bluuebunny/crossref_metadata_2025_split huggingface dataset:
pH-sensitive Spherical Micelles with Core–Corona Structure Based on Graft-like Block Copolymer Containing Biodegradable ε-Caprolactone Branches
Authors: Tao Youhua , Liu Ren , Liu Xiaoya , Chen Mingqing , Yang Cheng , Ni Zhongbin 
Published: October 2008

Abstract
pH-sensitive spherical micelles with obvious core–corona structure were fabricated by self-assembling of block copolymer of methylacrylic acid and macro-monomer FM [CH2=C(CH3)OOCH2CH2(OCOCH2CH2CH2CH2CH2)5OH] (PMAA-b-PFM). Transmission electron microscopy and laser light scattering studies showed that micelles were nanoscale with narrow size distribution. Solution pH value and the micelle concentration strongly influenced the hydrodynamic radius of the spherical micelles (32–90 nm). The obtained polymeric micelles should be useful for biomedical materials such as drug delivery vehicles.
Real-time Off/On-mode Fluorescence Assay for Enzyme Reactions Involving Nucleoside Polyphosphates by Use of a Xanthene ZnII–Dpa Chemosensor
Authors: Kohira Takahiro , Takashima Ippei , Nonaka Hiroshi , Ojida Akio , Hamachi Itaru 
Published: October 2008

Abstract
New real-time fluorescent assay systems using a zinc(II) complex as a chemosensor for two enzyme reactions catalyzed by Nudix hydrolases and glycosyltransferases have been developed.
Explanation of the Origin of Distortion and Residual Stress in Carburized Ring Using Computer Simulation
Authors: Arimoto K. , Yamanaka S. , Funatani K. 
Published: October 2008

Abstract
Case carburizing is recognized as a suitable process for realizing low distortion and high compressive stresses near the surfaces under optimal conditions. Patterns of distortion and residual stresses in carburized cylinders and rings under different conditions have been identified from measurements performed for many years. Some pioneers of the heat treatment simulation compared their simulated results of carburized and quenched parts with experimental data for verifying their programs. However, these early researchers did not sufficiently explain their distortion and stress generation mechanism using their simulated results. Although one of the authors tried to illuminate their mechanism of a carburized and quenched ring, the work has not been finished because the purpose was limited in examining the role of transformation plasticity in the process. In this paper, the same simulated results were analyzed more comprehensively for explaining the origin of distortion and residual stress in the ring based on a concrete strategy newly developed.
Ein maßstäbliches Experiment zur aktiven Schwingungsdämpfung eines Eisenbahn-Wagenkastens A Scaled Experiment for Active Vibration Control of a Railway Car Body
Authors: Kozek Martin , Benatzky Christian 
Published: October 2008

Zusammenfassung
Der Beitrag beschreibt Identifikation, Reglerentwurf sowie gemessene Resultate eines maßstäblichen Experiments für die aktive Schwingungsdämpfung eines Eisenbahn-Wagenkastens. Piezo Stack-Aktoren zusammen mit Piezo Patch-Sensoren werden zur aktiven Dämpfung der Struktur verwendet. Die optimale Platzierung der Aktoren und Sensoren, die Identifikation der Übertragungsfunktionen sowie der Entwurf eines robusten Reglers werden vorgestellt.
Vollständige Modale Synthese eines Wärmeleiters Parametric State Feedback Design for a Heat Conductor
Authors: Deutscher Joachim , Harkort Christian 
Published: October 2008

Zusammenfassung
Die Vollständige Modale Synthese wurde bisher nur für lineare zeitinvariante Systeme mit konzentrierten Parametern formuliert. Sie liefert einen expliziten Formelausdruck für die Zustandsrückführung in Abhängigkeit von den Regelungseigenwerten und Parametervektoren. In diesem Beitrag wird ein Wärmeleiter als Beispiel verwendet, um die Vollständige Modale Synthese auf lineare zeitinvariante verteilt-parametrische Systeme mit skalarem Zustand und verteiltem Eingriff zu erweitern. Durch Einführung der Regelungseigenwerte und Parametervektoren als Entwurfsparameter lässt sich ein expliziter Formelausdruck für die Zustandsrückführung des verteilt-parametrischen Systems herleiten. Neben der Eigenwertvorgabe erlaubt die neue Parametrierung eine gezielte Vorgabe der Regelungseigenfunktionen. Die Vorteile der neuen Entwurfsmethode werden anhand der Führungsentkopplung des Wärmeleiters diskutiert.
Über eine neue Methode zur Leistungssteigerung von Mensch-Maschine-Systemen durch gezielten Assistenzeinsatz About a New Method to Increase Performance of Man Machine Systems by Targeted Assistance Integration
Authors: Peinsipp-Byma Elisabeth 
Published: October 2008

Zusammenfassung
Eine ungünstige Systemauslegung kann den Menschen höher als notwendig belasten und dadurch die Gesamtleistung eines Mensch-Maschine-Systems geringer als möglich ausfallen lassen. In diesem Beitrag wird eine Methode vorgestellt, die die objektive Ermittlung von Aufgabenteilen, welche den Nutzer stark belasten, auf theoretischem Wege ermöglicht. Mit diesem Wissen kann die Systemauslegung optimiert werden, beispielsweise durch Assistenz, die den Menschen gezielt bei diesen Aufgabenteilen entlastet.
Resistivity through Casing Measurement Successfully Applied to Improve Oil Recovery and Water Shut Off: A Case Study from Western Desert, Egypt
Authors: Dutta Dhruba J. , Badr Abdallah B. 
Published: October 2008

Abstract
Improvement of oil recovery and reduction in water-cut in a matured field requires precise time lapse saturation monitoring. Behind casing resistivity, an important member of the comprehensive analysis behind casing services suite, provides the required answer by acquiring deep resistivity information through casing for subsequent formation evaluation. A time lapse saturation figure could be generated immediately after the acquisition which is extremely instrumental to take an immediate decision. The technology is well known in the industry and already proven beneficial in many occasions. In favorable conditions, this is the most effective methods available to date for saturation monitoring as being the deepest through casing measurement in terms of radial investigation.
The case study presented in the paper describes a successful water shutoff operation and improved oil recovery from the Bahariya formation in the western desert, Egypt. The well was drilled in early 2006 followed by logging and testing and was put on production immediately after completion. During the production time of little more than one year, the oil rate decreased by 70% with 84% water-cut. This significant fall in oil output with sharp early water break through, a common phenomenon in this mature field required a proper shutoff operation. The present example discusses in detail the reason in choosing resistivity behind casing acquisition and time lapse formation evaluation to monitor present saturation profile. Comparison between original and present water saturation level immediately detects the depleted zones and the degree of depletion across perforated intervals indicates the interval contributes most of the produced water. In the present example the cased-hole resistivity acquisition shows departure (lowering) of resistivity values against some perforated intervals. The zones were isolated after identification of the intervals that showed considerably lower resistivity values. This is considered as an indication of rise in oil-water-contact or lengthening of transition zone. In the present case, the remedial measures for water shut-off operation based on time lapse evaluation have enhanced oil recovery from 540 Barrel to 2250 Barrel oil per day with significant reduction in water cut from 84% to 0.5%.
The results were encouraging enough for the operator to reinvestigate the production performance and identify wells where this technique could be meaningfully utilized. The current analysis and workflow offers a fairly good understanding about the reservoir's production scenario, monitoring and future actions for enhanced recovery.
Linking Strategy to Performance in the Oil Industry
Authors: Fletcher A. J. P. , Davis J. P. 
Published: October 2008

Abstract
For an organisation, once having decided upon a given strategy, it is natural to want to assess subsequent performance against those strategic goals. However, it is notoriously difficult to quantify linkage between a strategy and seeing how it works. We propose a methodology to measure performance and establish the linkage between an agreed strategy to subsequent actions.
We argue that the key elements required to achieve the goal of a joined up system of strategy, overview and operation must include a shared ‘picture of the organisation’, an identification of real processes of that organisation and a direct linkage between the processes and the measurement of the success of those processes. This could be expressed as: Purpose, Process and Performance
We argue that a ‘shared picture of the organisation’ assists in communicating a consistent and unified picture to all those involved in transforming strategy into action
The authors present, through a consideration of organisational complexity and systems thinking, a process based method of representing an organisation to help identify the critical processes which will deliver strategic success and target performance measurement to monitor these critical processes.
Two studies are presented. Firstly, the selection and application of chemical EOR technology in the field is discussed with reference to projects conducted over the last two decades. Secondly, a study of options for gas developments with regards the NW Shelf of Australia is presented.
The methodology allows the creation of a hierarchical process model grounded in the values of the organisation; providing the capability of modeling at both strategic and operational levels. If communicated throughout the organisation, the model provides a consistent picture to all involved, reducing the irregularities that result from differing mental models and thereby increasing the potential for organisational learning.
A Method for Enhancing the RPM Performance in Matrix Reservoir
Authors: Sidiq Hiwa H. , Amin Robert 
Published: October 2008

Abstract
A methodology for enhancing the performance of relative permeability modifier (RPM) treatment presented here utilises a technique of injecting chemicals sequentially into the affected wells. This technique considers injecting a single RPM into matrix reservoir cannot occupy all the reservoir pores, because as RPM injected it will form a constant film on the reservoir rock grains that may plug small pores and reducing the effective size of larger pores. Therefore the RPM displacement will not be piston like and consequently the RPM treatments have shown low to moderate success. The aim of this method is to obtain a high dispersion rate of RPM polymers onto the reservoir rock grains to improve the performance of RPM treatments.
In this study we examined two injection methods; namely single and sequential injections. For the single chemical injection, three chemicals were tested each individually in Berea plugs having water permeabilities ranging from 5.5 to 18.5md and porosities from 14.1 to 19.6%. Thereafter three of these chemicals were injected successively into a Berea sample having water permeability of 34md and porosity of 20.4%.
The experiment results revealed that injecting chemicals sequentially is more effective method for conformance control in matrix reservoir than the single chemical injection method. For instance, for the first and second water alternate oil (WAO) cycles, the residual resistance factor to water Frrw obtained by this method was 5 and 2.5 times higher than the Frrw acquired by the single chemical injection method. The measured residual resistance factor to oil Frro using the sequential method was less than two, which is considered to be the upper limit for conformance control in matrix reservoirs. Accordingly injecting chemicals sequentially method can be applied to enhance RPM performance in matrix reservoirs.
The Effect of Wettability on Oil Recovery: A Review
Authors: Agbalaka Chinedu , Dandekar Abhijit Y. , Patil Shirish L. , Khataniar Santanu , Hemsath James R. 
Published: October 2008

Abstract
Numerous early reports on experimental works relating to the role of wettability in various aspects of oil recovery have been published. Early examples of laboratory waterfloods show oil recovery increasing with increasing water-wetness. This result is consistent with the intuitive notion that strong wetting preference of the rock for water and associated strong capillary imbibition forces give the most efficient oil displacement. However, an increasing number of examples of improved waterflood recovery with shift from strongly water-wet conditions to intermediate, weakly water-wet and oil-wet conditions have also been reported. All the early and more recently observed experimental outcomes, on wettability effects on waterflood oil recovery, point to the divergence of conclusions regarding the optimum wetting condition for maximum waterflood oil recovery.
The impact of the in-situ reservoir wetting state on miscible and /or immiscible gas flood oil recovery, though not as pronounced as that observed in waterflooding processes, is still nonetheless quite significant. It has been shown that wettability does indeed determine the gasflood oil recovery efficiency and changes in wetting states have resulted in observed improved gasflood recoveries.
This paper examines the effect of wettability on waterflooding and gasflooding processes respectively. Waterflood oil recoveries were examined for the dual cases of uniform and non-uniform wetting conditions. The uniformly wetted systems examined in this work are considered to be those systems in which the observed wetting state is uniformly distributed and covers the range from strongly water-wet through the intermediate-wet to strongly oil-wet conditions. The non-uniformly wetted systems examined include the mixed-wet and the fractionally-wetted systems. The effects of wettability on miscible and immiscible gas recovery processes (including WAG) are also examined. Other factors such as the spreading coefficient, mobility ratio, crossflows, etc. were also reported to affect gasflood oil recoveries.
Most experiments on wettability studies are performed on core samples and depending on the process of core sample recovery / retrieval, transportation and storage, the wetting state of the core sample may be altered. Consequently the importance of proper core handling procedure in ensuring that the reservoir native-state wettability is preserved is highlighted. In a situation where the native wetting state has been altered, the need for adequate care in the process of/approach to reproducing wettability is also mentioned.
Study of Produced CO2 Storage into Aquifer in an Offshore Field, Malaysia
Authors: Kartikasurja Dewanto Odeara , Lin Tan Giok , Sukahar M. Wakif , Viratno Bernato 
Published: October 2008

Abstract
To meet the ever increasing gas demand in Malaysia, many gas fields with high CO2 content are being considered for development. Located in offshore Peninsular Malaysia, B field is one of those gas fields. It is vital for the field development plan to focus on the issues of associated CO2 gas production disposal in view of the global warming effects of releasing CO2 to the atmosphere. The offshore separation and removal of CO2 has to be carried out to meet the gas sales specifications from an average CO2 of 29 mol % in the Full Well Steam (FWS) down to 8%, thus raising the issue of managing this huge volume of CO2 greenhouse gas production. The study on how to manage the disposal and storage of the CO2 separated from the gas stream was made as an integral part of the B field development plan, since a disposal site and an infrastructure for injection operations would be needed to store the produced CO2.
This paper presents the workflow and methods of evaluating the potential formation for subsurface disposal of produced CO2 into a saline aquifer over the entire life of the field and its impact in the field development plan. The main tasks associated with the study are the geological evaluation of the shallow subsurface and subsequent reservoir engineering and CO2 injection modeling challenges due to limited reservoir data. The water filled aquifer zones that were identified to be potential sequestration site are in the Group D with depth surfaces starting from 1170 m subsea and ending at 1300 m subsea, 5 km south of the A-Platform (main). All CO2 gas re-injection wells will be drilled from the satellite platform-B. All reservoirs which include potential aquifer zones below 1800 m subsea depth have been found to be over-pressured and are not suitable for CO2 sequestration.
A faulted geo-cellular model was built and subsequently characterized by stochastic facies and petrophysical distributions based on exploration/appraisal wells data and 3D seismic interpretation. Different sensitivity studies were carried out to have a good understanding of the key parameters that would control the re-injection process.
Based on the results of the model, the aquifer is adequate to store the volume of the re-injected CO2 using four injection wells. The model results show that by lengthening the CO2 migration path, the CO2 dissolution in the formation water can be maximized and thus minimizing the build-up of aquifer pressure. It is achieved by targeting the injection further down-dip of the aquifer. Furthermore, the low salinity of the aquifer water is also an important factor in helping to maximize the amount of CO2 dissolved. High injectivity wells are essential to minimize the bottom-hole pressure required to inject the gas, in order to stay below the fracture pressure limit. This factor becomes very important as the aquifer pressure builds up.
Killing of a Gas Well: Successful Implementation of Innovative Approaches in a Middle-Eastern Carbonate Field—A Field Case
Authors: Salehi S. , Hearland G. , Soroush M. , Dehkordi K. Khademi 
Published: October 2008

Abstract
A casing collapse occurred in a gas producing well with about 2.5 million cubic meters per day gas flow rate at a depth of 216 ft due to tectonic movements. As a result, the well blew out and different serious procedures were put into play to kill the well (Figure 1). This paper aims to review the practical and innovative approach that was used to secure and extinguish the well. Figure 1Gas Seepages in Kangan Field
Initially attempts to kill the well included pumping water and or cement into the well to kill and secure it but it was not successful. Two directional relief wells, Kanagan-23A and Kanagan-23B were drilled to secure the well, the latter one was successful. The 23B well was drilled down to total depth of 2500m and entered into drainage area of Kangan-23 gas well. Different directional surveys were tried according to geophysical and geological data for entering the target area. The well relief and intersection was done by combining the new wellpath with the old well and injecting different pills and acidizing the new well to generate connectivity between the two wells. This type of innovative techniques has never been used in killing a well successfully before. This paper presents the unique thinking and practical approach used for securing this well including the failures as well as successes. The successful procedure may be used in killing future wells under similar condition.
Estimating Fracture Permeability and Shape Factor by Use of Image Log Data in Welltest Analysis
Authors: Bahrami Hassan , Siavoshi Jamal , Esmaili Soodabeh , Karimi Mohammad Hussein , Bahraie Ramin 
Published: October 2008

Abstract
The identification of fractures is essential during exploration, drilling and well completion of naturally fractured reservoirs since they have a significant impact on flow contribution. There are different methods to characterize these systems based on formation properties and fluid flow behaviour such as logging and testing. Pressure-transient testing has long been recognized as a reservoir characterization tool. Although welltest analysis is a recommended technique for fracture evaluation, but its use is still not well understood.
Analysis of pressure transient data provides dynamic reservoir properties such as average permeability, fracture storativity and fracture conductivity. An infusion of geological knowledge helps reducing uncertainty associated with any well-test interpretation. The static properties of naturally fractured reservoirs such as fracture distribution, fracture aperture, matrix block size and fracture porosity can be obtained from processing of Image Log data.
Simulation of naturally fractured reservoirs needs defining fracture permeability, shape factor and fracture porosity in the fracture model. However, in most simulation studies, due to high uncertainties in estimating fracture permeability and shape factor values, these parameters are initially assumed in the model and they are usually tuned during history matching which can be time consuming and also affect other history match parameters. Reservoir simulation results and predictions might be inaccurate if the values of fracture properties in the model are not reliable.
This paper shows using image log data associated with welltest analysis in order to determine dynamic fracture parameters such as fracture permeability and shape factor for reservoir simulation. In this study, sensitivity analysis has also been performed on fracture permeability, fracture porosity and matrix block size in real simulation models in order to show importance of accurate determination of fracture parameters.
Optimal BHA Design for Steerability and Stability with Configurable Rotary-Steerable System
Authors: Sugiura Junichi 
Published: October 2008

Abstract
There have been significant attempts to optimize the various bottom-hole assemblies (BHAs) used in rotary steerable (RS) applications because the optimal RS assembly can provide operators with significant cost savings by providing less vibration, high BHA stability, high-quality borehole, and thus predictable steerability.
This paper presents the development of BHA analysis models using simplified mathematical equations. RS BHA optimization process is demonstrated through the extensive field test program. The predictions of BHA response and directional drilling performance of the RSS have been examined with the numerous field test data taken in a controlled and non-commercial environment, allowing single step changes in both the drill bit features and RS configurations.
The testing is unique since the specific rotary-steerable system (RSS) works in field-configurable point-the-bit and push-the-bit modes. Between two distinct RSS operation modes, consistency in stiffness, weight, force applying capability, and control system lead to a direct comparison of different BHA models. Confidential test sites were selected for evaluating different RS BHA configurations in both push-the-bit and point-the-bit modes. The systematic BHA testing was conducted in two different test facilities in North America.
A unique sensor system, integrated into the specific RSS, provided real-time measurement of near-bit borehole caliper and near-bit stick-slip and vibration1,2 This feature allowed real-time evaluation of bit and BHA stability and borehole quality while the maximum build-up test was performed. After each test run, memory data was retrieved and used for more detailed assessment of bit and BHA performance.
BHA configuration tests were systematically conducted in a controlled environment so that the relationship between BHA analysis models and actual BHA behaviors could be identified. As a result, the systematic testing and verification lead to the optimal RS BHA design in both push-the-bit and point-the-bit configurations for stability, steerability and borehole quality.