Influence Of Area Research Articles

Flowing Material Balance and Rate-Transient Analysis of Horizontal Wells in Under-Saturated Coal Seam Gas Reservoirs: A Case Study from the Qinshui Basin, China

Two phase flow and horizontal well completion pose additional challenges for rate-transient analysis (RTA) techniques in under-saturated coal seam gas (CSG) reservoirs. To better obtain reservoir parameters, a practical workflow for the two phase RTA technique is presented to extract reservoir information by the analysis of production data of a horizontal well in an under-saturated CSG reservoir. This workflow includes a flowing material balance (FMB) technique and an improved form of two phase (water + gas) RTA. At production stage of a horizontal well in under-saturated CSG reservoirs, a FMB technique was developed to extract original water in-place (OWIP) and horizontal permeability. This FMB technique involves the application of an appropriate productivity equation representing the relative position of the horizontal well in the drainage area. Then, two phase (water + gas) RTA of a horizontal well was also investigated by introducing the concept of the area of influence (AI), which enables the calculation of the water saturation during the transient formation linear flow. Finally, simulation and field examples are presented to validate and demonstrate the application of the proposed techniques. Simulation results indicate that the proposed FMB technique accurately predicts OWIP and coal permeability when an appropriate productivity equation is selected. The field application of the proposed methods is demonstrated by analysis of production data of a horizontal CSG well in the Qinshui Basin, China.

Interference between geothermal doublets across a fault under subsurface uncertainty; implications for field development and regulation

Direct Use Geothermal Systems (DUGS) are increasing their installed capacity worldwide and denser developments with multiple doublets are becoming more common. Interference between doublets therefore becomes an additional concern to subsurface uncertainties. Faults can be either barriers or conduits to flow and can affect the fluid pathways inside the reservoir. The interference between two doublets that are separated by a fault has not been previously studied for DUGS. In this work considering subsurface uncertainty in a full factorial design using 5184 3D reservoir simulations we show that a fault can reduce the system lifetime of a two-doublet system by more than 40 % if one doublet is at close proximity to it. Further, we identify that the fault can also improve both the system lifetime and generated Net Present Value (NPV) with appropriate development decisions. Contrary to previous results that did not consider reservoir architecture, a tramline well configuration is preferable when the doublets have the fault in the centre, while a checkerboard configuration is preferable as the distance to the fault decreases. The Heat In Place (HIP) recovery shows a linear relationship with flow rate and well spacing that is not affected by the fault distance or flow properties. The dimensions of the Influence Area (IA) previously considered are insufficient to capture the temperature drop at the producer wells and the fault position can increase this discrepancy. Our results show the importance of fault characterisation and well positioning with respect to a fault considering subsurface uncertainty and how this can affect denser field development of DUGS. Our findings suggest to integrate faults and the relative positioning of well doublets with respect to a fault more strongly in field development plans. Such considerations should also be included in future optimization plans of multi-well geothermal systems. Moreover, the regulatory framework should be revised to achieve a better match between the IA boundary and the production well temperature drop to enable better planning for denser development of DUGS.

ECOSYSTEM SERVICES WITHIN A KEY SUBTROPICAL REGION AFFECTED BY THE YACYRETA DAM IN PARAGUAY

One of the most striking features of the ecosystem concept is that theircomponents, through natural structures and processes, render ecological functions,which are valued by society. The objective of this research was to identify anddescribe ecosystem services provided by the Natural Reserve Yacyretá, inaccordance with the goal of Paraguay’s National Law Nº 3,001 of 2006 ofconservation, protection, recovery and sustainable development of national naturalresources and biological diversity through fair, timely and adequate valuation andpayment for ecosystem services. The study was conducted during an environmentalmonitoring campaign in October 2016 in the reserve, using an ecosystem serviceschecklist constructed based on the classification provided by The Economics ofEcosystems and Biodiversity. This reserve is part of the conservation, protectionand compensation actions carried out by the Yacyretá Binational Entity in the areaof influence of the dam constructed between Paraguay and Argentina for theHydroelectric Power Station Yacyretá. Its purpose is the protection of ecosystems,communities of biological elements that, due to their rareness, fragility, importanceor singularity deserve a special assessment. This reserve has a highrepresentativeness of the resources of the Ñeembucú eco-region, and the presenceof two ecosystems scarcely represented in Paraguay, such as forests of arary(Callophyllum brasiliense) and a small formation of vegetated dunes. The reserveprovides all four categories of ecosystem services, directly and indirectly. Theseresults will be practical for stablishing conservation strategies to update itsmanagement plan and assess access to the system of valuation and payment forecosystem services.

Two phase rate-transient analysis of a hydraulically fractured coal seam gas well: A case study from the Ordos Basin, China

Apart from implications related to coal seam gas (CSG) reservoir engineering such as stress- and desorption- dependent permeability, 2-phase flow of gas and water adds further complications to rate-transient analysis (RTA) techniques in CSG reservoirs. This paper introduces the concept of area of influence (AI) to calculate water saturation in transient formation linear flow for 2-phase RTA in hydraulically fractured CSG wells. The relevant equations are derived and discussed and the application of the AI is demonstrated using reservoir simulation. The area of influence allows a superior estimation of water saturation compared to the dynamic drainage area (DDA) in under-saturated CSG reservoirs and hence improves the estimation of fracture half-length.A practical workflow is also developed and presented to estimate reservoir and hydraulic fracture properties using 2-phase RTA for hydraulically fractured vertical wells. The presented workflow works in a reverse order by first analysing boundary-dominated flow regime and then proceeds to other existing flow regimes developed at earlier production history of the well. Although analysis of each flow regime provides a standalone method to calculate some of reservoir properties, the full development of all flow regimes allows crosschecking and brings more confidence into calculation. In this workflow, the reservoir properties derived from later flow regimes, feeds earlier flow regimes to extract other reservoir variables such as fracture half-length. A hydraulically fractured CSG well from the Ordos Basin, China, is analysed using AI and the proposed workflow to demonstrate the field application of this study.

Micro-scale sustainability assessment of infrastructure projects on urban transportation systems: Case study of Azadi district, Isfahan, Iran

Sustainability assessment and sustainability indicators are familiar terms that have gained significant importance. Non-compliance between the sustainable development principles and transportation infrastructure projects is changing the appearance of historic cities from livable and vibrant atmosphere into the car-oriented condition and cause environmental and social problems. There exist numerous studies on measuring the sustainability of transportation at the country, state, city, and even traffic zone levels, but few have addressed the sustainability of micro-scale projects. The objective of this study is to assess the sustainability of infrastructure projects on urban transportation systems and evaluate their compliance with principles of sustainable development. According to made intensive field visits, run expert interviews, and development master plans relevant to the case study, nine scenarios are proposed to improve the traffic situation of Azadi district in Isfahan city. Obviously, a slight change in the urban streets network, would have a significant effect on traffic performance in larger area, therefore, all the proposed scenarios are modeled in Trans Cad 5.0 software environment to determine their influence area (IA) as the study area. Ten quantitative indicators in three dimensions (environmental, social, and economic) pertinent to the urban transportation are selected based on review of the related literature and available data in Isfahan. The IA and all proposed scenarios are simulated and calibrated in AIMSUN 8.0 environment and the indicators are quantified in a direct and indirect manner through AIMSUN outputs. A composite sustainability index (CSI) is applied for integrating the effects of selected indicators based on their rankings given by the experts regarding to the goals of Isfahan vision in 2025. The results indicate that public transportation development projects are the most compliant scenarios with the principles of urban sustainable development and the best options for the future development in Azadi district. This proposed framework, would assist policy-makers and traffic engineers in other cities to evaluate the sustainability of urban transportation infrastructure projects.

Performance evaluation of a reverse-gradient artificial recharge system in basalt aquifers of Maharashtra, India

Drinking water scarcity in rural parts of central India in basaltic terrain is common. Most of the rural population depends on groundwater sources located in the fractured and weathered zone of the basaltic aquifers. Long-term indiscriminate withdrawal has caused an alarming rate of depletion of groundwater levels in both pre- and post-monsoon periods. The aquifer is not replenished through precipitation under natural conditions. To overcome this situation, an innovative artificial recharge system, called the reverse-gradient recharge system (RGRS), was implemented in seven villages of Wardha district of Maharashtra. The study described here presents a comparative analysis of recharge systems constructed in the year 2012 downstream of dug-well locations in these seven villages. The post-project comparative analysis reveals that the area of influence (AOI) of the groundwater recharge system, within which increases in groundwater levels and yield are observed, is directly related to the specific yield, thickness of the weathered and fractured zone, porosity, and transmissivity of the aquifer, showing high correlation coefficients of 0.92, 0.88, 0.85 and 0.83, respectively. The study indicates that the RGRS is most effective in vesicular weathered and fractured basalt, recording a maximum increase in well yield of 65–82 m3/day, while a minimum increase in yield of 15–30 m3/day was observed in weathered vesicular basalt. The comparative analysis thus identifies the controlling factors which facilitate groundwater recharge through the proposed RGRS. After implementation of these projects, the groundwater availability in these villages increased significantly, solving their drinking water problems.

Dynamics of atomic stick-slip friction examined with atomic force microscopy and atomistic simulations at overlapping speeds.

Atomic force microscopy (AFM) and atomistic simulations of atomic friction with silicon oxide tips sliding on Au(111) are conducted at overlapping speeds. Experimental data unambiguously reveal a stick-slip friction plateau above a critical scanning speed, in agreement with the thermally activated Prandtl-Tomlinson (PTT) model. However, friction in experiments is larger than in simulations. PTT energetic parameters for the two are comparable, with minor differences attributable to the contact area's influence on the barrier to slip. Recognizing that the attempt frequency may be determined by thermal vibrations of the larger AFM tip mass or instrument noise fully resolves the discrepancy. Thus, atomic stick-slip is well described by the PTT model if sources of slip-assisting energy are accounted for.

Clustering Algorithm Based on Improved Particle Swarm Optimization

K-means algorithm has therefore become one of the methods widely used in cluster analysis. But the classification results of K-means algorithm depend on the initial cluster centers choice. We present a new neighborhood for PSO methods called the area of influence (AOI) and consider the combination of K-means has strong capacity of local searching and PSO has power global search ability. The improved PSO, i.e., improves the K-means local searching capacity, accelerates the convergence rate, and prevents the premature convergence effectively.

The Finite Element Analysis of Coupling Law of Stress Field / Seepage Field in Impermeable Stratum Medium

In order to forecast the mining process of oil and gas field rightly, simulate the flow process of reservoir fluid accurately and reveal the fluid distribution law, it must be considered that multiphase fluid seepage caused by water injection and exploitation, the change of stress state and the coupling between the reservoir deformations. According to the basic theory of rock mechanics, fluid mechanics in porous medium, geologic mechanics, calculated mechanics and fluid-solid coupling seepage, a mathematical and numerical model of seepage field and stress field coupling is developed in porous medium and a computer program is designed with the method of finite element technique. The Coupling Law of depressurizing exploitation Seepage field /Stress field in porous medium is studied. By the method of numerical simulation the variation law of stress-strain with time and space around borehole of impermeable rock medium, variety law of rock physical properties parameters is studied. Results show that the quantity of change nearby oil well and the change gradient is bigger, so it reduces very quickly to the oil deposit boundary,the stress and the strain are also biger in the oil well control area's influence area.

Influence of Mandrel's Surface and Material on the Mechanical Properties of Joints Produced by Electromagnetic Compression

Electromagnetic compression of tubular profiles with high electrical conductivity is an innovative joining process for the manufacturing of lightweight structures. The mandrel's material has an influence on the transferable loads which is affected by the Young's modulus as well as the strength of the material. This was investigated, on the one hand, by changing the mandrel's material and, on the other hand, by using the same mandrel material with differing strength. Furthermore, taking conventional interference fits into account, the contact area's influence on the joint's quality seems to be of significance, as e.g. the contact area and the friction coefficient between the joining partners proportionally determine an allowed axial load or torsional momentum. Therefore, different contact area surfaces were prepared by shot peening and different machining operations and strategies. The mandrel's surfaces were modified by shot peening with glass beads and Al2O3 particles. An alternative preparation was performed using simultaneous five-axis milling, because potential joining partners in lightweight frame structures within the Transregional Collaborative Research Centre SFB/TR10 would be manufactured similarly. After that, the manufactured surfaces were characterized by measuring the surface roughness and using confocal whitelight microscopy. Afterwards the modified mandrels were joined by electromagnetic compression. The influence of different mandrel's surface conditions on the joint's mechanical properties was analysed by tensile tests. Finally, conclusions and design rules for the manufacturing of joints by electromagnetic compression are given.

Biological Significance of Low Weed Population Densities on Sweet Corn

Some weed plants escape current weed management systems in nearly all sweet corn (Zea mays L.) fields. Decisions to target escaped weeds, and justify the added expense, require knowledge of the biological significance of low weed population densities on the crop. The objectives were to (i) quantify giant ragweed (Ambrosia trifida L.) area of influence (AOI) on sweet corn, and (ii) investigate potential links among giant ragweed AOI and crop growth, development, and yield attributes. All measured crop attributes were influenced by giant ragweed AOI, including plant height near silk emergence (HT), thermal time to silk emergence, green ear mass (GMASS), husked ear mass (HMASS), filled ear length (LENGTH), ear width at midpoint (WIDTH), and kernel moisture (MOIST). Proportion of silked plants declined for sweet corn within 160 cm of giant ragweed, with less than one‐half of the crop plants producing a marketable ear within 42 cm of giant ragweed. Weed interference harmed ear attributes most when crop development was delayed, as evidenced by path analysis of giant ragweed's direct and indirect associations with yield attributes. Even the lowest population density of giant ragweed can be costly, with yield loss estimates ranging from $0.86 to $8.75 per weed plant, depending on crop market type.

Area of Influence (AOI) Development: Fast Generation of Receptor-Oriented Sensitivity Fields for Use in Regional Air Quality Modeling

An approach is developed and tested to extend discrete, source-based sensitivity results to provide a complete set of information for source-air quality impacts, including inversion of those results to develop receptor-oriented source-impact sensitivities. First, the decoupled direct sensitivity analysis method in 3D (DDM-3D) is used to calculate a finite number of forward sensitivities from discrete points. These results are then interpolated using tessellation to provide complete fields of forward, emissions-based sensitivities, i.e., how emissions in any one grid cell within the domain impact any other cell. Receptor-oriented sensitivities are then found by inverting the set of forward sensitivities and can be used to identify the area of influence (AOI). This economically provides results similar to what would be found using an adjoint model. The present approach is computationally less intensive than adjoint modeling for a large number of receptors, and provides both source-oriented and receptor-oriented pollutant response fields that can be used for air quality management and health impact analyses. The forward sensitivity interpolation procedure, as well as the receptor-oriented sensitivities, is evaluated using data withholding.

Area of influence (AOI) sensitivity analysis: Application to Atlanta, Georgia

Area of influence (AOI) analysis was applied to determine the geographical extent of the air pollutant precursors contributing to various pollutant levels in the Atlanta metropolitan area. Receptor-oriented sensitivities of ozone and particulate matter (PM) species to emissions of NO x , SO 2 , NH 3 , anthropogenic VOC, and elemental carbon were calculated for various combinations of precursor emissions during 1–10 August, 1999. The episode had high observed concentrations of ozone and PM across several days. AOIs differed significantly by day for each sensitivity as well as spatially between pollutants. Ozone sensitivities peaked at 1.0 ppb per 1.0 mole s - 1 (or per 4.0 ton day - 1 ) per 12 × 12 km 2 model grid of emissions of NO x , but averaged around 0.1 ppb over much of Atlanta. Sulfate was the major component of PM, with an average sensitivity of 0.03 μ g m - 3 per 1.0 mol s - 1 (or per 5.5 ton d - 1 ) per 12 × 12 km 2 model grid of SO 2 emissions and an average of 0.02 μ g m - 3 per 1.0 mol s - 1 per 12 × 12 km 2 of NO x emissions. Ammonia had a significant impact on PM through the formation of ammonium sulfate and ammonium nitrate. Elemental carbon had a geographically small area of influence with high values around the receptor.

Numerical Simulation of Radial Gas Flow: Effects of Soil Anisotropy, Well Placement, and Surface Seal

A variety of methods have been used to control gas flow in the vadose zone in order to remove volatile organic compounds. The effects of well configuration and engineered surface seals on gas flow are recognized but have not been thoroughly analyzed for the design of a vapor extraction well. This paper presents a numerical model to simulate axisymmetric gas flow toward an extraction well in the unsaturated zone. Simulations were conducted to analyze the behavior of gas flow under a variety of system conditions. Results indicate that soil anisotropy, length of the well screen, depth of the gas extraction well, and surface sealing need to be considered in the analysis of a vapor well. Anisotropic soils can significantly affect the area of influence (AI) where the upper surface is open to the atmosphere but generally play a lesser role in a confined soil zone. Setting screens deeper can generate a larger AI, while a longer screen can reduce the pressure drop at the extraction well without causing a major imp...

Effects of Compensatory Growth on Population Processes: A Simulation Study

The spatial extent of the canopy or root system of a plant is often used as an index of its potential to acquire resources, such as water and nutrients. This has given rise to the area of influence (AOl) and neighborhood concepts for quantifying competitive interactions between neighboring plants. Both are based on a circle of fixed radius centered on a plant, which presupposes that two plants in close proximity are always strong petitors. There is evidence that this is not always the case. In this paper, we present a simple model of plant population dynamics that extends the concept of AO by considering com- pensatory growth of root systems. The ability of a plant to grow roots into soil zones free of neighbors in response to competitive pressures is expressed by the value of a single parameter, X. Effects on population attributes resulting from competition in plants with compensatory growth are compared with populations with noncompensatory growth. Simulations show that compensatory plants are better able to utilize available space, have greater biomass, and outcompete noncompensatory plants. The change from a clumped to a regular distribution of individuals due to density-dependent mortality is delayed in noncompensatory plants. These theoretical results suggest that growth plasticity and the resulting asymmetry in space acquisition may play an important role in plant population dynamics.

EFFECTS OF COMPENSATORY GROWTH ON POPULATIONPROCESSES: A SIMULATION STUDY

The spatial extent of the canopy or root system of a plant is often used as an index of its potential to acquire resources, such as water and nutrients. This has given rise to the area of influence (AOI) and neighborhood concepts for quantifying competitive interactions between neighboring plants. Both are based on a circle of fixed radius centered on a plant, which presupposes that two plants in close proximity are always strong competitors. There is evidence that this is not always the case. In this paper, we present a simple model of plant population dynamics that extends the concept of AOI by considering “compensatory” growth of root systems. The ability of a plant to grow roots into soil zones free of neighbors in response to competitive pressures is expressed by the value of a single parameter, λ. Effects on population attributes resulting from competition in plants with compensatory growth are compared with populations with noncompensatory growth. Simulations show that compensatory plants are better able to utilize available space, have greater biomass, and outcompete noncompensatory plants. The change from a clumped to a regular distribution of individuals due to density-dependent mortality is delayed in noncompensatory plants. These theoretical results suggest that growth plasticity and the resulting asymmetry in space acquisition may play an important role in plant population dynamics.

Vegetation-free Area Influences Growth and Establishment of Rabbiteye Blueberry

`Tifblue' and `Brightwell' rabbiteye blueberries (Vaccinium ashei Reade) were planted in 1992 in a tall fescue (Festuca arundinacea Schreb.) sod. Vegetation-free areas of various sizes were maintained around plants to determine the area's influence on establishment and growth of young plants. Vegetation-free circles 0 (control), 0.6, 0.9, and 1.5 m in diameter were maintained from 1992 to 1994 by a combination of commercially recommended herbicides and hand-weeding. The treatments resulted in vegetation-free areas of 0, 0.3, 0.6, and 1.8 m2. Fall growth index values (derived from canopy height and width measurements) increased with size of vegetation-free area in each of the three years. The response was positive linear and negative quadratic, with little difference between the 0.6- and 1.8-m2 vegetation-free areas. Average shoot length in Fall 1992 showed a response similar to that of the growth index; total shoot count per plant was not affected by the treatments. Percent fruit set was not influenced by treatments; however, the number of flower buds per plant in Spring 1994 was correlated positively with size of vegetation-free area. The cultivars responded similarly. Thus, vegetation control seems to be important in establishing young rabbiteye blueberry plants, with the optimum vegetation-free area between 0.6 and 1.8 m2 during the first 2 to 3 years after planting.

SPATIAL STATISTICAL ANALYSIS FOR THE AREA-OF-INFLUENCE EXPERIMENTS

The area-of-influence (AOI) approach to quantifying crop/weed competition involves measuring the effect of individual weed plants on crop growth and yield at specified distances away from the weed plant. AOI experiments are often analyzed using classical statistical techniques based on the assumption that successive observations on crop response are independent in spite of their distribution in space. However, as the distance varies along the row, the competitive ability will vary spatially so that observations located nearby are expected to be more alike than those separated by large distances. Analyses based on spatial dependencies will therefore provide a more comprehensive understanding of factors influencing crop yield reductions. A spatial statistical approach for analyzing AOI experiments is presented and applications are demonstrated using data from a field experiment in South Central Idaho designed to determine the interference of three broadleaf weed species in sugarbeets.

Sleep-waking discharge of neurons in the posterior lateral hypothalamic area of cats

Damage to the posterior hypothalamic area produces a syndrome of EEG synchrony and behavioral somnolence. Cells of a recently described projection system within the posterior lateral hypothalamic area (PLHa) are potential candidates for mediating this area's influences on EEG and behavioral arousal. We examined PLHa neuronal activity during sleep and wakefulness in freely moving cats, identifying projection neurons by antidromic activation from stimulation sites in the external capsule, anterior cingulate bundle, or mesencephalic reticular formation. Orthodromic responses evoked from these sites were also investigated. Twenty-two cells were found to send axons outside the PLHa; 9 with ascending projections and 13 with descending projections. Projection cells were found to discharge phasically in relation to waking movements. Most seemed to be related to complex head movements, although specific movement correlates were difficult to ascertain. Discharge rates during periods of waking immobility were similar to those occurring during slow-wave sleep. Rates during phasic REM sleep were generally similar to peak waking rates. Cells with ascending and descending projections displayed similar discharge profiles, although the former had somewhat higher rates in all conditions. Seventy-four cells were orthodromically driven from external capsule or anterior cingulate bundle. Responses evoked from these two sites were similar, an initial brief period of excitation, followed by a sustained (mean >100 msec) episode of discharge suppression. Twenty-four cells exhibited orthodromic excitation from the mesencephalic reticular formation, but the duration of the subsequent discharge suppression was comparatively brief (mean<30msec). With few exceptions, the discharge correlates of orthodromically driven cells were identical to those described above for identified projection neurons. These results do not support a role for neurons within the PLHa in the control of tonic EEG arousal. They are consistent with a possible involvement in either motor function, or phasic movement-related aspects of EEG activation.

Oceanic area's influence on the range of multi-annual variations of the earth's magnetic field in France

The pluri-annual variations of the earth's magnetic field in France increase their range of influence from East to West. This leads to presume a discontinuity of electric conductivities at the transition from the continental to the oceanic area.