bluuebunny/crossref_metadata_2025 huggingface dataset:
Phytalgic®, a food supplement, vs placebo in patients with osteoarthritis of the knee or hip: a randomised double-blind placebo-controlled clinical trial
Authors: Jacquet Alain , Girodet Pierre-Olivier , Pariente Antoine , Forest Karelle , Mallet Laurent , Moore Nicholas
Published: December 2009

Introduction

The medicinal treatment of osteoarthritis (OA) is mostly symptomatic to relieve pain and incapacity with analgesics and non-steroidal anti-inflammatory drugs (NSAIDs), drugs with well-known risks. Complementary medicines might reduce the symptoms of OA and decrease the need for NSAIDs. This study tested the effects of a food supplement, Phytalgic®, on pain and function in patients with osteoarthritis and their use of analgesic and NSAIDs.

Methods

A randomized double-blind parallel-groups clinical trial compared Phytalgic® (fish-oil, vitamin E, Urtica dioica) to a placebo for three months, in 81 patients with OA of the knee or hip using NSAIDs and/or analgesics regularly. The main outcome measures were use of NSAIDs (in Defined Daily Doses per day - DDD/day) or analgesics (in 500 mg paracetamol-equivalent tablets per week (PET/week) measured each month, and Western Ontario-McMaster University Osteo-Arthritis Index (WOMAC) function scales.

Results

After three months of treatment, the mean use of analgesics in the active arm (6.5 PET/week) vs. the placebo arm (16.5) was significantly different (P < 0.001) with a group mean difference of -10.0 (95% CI: -4.9 to -15.1). That of NSAIDs in the active arm (0.4 DDD/day) vs the placebo arm (1.0 DDD/day) was significantly different (P = 0.02) with a group mean difference of - 0.7 DDD/day (95% CI: -0.2 to -1.2). Mean WOMAC scores for pain, stiffness and function in the active arm (respectively 86.5, 41.4 and 301.6) vs the placebo arm (resp. 235.3, 96.3 and 746.5) were significantly different (P < 0.001) with group mean differences respectively of -148.8 (95% CI: -97.7 to -199.9), -54.9 (95% CI: -27.9 to -81.9) and -444.8 (95% CI: -269.1 to -620.4).

Conclusions

The food supplement tested appeared to decrease the need for analgesics and NSAIDs and improve the symptoms of osteoarthritis.

Trial registration

Clinicaltrials.gov NCT00666523.
The Thyrotropin-Releasing Hormone Gene Is Regulated by Thyroid Hormone at the Level of Transcription in Vivo
Authors: Sugrue Michelle L. , Vella Kristen R. , Morales Crystal , Lopez Marisol E. , Hollenberg Anthony N.
Published: December 2009

The expression of the TRH gene in the paraventricular nucleus (PVH) of the hypothalamus is required for the normal production of thyroid hormone (TH) in rodents and humans. In addition, the regulation of TRH mRNA expression by TH, specifically in the PVH, ensures tight control of the set point of the hypothalamic-pituitary-thyroid axis. Although many studies have assumed that the regulation of TRH expression by TH is at the level of transcription, there is little data available to demonstrate this. We used two in vivo model systems to show this. In the first model system, we developed an in situ hybridization (ISH) assay directed against TRH heteronuclear RNA to measure TRH transcription directly in vivo. We show that in the euthyroid state, TRH transcription is present both in the PVH and anterior/lateral hypothalamus. In the hypothyroid state, transcription is activated in the PVH only and can be shut off within 5 h by TH. In the second model system, we employed transgenic mice that express the Cre recombinase under the control of the genomic region containing the TRH gene. Remarkably, TH regulates Cre expression in these mice in the PVH only. Taken together, these data affirm that TH regulates TRH at the level of transcription in the PVH only and that genomic elements surrounding the TRH gene mediate its regulation by T3. Thus, it should be possible to identify the elements within the TRH locus that mediate its regulation by T3 using in vivo approaches.
Partial Progress: Governing the Pharmaceutical Industry and the Nhs, 1948–2008
Authors: Abraham John
Published: December 2009

Coinciding with sixty years of the U.K. National Health Service (NHS), this article reviews the neglected area of the governance of the pharmaceutical industry and the NHS. It traces the relationships between the pharmaceutical industry, the state, and the NHS from the creation of the health service to the present, as they have grappled with the overlapping challenges of pharmaceutical safety, efficacy, cost-effectiveness, pricing, promotion, and advertising. The article draws on the concepts of “corporate bias” and “regulatory capture” from political theory, and “counter-vailing powers” and “clinical autonomy” in medical sociology, while also introducing the new concepts of “assimilated allies” and “pharmaceuticalization” in order to synthesize a theoretical framework capable of longitudinal empirical analysis of pharmaceutical governance. The analysis identifies areas in which the governance of pharmaceuticals and the NHS has contributed to progress in health care since 1948. However, it is argued that that progress has been slow, restricted, and vulnerable to misdirection due to the enormous and unrivaled influence afforded to the pharmaceutical industry in policy developments. Countervailing influences against such corporate bias have often been limited and subject to destabilization by the industry's assimilated allies either within the state or in the embrace of pharmaceuticalization and consumerism.
An Alternative Condition for Stochastic Domination
Authors: Hosaka Kenshi
Published: December 2009

We will propose an alternative condition for stochastic domination. This condition differs in an essential way from the strong likelihood ratio property. We also show an example which satisfies the new condition, but does not satisfy the strong likelihood ratio property.
The Wealth of Cities: Agglomeration Economies and Spatial Equilibrium in the United States
Authors: Glaeser Edward L. , Gottlieb Joshua D.
Published: December 2009

Empirical research on cities starts with a spatial equilibrium condition: workers and firms are assumed to be indifferent across space. This condition implies that research on cities is different from research on countries, and that work on places within countries needs to consider population, income, and housing prices simultaneously. Housing supply elasticity will determine whether urban success reveals itself in the form of more people or higher incomes. Urban economists generally accept the existence of agglomeration economies, which exist when productivity rises with density, but estimating the magnitude of those economies is difficult. Some manufacturing firms cluster to reduce the costs of moving goods, but this force no longer appears to be important in driving urban success. Instead, modern cities are far more dependent on the role that density can play in speeding the flow of ideas. Finally, urban economics has some insights to offer related topics such as growth theory, national income accounts, public economics, and housing prices. (JEL R11, R23, R31, R32)
Changes in Care and Support Needs Following Community-Based Intervention for Individuals With Acquired Brain Injury
Authors: Sloan Sue , Callaway Libby , Winkler Dianne , McKinley Kirsten , Ziino Carlo , Anson Katie
Published: December 2009

Objective:To examine the care and support and participation outcomes for individuals with severe Acquired Brain Injury (ABI) provided with three consecutive years of Community Approach to Participation (CAP) intervention.Method:A case series study design was undertaken with a total of 43 participants from two private occupational therapy practices specialising in community-based, CAP rehabilitation for people with severe ABI. Data were collected at four time points: January 2004 (Baseline), January 2005 (T1), January 2006 (T2), and January 2007 (T3) and included rating on the Care and Needs Scale (CANS); number of hours of paid and gratuitous weekly support; FIM™ and Community Integration Questionnaire scores; and number of current life roles (as recorded on Part 1 of the Role Checklist). Participants were an average of 6.73 years post injury and were living in a range of community environments and residential facilities.Results:There was considerable change in participants' CANS rating across the intervention period, with statistically significant decreases occurring from Baseline to T1 and T1 to T2. Ninety-five per cent of participants received some level of weekly paid support throughout the intervention period, with the amount varying considerably. Paid care decreased by an average of 10.78 hours per week from 85.85 hours per week at Baseline to 75.06 at T3. Although not statistically significant, this equated to an average cost saving of AU$324.84 per participant per week by the end of CAP intervention. There was an overall mean reduction of 4.96 hours of gratuitous care per week per participant over the intervention period, which was statistically significant. Increases in functional independence, community integration, and role participation were also found. On the FIM™, statistically significant improvement occurred between Baseline and T1 and on the CIQ between Baseline and T1 and T1 and T2. Significant increase on the Role Checklist occurred between Baseline and T1 and between T2 and T3. The number of life roles in which participants engaged increased by an average of 1.65 roles by the end of the intervention period. A reduction in care and support needs (measured by the CANS) was significantly associated with: (1) a reduction in total care hours, (2) and an increase in functional independence on the FIM™, and (3) an increase in community integration on the CIQ.Conclusion:With a long term approach and contextualised intervention targeted at skill development in the areas that underpin personally valued participation, increased role performance and community integration can be achieved by people with severe ABI, even many years post injury. This increased capacity has been found to be associated with a reduction in care and support needs, including paid and gratuitous care hours, over time.
Production of viable piglets for the first time using sperm derived from ectopic testicular xenografts
Authors: Nakai Michiko , Kaneko Hiroyuki , Somfai Tamas , Maedomari Naoki , Ozawa Manabu , Noguchi Junko , Ito Junya , Kashiwazaki Naomi , Kikuchi Kazuhiro
Published: December 2009

Xenografting of testicular tissue into immunodeficient mice is known to be a valuable tool for facilitating the development of immature germ cells present in mammalian gonads. Spermatogenesis in xenografts and/or in vitro embryonic development to the blastocyst stage after ICSI of xenogeneic sperm has already been reported in large animals, including pigs; however, development of the embryos to term has not yet been confirmed. Therefore, in pigs, we evaluated the in vivo developmental ability of oocytes injected after ICSI of xenogeneic sperm. Testicular tissues prepared from neonatal piglets, which contain seminiferous cords consisting of only gonocytes/spermatogonia, were transplanted under the back skin of castrated nude mice. Between 133 and 280 days after xenografting, morphologically normal sperm were recovered, and a single spermatozoon was then injected into an in vitro matured porcine oocyte. After ICSI, the oocytes were electrostimulated and transferred into estrus-synchronized recipients. Two out of 23 recipient gilts gave birth to six piglets. Here, we describe for the first time that oocytes fertilized with a sperm from ectopic xenografts have the ability to develop to viable offspring in large mammals.
Nanostructured TiO2 modified by perfluoropolyethers: Gas phase photocatalytic activity
Authors: Bianchi Claudia L. , Ardizzone Silvia , Cappelletti Giuseppe , Cerrato Giuseppina , Navarrini Walter , Sansotera Maurizio
Published: December 2009

A high-molecular-weight perfluoropolyether (PFPE-YR) and a perfluoropolyether containing ammonium phosphate (PFPE-F10) have been evaluated as fluorinated coating for high-surface-area titanium oxides. Coated nano-TiO2 shows hydrophobic properties and excellent buoyancy on water. In addition to photoactivity toward the degradation of toluene in gas phase, specific trial analyses have been completed to estimate the modified titanium oxide features. Brunauer–Emmett–Teller (BET) analysis for the surface area determination, ultraviolet-visible spectroscopy (UV-Vis) for the material electronic band gap, high-resolution transmission electron microscopy (HRTEM), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) for the morphology, structure, and surface composition, respectively, and water contact angle and infrared (IR) analysis have been performed to estimate the wettability and stability of coated titanium.
The Development of Novel Down-Hole Intervention Tools, a Change in Well Technology
Authors: Heijnen W. H. P. M.
Published: December 2009

Well Technology is traditionally dealing with drilling and completion as well as with well intervention and well integrity during the well life. The drilling and production engineers are the main players in this arena covering the full life cycle from design to abandonment of the well. The high-level governing factors in well design and well lifetime are the production forecast together with the PVT data and the geology based well trajectory. These three major data sets combined with historical drilling and production data is the basis for well design and its associated technology. The latter methodology was applied at oil prices, starting at 2 USD, mid of the last century to the 2008 price of 140 USD plus per barrel of oil.

The paradigm shift in well technology is driven by the disappearing vision that the hydrocarbon resources are unlimited. Well Technology is now not a function of executing a field development plan but becomes a tool to tap into older fields which were closed in or even abandoned at an oil price around 20 USD per barrel. This paper will demonstrate how Maersk Oil's Well Technology shifts the paradigm, that decline cannot be reversed in an offshore environment, where well intervention and well design became so expensive that, even at elevated oil prices, the wells became economically unattractive.

This paper will in detail describe a tool box, developed by Maersk Oil engineers. The tool box varies from shutting off water, which is conveyed by fractures between injectors and producers, seal off (stuck open) sliding side doors, overcome lubricator height limitations, to how to abandon the long horizontal section of a well which acts as a water highway resulting in an increasing water cut in several sound producers, leaving pockets of oil behind.

The goal of this effort by Maersk Oil is to increase the ultimate recovery and thereby increase the amount of hydrocarbons produced.
Analysis of Inflow Control Devices
Authors: Aadnoy Bernt S. , Hareland Geir
Published: December 2009

Inflow Control Devices (IDCs) were initially developed to avoid water coning problems in long horizontal wells. They have been used with success the past 15 years. There are, however, issues that needs to be resolved.

A pressure drop model of the ICD is presented herein. The physical model of the ICD consists of pressure drop equations from the reservoir, through the screen, through the flow conduit, through the ICD nozzle and into the production tubing, and, pressure drop through the lower completion system. Evaluation of the model shows that for current commercial tools, turbulent flow through the ICD dominates the pressure drop, leading to a density controlled flow. This is fortunate as density varies much less than viscosity over the production life of a field.

Due to the inherent non-linear nature of a production system, the pressure drop versus flow rate will vary with degree of depletion. An ICD may be optimal initially, but not when the reservoir pressure is depleted. This paper also presents a new designer IDC concept which maintains constant flow regardless of the degree of field depletion. It is based on a hydraulic feedback principle, and ensures controlled flow throughout the life of the oil field.
A Novel Diverting Acid Stimulation Treatment Technique for Carbonate Reservoirs in China
Authors: Zhou Fujian , Liu Yuzhang , Zhang Shaoli , Li Xiangdong , Xiong Chunming , Yang Xianyou , Liu Xiongfei , Shi Yang , Li Xiuhui , Zhang Fuxiang , Shi Hongxiang , Shen Jianxin , Yuan Xuefang
Published: December 2009

Carbonate reservoirs are wildly distributed in China, and the reserve is very large. Bulk of big and middle oil fields were discovered in Sichuan Basin, BoHai Gulf Basin, Ordos Basin, Tarim Basin and so on. The cumulative demonstrated geological oil reserve reaches 1.62 billion ton, and the gas reserve is 1.42 trillion.

Formations of the newly discovered carbonate oil/gas fields have the following features: deep buried (>5000m); serious heterogeneity; full of pores, caves and cracks; long well section. So, it's difficult for acid stimulation treatment. And the treatment effect using traditional polymer-based acid fluid system is not very good.

Based on surfactant, this paper develops a novel diverting acid stimulation treatment for carbonate formation. This kind of self-diverting acid system contains a special visco-elastic surfactant. The viscosity of fresh acid is very low. However, when it enters into the pores or cracks of carbonate formation and reacts with rocks, the viscosity will increase rapidly as the concentration of acid decreases, because the surfactant molecules will aggregate to baculate micelle along with the consuming of acid. The structure will increase the viscosity of system, and prevent the fluid from leaking off into wormholes and cracks which have been etched. The micelle structure of surfactant can be used as a diverting agent in the process of acid treatment, and can also be used to control the fluid leaking off in acid fracturing stimulation. This technique has been used in 5 carbonate oil fields on land in China. 38 wells were acid fractured and 25 wells were treated. The effect is very well.
Research on the Application of Environment Acceptable Modified Natural Macromolecule Based Drilling Fluid
Authors: He Xiaoqing , Zheng Lihui
Published: December 2009

Environment acceptable modified natural macromolecule based drilling fluid is mainly composed of shale inhibitor agent IND30, fluid loss control agent NAT20, bloomless white asphalt NFA-25 and dry powder of polyalcohols PGCS-1, which are biodegradable and environment acceptable. Results of rheological property tests of based mud, IND30 mud, NAT20 mud, NFA-25 mud and environment acceptable modified natural macromolecule based drilling fluid provide us with the best of dosage of each component and confirm that the drilling fluid system meets requirements of petroleum drilling. Other experiments indicate that environment acceptable modified natural macromolecule based drilling fluid has five merits. Firstly, it can bear a high temperature of 140□. Secondly, it has very good anti-contamination ability. Thirdly, inhibit ability of the system is very strong. Fourthly, it can control formation damage. Last but not least, both of the drilling fluid and the basic components are environment acceptable. Field applications of environment acceptable modified natural macromolecule based drilling fluid indicate that not only did the drilling fluid solve a series of complex problems it did not disturb other works such as well logging, casing and production. What's more, it is a kind of environment acceptable drilling fluid that can be used both on dryland operation and in marine drilling for different well types.
Geomechanical Modeling Integrating Subseismic Faults
Authors: Fouladvand Arash , Baroni Axelle , Cangémi Laurent , Deflandre Jean-Pierre , Bernard Pascal
Published: December 2009

Injection of gas in a saline aquifer reservoir modifies fluid saturation and pore pressure, and consequently changes effective stresses into but also around the reservoir: the mechanical equilibrium of the geological structure is affected. Stress variations depend on site characteristics: rock properties, fracturing, existing faults, fracture networks, …, and on the exploitation activity: injected volumes, exploitation rates, reservoir pressure…. The effective stress modifications on natural fractures and faults, can be monitored by measure of surface displacement, measure of pressure changes in overburden, and record of induced seismic activity…

The goal of our work is to develop techniques to exploit such information to calibrate and constrain coupled hydro-mechanical modeling. The mechanical phenomena have to be precisely identified, quantified and eventually associated with specific major discontinuities like faults. The way, investigated in this paper, is to validate and constrain geomechanical modeling, by exploiting interpreted results from passive seismic data. The scope of the paper is to present our approach and to discuss preliminary results. In this first step of the methodology, we focus on the integration of a subseismic fault in a 3D earth model, assuming simple mechanical law and no geochemical phenomena. Coupled hydro-mechanical modeling is achieved using a commercial software.
Deepwater Development Production and Export Options
Authors: Hartell W. D. , Greenwald J. R.
Published: December 2009

Deepwater discovery development activities can be located in remote locations far from existing infrastructure like other facilities and pipelines. Major deepwater developments typically consist of subsea wells tied back to floating surface production facilities such as semisubmersibles, SPARs, TLPs, or FPSOs. The choice of production and export options for liquid hydrocarbons and gas is important and is affected by the distance to other infrastructure, the waterdepths involved, geohazards, reservoir fluid characteristics, production rates, and reserves. Another important factor is whether adjacent undeveloped discoveries exist to potentially share facilities and export options. Conventional production and export options involve oil and gas production facilities and pipelines with shipping pumps or compression as required to reach the closest transmission pipelines or onshore markets. In SE Asia, deepwater developments are often located in remote locations hundreds of kilometers from markets onshore, so the development production and export options must be wider in order to obtain economic and timely choices. In addition to pipeline options, liquid hydrocarbons can be stored offshore in the floating production facility or in an adjacent FSO, then offloaded and shuttled to markets by tankers. Gas production and export options can include long distance gas pipelines, Compressed Natural Gas (CNG) vessels, purity product (butane and propane) liquefied petroleum gas (LPG) FPSOs, methanol/DME FPSOs, and floating LNG FPSOs. This paper will show some of the technical concepts, risks, costs, and economics involved in making these choices.
Wellbore Stability Study: Lessons and Learnings From a Tectonically Active Field
Authors: Han Gang , Henson Jo , Timms Andrew , Aziz Ilyah Abdul
Published: December 2009

Shales account for 75% of the formations drilled worldwide, while drilling troubles associated with shale represents 90% of wellbore stability problems reported. In this paper, a traditional wellbore stability study has been implemented at an onshore gas field in a tectonically active region. Despite following the program however, the drilling experienced significant challenges, particularly in the shales where the sonic logs have shown high velocity and therefore high rock strength.

To investigate the root cause, several mechanisms for the wellbore instabilities have been investigated, such as overpressure, weak bedding plane, chemical activity, insufficient mud weight, and fractured shales. The cavings collected and preserved from the wells, as big as several inches in size, have undergone XRD, SEM, thin-section, and strength tests. While most mechanisms have been ruled out, focus has turned to the fractured shales. With the evidence from the lab and collaborated with drilling experience in the field, it has found the troublesome shale formation has been extensively fractured during past and present tectonic movements. The presence of the fissure network becomes so significant that it dominates rock mechanical behavior and wellbore stability. More interestingly, it seems the sonic logs have overlooked the existence of fissures and still shown the response from a typical strong rock. Based on those findings, modified drilling strategies have been suggested and implemented in the region.

The field case presents a new challenge to the log-based wellbore stability interpretation routinely implemented in current drilling society. Being open-minded, closely monitoring and testing cavings, and updating the model with drilling experience may be as important as the model development itself.
How to Drill Mature, Depleted Reservoirs Without Downhole Losses Using Engineered Drilling Fluids
Authors: Calder Alan , Fitzgerald Barry , Lonca Matthieu , Gregoire Michel
Published: December 2009

Invert emulsion drilling fluids designed with an optimised range of pre-determined sized particulates have been used successfully to eliminate or minimise losses to the formation while drilling depleted reservoirs. Sands can be penetrated with up to 600 bar overbalance without encountering losses or differential sticking. Further, the wells have been drilled at pressures above their natural gradient. Selectively designing these fluids has also made it possible to successfully drill high-angle step-out sections through mature, depleted reservoirs.

This paper describes the development and implementation of this technology.

Fluid Design Phase – The selection and optimization of type, size and amount of particulates required takes place during the planning stage of the well based on the rock mechanics of the formations to be drilled, drilling fluid properties and the practicalities at the rig site. Execution Phase – Once the fluid design has been finalized, processes and procedures are developed to help ensure that during the project the fluid functions are designed taking account of the practicalities of the actual drilling phase.

Recent case histories of the application of this technology are discussed in detail: the first case highlights a severely depleted reservoir in an extreme high-pressure, high-temperature (HPHT) field and the second case relates to extended reach wells drilled through mature reservoirs which can be segmentally depleted.
Increased Earnings: Adding More Functions and Knowledge into Subsea Instrumentation to Increase Production, Keeping Safety Issues in the Driver Seat!
Authors: Brakstad Olav , Instanes Geir
Published: December 2009

The paper will give an introduction to sand problems and management in the oil & gas industry, and describe the challenges to overcome them. A major part of the presentation will be directed to deepwater and ultra deepwater applications with respect to sand management, subsea design and how the sand monitoring systems should be used with respect to sand production. The contractors are designing the subsea equipment more and more compact than ever and that adds challenges to designing and operation subsea sand monitoring equipment, ClampOn will address this, and show how this can be overcome by applying correct design to the project and operator.

It will be discussed why sand monitoring systems should be installed subsea and not at the surface since surface appears to be more cost-effective (and it is a fact that the operator have open access to the sensor, e.g. for tie back installations). An example from field will be shown to see the distinguished difference between a subsea installation and a topside installation. The example will explain the difference in quality of the measurement and the danger of filling up the production line with sand due to missing information about the nature of the sand production. It will be shown how an offshore operator can get real time information by installing the sand monitoring system subsea.

Part of the presentation will demonstrate how operators, by using a real life example, optimize the oil & gas production by the use of sand monitoring systems and the savings they make, in actual figures after installing sand monitors. Operators own experience with the sand control system will also be discussed – field data will be shown on several of these topics.

The paper will show the latest in development of ultrasonic sand monitoring systems – both for deepwater and ultradeep water installations. Further on it will show the development of a retrofit system that can be installed subsea on an existing flow line without any disturbance of the oil & gas production itself.

Also, the paper will discuss the probable future aspects of sand management and monitoring for subsea installations.
Sub-basalt Plays in the Rockall and Faroes-Shetlands Basins
Authors: Davison I. , Stasiuk Stefan , Nutall Peter , Keane Paul
Published: December 2009

The sub-basalt plays of the Faroes-Shetland and Rockall Basins are virtually untested. The seismic imaging below the basalts is generally poor and the thickness of the basalts is difficult to predict. Two recent wells (William and Brugdon) drilled in Faroes waters were suspended before reaching sub-basalt targets because the basalts were thicker than expected. New deep tow seismic reflection data shot by ION/GX Technology in 2008 has allowed imaging of the sub-basalt Mesozoic strata. The base basalt is non-reflective and is probably a transitional contact with a small acoustic impedance, but the underlying Mesozoic strata produce coherent reflectivity. Large structural closures produced by Cretaceous rifting and Cenozoic folding have been imaged in the Faroes-Shetland Basin and these may contain reasonable Mesozoic clastic reservoirs at drillable depths of about 4 km.

Some areas of the Rockall Trough are not covered by basalts and large Cenozoic age folded structures are present which produce potential traps at Late Cretaceous level where sandstones equivalent to the Nise Formation may occur. The Rockall Trough contains 4-6 km of Mesozoic strata and appears to be floored by stretched continental crust throughout. The lower section may contain Jurassic source rocks similar to the areas to the south and north of the basin. These are some of the largest undrilled structures in NW Europe and deserve a more dedicated exploration effort in the future.
A Novel Correlation for Estimation of Economic Thickness of Insulation for Process Piping and Equipments
Authors: Bahadori A. , Vuthaluru H. B.
Published: December 2009

Where the sole object of applying insulation to a portion of plant is to achieve the minimum total cost during a specific period (evaluation period), the appropriate thickness is usually termed as the economic thickness. The principle is to find at what thickness further expenditure on insulation would not be justified by the additional financial saving on heat to be anticipated during the evaluation period. Although an increase in the amount of insulation applied will raise the initial installed cost, but it will reduce the rate of heat loss through the insulation. Therefore it is necessary to reduce the total cost during the evaluation period. In this work, simple-to-use novel correlation is formulated to arrive at the economic thickness of hot insulation suitable for process piping and equipments. The correlation is a function of pipe diameter and thermal conductivity of insulation for hot surface temperatures at 100°C, 300°C, 500°C and 700°C. A simple interpolation formula generalizes this correlation for wide range of hot surface temperatures. The proposed correlation covers pipeline diameter and hot surface temperature up to 0.5 m and 700°C respectively. The average absolute deviation percent of proposed correlation for estimating the economic thickness of the hot insulator is 2.12% demonstrating the excellent performance of proposed correlation. Simple-to-use approach can be of immense practical value for the engineers and scientists to have a quick check on the optimum insulation thickness for wide range of conditions. In particular, practice engineers would find the proposed approach to be user friendly involving no complex expressions with transparent calculations.
Estimation of Static Bottom Hole Pressure from Well-Head Shut-in Pressure for a Supercritical Fluid in a Depleted HP/HT Reservoir
Authors: Nurafza Peyman R. , Fernagu Jeremie
Published: December 2009

A periodic measurement of static bottom-hole pressure to monitor the reservoir depletion is an essential reservoir management practice. In an HP/HT offshore environment, the unavailability of qualified permanent down-hole monitoring technologies and the risks and costs of occasional operations make gradient surveys very difficult to acquire on a routine basis.

On Elgin-Franklin (HP/HT gas condensate fields, North Sea, UKCS), the typical approach is to use an average fluid density to estimate the static bottom-hole pressure from the well-head shut-in pressure. This estimation is valid as long as there is only one phase present inside the well-bore. As soon as the pressure drops below dew point in the tubing, the vertical phase distribution changes and the bottom-hole pressure can not be accurately estimated using one single average density. Fluid segregation mechanisms involve complex thermo-convective phenomenon, in association to gravity, which are strongly related to the temperature gradient in the well bore.

Segregated phase distribution has been observed on some available static pressure gradient surveys, where three gradients were identified. They correspond to three different phases, i.e. gas at the top, condensate in the middle and supercritical gas at the bottom of the well. This phenomenon of having a low density fluid below a higher density fluid was referred to as "gradient reversals" (Bender and Holden, 1984). At that time, it was assumed to be only due to the increasing temperature with increasing depth, but not explicitly related to the thermo-dynamical behaviour of the critical fluid.

In this case, we show that the fluid densities numerically estimated from each phase composition, at the corresponding pressure and temperature in the tubing, are comparable to the densities derived from the measured gradients. Based on this, a robust correlation methodology has been developed to derive the static bottom-hole pressure from the well-head shut-in pressure using thermodynamic modeling.
Curing Shallow Water Flow in a North Sea Exploration Well Exposed to Shallow Gas
Authors: Opseth T. Landbø , Ribesen B. T , Syrstad B. , Huse A. , Bolstad L. , Saasen A.
Published: December 2009

Shallow water flow was severely hindering further drilling in the North Sea exploration well 16/1-9, "Draupne". The water depth was 111.5m. The 20" casing was set at 590m; above a shallow gas zone. After mounting the Blow Out Preventer (BOP), drilling the 17 1/2" section started and continued for a few 100 meters. The wellhead was routinely inspected using an ROV (Remotely Operated Vessel). After some time, a tiny flow was observed around the wellhead. The flow increased in strength and later a large wash out area was observed, and further drilling had to be terminated. Most likely, the water flow originated from a zone at a depth of 172m MSL.

To cure the shallow water flow it was decided to grout cement on the outside of the casings. Regular well cements was not desirable to use since these cements are somewhat retarded in itself by mineralogical composition. It was decided to use standard construction industry cement with a very short curing time. Before the grouting could start the BOP had to be removed. Because of the shallow gas zone underneath the 20" casing, two barriers had to be included in the well for well control. Two packers were used, one drillable and one retrievable. The BOP was removed and the grouting operation was performed successfully. No water flow or gas flow were observed while the cement was setting. After the cement was cured drilling resumed, first by drilling and retrieving the packers, then continuing to drill the 12 1/4" section. The paper describes all aspects of these operations in detail. It also focuses on necessary cleaning operation of bulk systems and logistical tanks to hinder polluting well cements with construction cements, and thereby avoid complicating other cementing operations.
Mature Field Production Optimisation Through Standardisation of Operating Procedures for Reservoir Monitoring
Authors: Bhushan Vikas , Lee Robert , Mukerji Parijat
Published: December 2009

The ultimate goal of excellence in brownfield management is to increase the value of a field through maximising production and ultimate recovery within its remaining economic life. The ability to successfully apply reservoir management techniques is essential in meeting the challenges of optimising late life production, particularly given the high costs of well interventions in an offshore environment. Further, the standardisation of operating procedures yields benefits both in terms of optimising the use of technical resources and in successfully meeting well intervention objectives. It also facilitates and promotes an active collaboration between the operator and service provider, both during offshore operations and later when the log data is evaluated and interpreted.

We will describe the development and application of robust Standard Operating Procedures (SOP&Amp;apos;s) for cased hole reservoir monitoring. These will be illustrated with recent examples from the Brent Field in the North Sea. Developing these SOP&Amp;apos;s was not a simple process, and required a detailed understanding of the rock & fluid properties, reservoir production mechanisms and contact movements, topsides constraints, and reservoir behaviour coupled with experience in data acquisition & interpretation methods which are tailored to meet the specific challenges of the field. The SOPs have been applied to meet a range of specific challenges such as the identification and perforation of gas zones, differentiating reservoir fluid type (e.g. formation/injection water and oil) to access bypassed oil, contact monitoring, and identifying impairment to increase production rates.

Success in the development and application of SOPs requires service company involvement and cooperation in all aspects: programme design, data acquisition (including real time support and monitoring to ensure data quality), processing, presentation and interpretation. Examples will be provided of how this involvement has been essential to the successful outcome of several interventions in the Brent field.
Managing Drilling Risk in a Mature North Sea Field
Authors: McIntyre Brett , Hibbert Ted , Keir Donald , Dixon Rachel , Orourke Tom , Mohammed Farid , Donald Adam , Chang Liu , Syed Anzar , Biran Valerie
Published: December 2009

As fields mature, drilling can become more difficult. The likelihood of losses increases as reservoir pressures decline while higher mud weights are needed to prevent collapse of overburden shales as targets are pushed further from the platform. Drilling parameters for the Forties field have become fairly well established after years of experience yet 65% of the wells drilled between 2002 and 2007 experienced incidents attributed to instability. As field production declined, economic viability demanded a step change in performance.

Through a better understanding of the field geomechanics and past drilling events, the Apache drilling team has implemented fit for purpose drilling procedures that have significantly improved drilling efficiency.

This paper describes how geomechanics analysis has been used to assist well planning. Incorporating the experience of recent wells, the Forties mechanical earth model has been refined and provides key inputs needed to optimise well plans and adapt drilling practices to changing conditions.

The adverse effects of anisotropy is a key reason for wellbore instability in the overburden. A joint Apache-Schlumberger team has been working to integrate geomechanics and geophysics knowledge of the field to quantify the effects of anisotropy related to bedding planes and weak shales.

It can be difficult to predict drilling and completion risks during well planning, often due to the lack of distinction between events caused by formation instability and those which are drilling induced (drilling practices, hole cleaning). Capturing and classifying historic drilling events is a fundamental key process in understanding the mechanism and causes of well bore failures.

Drilling performance in this mature field has been improved through the collaborative effort of Apache staff and key service providers. The refinement of the wellbore stability model has enabled sound practices and procedures to be developed.
The Role of Economics on Well and Fracture Design Completions of Marcellus Shale Wells
Authors: Schweitzer R. , Bilgesu H. I.
Published: December 2009

The demand for energy is increasing exponentially in the U.S and internationally. As a clean source of energy, the natural gas production is gaining importance. Many potential sources exist for gas production in the Appalachian Basin with the Marcellus shale being the largest resource in the U.S. This covers several states in the Eastern U.S. and plays a vital role in the future of gas production.

One of the unknowns of the Marcellus shale is the lack of commercially available information. Information on well and completion designs for the Marcellus shale is rather vague and tightly lipped. This information plays a key role in the production of these shale wells and can determine whether or not these wells may or may not be economical.

In this study, simulations have been conducted with several wellbore configurations for gas production from the Marcellus shale. Some of the parameters studied include lateral wellbore length, propped half length and the amount of fracture stages along with others. Economic evaluations were performed to determine the most cost efficient configuration. The average present day completion costs and projected sale price of gas are used in the calculation process.
Latin Hypercube Sampling (LHS) for Gas Reserves
Authors: Ekeoma E. , Appah D. A.
Published: December 2009

Latin Hypercube Sampling (LHS), unlike other simulation methods such as Monte Carlo Simulation (MCS), has not enjoyed wide applications in determination of reserve despite its capability to realize same accuracy as with the latter even with much fewer simulation trials. The parameters used in these distributions are extracted using software ‘digitizer’ from different plot of values derived from measurements of reservoir and fluid properties. This work dwells on analysis of two depleted gas fields for which the ultimate recovery is known. The distribution of porosity, water saturation, reservoir thickness and reserve size are input to crystalbal software to generate cumulative distribution function (CDF) and Probability density function (PDF) of original gas in place (OGIP) for each of the fields. The accuracy of Latin Hypercube Sampling is analysed by comparing the actual ultimate recovery and the OGIP predicted by LHS. The calculated recovery factors of 68.7% and 93.3%, for water driven and depletion driven gas reservoirs respectively, compare favourably with those of known gas reservoirs. Therefore, LHS is a good estimator of gas reserve. It is recommended that similar study should be carried out on condensate and oil reservoir, particularly on Niger Delta fields.
Stochastic Mortality: The Impact on Target Capital
Authors: Olivieri Annamaria , Pitacco Ermanno
Published: December 2009

In this paper, we take the point of view of an insurer dealing with life annuities, which aims at building up a (partial) internal model in order to quantify the impact of mortality risks, namely process and longevity risk, in view of taking appropriate risk management actions. We assume that a life table, providing a best-estimate assessment of annuitants' future mortality is available to the insurer; conversely, the insurer has no access to data sets and the methodology underlying the construction of the life table. Nonetheless, the insurer is aware that, in the presence of mortality risks, a stochastic approach is required. The (projected) life table, which provides a deterministic description of future mortality, should then be used as the basic input of a stochastic model.

The model we propose focuses on the annual number of deaths in a given cohort, which we represent allowing for a random mortality rate. To this purpose, we adopt the widely used Poisson model, first assuming a Gamma-distributed random parameter, and second introducing time-dependence in the parameter itself. Further, we define a Bayesian-inferential procedure for updating the parameters to experience in some situations. The setting we define does not demand advanced analytical tools, while allowing for process and longevity risk in a rigorous way.

The model is then implemented for capital allocation purposes. We investigate the amount of the required capital for a given life annuity portfolio, based on solvency targets which could be adopted within internal models. The outcomes of such an investigation are compared with the capital required according to some standard rules, in particular those proposed within the Solvency 2 project.
Legionella species and serogroups in Malaysian water cooling towers: identification by latex agglutination and PCR-DNA sequencing of isolates
Authors: Yong Stacey Foong Yee , Goh Fen-Ning , Ngeow Yun Fong
Published: December 2009

In this study, we investigated the distribution of Legionella species in water cooling towers located in different parts of Malaysia to obtain information that may inform public health policies for the prevention of legionellosis. A total of 20 water samples were collected from 11 cooling towers located in three different states in east, west and south Malaysia. The samples were concentrated by filtration and treated with an acid buffer before plating on to BCYE agar. Legionella viable counts in these samples ranged from 100 to 2,000 CFU ml−1; 28 isolates from the 24 samples were examined by latex agglutination as well as 16S rRNA and rpoB PCR-DNA sequencing. These isolates were identified as Legionella pneumophila serogroup 1 (35.7%), L. pneumophila serogroup 2–14 (39%), L. pneumophila non-groupable (10.7%), L. busanensis, L. gormanii, L. anisa and L. gresilensis.L. pneumophila was clearly the predominant species at all sampling sites. Repeat sampling from the same cooling tower and testing different colonies from the same water sample showed concurrent colonization by different serogroups and different species of Legionella in some of the cooling towers.