bluuebunny/crossref_metadata_2025 huggingface dataset:
Valence band spectroscopy on lignin
Authors: Klarhöfer Lothar , Roos Burkhard , Viöl Wolfgang , Höfft Oliver , Dieckhoff Stefan , Kempter Volker , Maus-Friedrichs Wolfgang
Published: November 2008

The valence band of lignin and sputtered lignin was studied by X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and metastable induced electron spectroscopy (MIES). The corresponding spectra were compared with those from fingerprint molecules, representing the various chemical groups of lignin. The results of this analysis show that valence band spectroscopy, in particular a combination of XPS, UPS and MIES, allows an identification of hydroxyl, methoxy and phenyl groups at the lignin surface.
Soda–AQ delignification of poplar wood. Part 1: Reaction mechanism and pulp properties
Authors: Venica Alberto D. , Chen Chen-Loung , Gratzl Josef S.
Published: November 2008

Soda and soda-anthraquinone (AQ) pulpings of poplar (Populus deltoides) wood performed in a flow-through reactor gives rise to the formation of coniferyl alcohol (1) sinapyl alcohol (2) and other low molecular weight (LMW) compounds in different stages of delignification. During the heating-up period, the formation of these compounds increases until the maximum pulping temperature (t
max, 170°C) is reached. Afterward, their concentration in the spent liquor decreases sharply. This effect is accompanied by solubilization of high molecular weight (HMW) lignin fractions. Compared with soda pulping, the soda-AQ pulping shows a higher production of LMW compounds because of the presence of AQ-anthrahydroquinone (AHQ) redox system. During the heating-up period, the formation of 1 and 2 – apparently originated from non-etherified β-aryl-ether moieties in the lignin – is accompanied by solubilization of lignin fragments with relative LMW. Lignin cores, having β-aryl-ether bonds as major hydrolyzable inter-unit linkages, remain in the fiber, and they give rise to solubilized lignin fragments with HMW at later delignification stages. The dissolved fragments, in particular those formed during heating-up period, undergo further degradation in the liquor. The degradation occurs via oligomers at the end of the pulping, while the residual lignin cores are more resistant. Pulps with low kappa number can be produced by maintaining higher alkali concentrations than the usual in the last delignification phase. When the pulping liquor is replaced in this stage with liquors of higher alkali concentration, extended delignification will be the result. As a consequence, less degraded lignin fragments will be deposited on fibers.
Manufacture of laminated strand veneer (LSV) composite. Part 1: Optimization and characterization of thin strand veneers
Authors: Weight Shilo W. , Yadama Vikram
Published: November 2008

The forest resources are changing due to fire prevention and depletion of old growth forest. Applications for small-diameter juvenile timber, especially for low-value species, such as ponderosa pine (Pinus ponderosa) are needed. In this study, a novel thin wood strand composite of P. ponderosa, 3.2 mm thick, is introduced as a veneer substitute. Optimization was performed for the processing parameters phenol formaldehyde resin content, platen temperature, and the aspect ratio strand length to thickness (L/t). Mean modulus of elasticity and modulus of rupture values of 10.2 GPa and 79.1 MPa, respectively, were obtained with the optimized formulation (5.5% resin, platen temperature 152°C, and aspect ratio of 430). These values were approximately 2–2.5 times higher than the parent small-diameter ponderosa pine lumber. The results indicate that fast-growing low-density species – such as hybrid poplars, or small-diameter timber with predominantly juvenile wood – could potentially be used to manufacture strand veneers of consistent quality with significantly higher strength and stiffness than parent material.
Automatisiertes Differenzialblutbild: Gegenwärtiger Stand und Perspektiven / Automated blood cell differential: State of the art and eye to the future
Authors: Nebe C. Thomas , Baurmann Herrad , Kuling Gudrun , Diem Heinz
Published: November 2008

Das automatisiert gemessene Differentialblutbild stellt eine der häufigsten Untersuchungen im medizinischen Labor dar. Wie zuverlässig ist die Methode als diagnostisches Sieb im Rahmen einer Stufendiagnostik? Welche pathologischen Bilder werden übersehen? Welche Körperflüssigkeiten können untersucht werden? Was sind die präanalytischen Vorraussetzungen? Wann ist eine mikroskopische Kontrolle erforderlich? Die Kostenerstattung hat einen Punkt erreicht, wo eine persönliche Begutachtung eines jeden Ergebnisses mit seinen Diagrammdarstellungen und die mikroskopische Untersuchung des Blutausstrichs kaum mehr geleistet werden kann. Die Technologie der aktuellen Geräte am Markt ist kürzlich an dieser Stelle beschrieben worden. Nachfolgend werden daher die Stärken und Schwächen der automatisierten Blutbilderstellung diskutiert, um im Labor eine Entscheidungsgrundlage zu haben für die Risiken einer Stufendiagnostik in Abhängigkeit von der Fachrichtung des Einsenders.
Budd-Chiari Syndrom und Portalvenenthrombose – Bedeutung der JAK2-Mutation als neuer Risikomarker / Budd-Chiari syndrome and portal venous thrombosis – relevance of the JAK2 mutation as a new risk marker
Authors: Roskos Martin
Published: November 2008

Das Vorliegen eines myeloproliferativen Syndroms wird als häufigster Risikofaktor für das Auftreten einer Pfortaderthrombose oder eines Budd-Chiari Syndroms angesehen. Von weiterer Bedeutung sind angeborene oder erworbene Gerinnungsstörungen und Lebererkrankungen. Etwa 25% der Thrombosen ereignen sich ohne ei-nen Hinweis auf eine mögliche Ätiologie. Bei einigen dieser Patienten finden sich jedoch zumindest im Knochenmarkbefund Hinweise auf das Vorliegen eines bcr-abl-negativen proliferativen Syndroms. Die im Jahre 2005 beschriebene V617F-Mutation im Gen der Januskinase 2 konnte die Diagnostik für einen Teil der myeloproliferativen Erkrankungen deutlich verbessern und das Verständnis für die pathobiochemischen und pathophysiologischen Prozesse bei myeloproliferativen Erkrankungen erweitern. Die nachfolgenden retrospektiven Studien bei Patienten mit einem Budd-Chiari Syndrom oder einer Pfortaderthrombose konnten zeigen, dass bei Patienten, deren Thrombosen bisher als idiopathisch eingestuft worden waren, zu einem hohen Prozentsatz eine V617F Mutation vorlag und dass ein Teil dieser Patienten nach dem thrombotischen Ereignis ein myeloproliferatives Syndrom entwickelte.
Tacitus, Stoicexempla, and thepraecipuum munus annalium
Authors: Turpin William
Published: November 2008

Tacitus' claim that history should inspire good deeds and deter bad ones (Annals 3.65) should be taken seriously: his exempla are supposed to help his readers think through their own moral difficulties. This approach to history is found in historians with clear connections to Stoicism, and in Stoic philosophers like Seneca. It is no coincidence that Tacitus is particularly interested in the behavior of Stoics like Thrasea Paetus, Barea Soranus, and Seneca himself. They, and even non-Stoic characters like Epicharis and Petronius, exemplify the behavior necessary if Roman freedom was to survive the monarchy.
“Master Arigo Ysach, Our Brother”: New Light on Isaac in Florence, 1502–17
Authors: Zanovello Giovanni
Published: November 2008

Recently discovered documents shed new light on Heinrich Isaac's biography in the sixteenth century: hitherto unknown payments by Isaac (ca. 1450–1517) to the Florentine confraternity of Santa Barbara. As it turns out, Isaac was a regular member of the association from 1502 and bequeathed a substantial sum at his death. The records, in conjunction with other documents, illuminate Isaac's life from three complementary perspectives: the composer's biography (especially in the years 1502–7 and 1509–17), the wider context of the actions Isaac took in preparation for his old age and death, and the issues they raise regarding the composer's social background and integration in Florence during the first years of the sixteenth century. Against this backdrop the new documents allow us to question a number of assumptions, including the notion that Isaac's main residence in 1502–17 was in the imperial lands and that his social integration in Florence was exclusively linked to the Medici. They enrich our understanding of the social history of northern musicians in Italy around 1500.
Commentary: Hormone Receptor Testing in Breast Cancer: A Distress Signal from Canada
Authors: Allred D. Craig
Published: November 2008

This commentary reviews recent events in Canada that underscore the substantial problems with estrogen receptor testing by immunohistochemistry in breast cancer.
PROPAGATION OF SCALE‐DEPENDENT EFFECTS FROM RECRUITS TO ADULTS IN BARNACLES AND SEAWEEDS
Authors: Methratta Elizabeth T. , Petraitis Peter S.
Published: November 2008

The interplay between local and large spatial scale processes in open systems is often dependent upon ecological context and species specific factors such as longevity, dispersal capability, or vulnerability to predation. When disturbance clears patches in open systems, the successful reestablishment of adult colonizers and the trajectory of succession may depend upon both the scale of the disturbance event and scale of life history characteristics. Here we examine the links between the size of a disturbance event and long term patterns of variation in recruitment, density, and percent cover in a relatively short‐lived but long‐range disperser, the acorn barnacle Semibalanus balanoides, and a relatively long lived and short range disperser, the fucoid alga Fucus vesiculosus. Further, a model of linked scale‐dependent processes is developed and we explore how long term patterns of scale‐dependent recruitment are related to successful establishment of adults. Recruitment, densities, and cover were monitored for five years for both species in a single experiment using clearings of different sizes spread over two north‐facing and two south‐facing bays on Swan's Island, Maine, USA. Barnacle recruitment was particularly variable in small clearings and was lower overall at more interior sites within bays. While local‐scale factors also strongly influenced patterns of variation in fucoid recruitment, fucoids dominate surface cover in large clearings and in south‐facing bays. Recruitment was a poor predictor of density, whereas density itself was a good predictor of percent cover for both species. These results indicate that scale dependencies, location‐specific factors, and life history traits contribute to patterns of community development on rocky shores and may ultimately determine whether an open patch converges to or diverges from its initial community state.
SPATIAL DENSITY DEPENDENCE SCALES UP BUT DOES NOT PRODUCE TEMPORAL DENSITY DEPENDENCE IN A REEF FISH
Authors: Forrester Graham E. , Steele Mark A. , Samhouri Jameal F. , Evans Bryn , Vance Richard R.
Published: November 2008

Field experiments provide rigorous tests of ecological hypotheses but are typically of short duration and use small spatial replicates. We assessed empirically whether the results of experiments testing for density dependence applied at larger spatial domains and explained temporal population dynamics. We studied a small coral reef fish, the goldspot goby (Gnatholepis thompsoni), in the Bahamas. We assessed the effects of interactions with conspecifics and with an ecologically similar species, the bridled goby (Coryphopterus glaucofraenum). Two density manipulations on small reef patches revealed that goldspot goby mortality over one month increased as conspecifics became crowded. On five large natural reefs, we correlated the initial year‐class density of both species (annual larval settlement) with the subsequent decline of goldspot goby year‐classes for five years. Mortality was correlated with conspecific density among reefs for all years, but not among years for all reefs. Thus, spatial density dependence in mortality scaled up qualitatively from small patches to entire reefs but was not associated with temporal density dependence. Our results support the conclusion that field experiments may be extrapolated to larger spatial domains with care, but that using small spatial comparisons to predict temporal responses is difficult without knowing the underlying biological mechanisms.
EARLY TO RISE MAKES A PLANT HEALTHY, WEALTHY, AND WISE
Authors: Luis M. de , Verdú M. , Raventós J.
Published: November 2008

Seedling emergence time is a crucial event in the life cycle of a plant, determining its fitness via different components including survival, growth, and fecundity. Precocious emergents usually survive, grow, and/or reproduce earlier in the life cycle, but for perennials it is unknown whether these benefits are maintained throughout the life of the plant. Here, we examine for the first time whether fitness benefits due to the early emergence of perennial plants are perpetuated or vanish with time. For nine years, in a Mediterranean gorse community, we followed the fate of 2118 seedlings belonging to the four dominant woody species. We estimated phenotypic selection gradients on emergence time for three fitness components (survival, growth, and fecundity), under two experimentally simulated scenarios (fire and fire + erosion), at two different times in the life of the plant (3 and 9 years). Fire and erosion represent two potential selective forces constraining the temporal window of seedling emergence in Mediterranean habitats. All the species exhibited selection for early emergence, but through different fitness components. Directional selection favoring early emergence via survival in both fire scenarios was detected in the two Cistaceae species (Helianthemum marifolium and Cistus albidus), in which precocious emergents had higher fitness values late in the life cycle (9 years). In contrast, Fabaceae species (Ononis fruticosa and Ulex parviflorus) were not selected for early emergence via survival. Early emergents of all species in both fire scenarios had higher fitness values through growth early in the life cycle; these benefits decreased slightly with time but remained statistically significant, except in H. marifolium. Finally, late fecundity was enhanced by early emergence in both fire scenarios in C. albidus and U. parviflorus but not in H. marifolium. In conclusion, benefits acquired by emerging early are perpetuated for at least nine years.
ABOVE‐ AND BELOWGROUND INTERACTIONS ARE MEDIATED BY NUTRIENT AVAILABILITY
Authors: Haase Josephine , Brandl Roland , Scheu Stefan , Schädler Martin
Published: November 2008

By influencing nutrient mineralization in the soil, decomposers may affect the performance of plants and their associated herbivores. The strength of above–belowground linkages may therefore depend on the availability of nutrients in ecosystems. We investigated the dependency of decomposer‐ and leaf‐herbivore‐mediated changes in plant performance on soil nutrient availability in microcosm systems. In separate treatments,Poa annuawas used as host plant for the herbivore and was grown in combination with different herb species:Plantago lanceolata,Trifolium repens, andSanguisorba minor. At three different levels of nutrient availability, the impact of Collembola (Folsomia candida) and aphids (Rhopalosiphum padi), as well as their interacting effects on plant performance, were investigated. We further assessed the effects of Collembola on the performance of aphids and vice versa, as well as the effects on element contents inP. annuaand soil nutrients.

Collembola increased total aboveground biomass and biomass of single plant species (exceptT. repens) only at low and moderate nutrient availability, whereas the negative effects of aphids onP. annuaand total aboveground biomass were highest at high nutrient availability. Collembola decreased relative root allocation. The negative effect of aphids on plant biomass was more pronounced in the presence of Collembola. Nitrogen concentration in shoots ofP. annuawas increased by Collembola. Aphids decreased the nitrogen concentration in grass shoots only when Collembola were present. These interacting effects can be related to indirect effects of decomposers on herbivore performance. At low and moderate nutrient availability, aphid numbers strongly increased due to decomposers, whereas at high nutrient availability this effect was much weaker. In turn, aphid herbivory increased the number of Collembola only at high nutrient availability.

We conclude that the role of both below‐ and aboveground food webs for the dynamics of vegetation depend on each other and the availability of nutrients in ecosystems. This suggests that nutrient enrichment of ecosystems may have important consequences for above–belowground linkages and their effects on natural communities.
Alveolar Ridge Augmentation With Titanium Mesh and a Combination of Autogenous Bone and Anorganic Bovine Bone: A 2‐Year Prospective Study
Authors: Pieri Francesco , Corinaldesi Giuseppe , Fini Milena , Aldini Nicolò Nicoli , Giardino Roberto , Marchetti Claudio
Published: November 2008

Background: Recently, the use of bovine bone mineral (BBM) in combination with autogenous bone for alveolar ridge augmentation before implant placement has increased in favor because of concerns over morbidity associated with extraoral donor sites. The aim of this prospective study was to evaluate the clinical and radiographic parameters of implants placed in augmented ridges using a 70:30 mixture of autogenous bone and BBM in association with micro‐mesh over a 2‐year period.

Methods: Sixteen partially edentulous patients requiring bone augmentation were consecutively treated for 19 reconstructive procedures and delayed implant placement (44 implants) after 8 to 9 months of submerged mesh healing. Clinical examinations were performed and radiographs of the implants were taken 6 months after prosthetic loading and once a year during a 2‐year follow‐up.

Results: Only one (5.3%) of the 19 micro‐meshes became exposed after 2 months and was removed. Computed tomography scans of the alveolar ridge pre‐ and postreconstruction demonstrated mean vertical augmentation of 3.71 ± 1.24 mm and mean horizontal augmentation of 4.16 ± 0.59 mm. All of the implants were retained after 2 years, yielding a 100% survival rate. The mean bone resorption around the implants was 1.37 ± 0.32 mm during the observation period. Only three implants demonstrated bone resorption >2 mm, whereas 41 implants were considered clinically successful, resulting in a success rate of 93.1%.

Conclusion: This 2‐year prospective study demonstrated that implants placed into augmented bone using this technique exhibited peri‐implant stability with high survival (100%) and success (93.1%) rates.
Relationship Between Periodontal Condition and Plasma Reactive Oxygen Metabolites in Patients in the Maintenance Phase of Periodontal Treatment
Authors: Tamaki Naofumi , Tomofuji Takaaki , Maruyama Takayuki , Ekuni Daisuke , Yamanaka Reiko , Takeuchi Noriko , Yamamoto Tatsuo
Published: November 2008

Background: The relationship between systemic antioxidative status and periodontal condition has been investigated in epidemiologic studies. However, little literature is available with regard to the correlation between systemic reactive oxygen species and periodontal condition. The purpose of this cross‐sectional study was to investigate the relationship between plasma reactive oxygen metabolites (ROM) and periodontal condition in patients in the maintenance phase of periodontal treatment.

Methods: Eighty‐one subjects (mean age: 57.4 years) who had entered a periodontal maintenance program were examined for probing depth (PD) and clinical attachment level (CAL). Plasma levels of ROM and biologic antioxidant potential (BAP) were determined with a free radical electric evaluator.

Results: The plasma level of ROM was positively correlated to mean CAL (r = 0.281; P = 0.011) and percentage of teeth with CAL ≥4 mm (r = 0.236; P = 0.034), but not mean PD (r = 0.196; P = 0.080). Logistic regression analysis showed that subjects with ROM levels >400 Carratelli units (CARR U) had significantly higher mean CAL compared to subjects with ROM ≤400 CARR U after adjusting for age, gender, and the number of teeth present (P = 0.011). However, the plasma level of BAP was not significantly correlated with the periodontal parameters.

Conclusions: A positive association was found between plasma oxidative status and CAL in patients in the maintenance phase of periodontal therapy. A systemic increase in oxidative stress may influence the rate of progression of periodontal disease.
Transcriptomes in Healthy and Diseased Gingival Tissues
Authors: Demmer Ryan T. , Behle Jan H. , Wolf Dana L. , Handfield Martin , Kebschull Moritz , Celenti Romanita , Pavlidis Paul , Papapanou Panos N.
Published: November 2008

Background: Clinical and radiographic measures are gold standards for diagnosing periodontitis but offer little information regarding the pathogenesis of the disease. We hypothesized that a comparison of gene expression signatures between healthy and diseased gingival tissues would provide novel insights in the pathobiology of periodontitis and would inform the design of future studies.

Methods: Ninety systemically healthy non‐smokers with moderate to advanced periodontitis (63 with chronic periodontitis and 27 with aggressive periodontitis) each contributed at least two diseased interproximal papillae (with bleeding on probing [BOP], probing depth [PD] ≥4 mm, and attachment loss [AL] ≥3 mm) and a healthy papilla, if available (no BOP, PD ≤4 mm, and AL ≤2 mm). RNA was extracted, amplified, reverse‐transcribed, labeled, and hybridized with whole genome microarrays. Differential expression was assayed in 247 individual tissue samples (183 from diseased sites and 64 from healthy sites) using a standard mixed‐effects linear model approach, with patient effects considered random with a normal distribution and gingival tissue status considered a two‐level fixed effect. Gene ontology analysis classified the expression patterns into biologically relevant categories.

Results: Transcriptome analysis revealed that 12,744 probe sets were differentially expressed after adjusting for multiple comparisons (P <9.15 × 10−7). Of those, 5,295 were upregulated and 7,449 were downregulated in disease compared to health. Gene ontology analysis identified 61 differentially expressed groups (adjusted P <0.05), including apoptosis, antimicrobial humoral response, antigen presentation, regulation of metabolic processes, signal transduction, and angiogenesis.

Conclusion: Gingival tissue transcriptomes provide a valuable scientific tool for further hypothesis‐driven studies of the pathobiology of periodontitis.
Effect of Microthreads and Platform Switching on Crestal Bone Stress Levels: A Finite Element Analysis
Authors: Schrotenboer Jason , Tsao Yi‐Pin , Kinariwala Vipul , Wang Hom‐Lay
Published: November 2008

Background: The aims of this study were to investigate the effects of implant microthreads on crestal bone stress compared to a standard smooth implant collar and to analyze how different abutment diameters influenced the crestal bone stress level.

Methods: Two‐dimensional finite element imaging was used to create a cross‐sectional model of an implant (5‐mm platform and 13 mm in length) placed in the premolar region of the mandible. The two tapered implant models consisted of one with microthreads at the crestal portion and the other with a smooth neck. The implant model was reverse‐engineered to resemble a commercially available microthread implant. Abutments of different diameters (4.0 mm: 20% platform switching; 4.5 mm: 10% platform switching; and 5.0 mm: standard) were loaded with a force of 100 N at 90° vertical and 15° oblique angles. Finite element analysis was used to analyze the stress patterns in bone, especially in the crestal region.

Results: Upon loading, the microthread implant model had 29% greater stress (31.61 MPa in oblique and 9.31 MPa in vertical) at the crestal bone adjacent to the implant than the smooth‐neck implant (24.51 and 7.20 MPa, respectively). When the abutment diameter decreased from 5.0 to 4.5 mm and then to 4.0 mm, the microthread model showed a reduction of stress at the crestal bone level from 6.3% to 5.4% after vertical loading and from 4.2% to 3.3% after oblique loading. The smooth‐neck model showed a reduction of stress from 5.6% to 4.9% after vertical loading and from 3.7% to 2.9% after oblique loading.

Conclusions: Microthreads increased crestal stress upon loading. Reduced abutment diameter (i.e., platform switching) resulted in less stress translated to the crestal bone in the microthread and smooth‐neck groups.
Hybrid 5-way Dune Statics Solution for an Abu Dhabi Land 3D Seismic Survey
Authors: Ajlani Ghiath , Mahgoub Mohamed , Leveque Andre , Haddabi Ali
Published: November 2008

ADNOC recently acquired a large land vibroseis 3D seismic survey in an area with steep and up to 300 meters AMSL high sand dunes interrupted by numerous sabkhas as shown in Figure 1. Additionally, each acquisition live patch covered a large 32 km2 6400 channels area with dense 12.5 × 12.5 meters bin size. These conditions dictated the need for innovative and effective statics solutions in acquisition and processing that can handle the large and complex long and short wavelength statics consistently throughout the survey.

In order to understand the in-dune sand velocities in the survey area an extensive uphole drilling program was executed in a regular grid of 70 meters sabkha-intermediate dunes upholes and 150 meters high sand dunes holes down to the base of sand. Using the uphole data, a 3D dune and near surface velocity model was constructed covering the entire survey area. Subsequently, automatic refraction statics first break picks with manual picking QC were merged with the 3D dune model in addition to the initially applied elevation statics in a hybrid integrated approach to calculate final statics.

For the longer wavelengths, a near offset reflection static flattening scheme was applied by picking and gridding a shallow 3D horizon on the geophone MSL stack and creating a smoothed and normalized low/high frequency volume in the shot and receiver domains. Additionally, two runs of optimized short wavelength residual statics were then applied at subsequent stages of the processing flow.

As a result of this 5-way hybrid statics approach, effective and high quality solution of the severe dune, sabakha and near surface velocity variations was implemented successfully.
Horizontal Well Performance Optimization using Linearized Inflow Control Devices
Authors: Krinis Dimitrios , Al-Dawood Naseem , Soremi Yinka
Published: November 2008

This paper presents two case studies that evaluate the impact of the Linearized Inflow Control Device (LICD) on horizontal wells performance in a Saudi Aramco giant carbonate field. Linearized Inflow Control Devices regulate inflow by diverting production either through spiral channel or through pre-determined choked ports. The net effect is to restrict high productivity segments while increasing flow in the low productivity segments. LICDs are being utilized as part of an initiative to use custom-fit technologies to optimize horizontal well performance, thereby improving sweep and recovery efficiency.

The objectives of drilling horizontal wells in this field are to prolong dry oil production, increase reservoir drainage and efficiently sweep oil beneath the gas caps and/or behind the flood front. Horizontal wells, however, have been faced with the challenge of producing reservoir fluids through non-uniform inflow from reservoir heterogeneities/pressure variations along laterals, presence of fractured zones and frictional effects along the wellbore. The non-uniform inflow promotes early water/gas break-through, leading to short-lived wells and unfavorable sweep.

As a solution to this challenge, LICDs have been installed in selective horizontal wells. Results to date show remarkable improvement in well performance, where gains in oil production with controlled water production has been achieved. Long-term reservoir simulation results also showed considerable recovery increase in the linearized case over the non-linearized case. This paper presents the evaluation and results of linearized ICD technology, and how it became a game changer in this field development.
Interface Management
Authors: Collins R. , Durham R. , Fayek R. , Zeid W.
Published: November 2008

The UAE has been progressively expanding its oil and gas production for the past decades and has ambitious plans to continue to do so. However, as the projects have become larger and more complex and some of them are extensions to existing facilities, there has been a vast increase in the array of interactions between the respective projects, the existing facilities and the infrastructure and third parties upon which they both depend and on which they impact. These interactions, if not managed effectively, can lead to major difficulties at both macro and local planning level.

Foster Wheeler, an engineering, procurement and construction contractor (EPC), is active in design and execution of major projects throughout the Middle East region and globally and is providing management services to several of the larger projects in Abu Dhabi; at Habshan, Asab and Ruwais. This paper outlines some of the challenges with key interfaces and interdependencies that were encountered in Abu Dhabi, together with the actions taken to manage them during the implementation of these large and complex projects.

Working closely with the GASCO management team, interfacing activities with eminent parties such as ADNOC for HSE studies approvals, the Supreme Petroleum Council to obtain project approvals, and working with ADNOC management, other ADNOC operating companies, EPC contractors, ADWEA, municipalities, foresty commission, local highways authorities, the Petroleum Port Authority at Ruwais, Port Zayed at Abu Dhabi, Critical National Infrastructure Authority, Police Authority etc, have all had their challenging moments. This experience has provided us with: An extensive insight into the way in which these interactions work here in Abu Dhabi andExcellent lessons learned regarding the critical success factors in making these interactions function well

In summary, this paper provides a useful case study which demonstrates that good interface management is vital to the successful delivery of large, complex projects, especially in today's busy contracting environment in the Middle East.
Novel Approach to High Water Cut Measurement in a Mature Oil Field
Authors: Sandau C. , Waddell J. , Berthelet T.
Published: November 2008

Canadian Nexen Petroleum Yemen (CNPY) produces two million barrels of fluid per day at 95 percent watercut from the Masila Block (Block 14) in Yemen. Asset development decisions are based on numerous factors, one of the most important being the amount of oil produced from a well. With increasing oil price, it is becoming economically feasible to produce wells at significantly higher watercuts. The analytical variability of volumetric methods used in Block 14 to measure watercut restricts the accuracy and precision of these measurements. The authors developed a robust and reproducible water cut determination method for this mature petroleum asset based on gravimetric measurement of oil and water phases.

The gravimetric measurement approach follows the volumetric method procedures but uses a balance to weigh the oil or water fractions. To keep consistent with historical reporting of oil production, the density of each phase is then used to correct the values to a volume basis.

The methodology outperforms the volumetric determination of water cut by being more reproducible (better precision) and allowing for the accurate measurement of water cuts up to 99.5 percent. In side by side comparison of the gravimetric and volumetric methods at 99.5 percent water cut, the gravimetric methodology showed a five fold increase in accuracy. In addition, the gravimetric method provides six to ten times better precision in the measurement of watercut on representative field samples compared to the volumetric methodology. The program at Block 14 investigated the use of a reference calibration matrix standard as a data quality system to establish the detection limits of the methodology and to institute a testing procedure to monitor laboratory performance.

The increased accuracy and precision in watercut measurement gives reservoir engineers the confidence to make economic decisions on well viability to maximize overall project NPV.
A Successful Process for Embracing Uncertainty and Mitigating Risk -From Geological Understanding to Development Plan Optimization of a Saudi Complex Reservoir
Authors: Elrafie Emad , Zabalza-Mezghani Isabelle , Abbas Tariq , Kozlov Yakov , Craghill Roderick
Published: November 2008

Integrated reservoir studies aim at synergizing all disciplines to form a reservoir understanding and best strategy to field development. Handling uncertainty and risk using probabilistic approach is a challenge since it becomes quickly overwhelming.

This paper describes the approach used to handle uncertainty and risk in the Saudi Aramco Event Solution process. This approach lies in between the conventional deterministic approach where the team agrees on one realization and the probabilistic approach where a whole family of realizations is covering all possible outcomes.

Here, throughout the process of understanding the reservoir, the team agrees on the most-likely value for all input variables, and set ranges of uncertainty for each of them. Testing the effect of these boundaries on the static models and OOIP, history matching quality or prediction strategy efficiency leads to discriminate the critical factors.

This discrimination helps to narrow down the number of uncertain factors and their ranges from one stage of the study to the next one and focuses on what really matters according to the study objective. The critical controllable factors are tuned to optimize production performances. Information plans are set to narrow down the uncertainty range on the uncontrollable factors.

Finally, a list of risks is stated for risk assessment. Potential risks are identified through four categories: level, probability, urgency and manageability, to which high, medium, and low values are assigned. Risks scoring 3 or 4 on the risk scale (meaning high in 3 or 4 categories) are flagged and mitigation plans are addressed.

This paper presents an application of this process on a Saudi complex oil reservoir, which results in developing a clear understanding of the critical uncertainties, project risks, and the agreed development plan, information plan and mitigation plan.
Commercial ASP Flood Test in Daqing Oil Field
Authors: Jiecheng Cheng , Dianping Xu , Wenguang Bai
Published: November 2008

Alkali-Surfactant-Polymer (ASP) pilot test with small well spacing and the test with enlarged well spacing for commercial ASP flood are successful in Daqing Oil Field, demonstrating ASP process can greatly enhance oil recovery and bring more economic benefits. However, there are also some problems appearing during ASP flood test, such as serious scale, produced fluids hard to be disposed, and with the well spacing enlarged these two disadvantages might be worse. Therefore, a commercial ASP field test is performed to study performances of ASP flood, scaling characteristics and processing techniques of produced fluids. The five-spot well pattern is adopted in test area, including 18 injection wells and 29 producing wells, and chemical agent, sodium alkylbenzene sulfonate, is produced by Daqing Oil Field. On the basis of laboratory core flood, the formula has been optimized, which can create ultra-low interfacial tension with wide ranges and favorable emulsification. The studies, laboratory core test and numerical simulation, show that ASP system can improve oil recovery 20% more than water injection. At present, polymer injection is following the ASP flood, and the performances from commercial ASP flood are different from those of previous ASP flood. When water cut is slight declined, the injectivity will be greatly increased; the scale is serious for ground equipment, but it is rarely found in the borehole. With the surfactant produced, oil and water separation of produced fluid becomes much harder. The oil recovery enhanced by commercial ASP flood is less than ASP pilot test. If the well spacing is shortened, surfactant performance further improved and ASP system is more optimized, oil recovery efficiency will be further enhanced.
"SIMOPS, Intending to Break North Field Records in String Time per Well"
Authors: Vos Anton , Cross Allan , Lismont Bart , Venrooij John van , Quaden Roy
Published: November 2008

Historically, development wells in Qatar's North Field have taken anywhere from 70 to 100 days to drill, complete, perforate, stimulate and clean up in preparation for their long term production. To date, optimisations have predominantly focused on the Drilling and Completion (installation) scope, as a mean's of reducing the rig's critical path. Although there have been initiatives to minimize cost impacts by using cheaper alternatives to rigs for Perforation, Stimulation and Clean Up, these do not address the total critical path impact that well delivery has on Project schedules. Pearl GTL's Well Delivery initiative "SIMOPS" could potentially address some of the imbalance.

What do we mean by SIMOPS?

"Undertaking drilling and completion operations with the rig, while simultaneously performing perforate, stimulation and clean up operations on previously drilled and completed wells"

Pearl SIMOPS options included; being entirely rig based and running concurrent operations from the rig's decks, upgrading temporary wellhead decks such that the well service operations were ‘self sufficient’, and or use of a barge alongside rig / temporary decks, and numerous variants/combinations of the afore mentioned.

Initially, SIMOPS value drivers focused on; HSE, innovation, and cost savings, which were used in part for justifying a high specification jack up rig. Cost savings, based on rig days saved, were in the order of $60MM. Yet when the upfront well count increased, during the planning phase prior to FID, schedule suddenly became a very significant value driver, Well Delivery was now very much on the Project critical path.
The Value of Formation Pressure Measurements While-Drilling a Case Study from Offshore Abu Dhabi
Authors: Poirier-Coutansais Xavier , Baud Emmanuelle , Mirto Ettore
Published: November 2008

Formation pore pressure and near-wellbore mobility are key parameters for reservoir description. Traditionally, these data are acquired with wireline formation pressure tester. However, today a large number of wells are being drilled at high deviation, as producers and injectors, and wireline can be a time-consuming operation, as the tools must be conveyed by drillpipe. Acquiring this type of formation evaluation data with a logging while-drilling tool represents a significant time and cost savings opportunity, simultaneously improving efficiency and safety while reducing risk and non-productive time. This paper discusses the planning phase, the operational results and the lessons learned from a well drilled utilizing formation pressure testing in combination with a full logging while-drilling data suite. The formation fluid pressures, mobility and pressure gradients were taken after drilling to the well total depth during a cleanout trip. Thirty-eight successful tests were taken over several carbonate reservoirs with mobility ranging from 0.1 to 100mD/cp, achieving 100% seal success rate. A fully automated testing sequence, time optimized to 5 minutes, with variable rate, volume and number of drawdowns downhole, was used. Seal integrity and tight tests could be readily identified in real time from 6-bits per second mud-pulse telemetry. The logging while-drilling service proved it could save two days of valuable rig time by eliminating one dedicated wireline pressure-measurement run and one cleanout trip. In addition, this improvement in operational efficiency minimized wellbore exposure time, thus reducing the risks during the casing run.
Substituting Nitrogen for Hydrocarbon Gas in a Gas Cycling Project
Authors: Linderman John , Al-Jenaibi Faisal , Ghori Saleem , Putney Kevin , Lawrence John , Gallet Michel , Hohensee Kurt
Published: November 2008

Injecting nitrogen instead of hydrocarbon gas for pressure maintenance can be an effective means to accelerate and increase the volume of hydrocarbon gas available for sale. This paper presents results of a joint study by Abu Dhabi National Oil Company (ADNOC) and ExxonMobil that used compositional full-field reservoir simulation to evaluate the suitability of N2 injection for gas cycling in a large, Middle East gas condensate reservoir. The results of the study show that substituting nitrogen for hydrocarbon gas during gas cycling has the potential to significantly accelerate the production of hydrocarbon gas for domestic gas consumption. Although late-life condensate recovery is slightly reduced, overall hydrocarbon recovery on an oil equivalent barrel (OEB) basis is improved due to higher ultimate recovery of reservoir gas. Increasing nitrogen concentrations in the produced gas stream after nitrogen breakthrough can be managed within acceptable limits by a combination of subsurface management, nitrogen removal facilities, and/or modifications to gas-consumption equipment. Various options for generating non-hydrocarbon gas for substitution were evaluated, and it was concluded that cryogenic air separation is the most cost effective method for generating large volumes of non-hydrocarbon gas within acceptable specifications.
Using the Optimal Through-Casing Measurement to Maximize Oil Recovery: A Case Study From The Western Desert, Egypt
Authors: Van Steene M. , Herold B. , Dutta D. J. , Abugren Y. , Hosny S. , Badr A. B. , Mahgoub I. , Zidan A.
Published: November 2008

Accurate time-lapse saturation information is the key to making the right decisions on completion strategy, maximizing oil recovery and reducing water cut. This paper presents a case study from the Bahariya Formation, a heterogeneous fluvio-marine channel deposit in the Western Desert, Egypt.

All the wells considered in this paper showed significant water production. To identify the main water-producing zones and the bypassed oil, all the wells were logged using a through-casing formation resistivity tool. One well was also surveyed with pulsed neutron capture logs.

Based on the log results, depleted zones were identified, and the intervals contributing most to the water production were isolated. Water cut was significantly reduced. In some wells, the saturation analysis revealed that the stacked reservoir zones had variable levels of depletion and that the depletion was not necessarily related to the distance to the original oil-water contact. In these wells, the water shutoff leaves oil behind, and a different completion strategy was recommended. The results from the resistivity and nuclear measurements are discussed in detail with respect to environmental effects.

This case study demonstrates that through-casing formation resistivity measurements provide more robust answers compared to neutron measurements in the studied environment. The deeper depth of investigation is extremely valuable, as the wells cannot be logged under dynamic conditions, and fluid reinvasion is always present.

Moreover, in view of increasingly high rig rates and limited rig availability, the simple nature of the processing and interpretation of the through-casing formation resistivity log enables fast decisions.

These examples from the Western Desert illustrate how analysis behind casing provides critical information to maximize oil production and facilitate water shutoff decisions.
Measurement of Water-Cut in Challenging Flow Conditions using Infrared Technology
Authors: Al-Saiyed M. A. , Warsi S. A. , Phillips J. E. , Gilani S. K. , Zareef M. A. , Lievois J.
Published: November 2008

The success of field management depends on the accuracy and availability of well performance data. Continuous monitoring provides information so that corrective action can be taken in a timely manner to better manage expensive well assets by maintaining well potential, managing water conformance and increasing the well life. Accurate water-cut monitoring can significantly reduce the dead well number by providing the data to implement timely corrective action.

Methods for measuring water-cut values range from conventional hand sampling to cutting edge technology. Saudi Aramco's traditional well testing practices, utilizing a test trap at a GOSP, limit the information available due to the infrequent tests for an individual well, usually exceeding one month or more. Test trap data also has inherent error built in, due to averaging and human error. What is needed is real-time, in-line and accurate water-cut monitoring.

When considering technologies for monitoring watercut, factors such as accuracy, data transfer rate, and cost play major roles. This paper presents how an infrared meter provides an accurate and cost effective means to monitor water-cut in complex wells. The infrared monitoring device is an in-line real-time monitoring system that provides accurate water-cut even, in very challenging flow conditions. A pilot test of the infrared water-cut meter was successfully conducted in a major oil field in Saudi Arabia. Results from this test will be included in the paper.
Proposed Methodology to Predict Electric Power Requirements for ESP Wells in a Heavy Oil Field - A Case Study
Authors: Brito Rosmer , Montero Jacobo
Published: November 2008

This paper describes the methodology used to determine the electric power requirements of all the ESP systems to be installed over a period of study (2007-2017) in the Icotea-Misoa heavy oil reservoir, Urdaneta West field, Venezuela, in order to ensure a reliable and safe electric supply to cover the field development plan. The methodology used consisted in: selection of a representative sample of the ESP wells population; running several sensitivities on the ESP and well performance using an industry proved ESP software for the most critical cases of reservoir, equipment and production conditions; tabulate and analyze the data obtained from the simulations with statistical techniques to determine the most probable electric power requirement range as well as its tendency over time; finally, generate relationships between the electric power consumption and different production parameters (total production rate, oil and water production rates, reservoir pressure, productivity index and sand production) to predict the power requirements changes with time. The results will be used by the operating company to decide whether the existing surface electrical facilities are sufficient for the field development plan, or if a KVA capacity expansion is required. One of the main conclusions from the study was that the required electric power capacity was being overestimated, based on simple predictions using only historical consumptions or non-statistical methods. The methodology applied led to a more reliable prediction of the power consumption per well. This will allow the company to better estimate the required facilities and hence, reduce the expected costs of investment required.