bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hierarchical Long-Term and Short-Term Production Optimization
Authors: van Essen G. M. , Van den Hof P. M. J. , Jansen J. D. 
Published: December 2009

Abstract
Model-based dynamic optimization of oil production has a significant potential to improve economic life-cycle performance, as has been shown in various studies. However, within these studies short-term operational objectives are generally neglected. As a result, the optimized injection and production rates often result in a considerable decrease in short-term production performance. In reality however, it is often these short-term objectives that dictate the course of the operational strategy. Incorporating short-term goals into the life-cycle optimization problem is therefore an essential step in model-based life-cycle optimization. We propose a hierarchical optimization structure with multiple objectives. Within this framework, the life-cycle performance in terms of net present value (NPV) serves as primary objective and short-term operational performance is the secondary objective. Within this structure, optimality of the primary objective constrains the secondary optimization problem. This requires that optimality of the primary objective does not fix all degrees of freedom (DOF) of the decision variable space. Fortunately, the life-cycle optimization problem is generally ill-posed and contains many more decision variables than necessary. We present a method that identifies the redundant DOF in the life-cycle optimization problem, which can subsequently be used in the secondary optimization problem. In our study we used a 3-dimensional reservoir in a fluvial depositional environment with a production life of 7 years. The primary objective is undiscounted NPV, while the secondary objective is aimed at maximizing short-term production. The optimal life-cycle waterflooding strategy that includes short-term performance is compared to the optimal strategy that disregards short-term performance. The experiment shows a very large increase in short-term production, boosting first year production by a factor 2, without significantly compromising optimality of the primary objective, showing a slight drop in NPV of only −0.3%.
Platform Life Extension
Authors: Hudson Brian G 
Published: December 2009

Abstract
This paper will detail a structured and holistic methodology to support the extension of the life of an offshore platform beyond that indicated by original design philosophy. The approach identifies the key asset reliability, integrity and process safety issues that need to be addressed in operating an asset beyond its design life. This methodology captures the key issues that arise in operating assets at or beyond design life, including; corrosion, obsolescence of equipment, change in design duties, change in oil or gas properties or production profiles, availability of historic information etc.
This methodology and has been applied to extending the life of the offshore oil and gas platforms in the UK, Danish and Norwegian shelf of the North Sea. In Norway it is a requirement to gain consent from the regulatory body prior to extending the life of a platform or field beyond original design. In the UK, the regulatory body sees such an extension in life as a significant and material change to the "Safety Case". In other parts of the world the shareholders, legislators and other stakeholders require assurance on the reliability and integrity of the asset.
The output from this type of study will identify the key Asset Integrity and Vulnerability risks for the platform or field and include a fully costed programme of activities that operators need to carry out to extend and continue to maintain the asset life.
With the volatile oil price and aging profile of existing offshore platforms, the ability for operators and prospective investors to run assets beyond the original design life, whether for the short, medium or long term and still maintaining high standards of HSE and Integrity Management, is of paramount importance and forms a key part of any strategy to manage current and future business risk.
Offshore Pipeline and Riser Integrity—The Big Issues
Authors: Marsh Jonathan , Duncan Phil 
Published: December 2009

Abstract
This publication examines the dominant corrosion and integrity issues affecting the offshore rigid and flexible pipelines and risers that exist in the North Sea, as identified from the experience of the authors and their companies. The aim is not to examine all possible integrity issues, but to identify those that appear to be causing the most problems. For many aging rigid pipelines extension of life to beyond the design criteria is becoming increasingly common, and the increasingly dominant integrity issues are associated with internal and external corrosion. With respect to external corrosion issues, anode depletion is an increasingly common phenomenon below the water line. At and above the water line, coatings often passed the end of their service life in the late 90s and were not renewed due to low oil prices and reduced fabric maintenance spending. For internal corrosion, different corrosion mechanisms dominate in gas, multiphase, oil and water pipelines. Dominant issues for gas and multiphase production are preferential weld corrosion and localized CO2 corrosion mechanisms occurring under scales, deposits or due to increasing H2S levels. In oil transport pipelines, as oil volumes reduce, water drop and MIC are increasingly problematic due to low flow, and pigging operations become vital. In water injection pipelines, aging infrastructure leads to both inefficient de-aeration and an increase in MIC due to contamination over many years. All these issues lead to a need for effective corrosion and integrity management.
The experience of use of flexible pipes is increasing exponentially and by definition it is ageing. Over the coming years an increasing number of flexible pipes will reach the end of their design life, therefore prudent operators should focus on understanding the integrity status of their flexible pipes. Understanding and effectively managing the integrity of flexible pipes is necessary to prevent, predict, and detect the presence of any loss of integrity. This publication presents an update on the guidelines (based on an ongoing Oil and Gas UK JIP) for developing and implementing an integrity management strategy. This approach utilizes the correct mix of inspection and assessment tools, and operating procedures that will allow the operator to assess the opportunity for life extension of flexible pipes. For specific issues, damage or rupture of the outer sheath and subsequent annulus flooding is also examined, as this is the commonest integrity problem that is encountered in practice.
Intelligent Top-Down Reservoir Modeling of New Albany Shale
Authors: Dahaghi Kalantari A. , Mohaghegh S. D. 
Published: December 2009

Abstract
Although the New Albany Shale of the Illinois Basin has been estimated to contain approximately 86 TCF of natural gas in place, the full development of this potentially large resource has not yet occurred. The intent of this study is to reassess the potential of New Albany shale using a novel integrated workflow, which incorporates field production data and well logs using a series of traditional reservoir engineering analyses with artificial intelligence & data mining techniques. The model developed using this technology is a full filed model and its objective is to predict future reservoir/well performance in order to recommend field development strategies.
In this integrated workflow unlike traditional reservoir simulation and modeling, we do not start from building a geo-cellular model. Top-Down intelligent reservoir modeling(TDIRM) starts by analyzing the production data using traditional reservoir engineering techniques such as Decline Curve Analysis, Type Curve Matching, Single-well History Matching, Volumetric Reserve Estimation and Recovery Factor. These analyses are performed on individual wells in a multi-well New Albany Shale gas reservoir in Western Kentucky that has a reasonable production history. Data driven techniques are used to develop single-well predictive models from the production history and the well logs (and any other available geologic and petrophysical data).
Upon completion of the abovementioned analyses a large database is generated. This database includes a large number of spatio-temporal snap shots of reservoir behavior. Artificial intelligence and data mining techniques are used to fuse all these information into a cohesive reservoir model. The reservoir model is calibrated (history matched) using the production history of the most recent set of wells that have been drilled in the field. The calibrated reservoir model is utilized for predictive purposes to identify the most effective field development strategies including locations of infill wells, remaining reserves, and under-performer wells. Capabilities of this new technique, ease of use and much shorter development and analysis time are demonstrated as compared to the traditional simulation and modeling.
Oilfield Emulsion Control: A Major Issue During Heavy Crude Oil Production
Authors: Opawale Adekunle 
Published: December 2009

Abstract
The dehydration of oil to meet pipeline water specifications usually involves the resolution of the intractable water in oil emulsions present in the crude oil, and the use of some separation equipments. However, emulsion resolution may be very problematic and challenging when highly stabilized heavy crude oil types are produced. They often require more chemical injection and time to be resolved. One such study was conducted to observe the effect of specific gravity and viscosity reduction on emulsion stability, which in turn is defined by no less than three parameters – Rate of water drop, Oil dryness and interface quality.
Several hours of demulsification bottle testing with a typical 20 0 API heavy crude oil, a light straight run Gasoline as a diluent to reduce the crude's viscosity, and a typical front-end demulsifier chemical for emulsion resolution were carried out. The crude oil was blended with Gasoline at different ratios in six 100ml test bottles. The emulsion blends at its wellhead temperature of 45 0 C were resolved with 2ppm of demulsifier chemical which is a reduced treatment rate from 5ppm. The experiment revealed a number of interesting trends.
Addition of about 5ml of Gasoline in one of the test bottles led to 63% reduction in the oil's absolute viscosity, without the use of any additional heat except that attained at the wellhead of the operator's oilfield. This sample dropped about 96% of its emulsified water after 5 minutes of chemical injection, with a very sharp oil/water interface. The top oil had trace Basic sediment and water BS&W, and the separated water, an improved Total Petroleum Hydrocarbon TPH of about 50ppm. These Data demonstrated a good quality and sellable dry oil, easy to handle and can be pumped with little cost since its viscosity is appreciably reduced. Besides the effluent water is safe for disposal at the operator's terminal. On the basis of this bottle test, this research could result into the following benefits to the Operator: A 60% reduction in chemical usage and logistics costs A 45% – 50% reduction in production chemical costs Reduction in the unavoidable use of heaters in oilfield for emulsion resolution Production of a high quality and sellable crude oil for export and improved oil in water content of the produced water discharge.
The case study discussed in this paper is that of a heavy crude oil emulsion collected from a major operator's flowstation in the eastern Niger delta area of Nigeria.
Petrophysical Evaluation and Sequence Stratigraphic Model of ‘Indigo Field’ in Greater Ughelli Depobelt, Niger Delta, Nigeria
Authors: Okeke Chinwendu O. , Mode Ayonma W. , Obi Ifeanyichukwu S. , Odokoh Anthony O. 
Published: December 2009

Abstract
Detailed Petrophysical studies and Sequence stratigraphic analyses of three wells in the ‘Indigo Field of Niger Delta was carried out using wireline logs and high resolution biostratigraphy. Three sequence boundaries (SB 27.3Ma, 29.3Ma and 32.4Ma) and maximum flooding surfaces (MFS 26.2Ma, 28.1Ma and 31.3Ma) were identified. Three systems tracts were delineated in wells A and B, while only two were delineated in well C. Nine reservoir units (A1-A9) analyzed in well A show porosity, permeability and Vshale of 13-18%, 89.35-2775.8md and 0.026-0.05v/v decimal, respectively. Reservoirs A1, A4, A7, A8, and A9 contain oil, A2 and A3 contain gas, and A5 and A6 contain water. Porosity and Vshale values for three reservoir units in well B (B1-B3) are 16-25% and 0.03-0.045v/v decimal, respectively. Reservoirs B1 and B2 contain water, and B3 contains gas. Six reservoir units (C1-C6) delineated in well C have average porosity, permeability and Vshale values of 19-24%, 1063.92-3674.4md and 0.05-0.1v/v decimal, respectively. Reservoir C1 contains oil and water; C2, C3 and C6 contain only water, and C4 and C5 contain oil only. Water saturation, moveable hydrocarbon index (MHI) and net sand count were 14-79%, 0.42-0.46, and 6-40m respectively, in well A; 24-65%, 0.55-0.56 and 7-26m in well B; and 21-67%, 0.44-0.54 and 11-22m in well C. Well A, being with thicker and more porous sands with lower Vshale is more productive than wells B and C.
Successful implementation of 9 5/8-in. casing drilling in Nigeria: Case history of AKAMBA-2
Authors: Kenga Yannick , Atebe Jude , Feasey Guy 
Published: December 2009

Abstract
Drilling-with-casing (DwC) is a field-proven technology that has seen its application showcased as an innovative solution to mitigate wellbore stability issues and reduce well-construction costs. This technology has been around for several years, but was first deployed by Total Exploration & Production Nigeria (TEPNG) in November, 2006 on the well AKAMBA-2.
AKAMBA-2 is a vertical exploration well drilled on the north-east sector of Total's Oil Mining Lease (OML) 102 offshore field (55 m water depth) in Nigeria. It was drilled as a stand-alone well using drilling-with-casing technology comprising 9 5/8-in.casing with PDC casing bit drilling shoe to drill the 12 1/4-in. section. By eliminating bit trips and other unplanned events related to conventional drillpipe drilling, this application resulted in significant time and cost saving and the attainment of a world record depth of 1,036 m for this size of casing drilling.
This paper will describe this first application of the drilling-with-casing technology in the Niger Delta, its challenges and the cost saving benefits achieved with its application.
THz radiation sensors
Authors: Sizov F. 
Published: December 2009

AbstractIn the paper, issues associated with the development and exploitation of terahertz (THz) radiation detectors are discussed. The paper is written for those readers who desire an analysis of the latest developments in different type of THz radiation sensors (detectors), which play an increasing role in different areas of human activity (e.g., security, biological, drugs and explosions detection, imaging, astronomy applications, etc.). The basic physical phenomena and the recent progress in both direct and heterodyne detectors are discussed. More details concern Schottky barrier diodes, pair braking detectors, hot electron mixers, and field-effect transistor detectors. Also the operational conditions of THz detectors and their upper performance limits are discussed.
Stuttered and fluent speakers' heart rate and skin conductance in response to fluent and stuttered speech
Authors: Zhang Jianliang , Kalinowski Joseph , Saltuklaroglu Tim , Hudock Daniel 
Published: December 2009

Background: Previous studies have found simultaneous increases in skin conductance response and decreases in heart rate when normally fluent speakers watched and listened to stuttered speech compared with fluent speech, suggesting that stuttering induces arousal and emotional unpleasantness in listeners. However, physiological responses of persons who stutter observing stuttering and fluent speech has not been measured. Research suggests that the mechanism responsible for listeners' reactions is the mirror neuron system. The mirror neuron system activates when perceiving and producing goal‐directed actions and forms the link between action perception and action production.Aims: To compare physiological responses elicited via fluent and stuttered speech in fluent and persons who stutter groups.Methods & Procedures: Participants included 15 adult persons who stutter (mean age = 29.7 years) and 21 normally fluent controls (mean age = 23.7 years). Participants watched and listened to six speech samples read by three persons who stutter speakers and three fluent speakers, while their skin conductance response and heart rate were recorded simultaneously. Participants' responses to each speech sample were defined as changes in mean heart rate and mean skin conductance response between 15 s before and 15 s during stimuli presentation.Outcomes & Results: Both groups showed similar patterns of response: skin conductance response was significantly increased and heart rate was significantly decreased in response to stuttered versus fluent speech. Similar to previous findings, the highest skin conductance response measures were induced by the first presentation of stuttered speech, with the response attenuating on subsequent presentations, while the heart rate was stable over time.Conclusions & Implications: Results confirmed past research that showed arousal and emotional unpleasantness when observing stuttering. Clinically, these results acknowledge the arousal and emotional discomfort in fluent speakers and persons who stutter. The physiological responses to stuttering and the underlying emotional aspects should be discussed in the therapeutic milieu with notions about coping strategies.
Pentacam Scheimpflug Quantitative Imaging of the Crystalline Lens and Intraocular Lens
Authors: Rosales Patricia , Marcos Susana 
Published: December 2009

Purpose:
To implement geometrical and optical distortion correction methods for anterior segment Scheimpflug images obtained with a commercially available system (Pentacam, Oculus Optikgeräte GmbH).

Methods:
Ray tracing algorithms were implemented to obtain corrected ocular surface geometry from the original images captured by the Pentacam's CCD camera. As details of the optical layout were not fully provided by the manufacturer, an iterative procedure (based on imaging of calibrated spheres) was developed to estimate the camera lens specifications. The correction procedure was tested on Scheimpflug images of a physical water cell model eye (with polymethylmethacrylate cornea and a commercial IOL of known dimensions) and of a normal human eye previously measured with a corrected optical and geometrical distortion Scheimpflug camera (Topcon SL-45 [Topcon Medical Systems Inc] from the Vrije University, Amsterdam, Holland).

Results:
Uncorrected Scheimpflug images show flatter surfaces and thinner lenses than in reality. The application of geometrical and optical distortion correction algorithms improves the accuracy of the estimated anterior lens radii of curvature by 30% to 40% and of the estimated posterior lens by 50% to 100%. The average error in the retrieved radii was 0.37 and 0.46 mm for the anterior and posterior lens radii of curvature, respectively, and 0.048 mm for lens thickness.

Conclusions:

The Pentacam Scheimpflug system can be used to obtain quantitative information on the geometry of the crystalline lens, provided that geometrical and optical distortion correction algorithms are applied, within the accuracy of state-of-the art phakometry and biometry. The techniques could improve with exact knowledge of the technical specifications of the instrument, improved edge detection algorithms, consideration of aspheric and non-rotationally symmetrical surfaces, and introduction of a crystalline gradient index. [
J Refract Surg.
2009;25:421–428.]
Prostaglandin E2 Inhibits IFN-α Secretion and Th1 Costimulation by Human Plasmacytoid Dendritic Cells via E-Prostanoid 2 and E-Prostanoid 4 Receptor Engagement
Authors: Fabricius Dorit , Neubauer Marina , Mandel Birgit , Schütz Catharina , Viardot Andreas , Vollmer Angelika , Jahrsdörfer Bernd , Debatin Klaus-Michael 
Published: December 2009

AbstractPlasmacytoid dendritic cell (PDC)-derived IFN-α plays a central role in antiviral defense and in Th1-driven autoimmune diseases, such as systemic lupus erythematosus (SLE). In the current study, we explored how PGE2 effects the phenotype of PDCs from healthy and SLE subjects. Although PGE2 is considered to mediate mainly proinflammatory effects, we show that PGE2 and PG analogs potently inhibit secretion of IFN-α by TLR-activated PDCs. This effect is mainly mediated by PG receptors E-prostanoid 2 and E-prostanoid 4 and involves inhibition of IFN regulatory factor 7 expression. Of note, profound IFN-α inhibition by PGE2 is also seen in PDCs from SLE subjects, independent of age, disease activity, and therapy. We show that TLR9-activated PDCs treated with PGE2 exhibit DC2-like characteristics with enhanced expression of CD86 and CD62L, and decreased expression of CD80 and MHC class I. Consequently, PGE2-treated PDCs suppress secretion of Th1 cytokines by T cells while increasing the secretion of Th2 cytokines. Prevention of CpG-induced CD62L downregulation by PGE2 suggests that it may induce the retreat of PDCs from inflamed tissues. Our data on the effects of PGE2 on PDCs may explain occasional reports about the induction of SLE-like symptoms by cyclooxygenase inhibitors as well as improvement of such symptoms by treatment with PG analogs. In conclusion, our data suggest that PGE2 and certain PG analogs, some of which are already in clinical use, should be evaluated as a novel and inexpensive treatment approach for patients with SLE and other IFN-α–dependent, Th1-driven autoimmune diseases.
Granzyme A- and B-Cluster Deficiency Delays Acute Lung Injury in Pneumovirus-Infected Mice
Authors: Bem Reinout A. , van Woensel Job B. M. , Lutter Rene , Domachowske Joseph B. , Medema Jan Paul , Rosenberg Helene F. , Bos Albert P. 
Published: December 2009

Abstract
Lower respiratory tract infection by the human pneumovirus respiratory syncytial virus is a frequent cause of acute lung injury in children. Severe pneumovirus disease in humans is associated with activation of the granzyme pathway by effector lymphocytes, which may promote pathology by exaggerating proapoptotic caspase activity and proinflammatory activity. The main goal of this study was to determine whether granzymes contribute to the development of acute lung injury in pneumovirus-infected mice. Granzyme-expressing mice and granzyme A- and B-cluster single- and double-knockout mice were inoculated with the rodent pneumovirus pneumonia virus of mice strain J3666, and were studied for markers of lung inflammation and injury. Expression of granzyme A and B is detected in effector lymphocytes in mouse lungs in response to pneumovirus infection. Mice deficient for granzyme A and the granzyme B cluster have unchanged virus titers in the lungs but show a significantly delayed clinical response to fatal pneumovirus infection, a feature that is associated with delayed neutrophil recruitment, diminished activation of caspase-3, and reduced lung permeability. We conclude that granzyme A- and B-cluster deficiency delays the acute progression of pneumovirus disease by reducing alveolar injury.