bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Impulse Responses Characteristics of an Optical Delayed Feedback Semiconductor Laser
Authors: Senlin Yan 
Published: October 2011

Abstract
Impulse response characteristics of a semiconductor laser with weak optical feedback (OF) is studied. Equations about the amplitude and frequency responses of the laser under the current modulation condition are deduced. We demonstrate theoretically that the equations are the function of the modulation frequency, optical feedback level and delayed time. We give the impulse response function under the jump signal modulation condition with OF and without OF, this is helpful for digital laser communications. The numerical results demonstrated that OF can make the laser obtain the enhancement of the modulation response and bandwidth and can reduce the frequency respond in the some parameters range. OF can enhance gently the relaxation oscillation of the foreland or the tail of the impulse response signal under the weak OF case while the oscillation can be enhanced sensitivity to the modulation under the larger OF case
A Modified Oxygen Consumption Test to Evaluate Gas Flux through Oxygen Barrier Cover Systems
Authors: Dagenais Anne-Marie , Mbonimpa Mamert , Bussière Bruno , Aubertin Michel 
Published: October 2011

Abstract
The evaluation of an oxygen barrier cover performance is an integral part of many reclamation programs that aim at limiting acid mine drainage (AMD) production from sulphide tailings. The oxygen flux through the cover to the underlying reactive tailings should then be much smaller (by a factor of 1000 or more) than the flux into exposed (uncovered) tailings. Different techniques have been developed over the years to assess this flux. Given the limitations encountered when using available approaches to measure such low oxygen flux, the authors have developed a modified testing and interpretation method based on the oxygen consumption (OC) test, which is commonly used to determine oxidation rates of uncovered tailings. The proposed modifications to the OC testing procedure are presented in this paper, together with the new interpretation method. Typical tests results obtained with the modified OC method on an existing site, reclaimed using a layered cover with capillary barrier effects (CCBE), are presented and discussed. The results demonstrate that the modified oxygen consumption (MOC) test is an effective tool to assess the performance of oxygen barrier covers used to prevent AMD.
Experimental Testing and Numerical Evaluation on Freezing for Water Hydraulics Application under Sub-Freezing Ambient Temperature Environment
Authors: Chua Patrick S. K. , Tan F. L. , Zhang J. 
Published: October 2011

Abstract
The work reported in this paper explores both experimental and numerical simulations on the process of freezing of pressurized fluids in stainless steel pipes for water hydraulics systems under sub-freezing ambient temperature conditions. Preliminary experimental studies were conducted to investigate the time taken for water to freeze under sub-freezing temperature conditions and to explore ways to delay and prevent the water from freezing. A test rig was designed and tested. The results of the experiments deduced that the use of insulation would delay the time for water to freeze and the use of heating pads (heaters) mounted on the insulated piping could prevent freezing altogether. Computational Fluid Dynamics (CFD) simulation software, FLUENT, was used to identify the relevant parameters, such as the thickness of the insulation, flow velocity, pipe length, and the heat flux applied along the pipe length, which could prevent the freezing of the water throughout the solution domain with proper geometries and boundary conditions.
The Effect of Nano-precipitates on Strength in a Micro-alloyed Ferritic Steel
Authors: Askari H.A. , Shen Y.F. , Wang C.M. , Sun X. , Zbib H.M. 
Published: October 2011

ABSTRACTA high strength ferritic steel with finely dispersive precipitates was investigated to reveal the fundamental strengthening mechanisms in this alloy. Using energy dispersive X-ray spectroscopy (EDXS) and transmission electron microscope (TEM), fine carbides with an average diameter of 10 nm were observed in the ferrite matrix of the 0.08%Ti steel, and some cubic M23C6 precipitates were also observed at the grain boundaries and the interior of grains. The dual precipitate structure of finely dispersive TiC precipitates in the matrix and coarse M23C6 at grain boundaries provides combined matrix and grain boundary strengthening. The resulting yield stress is two or three times higher than that of conventional Ti-bearing high strength hot-rolled sheet steels. The effect of the particle size, particle distribution and intrinsic particle strength have been investigated through dislocation dynamics (DD) simulations and the relationship for resolved shear stress for single crystal under this condition has been presented using simulation data. The results show that the finely dispersive precipitates can strengthen the material by pinning the dislocations up to a certain shear stress and retarding the recovery as well as annihilation of dislocations. The DD results also show that strengthening is not only a function of the density of the nano-scale precipitates but also of their size. This size effect is explained using a mechanistic model developed based on dislocation-particle interaction.
Tuning lattice thermal conductance in ultra-scaled hollow SiNW: Role of porosity size, density and distribution
Authors: Pau Abhijeet , Miao Kai , Luisier Mathieu , Klimeck Gerhard 
Published: October 2011

ABSTRACTPorous crystalline Si nanowires (PC-SiNW) represent an attractive solution for enhancing the thermoelectric efficiency (ZT) of SiNWs by reducing the lattice thermal conductance (κl). A modified valence force field (MVFF) phonon model along with Landauer’s approach is used to analyze the ballistic κl in PC-SiNWs. A systematic study focusing on the influence of pore size, density, and distribution on the ballistic κl of PC-SiNWs is presented. The model predicts a maximum reduction of ∼19%, ∼23% and ∼30% for 1, 2 and 3 pores, respectively with a constant removal of ∼12% of the atoms in all the cases. The model also predicts a higher reduction of the ballistic κl as the pore separation increases, in the case of 2, 3 and 4 pores, for the same percentage of atoms removed (∼12%) in all the cases. Thus, the presence of a high number of small, well-separated pores suppress κl strongly. This reduction in ballistic κl, in the coherent limit, is attributed to the reduction of the total number of phonon modes and smaller participation of phonon modes (in κl) with increasing number of pores.
Injection Fall-Off Analysis of Polymer Flooding EOR
Authors: Mahani H. , Sorop T. G. , van den Hoek P. J. , Brooks A. D. , Zwaan M. 
Published: October 2011

Abstract
Polymer solutions, in contrast to water, exhibit non-Newtonian rheological behavior, such as in-situ shear-thinning and shear-thickening effects, leading to a varying viscosity distribution in the reservoir. Consequently, a different pressure distribution and a rather slower pressure decline rate are exhibited during Pressure Fall-Off (PFO) test (compared to a waterflooding case). Therefore, applying a different interpretation method, compared to conventional approaches for Newtonian fluids is required.
In this paper we provide a new, simple and practical method to infer the in-situ polymer rheology and the induced fracture dimensions from PFO tests performed during polymer injection. This is based on a combination of numerical flow simulations and analytical pressure transient calculations, resulting in generic type curves that are used to compute consistency index, flow behavior index, fracture dimensions, and reservoir parameters (kh, faulting, etc.) from the measured pressure derivative curves.
The novelty of this study are the analysis of interference caused by fracture sizes on the radial stabilization of polymer, as well as the use of realistic polymer rheology, combined with an analysis method that derives polymer rheology parameters based on the pressure derivative curve.
This method can be used for interpretation of PFO tests on existing EOR polymer flooding projects, where monitoring of injection performance and of in-situ effective polymer rheology are key in the success of a project.
Incorporating PLT-Distributed Dynamic Permeability — into Reservoir Simulation Models — Improves and Accelerates the History Matching Process
Authors: Abdel-Ghani Rida , Krinis Dimitris , Camargo Jorge Nieto 
Published: October 2011

Abstract
Integrating dynamic data into reservoir numerical models is essential for capturing the actual dynamic flow behavior. History matching efforts could prove to be fruitless without including such data into the reservoir model. For example, open hole logs and core sampling do not provide a satisfactory characterization of fractures and super-high permeability streaks — two important flow features that can be overlooked.
Failing to incorporate these small but critical flow features can lead to inaccurate simulation models, even if the total rates at the wellhead are captured by the history match. This inaccuracy usually transpires when model results are compared to actual production profiles, and could go unnoticed until the field performance starts to deviate from predictions.
The inclusion of dynamic permeability data into the reservoir model can be performed, either during the static geological modeling, or into the dynamic simulation model, as a conditioning step. Either way, the process starts by comparing the correlation based kh values to those obtained from pressure transient testing. Various methods can be used to utilize the results of this comparison, which vary from simple zone averaging to highly detail vertical permeability profiling.
In the geocellular model, the adjusted dynamic profiles are input for the permeability population by using several methods that range from kriging to stochastic approaches. The final conditioned permeability fields can be in addition to incorporating discrete fracture models or stratiform characterization and mapping as 2D or 3D trend parameters.
This paper explains how PLT profile based distribution of the dynamic permeability resulted in a large improvement of the history match results, and just as importantly, a shorter history matching process for a giant carbonate Middle East reservoir. The paper also shows alternative approaches for incorporating the dynamic permeability into the simulation model, but which did not produce the same desired results.
Slippage Effect and Quasi Starting Pressure in Low Permeability Water-Bearing Gas Reservoirs
Authors: Liu Xiaojuan , Yan Jian , Liu Yi 
Published: October 2011

Abstract
Lab tests were carried out to study the gas slippage and quasi starting pressure in water-bearing gas reservoirs of low permeability. The permeability of the testing cores is mainly lower than 1 mD. The testing results indicate that: for similar water saturation, the lower the permeability is, the more serious the gas slippage is. For similar permeability, with the increasing of water saturation, the gas slippage effect increases first and then decreases. The turning point is called critical water saturation (Sw)c1. The relationship between the critical water saturation and the core coefficient is binomial, where the core coefficient is the ratio between permeability and porosity. By curve fitting, it was found that, when the water saturation is lower than a critical value, gas slip factor is a logarithmic function of the ratio of core coefficient and water saturation; when water saturation is higher than the critical value, the gas slip factor is a logarithmic function of the multiplication of core coefficient and water saturation. The quasi starting pressure gradient may exist when the gas flow in porous media that contains water. The reason is that the increase of capillary resistance is larger than gas slippage as the water saturation rises. In further, it was concluded that there is another critical water saturation (Sw)c2. When the water saturation is larger than the critical value (Sw)c2, the quasi starting pressure gradient exists. The relationship between the quasi starting pressure gradient and the ratio of core coefficient and water saturation is a power function. Further more, the relationship between the critical water saturation and absolute permeability is also a power function.
Seismic-to-Simulation for Unconventional Reservoir Development
Authors: Cipolla C. L. , Fitzpatrick T. , Williams M. J. , Ganguly U. K. 
Published: October 2011

Abstract
The completion strategy and hydraulic fracture stimulation are the keys to economic success in unconventional reservoirs. Therefore, reservoir engineering workflows in unconventional reservoirs need to focus on completion and stimulation optimization as much as they do well placement and spacing. This well-level focus requires the integration of hydraulic fracture modeling software and the ability to utilize measurements specific to unconventional reservoirs. This paper details a comprehensive integration of software, data, and specialized measurements specific to unconventional reservoirs that allows efficient full-cycle seismic-to-simulation evaluations.
It is very important to properly model hydraulic fracture propagation and hydrocarbon production mechanisms in unconventional reservoirs, a significant departure from conventional reservoir simulation workflows. Seismic-to-simulation workflows in unconventional reservoirs require hydraulic fracture models that properly simulate complex fracture propagation which is common in many unconventional reservoirs, algorithms to automatically develop discrete reservoir simulation grids to rigorously model the hydrocarbon production from complex hydraulic fractures, and the ability to efficiently integrate microseismic measurements with geological and geophysical data. The introduction of complex hydraulic fracture propagation models now allows these work-flows to be implemented.
This paper documents an efficient, yet rigorous, integration of geological and geophysical data with complex fracture models, single-well completion and stimulation focused reservoir simulation, and microseismic measurements. The implementation of a common software platform and the development of specialized gridding algorithms allow complex hydraulic fracture models to be calibrated using microseismic measurements in the context of local geology and structure. The complex hydraulic fracture geometry, including the distribution of proppant, is automatically gridded to a common Earth Model for single-well reservoir simulation. The software platform, newly developed complex hydraulic fracture models, and automated gridding algorithms are illustrated in a case history from the Barnett Shale unconventional gas play.
Horizontal Well Modeling in Case of Highly Heterogeneous Anisotropic Reservoir
Authors: Tsyganova E. F. 
Published: October 2011

Abstract
Horizontal wells application in heterogeneous reservoirs is challenging as assumes high expenditures in conditions of problems with such wells modeling. The model matched to history data can show inaccuracy in horizontal wells performance forecast. In this paper the issue is investigated with using of integrated approach.
Uncertainties related to reservoir complexity are considered as possible sources of erroneous prediction. Reservoir study coupled with the review of analytical solutions is conducted to identify the uncertain parameters influencing horizontal well performance. Their ranges of variation obtained from research data are included into qualitative analysis of uncertainties impact. It is performed on the model with estimation of oil production as a main decision criterion. All the uncertainties are incorporated into simulation process with using of Monte Carlo technique and automatic history matching. Non-unique nature of the model is shown and the significance of performing multivariant prediction for horizontal wells is proved.
As a result the modeling procedure with uncertainties inclusion is proposed and methods of uncertainties reduction are recommended in order to increase model reliability. This will allow uncertainties management and more founded decision making.
Assessing Structured Uncertainty in a Mature Fractured Reservoir, Using Combination of Response Surface Method and Reservoir Simulation
Authors: Khosravi Maryam , Fatemi Shohreh , Rostami Behzad 
Published: October 2011

Abstract
In recent years the oil industry has given great importance to reservoir uncertainty analysis, because, it would control the financial uncertainties; however, the development of a method that could model it based on pure reservoir simulation would be complex while the influence of the parameters on reservoir performance is non linear. Therefore, different approaches such as experimental design, response surface methodology and Monte Carlo simulation have been combined with reservoir modeling to simplify addressing the uncertainties.
In this work, dynamic model of a fractured mature reservoir has been constructed from a static primary structure. But, this process is totally crucial and challenging, because of limited knowledge of fracture network parameters and characteristic, that could be source of uncertainty in reservoir performance. Therefore, response surface method is used to realize the most influential parameters on pressure drop and recovery factor changes, regarding their practical levels of uncertainties during the development of fractured reservoir model. The present approach is performed to magnify the significant parameters and developing compatible and more realistic proxy equation for forecasting oil recovery from a typical low permeable fractured reservoir. The proxy model allows Monte-Carlo analysis to determine sensitivities and the quantification of the impact of uncertainty on production forecasts. Furthermore, it helps making reliable decision during the reservoir development.
Results indicate that the oil recovery is more sensitive to aquifer strength, fracture permeability and block height. However the interaction between other parameters such as matrix size, fracture permeability and aquifer volume, showed a degree of importance during this analysis. Monte-Carlo analysis forecasts wide range of oil recovery for this field development. The result indicates that the range of fracture permeability and aquifer characteristic should be attained carefully to reduce degree of uncertainties in field development strategies.
Reservoir Rock Typing of a Giant Carbonate Field
Authors: Al Ameri Mohamed B. , Shebl Hesham 
Published: October 2011

Abstract
Reservoir Rock Types of Kharaib reservoirs have been defined as an interval of rock within which the geological and petrophysical properties that effect fluid flow are consistent and predictable. Lithofacies classifications are a purely geological grouping of reservoir rocks, which have similar lithology, texture, grain size, sorting etc. Each lithofacies indicates a certain depositional environment with a distribution trend and dimension. Petrophysical groups are classified by Porosity, Permeability, Capillary Pressure and Pore throat size distribution.
A Rock Type combines both these classifications by linking petrophysical properties and lithofacies as part of the reservoir rock type definition. It has been previously shown that the static rock types are not always representative of multi-phase flow behavior in the reservoir. In this paper, we will present evolution of the rock type scheme within ZADCO. We discuss criteria used to define reservoir rock types in the current unified scheme. The objective of the proposed rock type scheme is to address shortcomings identified with the previous one in use and is based on the following criteria: a) each Rock Type can be characterized by similar depositional environment and diagenetic process; b) Porosity/Permeability overlap is minimal between different rock types; c) each rock type has a typical and unique set of Pore Throat Size Distribution; and d) each rock type has similar set of Capillary Pressure/Relative Permeability curves at a given wettability.
The recognized Reservoir Rock Types have been assigned to reservoir layers were built within a framework based on sequence stratigraphic concepts to ensure that the spatial 3D distribution of each rock types is predictable within a well-defined geological framework and finally to be used in history matching simulation models.
Assessing the Impact of Fault Connectivity Uncertainty in Reservoir Studies using Explicit Discretization
Authors: Cherpeau Nicolas , Caumon Guillaume , Caers Jef , Lévy Bruno 
Published: October 2011

Abstract
Reservoir production curves provide significant information about reservoir compartmentalization and connectivity, but are most often used at late stages of reservoir modeling workflows, leading to possible inconsistencies between static and dynamic reservoir models. In this paper, we propose to use this information during structural modeling to reduce fault-related uncertainties induced by subsurface imaging and interpretation ambiguities.
We first generate stochastic fault networks from prior information about faults hierarchy, size, orientation, roughness and localization. Then, the results are discretized into a set of nodes and pipes, called a pipe network, which represents the control volumes connectivity graph. This discretization data structure accurately represents fault surfaces and fault connections while limiting the number of nodes to represent the domain of interest as a connectivity graph that can be fed to a flow simulator. In a third step, we select models that best match the production curves.
The proposed method is flexible enough to assess high uncertainties that may require to add or remove faults, or to perturb the fault connectivity, without need for simplification of the fault network into a corner-point reservoir grid. The method is applied to a synthetic example of high uncertainties relative to a poorly imaged 3D fault zone.