (e.g., surrounding vehicle positions). The decision-making problem is formulated as a Markov decision process so that autonomous vehicles can learn a practical movement strategy of making long relays by a reinforcement learning (RL) algorithm. This paper designs a learning algorithm based on a sophisticated deep reinforcement learning algorithm, asynchronous advantage actor-critic (A3C), which enables vehicles to learn a complex movement strategy quickly by its deepneural-network architecture and multi-agent-learning mechanism. Once the strategy is well trained, vehicles can distributedly move to positions where the long relay to the RSU is established. Simulations results confirm that the proposed method can increase the relay length and coverage even if the traffic conditions and penetration ratio of mmWave communication devices in learning and operation phases are different.

A novel impact-assessment framework for distributed PV installations in low-voltage secondary networks

This paper proposes an impact-assessment framework to appropriately assess the impacts of two different types of distributed solar photovoltaic (DPV) installation on a realistic distribution network. To examine the spontaneous customer-based installations, a detailed Monte Carlo-based technique is introduced. For the controlled utility-based installation, a multi-objective optimization problem for the sizing and location of DPV installation is formulated aiming to improve energy loss, voltage deviation, and voltage fluctuation, avoiding reverse power flow and voltage violation. Solar insolation study is performed using light detection and ranging (LiDAR) data to estimate the potential of the network for DPV installation. In addition, a synthetic load profile modeling is developed to create yearly electricity load profiles for all the buildings in the given distribution network. The proposed framework is applied to a local distribution network with synthetic load profiles, Geographic Information System (GIS), and realistic solar insolation. It is found that for customer-based installation, voltage violation occurs beyond 30% of DPV penetration level, demonstrating the necessity of utility-based installation scheme for higher penetration ratios. Beyond a specific threshold, the probability of reverse power flow significantly increases in customer-based installation. Therefore, to achieve higher penetration ratios without reverse power flow and other negative impacts, utility-aided installation is necessary.

Study on the particle stratification and penetration of a swing vibrating screen by using DEM

PurposeAs for vibrating screen, the separation of granular materials is a very complicated process, particularly the screening with a swing trace. To study the characteristics of stratification and penetration in the swing vibrating screen, a three-dimensional numerical model was developed to simulate the screening process.Design/methodology/approachThe discrete element method (DEM) was used to perform the numerical simulation, and the kinetic model of the swing screening was established. The regions of stratification and penetration were defined, and the mathematical functions relating fine particle ratio of stratification and penetration to time were presented using the least squares method.FindingsThe results show that the low value of frequency (5 and 10 Hz) has a limited effect on the stratification, while the obvious effect can be found at high frequency. A low frequencies or small swing angles may enhance the particle penetration. By studying the vibration parameters affecting the stratification and penetration rate, it is found that the frequency has more influence than the swing angle.Originality/valueThe higher screening efficiency and processing capacity can be further obtained for the swing vibrating screen by comparing with the linear vibrating screen. These results reveal the fundamental characteristics of particle motion in the swing screening, which will provide reliable guidance for studying the design optimization of vibrating screen.

Effects of fuels on flash boiling spray from a GDI hollow cone piezoelectric injector

Flash-boiling of fuel sprays can have a significant effect on spray formation and its characteristics due to bubble nucleation, growth, and phase change, producing explosive-like atomization and complex spray structures. In this work, experiments were conducted to study the spray of both pure substance fuels (pure isooctane, pure ethanol) and multicomponent fuels (50/50 mixture of isooctane and ethanol, commercial gasoline), under flash boiling conditions and non-flash boiling conditions. Under different temperature and ambient pressure, different superheated degrees can be achieved for the fuels. Pure substances have a single vapor pressure curve, while mixtures do not have a single boiling point at a given pressure, and a two-phase region exists for multicomponent fuel. Under the same conditions, ethanol has higher superheated degree compared to isooctane, but the heat of vaporization for ethanol is also much higher. This contributes to the fact that less boiling is observed in the ethanol spray with longer penetration in several cases. Mixture 50/50 shows a good average of isooctane and ethanol for spray penetration and spray front plume ratio analysis. Gasoline, due to its low initial boiling point and wide range of components, has the widest plume ratio distribution and smallest gradient, as well as complex peak penetration velocity distribution. The results also imply that adding low boiling point (preferably with low heat of vaporization as well) additive or component to high boiling point fuel can facilitate flash boiling, fuel vaporization and mixing.

Pulsed Nd:YAG laser spot welding of an AZ31 magnesium alloy

The relationships between the processing parameters and the welding modes, dimensions, microstructures, and defects are studied for pulsed laser spot welding of an AZ31 alloy. Conduction mode occurs at the welds with peak power densities between 2.5 and 4.5 GW/m2, and when the peak power density exceeds 4.5 GW/m2, the welds of keyhole mode are generated. In conduction welding, the laser beam radiates on the pool surface, and the melt flow is driven by the buoyancy convection and Marangoni convection, resulting in a wide and shallow cross section and the welding diameter and penetration are not affected by processing parameters. For keyhole welding, the laser beam passes through the keyhole and directly radiates on the base material at the bottom of the molten pool under the influence of recoil pressure, which increases the absorption rate and then greatly increases the welding penetration and aspect ratio. In the keyhole, a large bubble is formed, which is mainly composed of magnesium vapor, causing porosity and overfill after welding. The cooling rate in the deep of the molten pool is higher, which is helpful to the formation of solidification cracks. The area percent of the porosity and overfill and the solidification crack sensitivity increase with peak power density. As the energy density increases, the temperature gradient becomes larger, and the constitutional supercooling decreases, leading to the transformation of microstructures near the fusion boundary of the welding surface from columnar crystals to cellular crystals, and the area of the cellular crystals gradually widens.

Flux Dynamics and Thermal Behavior of a GdBaCuO Bulk Magnetized by Single- and Double-Pulse Techniques Using a Split-Type Coil

We have investigated the trapped field properties of a GdBaCuO disk bulk during single- and double-pulsed field magnetization (PFM) using a split-type coil for various pulse sequences for the first time. It is well known that the multi-PFM technique using a solenoid-type coil and the single-PFM technique using a split-type coil are effective to enhance the trapped field due to a lower temperature rise. However, it was found, in this work, that the trapped field by double-PFM using the split-type coil was not enhanced in spite of lower temperature rise. We analyzed the magnetizing process using two parameters, the “magnetic flux penetration ratio,” Rin, and the “magnetic flux residual ratio,” Rout, for various pulse sequences for the split-type and solenoid-type coils. The Rin value was decreased by the double-PFM for both coils, and the Rout value was improved only by the double-PFM using the solenoid-type coil. As a result, the trapped field for single-PFM using the split-type coil, which has a higher Rin, reduced after the double-PFM due to a decrease of Rin and no enhancement of Rout. These results are in clear contrast to those using the solenoid-type coil.

Study on Magnetic Flux Dissipation and Field-Trapping Performance of HTS Bulk-Shaped Magnesium Diboride in Pulse-Field Magnetizing Processes

The magnetic flux dissipation from the MgB 2 bulk magnets during pulsed field magnetization (PFM) processes has been estimated for the samples fabricated by hot-pressing (HP) and spark plasma sintering (SPS). We defined the parameters as field penetration ratio B P /B a and the field trapping ratio B T /B P to evaluate the flux motion and performance. The data plots of trapping ratio B T /B P showed us two regions which originate from the fast flux flow and flux jump. The field trapping performance was drastically degraded when the flux jump happened. Flux jump happened at various times after the peak field. A very late flux jump happened at 420 ms which severely degraded the trapped field. This time delay, much larger than the heat propagation time in the MgB 2 sample, remains to be explained.

Retail payments and the real economy

This study investigates how retail payment methods affect aggregate macroeconomic activity. By tracing the relative norms and practices of paper-based payment instruments (checks) and electronic payment methods (payment cards, credit transfers and direct debits) in 27 European Union member countries, the paper reports that a higher penetration ratio of electronic payment methods is generally associated with greater GDP, trade, consumption and tax revenue. The 2008 financial crisis and a country’s shadow economy level have an incremental impact on the relationship between payment methods and economy. The study also finds substitution effects between paper-based and electronic payment methods and complementary effects across electronic payment methods. The findings are robust after controlling for endogeneity. Our study supports policies promoting further repositioning and transfer to efficient electronic payment instruments.

Comparative pharmacokinetics of tedizolid in rat plasma and cerebrospinal fluid

To investigate the possibility of tedizolid phosphate's application in the treatment of intracranial infection, a preclinical comparative pharmacokinetic study was designed. Based on the assumption that the classic efflux transporters P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) may participate in the transportation of TDZ, two groups of rats were intravenously administered 6 mg/kg tedizolid phosphate alone or 6 mg/kg tedizolid phosphate combined with 1 mg/kg elacridar which was an inhibitor of P-gp and BCRP. Plasma and cerebrospinal fluid samples were collected according to a pharmacokinetic schedule. All the plasma and cerebrospinal fluid samples were assessed with a validated LC-MS/MS method. The penetration ratio of tedizolid from the blood to cerebrospinal fluid was calculated, and a comparison of the penetration ratios between the two groups was made. The mean Cmax of tedizolid in the CSF in the tedizolid phosphate group and the tedizolid phosphate combined with elacridar group was 154 ng/mL and 300 ng/mL, respectively, and the mean penetration ratio of tedizolid in the tedizolid phosphate group and the tedizolid phosphate combined with elacridar group was 2.16% and 3.53%, respectively. The relatively high Cmax in the CSF proved the possibility of tedizolid phosphate's application in the treatment of intracranial infection, and the higher penetration ratios, Cmax, csf and AUCcsf of the rats in co-administered elacridar group than those in the single-administration group indicated that the transporters P-gp and BCRP might be involved in the transportation of tedizolid.

Analyzing chaotic effect of reinforced concrete pile driving in cohesive soil

This paper presents the chaos phenomenon in pile driving. Firstly, the pile wave equation that Smith put forward is used for painting Poincare section, and then the basic features of chaos are obtained. By analyzing the Poincare section, a point with which the ratio of penetration to velocity is the largest is discovered, and that is to say energy consumption is the lowest at this point. Moreover, the relationship between hammer weight and dropping height is proved to satisfy the construction experience of light blow with heavy hammer through curve fitting. So according to the theory, the value of impact force and initial value can change to get the hammer weight and dropping height for different square and circular piles under the lowest energy consumption. The results show it is better to use square piles during driving, and the relationships between square and circular piles with different cross-sections and its impact force on pile top, hammer weight and dropping height satisfy a certain function equation, respectively. Hence, the corresponding hammer weight and dropping height can be selected to save energy consumption and reduce the cost during construction according to their functional relation.

A numerical assessment of two geometries for reducing elbow erosion

Elbows in pneumatic conveying systems are normally prone to the erosive effects of conveyed particles. There are a number of solutions available to reduce such damage. A widely used geometric alternative for replacing the 90° elbow and reducing erosive wear is the plugged tee. Another option, although less commonly used, is the vortex-chamber elbow. In both cases, the effective reduction in erosion brought about is unclear, as it strongly depends on the operating conditions. The present study assesses relative erosion among the plugged tee, vortex-chamber elbow, and standard elbow for a dilute gas–solid multiphase flow. A numerical model is employed to predict the penetration ratio and validated using experimental data for the plugged tee. Simulations are run for the standard and vortex-chamber elbows and plugged tee under the same conditions to compare the mechanics involved and the relative erosion reduction. The analysis uses variables relating to particle–wall interactions (impact angle, impact velocity, impact frequency) to illustrate the nature of the erosive process in each pipe fitting. In general, the geometric configurations of both the plugged tee and vortex-chamber elbow promote changes in particle dynamics that reduce the rate of erosion. On the basis of the relative erosion of the standard elbow, the plugged tee proves to be an interesting option in cases of a low mass loading, while the vortex-chamber elbow demonstrates its erosion reduction potential for higher mass loading conditions. Furthermore, the advantages and disadvantages of each fitting are highlighted.

An equivalent structural stress-based fatigue evaluation framework for rib-to-deck welded joints in orthotropic steel deck

Rib-to-deck welded joints in orthotropic steel decks have demonstrated different fatigue failure modes that have different fatigue resistance. Among the different failure modes, the mode corresponding to the lowest fatigue resistance governs the fatigue resistance of the welded joint. The ability of determining the governing failure mode is essential for predicting the fatigue resistance of the welded joints. This research establishes a fatigue evaluation framework for determining the dominant failure mode of rib-to-deck welded joints. The framework is established based on the equivalent structural stress method and validated using model test data. The results indicate that the proposed framework provides accurate prediction of the dominant fatigue failure mode of rib-to-deck welded joints. Based on the presented framework, the fatigue resistance of the welded joints is reasonably predicted, and the effect of weld penetration ratio on the fatigue failure mode is investigated.

Behavior of compacting reservoirs with restricted entry wells

We investigate the simultaneous effect of changes in thickness, permeability and porosity. These depend on changes in fluid pressure. Fluid withdrawal in stress-sensitive reservoirs may have serious environmental, technical and economic ramifications. Appraisal wells are often vertically drilled to delineate fluid contacts, reservoir extension, etc. Some of these may be of restricted entry type when tested. In addition, restricted entry production wells may be designed to mitigate fluid coning. The objective of this study is to predict the change in formation thickness and/or permeability in compacting reservoirs. The proposed method depends on the assumption of exponential pressure dependency of thickness, permeability and porosity, Pedrosa (1986). We consider vertical wells in confined reservoirs. The method depends on an initial value property, which may be explained as follows: the ratio between two pressure-dependent variables of the same type will remain constant and equal to its initial value. For example, the well penetration ratio will remain constant during fluid withdrawal. The initial value property is valid for any arbitrary dimensionless pressure function. Our restricted entry model is a generalization of a classical one. The methodology depends on the use of the finite cosine transform in the vertical direction and the Laplace transform in the radial (Hantush in J Hydraul Div 87(HY 4):83–98, 1961). His method depends on “primed values”. Any vertical distance normalized to the thickness is a primed variable. Hence, the primed variable is characterized by the initial value property. Then, his methodology may be extended to shrinking reservoirs. A reduction in fluid pressure may lead to altered permeability and reduced thickness. This may lead to reduced well performance and well integrity. In some cases, even subsidence at the surface and earthquakes may occur. Such dramatic consequences are rare. They are costly to amend, if possible at all. In the majority of reservoirs, the effect of stress sensitivity is mild. Severe cases, however, have occurred in many places around the world. Due to the environmental costs, possible problems should be identified and preventive actions are taken as soon as possible. We find that pressure transient analysis offers a promising and cost-effective technique to predict future consequences of compaction. A well test has the advantage that it may be conducted once a producing formation has been penetrated. Fluid injection with, or without, extraction may mitigate further damage. We find that fluid withdrawal at a reduced rate may have a palliative effect on reservoir compaction. Likewise, increasing the productive interval and/or the radial permeability has the same effect. Furthermore, a decreased viscosity will also alleviate the problem. Despite possible adverse consequences, reservoir shrinking has received little attention in pressure transient analysis.

Semi-analytical prediction of critical oil rate in naturally fractured reservoirs with water coning

Naturally fractured reservoirs (NFRs) with bottom water are generally produced above their critical oil rate (maximum possible oil production rate without water breakthrough) that is difficult to determine as it varies between wells, depending on the well's location in the fracture network. In principle, wells can either be completed in matrix or fractures. Present formulas of critical-rate in NFR are oversimplified ignoring the network heterogeneity and anisotropy ratio of fractures, and they also do not consider the difference between on-fracture/off-fracture well completion placements. Presented is development of a new semi-analytical formula that considers these effects– with emphasis given to well placement assessment.The critical rate model is derived from mechanistic principles and then improved with statistical calibration. The mechanistic approach (Chaperon (1986)) considers vertical equilibrium of viscous and gravity forces for a hemispherical flow to a point-source well in a dual porosity/dual permeability model of naturally fractured reservoirs. The model considers the water cone instability, and anisotropy ratio of NFR only for a short-perforated completion interval. The model is tested for wide variety of NFRs for short completions. The model is then statistically calibrated to including the effect of long penetration ratio, using a designed matrix of simulated experiments covering wide ranges of NFR properties. This statistical approach allows the model to consider any change in flow regime from semi-spherical to non-radial distorted flow.The comparison of Chaperon's analytical model and NFR simulations shows that the model is good for NFRs for penetration ratio smaller than 0.35. For penetration ratio greater than 0.35, a new semi-analytical model of critical-rate for NFR is developed by statistically calibrating the Chaperon's analytical model. The new model considers the parameters ignored in the previous models of NFR. Finally, a new mechanistic derivation of critical rate for wells completed in matrix block of NFR is determined by analytically including the effect of well's distance to fracture in a critical rate formula for NFR. The model matches well with the simulated data when compared with it. The model shows that the wells accidently completed off-fractures may display higher values of critical rates and the difference relates to their distance to the nearest fractures. It is also shown that the off-fracture well's formula reduces to the on-fracture well's formula when the distance is reduced to zero.

Effect of process parameters on formability and surface quality of selective laser melted Al-Zn-Sc-Zr alloy from single track to block specimen

The effects of the laser power and the scanning speed on molten pool shape, liquid metal spreading characteristics, and surface quality of the Al-Zn-Sc-Zr alloy fabricated by selective laser melting (SLM) were studied. The results showed that at the highest laser power of 360 W and the lowest scanning speed of 400 mm/s, the width and penetration of single track reached the maximum values of 244 μm and 241 μm. The powders were fully melted, and the liquid metal had more time to spread out when the line energy input is 800 J/m. The hole and balling defects disappeared, and the surface quality of the block specimen was significantly improved. With a decrease in the line energy density, the width, penetration, and overlap ratio of the single track gradually decreased. The surface morphology became rough with less melting and spreading time of the liquid metals. When the line energy density decreased from 800 J/m to 160 J/m, the roughness of the top surface increased from 9.4 to 16.1, and the densities of the block specimen increased from 98.1% to 99.5%.

Root Growth Responses of Maize (Zea mays L.) and Soybean (Glycine max L.) to Soil Compaction and Fertilization in a Ferric Acrisol

Mechanical impedance to root growth is one of the most important factors determining root elongation and proliferation within a soil profile. Two pot experiments were conducted at the Department of Horticulture, KNUST, Kumasi, Ghana, to determine the impact of subsurface compaction and different fertilizer amendments on the root growth of maize (Zea mays L.) and soybean (Glycine max L.). The experiments were arranged in a factorial Completely Randomized Design (CRD) with three replications. Maize and soybean varieties, “Obaatanpa” and “Anidaso” were sown in 72 plastic buckets (36 for each crop) of 12 L volume filled with a Ferric Acrisol. The treatments were different levels of compaction, using bulk density as proxy – 1.3, 1.5 and 1.7 Mg m-3, and fertilizer amendments of 100% poultry manure (15 g/pot), 100% NPK fertilizer (2.89 g/pot) and 50% each of poultry manure (7.5 g/pot) and NPK fertilizer (1.45 g/pot). The highest root growth occurred in the uncompacted soil and along the periphery of the soil core. The applied soil amendments significantly increased the root penetration ratio (RPR) of both crops in relation to the control. The shoot biomass of both crops decreased with increasing soil bulk density. All the applied soil amendments significantly increased the shoot biomass of maize and soybean over the control. The magnitude of response of the crops to the soil amendments was greater in soybean than in maize.

SHEAR STRENGTH OF SOFT CLAY REINFORCED WITH ENCASED LIME BOTTOM ASH COLUMN (ELBAC)

Soft clay soils are problematic soil that causes bearing capacity failure and excessive settlement, leading to severe damage to buildings and foundation. In this study, bottom ash is used to replace the natural aggregate while quicklime is used to increase the bonding between bottomash particles. This research is aimed to investigate the role of single encased lime bottom ash column (ELBAC) in improving the shear strength by using laboratory scale model. Kaolin is being used as soil sample while lime bottom ash as the reinforced column and the column is encased with non-woven geotextile. Laboratory tests are conducted to determine the physical properties of bottom ash, kaolin clay, and quicklime sample. Unconfined Compression Test (UCT) also used to test the shear strength of the reinforced kaolin samples. There are 21 kaolin samples being tested in this study and the dimension of the specimen used is 50mm in diameter and 100mm in height. However, there are two different types of the diameter of single lime bottom ash column being used which are 10mm and 16mm. The heights of the column are 60mm, 80mm and 100mm. The improvement of shear strength of single encapsulated lime bottom ash column with area replacement ratio of 4.00% (10mm column diameter) and 10.24% (16mm column diameter) are 43.58%, 50.00%, 49.17% and 38.08%, 42.67%, 32.75% at sample penetration ratio, Hc/Hs of 0.6, 0.8 and 1.0 respectively. It can be concluded that the shear strength of soft clay could be improved by the installation of the single encapsulated lime bottom ash column.