bluuebunny/crossref_metadata_2025 huggingface dataset:
Data Access and Integration for Major Capital Projects: A Case Study
Authors: Bell Melanie , Fisk Jill
Published: February 2008

It is often perceived that green fields present the ideal opportunity to implement new technology and processes to achieve world class operations via integrated field management. But there are still the challenges of limited recourses, change management and integration into existing operational systems.

This paper will present the results of IT involvement and challenges in 2 different Chevron major capital projects, the BBLT project in Angola and the Gorgon project in Australia. It will look at the construction of current state and future state plans, the prioritization of the project queues, the involvement of local IT support and vendor support, the change management approach for the user community and integration of data within the business value chain and across geographical locations. The project focused on the systems, data management and communications for the operations field teams and the subsurface asset teams.

Data access and integration included well data systems of record, real time drilling data, real time access to time series operational data, especially down hole pressure and temperature and integration of operational data to production allocation, reservoir simulation and well optimization analysis tools.

The project goals were achieved to reduce time and effort in finding and reformatting data, reducing the duplication of data, allowing data access across the globe and enabling better decision making by ensuring that the best data was available for analysis in an appropriate time frame. The data access processes also allowed us to reduce the number of people offshore.
A Survey of Wireless Technology for the Oil and Gas Industry
Authors: Petersen Stig , Myhre Bård , Doyle Paula , Mikkelsen Erik , Carlsen Simon , Sjong Dag , Skavhaug Amund , van der Linden Jan Hendrik , Sansom Mark
Published: February 2008

The IEEE 802.11/a/b/g specifications for wireless local area networks (WLAN), the IEEE 802.15.4 specification for low-rate wireless personal area networks, and radio-frequency identification (RFID) specifications have enabled a wide range of wireless applications such as wireless networking, wireless sensing, monitoring and control, and asset and personnel tracking. For the Oil & Gas industry, using this technology will lead to reduced operating costs as well as enable new applications.

This paper identifies the technical requirements for wireless technology within the boundaries of the Oil & Gas industry. Experiments have been performed on wireless solutions within three application areas in order to examine whether or not currently available technologies fulfill these requirements. The conclusion is that WLAN technology is ready for deployment in Oil & Gas installations, while there still is a need for an open industrial standard for wireless sensor networks. Regarding RFID, our experiments show that solutions with passive tags are not suitable for asset and personnel tracking applications.
The Status of WITSML as an Intelligent Energy Real-Time Enabler
Authors: Kolstad Børge , Chmela William , Skarbø Rune , Gibson Nicholas
Published: February 2008

The XML based Wellsite Information Transfer Standard Markup Language (WITSML) wellsite data exchange format provides the hydrocarbon extraction industry with a bandwidth efficient, real-time drilling data management and exchange format. Drilling data can be supplied to the data consumer within seconds, regardless of their global location.

With recent industry talk of the big demographic bulge or crew change being due within five years and ongoing difficulty in sourcing new recruits into the hydrocarbon extraction industry, the ability to take the data to the expert, rather than the expert to the data, provides both Oil and Service Companies with workflow challenges and opportunities.

This paper reviews three cases that show the WITSML data standard and associated infrastructure being used to automate or improve the distinct organizational workflows. The provision of real-time well and drilling data via an internet protocol based data standard and data management infrastructure brings measureable improvements within the discussed workflows.
Evolution of Decision Environments: Lessons Learned From Global Implementations and Future Direction of Decision Environments
Authors: Hauser Michael , Gilman Helen
Published: February 2008

Chevron and Science Applications International Corporation (SAIC) are working together to implement Asset Decision Environments (ADEs) across business units as part of the Chevron i-field™1 initiative. This paper describes lessons learned from the program to date, covering types of ADE, challenges faced, solutions delivered and benefit realized. It goes on to discuss the future development of the ADE concept.

Chevron has explored ADE value and usage through the implementation of different types of environments targeted at different problems, and this paper will outline the logic behind this multi-strand approach, and the benefits delivered. Examples will include Decision Support Centers, collaboration environments, and training environments. As the initial implementations deliver success and collaborative working becomes more widespread, questions are being asked about how far we can go with collaborative working and decision-making. The paper will provide some insight into the vision for the ADE in the future.

This paper will set out practical lessons learned on how to design an ADE to address current problems, deliver value and still remain flexible to developments in the future. It will describe challenges and solutions for many aspects of ADE design and implementation, highlighting issues, solutions and benefits delivered. The paper will share a vision for a multi-functional and multi-asset operational ADE of the future, including key challenges that still need to be resolved.

Decision and collaboration environments are being deployed by companies to address challenges associated with response to real-time data, scarcity of experienced resources, and integration and collaboration between disciplines and locations. This paper provides a Chevron and SAIC perspective on the questions: How can decision environments deliver value, and how might they evolve in the future to deliver more integration and collaboration?
The Integrated Collaboration Environment as a Platform for New Ways of Working: Lesson Learned From Recent Projects
Authors: Vindasius Julia
Published: February 2008

Upstream oil and gas organizations continue to face challenges to prove that the digital oilfield will improve decision-making, achieve higher quality analysis, and effectively use smaller pools of skilled resources. Both corporate and business unit champions recognize that an Integrated Collaboration Environment (ICE) can be the integration platform to support various digital oilfield and performance improvement initiatives. Initially, some companies took a "Field of Dreams" approach, expecting that once video-conferencing and visualization workspaces are built, their professional staff "will come." Increasingly, even these companies now recognize that successful projects must develop a plan to integrate people, process, technology, and facilities to enable new ways of working.

This paper proposes a framework to realistically diagnose performance requirements against a company's digital oilfield or integrated operations strategy, and to chart an ICE development path to match. In addition, we share some lessons learned from recent ICE implementations projects for drilling, production operations, and/or optimization. Whether for new or legacy assets, we are learning that success depends on (a) engaging objective, third-party consultation to help the management team articulate a shared vision for collaboration, integration, and real-time support; (b) investing time and resources in a participatory conceptual design phase that focuses on the user experience; and (c) a design/implementation methodology that addresses all the dimensions of change—process, organization, people, technology, and facilities, inclusive of a professional project management with experience leading joint internal/external teams to deliver complex system integration projects.

By clarifying the performance vision framework and applying some of the lessons learned from early adopters, we see that a well-designed and professionally implemented ICE can resolve inefficiencies, "handoff" disconnects, and communications gaps between the field and the office. Better yet, the ICE will generate a step-change improvement in "real-time" surveillance, interpretation, decision-making, and quality execution, embedding it as the new and "natural" way of working.
Human Factor Principles in Remote Operation Centers
Authors: Brannigan James , Veeningen Daan , Williamson Mark , Gang Zhao
Published: February 2008

The uptake of operation support centers for monitoring and remotely controlling wellsite operations in real time is accelerating in the industry. This paper identifies and discusses the human factors involved with the successful design and operation of these centers.

The introduction of remote operation centers is having a significant impact on the physical and cognitive abilities of engineers working within the centers. Human Factors is a discipline that focuses on how people interact with tasks, machines, and the environment with the consideration that humans have limitations and capabilities. Human Factors must be considered in the planning, design and operation of any remote operation center to ensure productive and safe operation of the center. Locating operators remote from the tasks they are controlling or monitoring will affect not only the direct control and decision making processes, but will also affect their cognitive abilities and ongoing knowledge management and training.

In order to maximize the productivity of any system it is essential to design the workflow to take account of the new operational methods rather than trying to duplicate the existing workflows in a remote environment.
Intelligent Wells to Intelligent Fields: Remotely Operated Smart Well Completions in Haradh-III
Authors: Al-Arnaout Ibrahim H. , Al-Driweesh Saad M. , Al-Zahrani Rashad M. , Rahman Zuhed Abdul , Jacob Suresh
Published: February 2008

Haradh-III, Saudi Aramco's latest developed field within Giant Ghawar Field, is regarded as one of the industry firsts in terms of its application of advanced drilling techniques, multilateral wells, smart well completions and permanent monitoring systems. This recently commissioned field, on February 2006, integrated all of the above mentioned technologies with an advanced SCADA system that enable the real time monitoring and control of the downhole and surface equipment remotely from the control room.

The design and installation of the automated surface control system to remotely monitor and control the smart completions is a multidisciplinary project integrating subject experts and tools from well completions, production engineering, facilities, instrumentation, and communication engineers. The system enables the operator in the control room to remotely operate the downhole valves in all the multilateral smart wells through the SCADA system.

The paper will present the design, installation and commissioning of the surface control system and remote monitoring capabilities and cite a field case of remote operation to flow test a well with three zones smart well completion, permanent downhole gauge and surface multiphase flow meter. The system has enabled the operator to remotely perform flow testing of the individual laterals of the multilateral wells through different settings of the downhole valves. The remote control capabilities enabled these tests to be done from the control room without the engineer spending extended periods in the well site.

The learning discussed in this paper will provide an insight into how the implementation of such control system was systematically handled to achieve a successful conclusion.
Integrated Operations–A Key Enabler to Operational Excellence in Maintenance Management of FPSO’s
Authors: Stenvaag Sverre , Lindrupsen Terje , Bye Roar , Østerås Trond
Published: February 2008

Teekay Petrojarl Production (TKP), the largest operator of Floating Production, Storage and Offtake (FPSO) vessels in the North Sea, has an ambition to retain its leading position as FPSO contractor in harsh environments while also expanding its business into benign waters worldwide. One of the important measures to attain this is by establishing and implementing best practice within E&P operations business worldwide. Several projects have been started to support TKP's effort to reach operational excellence. This paper is concerned with one of the projects, "Integrated Operations – A Key Enabler to Operational Excellence in maintenance Management of FPSOs". The main objective of this project is to enable TKP to take a step further into operational excellence by implementing more effective work processes, and developing new theory, methods and tools for maintenance optimization. TKP regards Integrated Operations (IO) as an important instrument to reach this objective. The research project focuses on three activities; 1) Describe and analyse future work processes for strategic and tactical analyses, 2) develop tools and methods to support strategic and tactical maintenance decisions, and 3) implement and verify work processes, tools and methods. Cases are used to develop, test and verify work processes, tools and methods prior to implementation, and have proven essential to create consensus. Recent experience shows that challenges with IO are more related to organisation and competence than technology itself. The Man, Technology and Organisation (MTO) focus is chosen when developing new work processes to meet the challenges related to competence and organisation. Close cooperation with onshore and offshore staff is critical when developing the new work processes. The main challenge for the development of tools and methods is related to balancing simplicity and theoretical basis. It is seen that many of the new tools and methods may be feasible just because the IO setting enables the use of onshore centralised expertise. The project has clearly seen that a successful implementation of IO, to reach operational excellence in maintenance management, requires full attention to balancing personnel competence, technology complexity and organisation (MTO), and ensuring management ownership (visions, maintenance strategy, measurable goals).
Remote Intelligence—The Future of Drilling is here
Authors: Gorgone Ignacio , Gomez Juan , Uddenberg Gary
Published: February 2008

It is well recognized that oil and gas companies have increased the implementation of collaborative centers to improve real-time decision making. This reduces nonproductive time (NPT) and improves efficiency in oilfield operations. Emerging technologies now enable end users to receive and send intelligent commands while tools operate under downhole conditions. This not only provides the advantage of fewer trips in and out of the hole, but also the ability to control operations from an office-based environment.

In the last few years, Schlumberger has increased the number of collaborative centers, known as Operation Support Centers (OSC™), to work closely with operators throughout the world. Surface and downhole data are currently transmitted to these centers in real-time as part of the execution phase in the drilling optimization process. While the focus of this paper is on drilling, real-time data is clearly not limited to the drilling phase and in many cases has been used for completion monitoring and control.

As the implementation of these centers has continued, drilling activity increased more quickly than experts could be developed in all areas of operation and support, despite aggressive recruiting and intense training and development. As a result, experts gathering in one room to advise jointly on several simultaneous rig operations became the norm and operators who experienced it quickly embraced the OSC™ concept.

Real-time centers, therefore, have become the chief venue for collaboration, data capture, sharing and training, in a way that better meets the needs of fast-growing operations. Interestingly, they have also become a focal point for better coordination of operational changes, as improved communication with tools downhole and with service personnel have facilitated reduced crew and support requirements.

This paper describes the challenges faced in implementing remote drilling operations, the work processes that allow one directional driller (DD) and one measurement while drilling (MWD) engineer to oversee several rigs simultaneously, and details the necessary infrastructure, communication systems and operating results.
Gas Coning Control for Smart Wells Using a Dynamic Coupled Well-Reservoir Simulator
Authors: Leemhuis A. P. , Nennie E. D. , Belfroid S. P. C. , Alberts G. J. N. , Peters E. , Joosten G. J.P.
Published: February 2008

A strong increase in gas inflow due to gas coning and the resulting bean-back because of Gas to Oil Ratio (GOR) constraints can severely limit oil production and reservoir drive energy. In this paper we will use a coupled reservoir-well model to demonstrate that oil production can be increased by using controlled inflow from a gas cone as a natural lift. This model was developed in the knowledge centre Integrated System Approach Petroleum Production (ISAPP) of TNO, TU Delft and Shell, and is based on a commercially available dynamic multiphase well simulation tool (OLGA) and a dynamic multi-phase reservoir simulator (MoReS).

In order to give a proof of principle we have implemented a PID feedback controller, which controls the gas fraction in a well by changing its wellhead choke or inflow control valve (ICV) settings, on a realistic test case. We introduce a strategy to find an optimal production set point for this controller and the benefits of using downhole ICVs in comparison to the wellhead choke are investigated.

Simulation experiments show that a PID controller is an effective means to prevent a full gas breakthrough and, moreover, can be used to increase the produced oil rate by tuning ICV settings to achieve an optimal well gas fraction. Results show that the coupled simulations could be significantly more accurate in comparison to stand-alone well or reservoir simulations.

In current operations ICVs are mostly used to completely shut down well segments that experience gas coning. We show that by keeping these ICVs open in a controlled way the - otherwise undesirable - phenomenon of gas coning can be used to increase oil production.
Short-Term Production Optimization by Automated Adaptive Modeling and Control
Authors: Awasthi Ankur , Sankaran Sathish , Nikolaou Michael , Saputelli Luigi , Mijares Gerardo
Published: February 2008

Short-term production optimization relying on model-based predictions over a short period (weeks to months) requires the use a near-borehole reservoir model. Such a model is usually developed and validated through standard well testing. Standard well testing has to be repeated periodically, with related loss of production. Production losses may be reduced by prolonging the interval between tests, but that may compromise the quality of information about reservoir properties, such as skin (or productivity index), which would ultimately compromise production as well. Therefore, a need exists for a methodology that maximizes both reservoir information and production simultaneously. Because these two tasks are inherently contradictory, a compromise has to be found. In this work we propose a methodology that combines well testing and production in an optimal way, resulting in overall production optimization. This methodology relies on a short-term moving-horizon optimization of an objective function that includes terms referring both to the quality of reservoir information and to production net present value. Reservoir information is captured by empirical (proxy) models that are built adaptively on-line as a result of optimal perturbations of production rates and recording of dynamic responses of related bottomhole pressures. Besides, the entire workflow can be automated. Simulations are presented that illustrate the mechanics and value of the proposed methodology.
From Intelligent Injectors to Smart Flood Management: Realizing the Value of Intelligent Completion Technology in the Moderate Production Rate Industry Segment
Authors: MacPhail Warren F. , Konopczynski Michael
Published: February 2008

This paper is a case history which examines the successful application of Intelligent Completion (IC) technology in a cost sensitive, mature, onshore North American environment where an existing hydrocarbon miscible flood (HCMF) horizontal injection well was retrofitted to manage the injection support of two geologically distinct reservoir regions covering two well patterns. The value of IC technology is explored in this early deployment which saw a relatively low cost application targeted towards a mature asset. The beneficial results of this application of IC technology were measured in terms of well intervention cost savings and affected oil production. This paper presents a relative comparison of those benefits. Though this application of IC technology was originally justified by the avoidance of certain future well interventions to modify the injection profile, an analysis of the affected pattern production in the post-installation period showed that the benefit to the operator was appreciably more from enhanced reservoir management than from the cost savings which were associated with workover avoidance.

Based on the success described in this case history, and reflecting upon the trends of intelligent well and smart field technology, the authors explore reasons for its relatively slow uptake in moderate production rate, brownfield applications. Large scale reservoir management of miscible flood projects using intelligent well and smart field technologies should provide significant value in terms of improved solvent/oil ratio through more efficient monitoring and management of the flood. This is probably the most compelling value proposition for IC technology application in moderate production rate land applications. This case history is intended to provide credible evidence of the benefit of IC technology in an application with cost challenges analogous to those faced by operators who are responsible for cost sensitive, moderate production assets. Secondly, it is intended to encourage the IC technology providers to develop more solutions for the brownfield segment of the industry, where profitability and value definition can be challenging.
Enhanced Awareness for Offshore Teleoperation
Authors: Skourup C. , Pretlove J. , Stembridge N. , Svenes M.
Published: February 2008

The major challenges for future oil & gas installations are to create and increase business value in addition to improve HSE (Health, Safety and the Environment). The Oil & Gas industry has recognised the potential of operating with ‘normally unmanned areas' where access to the entire process is based on utilisation of new technologies from remote onshore locations. During maintenance, personnel have only got restricted access when the process is shut-down, but this is primarily handled remotely. This paper concerns teleoperation and telepresence of oil & gas installations. The challenges involve more than the technology of transferring data and performing operations. A teleoperator or a telerobot is a "machine" which extends a human operator's sensing and manipulation capability to a remote environment. An essential issue of telepresence is to keep the human operators in the control loop to enable them to use their high levels of skill to complement the power of remote manipulators. Teleoperation within oil & gas differs from other known applications as offshore installations represent large, complex and dynamic processes located hundreds of miles away in very harsh environments where failures may result in major consequences for the environment and process equipment.

The challenges of offshore teleoperation are to enhance the operator's perception of the current situation so that the operator has a complete understanding of state of the process and operates the process as if he was offshore without hundreds of miles and complex technology in between. Safe and efficient teleoperation is critical for operation of unmanned platforms to secure added value and optimal production within a distant environment.
Successful Interaction Between People, Technology and Organisation—A Prerequisite for Harvesting the Full Potentials From Integrated Operations
Authors: Roland Steinar , Yttredal Olav , Moldskred Ivan O.
Published: February 2008

The full value potential of implementing Integrated Operations on the NCS is estimated to $42 billion. In order to harvest this full potential we argue that a balanced integration of people, technology and organization (PTO) is necessary. Our focus is on the people and organisation aspects; what characterizes teamwork and collaboration in the new IO arenas; and, composition of teams and team performance.

IO represents a set of new work forms, and we argue that collaboration and team work are fundamental aspects in this new reality. Hence, we have used Dr. M. Belbin and his theories on roles and team composition to show how to design and develop good teams.

Our observations and findings indicates that it is important with continuously focus on the people and organizational aspects in order to harvest the full potentials from Integrated Operations. However, this focus must be balanced with technology in order achieve the most optimal work processes, which will give all parties safer and better decisions faster, and contribute to added value.
Industrial Wireless Technology for Oil Fields Connectivity "Wireless I-Field"
Authors: Al-Walaie Soliman A. , Almadi Soliman M. , Al-Shammari Saud F.
Published: February 2008

Wireless Technology is a potential cost-effective and efficient connectivity solution for several oil and gas explorations and producing applications. Remote oil wells, water injection plants, pump stations, pipelines operations can benefit from the first mile wireless access to connect to the corporate Process Automation Network (PAN). This would result in improving productivity, providing faster and more accurate data collection and reducing capital and operating expenditures.

In this paper, authors will provide an overview of industrial wireless technology for Oil Field Connectivity as well as the discussing key requirements and challenges for reliable and secure industrial wireless solution. Furthermore, emphasis will be on the use of industrial Fixed Broadband Wireless (BFW) for first mile field access. The successful field trial implementation of industrial BFW solution for microseismic field connectivity will be presented in this paper.
Efficient Well Placement Optimization with Gradient-based Algorithms and Adjoint Models
Authors: Sarma Pallav , Chen Wen H.
Published: February 2008

A key reservoir management decision taken throughout the life of a reservoir is the determination of optimal well locations that maximizes asset value (such as Net Present Value, NPV). Because this well placement optimization problem is a discrete-parameter problem (well locations are discrete parameters in the simulation model), gradients of the objective function (NPV) with respect to these parameters are not defined. Thus, gradient-based methods have not found much applicability to this problem, and most existing algorithms applied to this problem are stochastic in nature, such as genetic algorithms, simulated annealing, and stochastic perturbation methods. These methods are usually quite inefficient requiring hundreds of simulations and thus may have limited application to large-scale simulation models with many wells.

We propose a novel, continuous approximation to the original discrete-parameter well placement problem such that gradients can be calculated on the approximate problem, and gradient-based algorithms can then be employed for efficiently determining the optimal well locations. The basic idea is to first replace the discrete parameters (i, j well location indices) with their continuous counterparts in the spatial domain (x, y well locations) and then obtain a continuous functional relationship between the objective function and these continuous parameters. Such a functional relationship is obtained by replacing the discontinuous Dirac-delta functions (defining wells as point sources) in the underlying governing PDE with continuous functions (which in the limit tends to the Dirac-delta function, such as the bivariate Gaussian function). Numerical discretization of the modified PDE leads to well terms in the mass balance equations that are continuous functions of the continuous well location variables. As a result of this continuous functional relationship, adjoints and gradient-based optimizations algorithms can now be applied to obtain the optimal well locations. The efficiency and practical applicability of the approach is demonstrated on a few synthetic waterflood optimization problems.
Production Data Standards: The PRODML Business Case and Evolution
Authors: Shipley David , Weltevrede Ben , Doniger Alan , Klumpen Hans Eric , Ormerod Laurence
Published: February 2008

PRODML™ is a set of production data standards, initiated by 13 upstream oil and service companies with the industry standards body Energistics (then POSC) in 2005. In November 2006, PRODML Version 1.0 was released. The focus was on production optimization processes which could produce results implementable within a day. The domain was from perforations through to start of processing on the surface. The objective was to enable plug and play integration of current upstream applications while supporting a variety of optimization processes.

In 2007, the PRODML community, now expanded to 23 companies, worked on extensions addressing production reporting, the use of a common "flow network model", and into "smart wells".

This paper, authored by experienced members of the PRODML community, explains the evolution from a concept to "do something about production data" into a well-defined series of interoperable services, with a defined future path.

A practical approach to the implementation of an integrated production optimization "analytic environment" will then be described, illustrated by a richly detailed and broad-based real life case study as deployed by Chevron.

The strategy that current members have set for the next three years will be outlined. This covers expansion of the "footprint" of PRODML, (reflecting the need for a clear understanding of business drivers for end-users and for developers), functionality (supporting above all a focus on "usability" – ensuring that PRODML expands while remaining accessible and quick to pick up for new developers), support, and governance.
Implementation Results for Chevron's i-field in San Joaquin Valley, California
Authors: Oran Kenan , Brink James , Ouimette James R.
Published: February 2008

This paper summarizes results to date of implementing i-field projects in selected assets in Chevron's San Joaquin Valley Business Unit (SJVBU) in California. The i-field projects include collaborative environments to transform operational processes at a basin-wide or asset level remote collaboration and visualization has been implemented to help execute reservoir management and major capital project targets reliably and efficiently in the field. Successful asset prototypes are standardized and replicated across the business unit. The results to date demonstrate business value and take-up of the technology and processes by oilfield operations.
Enabling Change with New Technology and Integrated Operations
Authors: McNicol James , Stavland Marianne
Published: February 2008

The introduction of a new downhole digital technology has the potential to revolutionize well intervention operations through performance management, faster decision cycles and organizational change. The new system has the ability to send real-time downhole data from well intervention operations to the surface, and from there to data centers anywhere in the world. The system facilitates collaborative work by engaging a broader spectrum of specialists than has been traditionally available at the wellsite.

A major benefit is the technology's capability as the catalyst for bringing about the significant organizational change required to replace currently aging offshore personnel with an adequate supply of competent employees within the context of the existing management and supply chain systems. Case studies are presented taken from over 20 field runs conducted during field integration testing.
Transforming E&P data into knowledge: applications of an integration strategy
Authors: Couput Jean-Paul , Louis Alain , Danquigny Jacques
Published: February 2008

The full added value of a field performance strategy is only achieved when every effort is treated as an integral part of the complete and larger production system, which ranges from reservoir to export. By combining data gathering, integrated modelling, and control elements in so-called "value loops", optimization opportunities of the field efficiency are achieved in every phase of the asset lifecycle.

The Field Monitoring solutions of TOTAL, aim at improving this field performance through the execution of pertinent analyses, that help take strategic decisions; these decisions are based on a common, single and widely shared view of the information, that provides a better understanding of ongoing events on each asset.

This paper presents TOTAL field examples of Data Validation and Reconciliation (DVR) applied to flow measurement (metering) systems; and the resulting added value: in improving production allocation along with reservoir and surface material balance,in reconciling surface and subsurface monitoring for production and reserves optimization.

It evidences in particular: That DVR implementation associated with flow modelling improves the reliability and accuracy of the production estimates, and of the subsea and downhole measurement devices,The high potential of DVR in analyzing, qualifying and interpretating large amounts of measurements, and in providing more information from existing sensors, which is of particular interest when key measurements fail or are non available.
Incisor Root Resorption Due to Ectopic Maxillary Canines
Authors: Falahat Babak , Ericson Sune , Mak D'Amico Rozmary , Bjerklin Krister
Published: February 2008

Objective: To document the long-term fate of maxillary incisors with resorbed roots after correction of the associated ectopic canines.

Materials and Methods: The subjects were recruited from 107 children and adolescents age 9–15 years (mean 12.5 years) at initial registration, with 156 ectopically positioned maxillary canines. The children were referred to the specialist orthodontic clinic for consultation because of the risk of incisor root resorption. Of 51 patients contacted, 16 failed to attend. Eight of the remaining 35 were excluded because their lateral incisors had been extracted, leaving 27 subjects for follow-up registration. At initial consultation, all subjects had undergone radiographic examination, including computed tomography (CT) scans. At the follow-up consultation, the radiographic examination was limited to intraoral films.

Results: No resorbed incisor was lost during the 2- to 10-year follow-up period. The resorptive lesions had undergone repair in 13 teeth, remained unchanged in 12 teeth and progressed in 7 teeth. In the 13 teeth exhibiting signs of repair, no resorption was detectable in 11 teeth and minor resorption was detected in 2 lateral incisors. At the initial registration, severe or moderate resorption had been diagnosed in 12 lateral and 5 central incisors, compared with 11 lateral and 6 central incisors at follow-up. In 10 subjects initially diagnosed with resorption of 13 incisors, the lesions were no longer discernible on intraoral radiographs at follow-up.

Conclusions: Even in cases of severe resorption, the incisor roots show good long-term healing. Incisors with root resorption can be used in an orthodontic appliance system.
Molar Changes with Cervical Headgear Alone or in Combination with Rapid Maxillary Expansion
Authors: Marchiori Farret Marcel , de Lima Eduardo Martinelli S. , Pereira Araújo Vanessa , Deon Rizzatto Susana Maria , Macedo de Menezes Luciane , Lima Grossi Marcio
Published: February 2008

Objective: To test the hypothesis that there is no difference in the distal movement of the maxillary first permanent molars when cervical headgear is used alone or in combination with rapid maxillary expansion.

Materials and Methods: The sample was composed of 36 subjects (aged 9 to 13 years), treated in the Faculty of Dentistry, Pontifícia Universidade Cat;aaolica, Rio Grande do Sul, Brazil. The individuals were in good health and in their pubertal growth period. All had Class II division 1 malocclusion. The patients were divided into two groups: group 1 (22 subjects), Class II, with a normal transverse maxilla treated with cervical traction headgear (HG) 400 g 12 h/d, and group 2 (14 subjects), Class II maxillary transverse deficiency treated with rapid maxillary expansion plus cervical traction headgear (RME + HG). An additional group 3 (17 subjects) served as a control group and included individuals with the same characteristics. All subjects had two lateral cephalograms: initial (T1) and progress (T2), taken 6 months later. Differences between T1 and T2 were compared with the Student's t-test, and three groups were compared by the analysis of variance and Tukey multiple comparison test.

Results: Results showed greater distal tipping and greater distal movement of the first permanent molars in group 1 (HG) than in group 2 (RME + HG), P < .05. No extrusion of first permanent molar occurred in either group (P > .05).

Conclusion: The hypothesis was rejected. Cervical traction headgear alone produced greater distal movement effects in maxillary first permanent molars when compared with rapid maxillary expansion associated with cervical headgear.
Surface Roughness of Auto Polymerized Acrylic Resin According to Different Manipulation and Polishing Methods
Authors: Gonçalves Tatiana Siqueira , Spohr Ana Maria , de Souza Rodrigo Matos , Macedo de Menezes Luciane
Published: February 2008

Objective: To test the hypothesis that no differences exists in the in situ level of surface roughness of an auto polymerized acrylic resin irrespective of the method of manipulation and polishing.

Materials and Methods: Forty volunteers received the test specimens. Surface roughness was evaluated using a rugosimeter. Samples of auto polymerized acrylic resin were submitted to two methods of manipulation—mass and addition—as well as to two types of polishing—mechanical and chemical. Four test groups were designated according to manipulation and polishing techniques: mass-mechanical, mass-chemical, addition-mechanical, and addition-chemical. Five measures of surface roughness were taken from each sample and average surface roughness (Ra) was determined before and 20 days after the samples were worn by the volunteers. The data obtained were analyzed by the Student's t-test for paired samples as well as by analysis of variance.

Results: Significant differences in Ra were found between mechanical and chemical polishing. Surface roughness was not influenced by manipulation techniques. Mechanical polishing presented the lowest values of Ra. There was a significant increase in surface roughness after volunteers wore the specimens for 20 days.

Conclusions: The hypothesis is rejected. There were differences on the surface roughness according to the different methods of manipulation and polishing used, but high values of surface roughness were found for all groups. Mechanical polishing showed the lowest values of surface roughness and thus should be preferred.
“Effective” TMJ and Chin Position Changes in Class II Treatment
Authors: Serbesis-Tsarudis Christos , Pancherz Hans
Published: February 2008

Objective: To evaluate the “effective” temporomandibular joint (TMJ) changes (the sum of condylar modeling, glenoid fossa modeling, and condylar position changes within the fossa), and their influence on chin position in patients with a Class II division 1 malocclusion treated orthodontically with a multibracket appliance and Class II elastics (Tip-Edge) and orthopedically with a fixed functional appliance (Herbst).

Materials and Methods: Two groups of successfully treated subjects were evaluated: Tip-Edge (n = 24) and Herbst (n = 40). The Bolton Standards served as a control group. Lateral head films obtained before treatment and after an observation period of 2.6 years (Herbst also after 0.6-year period) were analyzed.

Results: In comparison with the Herbst and control groups, the Tip-Edge group exhibited less favorable sagittal “effective” TMJ growth and chin position changes necessary for skeletal Class II correction.

Conclusions: Orthodontic therapy with a multibracket appliance and Class II elastics seems not to have any favorable sagittal orthopedic effect on the mandible, while bite jumping with the Herbst appliance has a favorable sagittal orthopedic effect on a short-time basis.
In Vivo Comparison of Conventional and Cone Beam CT Synthesized Cephalograms
Authors: Kumar Vandana , Ludlow John , Soares Cevidanes Lucia Helena , Mol André
Published: February 2008

Objective: To compare measurements from synthesized cone-beam computed tomography (CBCT) lateral cephalograms using orthogonal and perspective projections with those from conventional cephalometric radiographs.

Materials and Methods: Thirty-one patients were imaged using CBCT and conventional cephalometry. CBCT volume data were imported in Dolphin 3D. Orthogonal and perspective lateral cephalometric radiographs were created from three-dimensional (3D) virtual models. Twelve linear and five angular measurements were made on synthesized and conventional cephalograms in a randomized fashion. Conventional image measurements were corrected for known magnification. Linear and angular measurements were compared between image modalities using repeated measures analysis of variance. Statistical significance was defined as an α level of .01.

Results: With the exception of the Frankfort-mandibular plane angle (P < .0001), angular measurements were not statistically different for any modality (P > .01). Linear measurements, whether based on soft or hard tissue landmarks, were not statistically different (P > .01).

Conclusions: Measurements from in vivo CBCT synthesized cephalograms are similar to those based on conventional radiographic images. Thus, additional conventional imaging may generally be avoided when CBCT scans are acquired for orthodontic diagnosis.
Media Advertising Effects on Consumer Perception of Orthodontic Treatment Quality
Authors: Edwards Daenya T. , Shroff Bhavna , Lindauer Steven J. , Fowler Chad E. , Tufekci Eser
Published: February 2008

Objective: To determine the effect of media advertising on consumer perception of orthodontic treatment quality.

Materials and Methods: A survey instrument was designed to evaluate factors influencing consumer selection of an orthodontist and consumer perception of different forms of media advertising (radio, television, newspaper, magazine, direct mail, and billboard) by orthodontic practices. The surveys were distributed by eight orthodontic offices in and around the Richmond, Virginia area. The survey return rate was 97%.

Results: Respondents most often cited dentist and patient referrals as how they learned of the orthodontic practices they visited (50% to 57%). A caring attitude and good practitioner reputation were the top reasons influencing actual selection of an orthodontist (53% and 49%, respectively). Of respondents, 14% to 24% felt that advertising orthodontists would offer a lower quality of care than nonadvertising orthodontists. Newspaper, magazine, and direct mail advertisements were viewed more favorably than radio, television, and billboard advertisements. Chi-square analyses revealed few statistically significant differences in perception between different income and education groups.

Conclusions: The majority of patients do not perceive advertising to reflect poorly on the quality of orthodontic care. However, patients with different income and education levels perceive media advertising differently.
Success Rate and Risk Factors Associated with Mini-Implants Reinstalled in the Maxilla
Authors: Baek Seung-Hak , Kim Bo-Mi , Kyung Seung-Hyun , Lim Joong Ki , Kim Young Ho
Published: February 2008

Objective: To determine the difference in the success rate for two types of oral installed mini-implants (OMIs): one type of initially installed OMI and a new implant of the same type that is reinstalled.

Materials and Methods: The subjects consisted of 58 patients (19 male, 39 female; mean age = 21.78 ± 5.85 years) who had received at least one OMI (self-drilling type, conical shape with 2.0-mm upper diameter and 5-mm length) in the attached gingiva of the upper buccal posterior regions for maximum anchorage during en masse retraction. If an OMI failed, a new one was immediately installed in the same area after 4 to 6 weeks or in an adjacent area immediately. The total number of initially installed OMIs (II-OMI) was 109 and the total number of reinstalled OMIs (RI-OMI) was 34. Statistical analysis was performed using χ2 test, Kaplan-Meier method, log-rank test, and Cox proportional hazards regression model.

Results: The success rate and mean duration were 75.2% and 10.0 months, respectively, for II-OMI and 66.7% and 6.4 months, respectively, for RI-OMI. Age, vertical skeletal pattern, and site and side of implantation were not related to the success rates of II-OMI and RI-OMI. Log-rank test showed that II-OMI in males and Class III malocclusions were more prone to failure. The relative risk of II-OMI failure in Class III malocclusions as opposed to Class I malocclusions was 5.36 (95% confidence interval, 2.008 to 14.31, P = .001).

Conclusion: The success rate of the II-OMI was not statistically different from that of the RI-OMI. Sex and ANB angle might be more important factors for better II-OMI results.
TMJ Osteoarthritis/Osteoarthrosis and Immune System Factors in a Japanese Sample
Authors: Nishioka Masato , Ioi Hideki , Matsumoto Ryusuke , Goto Tazuko K. , Nakata Shunsuke , Nakasima Akihiko , Counts Amy L. , Davidovitch Ze'ev
Published: February 2008

Objective: To determine whether there is an association between temporomandibular joint (TMJ) osteoarthritis/osteoarthrosis (OA) and immune system factors in a Japanese sample.

Materials and Methods: The records of 41 subjects (7 men, aged 22.0 ± 3.8 years; 34 women, aged 24.8 ± 6.3 years) and 41 pair-matched controls (7 men, aged 22.1 ± 2.3 years; 34 women, aged 24.8 ± 6.4 years) based on age and gender were reviewed. Information on medical history included local or systemic diseases, details on medication type and use, and the presence of allergies and asthma. Dental history questions referred to details regarding past oral injuries. The validity of the hypothesis, defining allergies and asthma as risk factors in OA, was tested by using a logistic regression analysis.

Results: The incidence of allergy was significantly higher in the TMJ OA (P = .008), with a mean odds ratio of 4.125 and a 95% confidence interval of 1.446–11.769.

Conclusion: These results suggest that allergy may be a risk factor in association with TMJ OA in this Japanese sample.