bluuebunny/crossref_metadata_2025 huggingface dataset:
Economic Impact of Truck–Machine Interference in Forest Biomass Recovery Operations on Steep Terrain
Authors: Zamora-Cristales Rene , Sessions John , Murphy Glen , Boston Kevin
Published: December 2013

In forest biomass recovery operations from harvest residues, processing equipment can work most productively if they can work without interference or waiting on trucks. A deterministic simulation model was developed to estimate the economic effect of truck–grinder interference in forest biomass processing and transport operations on steep terrain. Truck–machine interference can occur in situations where the grinder is waiting for trucks or vice versa. We analyzed how the number of available trucks and road characteristics affect grinder utilization and biomass delivery cost. Three cases based on different road characteristics were designed and applied to actual operations in order to illustrate how particular road features in relation to the spatial location of the grinder can affect the economics of the operation. An economic model was also developed to estimate the waiting cost of trucks and machinery due to truck–machine interferences. Grinder location in relation to available truck turnaround, turnouts, truck turning-around time, truck positioning time, and distance traveled on each road surface have a significant effect in forest residues processing and transport economics at the operational level. After the optimization was performed, the grinder utilization rate on a harvest unit with highly constrained road access reached 60 percent using six trucks. Waiting cost represented 15.15 percent of total grinding cost. On the medium constrained road access harvest unit, maximum grinder utilization reached 77 percent using five trucks. A loop road case resulted in a grinder utilization rate of 81 percent using five trucks.
Withdrawal Capacity of Plain, Annular Shank, and Helical Shank Nail Fasteners in Spruce-Pine-Fir Lumber
Authors: Luszczki Garrett E. , Clapp Joshua D. , Davids William G. , Lopez-Anido Roberto
Published: December 2013

This study examines the withdrawal load and energy capacity of three types of nail fasteners that are commonly used to attach sheathing to framing members: 8d common, annular ring shank, and helical shank. A baseline set of data was collected for single nails in accordance with test methods defined in ASTM D1761. Tests were performed until complete withdrawal occurred in order to quantify the total withdrawal energy. The average peak loads from testing were within 7 to 8 percent of predicted values. The annular and helical nails had much higher peak load capacity as expected, and the withdrawal energy was also greater. A new device was developed in order to subject multiple nails to withdrawal loading simultaneously. Reinforced sheathing was used to transfer load from the hydraulic actuator to the nails, which is more representative of actual structural response where there is load sharing among the nails. This device allowed direct comparison with the single nail results. Further, it also allowed the examination of a “stitched” nailing pattern, where fasteners are driven at alternating angles of ±60° measured from the framing member face. It was found that the stitched pattern resulted in 42 percent higher peak load capacity per fastener for 8d common nails, but for the helical and annular nails, peak load was similar to that achieved with a normal 90° drive angle. Withdrawal energy was 24 to 48 percent higher for all nail types using the stitched pattern.
Geovisualización de la población: nuevas tendencias en la web social
Authors: Mateos Pablo
Published: December 2013

La visualización geográfica, o geovisualización, sitúa al espacio como eje central en la exploración del conocimiento sobre el mundo que nos rodea. En este artículo se resumen algunas de las nuevas tendencias en la geoweb y la geovisualización de información sociodemográfica. Se presentan una serie de aplicaciones desarrolladas en proyectos de investigación en University College London (UCL), Reino Unido. Dichos proyectos de geovisualización tienen como fin hacer accesibles al público en general, representaciones alternativas de fenómenos sociales y poblacionales en el territorio. Para ello se facilita la contribución de contenido proveniente de diversas fuentes y sitios web, que puede ser integrado virtualmente a través de mapping mashups. Estos “agregados cartográficos” son configurados a gusto del usuario final sin ningún costo, permitiéndole compartir con el mundo su particular representación de la realidad socio-espacial en maneras inimaginables hace tan solo siete años.
Importancia de los procesos de validación topológica en la gestión de alteraciones catastrales
Authors: Navarro Carrión José Tomás , Ramón Morte Alfredo
Published: December 2013

Las tecnologías de la información y la comunicación están consiguiendo que la información geográfica sea asequible a un mayor número de profesionales a través de las Tecnologías de la Información Geográfica. La intervención multidisciplinar en el territorio enriquece la investigación y las formas de aplicación de este tipo de recursos tecnológicos. Pero esta facilidad tecnológica puede suponer el riesgo de un uso inadecuado, por falta de conocimientos técnicos adecuados a la complejidad de la información geográfica o por el mal uso de las aplicaciones informáticas. El trabajo catastral puede beneficiarse mucho del empleo de estas tecnologías de información geográfica, al facilitar el uso, la comunicación y su administración electrónica, pero el desconocimiento de las propiedades geométricas y topológicas de la información geográfica puede llevar a cometer errores de graves consecuencias a profesionales no especializados. En este artículo ofrecemos el resultado de la investigación del trabajo de diversos juristas y técnicos, con el objetivo de desarrollar métodos automatizados y aplicaciones informáticas que permitan a los especialistas no expertos en Cartografía usar este tipo de información con garantías de exactitud al más alto nivel, como una solución eficaz para que la información geográfica con calidad topológica enriquezca la seguridad jurídica en el tráfico inmobiliario.
La caracterización del paisaje de Menorca a través de la toponimia
Authors: Ordinas Garau Antoni , Binimelis Sebastián Jaume
Published: December 2013

La toponimia constituye un excelente indicador del paisaje y el espacio geográfico. A través del análisis tanto cualitativo como cuantitativo de los topónimos que identifican y frecuentemente describen el territorio, se puede obtener un profundo conocimiento de su geografía, a menudo ampliada con numerosas referencias a su evolución histórica. Los nombres geográficos de Menorca nos han permitido detectar los elementos geográficos más representativos del paisaje de la isla confirmando los principios de transparencia y de significación territorial formulados por algunos geógrafos pioneros en abordar el vasto y fructífero campo que comparten la toponimia y la ciencia geográfica.
Recovery of adrenal function in a patient with confirmed Addison's disease
Authors: Baxter M , Gorick S , Swords F M
Published: December 2013

Addison's disease is a condition characterised by immune-mediated destruction of the adrenal glands leading to a requirement of lifelong replacement therapy with mineralocorticoid and glucocorticoid. We present a case of a 53-year-old man who presented at the age of 37 years with nausea, fatigue and dizziness. He was found to have postural hypotension and buccal pigmentation. His presenting cortisol level was 43 nmol/l with no response to Synacthen testing. He made an excellent response to conventional replacement therapy with hydrocortisone and fludrocortisone and then remained well for 16 years. On registering with a new endocrinologist, his hydrocortisone dose was revised downwards and pre- and post-dose serum cortisol levels were assessed. His pre-dose cortisol was surprisingly elevated, and so his dose was further reduced. Subsequent Synacthen testing was normal and has remained so for further 12 months. He is now asymptomatic without glucocorticoid therapy, although he continues on fludrocortisone 50 μg daily. His adrenal antibodies are positive, although his ACTH and renin levels remain elevated after treatment. Addison's disease is generally deemed to lead to irreversible cell-mediated immune destruction of the adrenal glands. For this reason, patients receive detailed counselling and education on the need for lifelong replacement therapy. To our knowledge, this is the third reported case of spontaneous recovery of the adrenal axis in Addison's disease. Recovery may therefore be more common than previously appreciated, which may have major implications for the treatment and monitoring of this condition, and for the education given to patients at diagnosis.

Learning points

Partial recovery from Addison's disease is possible although uncommon.

Patients with long-term endocrine conditions on replacement therapy still benefit from regular clinical and biochemical assessment, to revisit optimal management.

As further reports of adrenal axis recovery emerge, this may influence the counselling given to patients with Addison's disease in the future.
Simulations of Shocked Methane Including Self-consistent Semiclassical Quantum Nuclear Effects
Authors: Qi Tingting , Reed Evan J.
Published: December 2013

A methodology is described for atomistic simulations of shock-compressed materials that incorporates quantum nuclear effects on the fly. We introduce a modification of the multi-scale shock technique (MSST) that couples to a quantum thermal bath described by a colored noise Langevin thermostat. The new approach, which we call QB-MSST, is of comparable computational cost to MSST and self-consistently incorporates quantum heat capacities and Bose-Einstein harmonic vibrational distributions. As a first test, we study shock-compressed methane using the ReaxFF potential. The Hugoniot curves predicted from the new approach are found comparable with existing experimental data. We find that the self-consistent nature of the method results in the onset of chemistry at 40% lower pressure on the shock Hugoniot than observed with classical molecular dynamics. The temperature change associated with quantum heat capacity is determined to be the primary factor in this shift.
Probing Laser Induced Space Charge Fields with Rare Earth Dopants
Authors: Odhner Hosanna , Stone Greg , Dierolf Volkmar
Published: December 2013

Spectral shifts of the emission lines of Erbium ions in Lithium Niobate are used to determine the build-up of intrinsic electric fields under intense light irradiation. The observed spectral shifts can be translated into internal electric fields through a calibration using applied external fields. The studies show that a substantial field can be created locally (up to 150kV/mm) with observed occasional electric breakthroughs that have a corresponding field strength of up to 35kV/mm. In addition, a modification of some Erbium incorporation sites is observed suggesting its relationship with a defect that can by photo-ionized, such as Fe2+/Fe3+.
Study of the Size Dependence of Time-dependent Plastic Deformation of Gold Micro-pillars and Micro-spheres
Authors: Islam AZM Ariful , Klassen Robert J.
Published: December 2013

In this study the length scale dependence of the operative mechanisms of time-dependent plastic deformation was studied using room temperature compression tests performed on Au micro-pillars and micro-spheres of 1.0 to 5.0 µm diameter. All the samples tested displayed deformation that had a component of random strain jumps. In the case of the Au micro-pillars, the frequency of the strain jumps showed a bilinear dependence upon pillar diameter with the frequency being larger, and more sensitive to diameter, when the pillar diameter was small (and τR was high). We suggest that this indicates a transition from deformation occurring by deformation on multiple slip planes to deformation occurring predominantly by single-plane dislocation slip when the pillar diameter is less than 2 µm.

The strain jump frequency during the constant-load micro-pillar creep tests showed a linear dependence upon τR. Creep tests performed on the micro-spheres of 5.0 µm diameter displayed displacement jump frequency that was essentially independent of the applied load while the jump frequency increased with increasing load for the smaller 2.5 µm diameter micro-spheres. We suggest that this difference is related to the volume of the micro-sphere. When the volume is small, the component of the deformation that occurs by a stochastic dislocation glide process is increased and becomes strongly dependent upon the magnitude of the local shear stress.
Surface smoothing of glass substrate by irradiation of ionic liquid ion beams
Authors: Takeuchi Mitsuaki , Hamaguchi Takuya , Ryuto Hiromichi , Takaoka Gikan H
Published: December 2013

Surface smoothing of a barium borosilicate glass substrate by irradiation of ionic liquid ion beams were investigated. 1-ethyl-3-methylimidaolium tetrafluoroborate (EMIM-BF4) and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) were used for the source liquid. Surface roughness represented as the arithmetic mean value decreased from 0.17 nm to 0.13 nm by the BMIM-PF6 negative ion beam. Secondary electron microscope (SEM) observation for the glass surface irradiated with the BMIM-PF6 negative ion beam showed a clear image without an electrical charge-up, though the EMIM-BF4 negative ion beam irradiated glass yielded a charged up image. X-ray photoelectron spectroscopy (XPS) analysis implied that the surface layer including cation-anion pair of BMIM-PF6 was deposited by the BMIM-PF6 negative ion beam irradiation, while an insulated surface with barium fluoride was formed by the EMIM-BF4 negative ion beam irradiation.
Electrophoretic deposition of TiO2 nanopillars from stable colloidal solution.
Authors: Jouenne Vincent , Duvail Jean-Luc , Brohan Luc , Richard-Plouet Mireille
Published: December 2013

Titanium dioxide nanoparticles were synthesized by solvothermal treatment in the presence of oleic acid and oleylamine. As Ti(IV) reactant, crystals of [Ti8O12 (H2O)24]Cl8, HCl, 7H2O were preferred because their hydrolysis and condensation can be controlled in ethanol/water solution. The organic surfactants allowed the control of the shape and they can be removed by an acid treatment of the particles. The TiO2 nanoparticles can then be re-dispersed in an ethanol-based charging solution. A fixed applied voltage promotes the electrophoretic deposition of the nanoparticles (<15 nm in size) into pores of anodized aluminium oxide (AAO) template.
Enhanced Light Trapping in Periodic Aluminum Nanorod Arrays as Cavity Resonator
Authors: Abdulrahman Rosure B. , Alagoz Arif S. , Karabacak Tansel
Published: December 2013

Metallic nanostructures can exhibit different optical properties compared to bulk materials mainly depending on their shape, size, and separation. We present the results of an optical modeling study on ordered arrays of aluminum (Al) nanorods with a hexagonal periodic geometry placed on an Al thin film. We used a finite-difference time-domain (FDTD) method to solve the Maxwell's equations and predict the reflectance of the nanorod arrays. The thickness of the base Al film was set to 100 nm, and diameter, height and nanorod center-to-center periodicity were varied. Incident light in the FDTD simulations was an EM-circular polarized plane wave and reflectance profiles were calculated in the wavelength range 200-1800 nm. In addition, we calculated spatial electric field intensity distributions around the nanorods for wavelengths 300, 500, and 700 nm. Our results show that average reflectance of Al nanorods can drop down to as low as ∼50%, which is significantly lower than the ∼90% reflectance of conventional flat Al film at similar wavelengths. In addition to the overall decrease in reflectance, Al nanorod arrays manifest multiple resonant modes (higher-order modes) indicated by several dips in their reflectance spectrums (i.e. multiple attenuation peaks in their absorption profiles). Positions of these dips in the reflectance spectrum and spatial EM field distribution vary with nanorod height and diameter. Multiple reflectance peaks are explained by cavity resonator effects. Spatial EM field distribution profiles indicate enhanced light trapping among the nanorods, which can be useful especially in optoelectronic and solar cell applications.
Nanostructurally Designed Ultra-hydrophilic Hard Ceramic Oxide Coatings for Orthopaedic Application
Authors: Namavar Fereydoon , Sabirianov Renat F. , Zhang Jiaming , Cheung Chin Li , Blatchley Charles , Miralami Raheleh , Sharp John G. , Garvin Kevin L.
Published: December 2013

This paper addresses the application of engineered nanocrystalline ultrahydrophilic titanium oxide films to artificial orthopaedic implants. Titanium (Ti) is the material of choice for orthopaedic applications and has been used for over fifty years because of its known bio-compatibility. Recently it was shown that biocompatibility of Ti metal is due to the presence of a thin native sub-stoichiometric titanium oxide layer [1] which enhances the adsorption of mediating proteins on the surface thus enhancing cell adhesion and growth [2,3,4]. Improving the quality of surface oxide, i.e. fabricating stoichiometric oxides as well as nanoengineering the surface topology that matches the dimensions of adhesive proteins, is crucial for the increase of protein adsorption [2] and, as a result, the biocompatibility of Ti implant materials. We have fabricated ultrahydrophilic nano-crystalline transparent films of anatase phase of titania (TiO2) by ion beam assisted deposition (IBAD) processes in an ultrahigh vacuum system. Source material was 99.9% pure rutile TiO2. Various ion beam conditions were used to produce these coatings with different grain sizes (4 to 70 nm) that affect the wettability, roughness, and the mechanical and optical properties of the coating [5]. Our biological experiments have shown that biocompatibility of these ultrahydrophilic nanoengineered TiO2 coatings are superior to commonly used orthopaedic titanium and even hydroxyapatite.
Optical Characterization of Shock-Induced Chemistry in the Explosive Nitromethane using DFT and Time-Dependent DFT
Authors: Pellouchoud Lenson A. , Reed Evan J.
Published: December 2013

A thorough understanding of chemistry in extreme environments is a major challenge in experimental as well as theoretical work. With continual improvements in ultrafast optical measurements and new methods for simulations of shock-induced chemistry for timescales approaching a nanosecond, the opportunity is beginning to exist to connect experiments with simulations on the same timescale. In the present work, we compute the optical properties of the energetic material nitromethane (CH3NO2) for the first 100 picoseconds behind the detonation shock front in a molecular dynamics simulation. We compute optical spectra using the Kubo-Greenwood approach with DFT Kohn-Sham electronic states and compare with spectra computed by linear-response time-dependent density functional theory (TDDFT). The latter typically yields more accurate spectra for molecular systems. At optical wavelengths, the TDDFT method offers a correction of up to 25% in the real part of conductivity relative to the Kubo-Greenwood calculation. We also study the effects of thermal electronic excitations on the calculated spectra, and find no discernible change at optical wavelengths. In all of our calculations, we observe a non-monotonic change over time in the entire spectrum of optical properties as decomposition products evolve. The most optically relevant decomposition products are found to be NO, CNO, CNOH, water, and larger transient molecules. In particular, the disappearance of transient NO and CNO molecules (about 90 picoseconds behind the shock front) is coincident with a substantial decrease in conductivity across the optical spectrum.
N-Heterocyclic Carbene Chelated Metal Complexes as Polymerization Catalysts
Authors: El-Batta Amer A.
Published: December 2013

The synthesis of titanium and zirconium complexes ligated by bidentate “salicylaldimine-like” N-heterocyclic carbenes (NHCs) is reported. These complexes are rare examples of group IV transition metal NHC adducts. In the presence of methylaluminoxane these complexes are useful initiators for the polymerization of ethylene and the copolymerization of ethylene with norbornene and 1-octene. Linear high density polyethylene could be produced. The Ti complexes are also utilized to yield highly syndiotactic polystyrene.
Martensitic Transformation in Submicron Cu-Al-Ni Pillar
Authors: Liu Lifeng , Zhou Yumei , Lv Lan
Published: December 2013

The transformation plateau on the strain-stress curve is the characteristic of superelasticity of bulk shape memory alloys upon tension/compression loading. However, recent studies show that such transformation plateau is hard to see when the sample size of shape memory alloys decreases to submicrons. In order to see what happened in such small scale samples during loading, in-situ compression test has been done with single crystal Cu-14.2Al-4.0Ni (wt %) submicron pillars. Our in-situ observation during compression demonstrates that the stress-induced martensitic transformation indeed occurs in submicron pillars, but is not suppressed. Furthermore, the transformation proceeds in a sequential nucleation-growth-nucleation dominated mode, but not the transient way like that in bulk materials. As a result, the stress keeps increasing throughout the transformation and no obvious transformation plateau can be detected. However, the underlying reason for such contrast transformation behaviors between our submicron pillars and bulk materials still needs further investigation.
High Pressure Low Temperature Studies on 1-2-2 Iron-based Superconductors Using Designer Diamond Cells
Authors: Uhoya Walter O. , Tsoi Georgiy M. , Vohra Yogesh K. , Mitchell Jonathan, E. , Safa-Sefat Athena , Weir Samuel
Published: December 2013

High pressure low temperature electrical resistance measurements were carried out on a series of 122 iron-based superconductors using a designer diamond anvil cell. These studies were complemented by image plate x-ray diffraction measurements under high pressures and low temperatures at beamline 16-BM-D, HPCAT, Advanced Photon Source. A common feature of the 1-2-2 iron-based materials is the observation of anomalous compressibility effects under pressure and a Tetragonal (T) to Collapsed Tetragonal (CT) phase transition under high pressures. Specific studies on antiferromagnetic spin-density-wave Ba0.5Sr0.5Fe2As2 and Ba(Fe0.9Ru0.1)2As2 samples are presented to 10 K and 41 GPa. The collapsed tetragonal phase was observed at a pressure of 14 GPa in Ba0.5Sr0.5Fe2As2 at ambient temperature. The highest superconducting transition temperature in Ba0.5Sr0.5Fe2As2 was observed to be at 32 K at a pressure of 4.7 GPa. The superconductivity was observed to be suppressed on transformation to the CT phase in 122 materials.
Whole‐lake experiments reveal the fate of terrestrial particulate organic carbon in benthic food webs of shallow lakes
Authors: Scharnweber K. , Syväranta J. , Hilt S. , Brauns M. , Vanni M. J. , Brothers S. , Köhler J. , Knežević-Jarić J. , Mehner T.
Published: December 2013

Lake ecosystems are strongly linked to their terrestrial surroundings by material and energy fluxes across ecosystem boundaries. However, the contribution of terrestrial particulate organic carbon (tPOC) from annual leaf fall to lake food webs has not yet been adequately traced and quantified. In this study, we conducted whole‐lake experiments to trace artificially added tPOC through the food webs of two shallow lakes of similar eutrophic status, but featuring alternative stable regimes (macrophyte rich vs. phytoplankton dominated). Lakes were divided with a curtain, and maize (Zea mays) leaves were added, as an isotopically distinct tPOC source, into one half of each lake. To estimate the balance between autochthonous carbon fixation and allochthonous carbon input, primary production and tPOC and tDOC (terrestrial dissolved organic carbon) influx were calculated for the treatment sides. We measured the stable isotope ratios of carbon (δ13C) of about 800 samples from all trophic consumer levels and compared them between lake sides, lakes, and three seasons. Leaf litter bag experiments showed that added maize leaves were processed at rates similar to those observed for leaves from shoreline plants, supporting the suitability of maize leaves as a tracer. The lake‐wide carbon influx estimates confirmed that autochthonous carbon fixation by primary production was the dominant carbon source for consumers in the lakes. Nevertheless, carbon isotope values of benthic macroinvertebrates were significantly higher with maize additions compared to the reference side of each lake. Carbon isotope values of omnivorous and piscivorous fish were significantly affected by maize additions only in the macrophyte‐dominated lake and δ13C of zooplankton and planktivorous fish remained unaffected in both lakes. In summary, our results experimentally demonstrate that tPOC in form of autumnal litterfall is rapidly processed during the subsequent months in the food web of shallow lakes and is channeled to secondary and tertiary consumers predominantly via the benthic pathways. A more intense processing of tPOC seems to be connected to a higher structural complexity in littoral zones, and hence may differ between shallow lakes of alternative stable states.
Links between deep‐sea respiration and community dynamics
Authors: Ruhl Henry A. , Bett Brian J. , Hughes Sarah J. M. , Alt Claudia H. S. , Ross Elizabeth J. , Lampitt Richard S. , Pebody Corinne A. , Smith Kenneth L. , Billett David S. M.
Published: December 2013

It has been challenging to establish the mechanisms that link ecosystem functioning to environmental and resource variation, as well as community structure, composition, and compensatory dynamics. A compelling hypothesis of compensatory dynamics, known as “zero‐sum” dynamics, is framed in terms of energy resource and demand units, where there is an inverse link between the number of individuals in a community and the mean individual metabolic rate. However, body size energy distributions that are nonuniform suggest a niche advantage at a particular size class, which suggests a limit to which metabolism can explain community structuring. Since 1989, the composition and structure of abyssal seafloor communities in the northeast Pacific and northeast Atlantic have varied interannually with links to climate and resource variation. Here, for the first time, class and mass‐specific individual respiration rates were examined along with resource supply and time series of density and biomass data of the dominant abyssal megafauna, echinoderms. Both sites had inverse relationships between density and mean individual metabolic rate. We found fourfold variation in echinoderm respiration over interannual timescales at both sites, which were linked to shifts in species composition and structure. In the northeastern Pacific, the respiration of mobile surface deposit feeding echinoderms was positively linked to climate‐driven particulate organic carbon fluxes with a temporal lag of about one year, respiring ∼1–6% of the annual particulate organic carbon flux.
Uncertainty Quantification Workflow for Mature Oil Fields: Combining Experimental Design Techniques and Different Response Surface Models
Authors: Ahmed Syed Jawwad , Recham Reda , Nozari Ali , Bughio Shamsudin , Schulze-Riegert Ralf , Salem Ryadh Ben
Published: December 2013

Simulation models for large complex reservoirs with a long production history are traditionally used in the framework of deterministic forecasts. The estimation of prediction uncertainties based on reservoir models with long run times is often impractical due to limited statistical data generated from direct full field reservoir simulation runs. Here, we use surrogate models to capture key performance indicators as a function of reservoir uncertainties. Monte Carlo sampling processes are applied for generating key parameter distributions and to identify representative simulation models for field development planning. Transparent workflow steps and a thorough validation exercise of the predictability of surrogate models is a prerequisite for obtaining prediction uncertainties based on proxy modeling results.

In this work we present a case study for estimating prediction uncertainties including history data of a large mature offshore oil field. A workflow is designed for a limited number of simulation runs which is expected to affect the stability of statistical reservoir performance indicators. Proxy models are introduced in that framework for analyzing sensitivities and to prepare a basis for extensive data sampling. Alternative proxy modeling techniques are used to cross validate results.

To assure an acceptable quality of the history match simulated field oil production rate and gas oil ratio as well as water cut and shut-in pressures in several wells are compared to their historical data. A quantitative measure for the simulation error is calculated for each case. Filtering techniques are applied for discriminating cases with a poor match quality. Sensitivities and correlation effects between field wide uncertainties and reservoir performance indicators are calculated. Representative full field simulation models representing P10, P50 and P90 for oil reserves are identified.

The uncertainty quantification workflow was validated for a mature field case study and serves as a basis for field development planning scenarios.
Horizontal Well Correlation Using Real Time Data and Log Prediction in Geosteering Complex Reservoirs of Saudi Arabia
Authors: Al-Maskeen Abdul Mohsen A. , Sung Roger R. , Ali Sadaqat S.
Published: December 2013

Real time geosteering requires a continuously updated geological model made using real time log data. Although technologies in horizontal drilling, real time monitoring, and geological interpretation have advanced significantly during the last few years, occasional conceptual gaps may occur in well plans proposed by geoscientists and engineers.

This paper presents a case study of a new workflow technology that uses real time Logging-While-Drilling (LWD) data and a new horizontal well correlation technique, to dynamically update a structural framework that can be used to geosteer an actively drilling well. Historically, well correlation approaches have been limited by the vertical well trajectory assumption even when large sections of the well were horizontal. Correlations were also typically based on 2D cross sections which did not account for apparent dip, which is an important requirement for accurate reservoir thickness calculations.

The workflow presented in this paper begins with the creation of predicted logs using an initial structural framework and well plan. The predicted logs are then correlated to the LWD logs using anchor points and an interactive stretching and squeezing technique that honors the true stratigraphic thickness. Each anchor point results in the creation of an additional pseudo-well point and inter-well control that is used to create a more precise structural framework surface.

The benefits of this new approach include faster well log interpretation, and the ability to dynamically and more accurately update the subsurface model during drilling to more efficiently steer the wellbore into the most productive parts of conventional and unconventional reservoirs. In this case study we demonstrate how wells with over 10,000 feet of horizontal reservoir contact are correlated in a real time geosteering environment to enhance the accuracy and reduce the turn-around time of updates to a structural model. A major stride in the process of understanding and modeling the heterogeneity of complex reservoirs has been achieved.
Custody Measurement Best Practices
Authors: Suwaidan Khalid
Published: December 2013

Custody transfer in dynamic fluid measurement is defined as a metering point location, where the fluid is being measured for sale from one party to another. During custody transfer; accuracy and precision are very important and vital to both the company delivering the material and the eventual receiver. Best practices should be made for volume calculation to get near as much as possible to the true value.

To achieve the custody transfer accuracy requirements, Kuwait Oil Company (KOC) uses turbine and PD flow meters at locations designated as custody transfer type to measure the volume of crude oil transferred from one owner to the other. There are several factors that affect the operation of these flow meters, such as the liquid temperature, the pressure in the system, density of the product dispatched, water content….etc These variables are taken into account in order to calculate the "corrected" volume dispatched which is equivalent to the raw volume reported by the flow meters affected by correction factors obtained from established formulas based on the process variables. Established procedures for calibrating and testing the equipment’s required to measure process variables with the aim of obtaining accurate and representative values, are included in various International Standards such as the API, ASTM, ISO, IP Publications.

In KOC, Export Operations (EO) Lab, which holds International accreditation (ISO) IEC 17025 and is the only accredited lab in the country, is responsible to run the analysis required to obtain the required quality values needed to obtain the Gross Standard Volume (GSV) and Net Standard Volume (NSV) of the quantities dispatched to Refineries and Export.
Salt Water Disposal System Modification During Low Water Flow Rates from Khurais Fields
Authors: Al-Juaid Mazen , Al-Muaibed Mohammad , Randall Franklin , Khan Ashiff , Al-Jubran Mustafa , Al-Doosary Awwad , Al-Shammary Sabhan
Published: December 2013

The Khurais Central Processing Facility (KhCPF) includes four salt water disposal (SWD) systems distributed among four oil trains. Each SWD system is comprised of one water-oil separator (WOSEP), three 33% salt water disposal pumps, and necessary piping from pump discharge, which are terminated at the water injection header. The SWD system has been designed to accommodate ultimate produced formation water (30% water cut from Khurais fields); however, due to the unexpected very low water flow rate from the fields since the commissioning period of the facility, SWD systems are encountering inconvenient operation and frequent equipment failure.

To eliminate the operational difficulties and protect the major pieces of equipment, various options were evaluated. The most optimum solution found was to divert salt water from three WOSEPs to a depressurizing vessel by pressure transfer and then recycling it back to a single train. The benefits from modification included — energy conservation by minimizing the running of salt water disposal pumps, reducing the environmental impact and huge operational flexibility for the facility — even if the water cut increases in the future. This modification is expected to be one of the best solutions for the gas-oil separation plants (GOSPs) that that are facing operational difficulties due to low water flow rates from an oil field.

This paper describes the modifications in a salt water disposal system, hydraulic assessments, HAZOP study and the field modification that are planned in the KhCPF for the recycling of salt water from the WOSEP to the depressurizing vessel.
Diagenetic Events as The Key Omprovement of Carbonate Reservoir Quality in The Senoro Field, Central Sulawesi, Indonesia
Authors: Hasanusi Deddy , Wijaya Rahmat , Priyantoro Agus , Herawati Neni , Shahab Indra
Published: December 2013

The Mentawa Reefal Build-up member and Minahaki carbonate sequences are the main hydrocarbon bearing reservoir of the Senoro field, in the Block Senoro-Toili, Central Sulawesi of the eastern Indonesia, especially in the Banggai- Sula basin. Carbonate reservoir of Mentawa member of Minahaki Formation commonly recognized as pinnacle reef build up type which were growth in the structural high areas and having orientations relatively northeast to southwest direction, following the tectonic setting in the areas. On the other hand, the platform carbonate which is most identified as globigerinids wackstone and globigerinids packstone facies spread out dominantly in the deeper areas enveloping the higher areas as the places of carbonate build-up (in back reef and open marine area). Combination of diagenetic events especially on the vadose zone (above water table) which are controlled by relative sea level drop and rock composition as indication of main control in improvement of the carbonate reservoir quality (both carbonate re-build-up and platform types) that initially by two events. First, presence of aggrading neomorphism / re-crystallization of the carbonate mud matrix to micro crystalline calcite (micrite) and - micro sparite that having crystal size range from 3 – 20 μ with average around 12 μ (for carbonate build-up) and 6 μ (for carbonate platform). Second, presence of intensive dissolution of both selective bioclast grains and carbonate mud matrix contents created secondary moldic, micro-macro vuggy and honeycomb porosities and it has maximum size reach-up 3.2 cm (measure from conventional core). Both re-crystallization and dissolution process was intensively well developed in the Mentawa reef build-up member of Minahaki Formation that resulted fantastically in increasing porosity and permeability value. The data measurement of routine core analysis of the carbonate reef build-up having porosity and permeability values ranges from good to excellent classes. Whereas, in the carbonate platform type, the porosity indicated good to very good classes, nevertheless the permeability value turn out to be commonly low and having a very contrast value. This condition was controlled by dominantly micro-intercrystalline and intraparticle porosity types. This phenomenon probably having relationship with composition and main diagenetic event that undergone of the both carbonate build-up and carbonate platform.
Overcoming Unconventional Gas Challenges by Creating Synthetic Sweetspot and Increasing Drainage Area
Authors: Al-Nakhli Ayman R. , Abass Hazim , KwaK Hyung T. , Al-Badairy Hameed , Al-Ajwad Hassan A. , Al-Harith Abdullah , Al-Otibi Ahmad
Published: December 2013

The huge resources of unconventional gas worldwide along with the increasing oil demand make the contribution of unconventional gas to be critical to the world economy. However, major challenges that operators face to produce from unconventional resources are due to the need for identifying a sweetspot, commercial stimulation technique that creates sufficient stimulated reservoir volume, very low permeability and different damage mechanisms such as water blocking, filtrate invasion during drilling, completion, stimulation or production.

This paper describes a new stimulation technique that creates synthetic sweetspot by thermal and mechanical energies. An energized fluid was used to generate localized heat and pressure in tight core samples and therefore create microfracturing. Created microfractures significantly increased permeability, porosity, and stimulated reservoir volume. A synthetic sweetspot nearby a wellbore or fracture area can be created by the new treatment mechanism. Permeability of tested cores was measured by Coreflood system and showed significant increase with new treatment technique. Communication between micro and macro pores was also found as a result of the treatment.

The treatment doesn’t utilize any hydrocarbons and have no lift overs or potential damage. The generated high temperature and pressure can remove any damaging material or condensate banking near wellbore or fracture area. The new treatment technique was evaluated using Coreflood system with actual tight core samples collected from tight reservoirs in Saudi Arabia. ESEM, NMR and CT-Scan analysis were used to show creation of microfracturing and permeability porosity changes.
The Evolution of Expandables: A New Era of Monobore Expandable Well-Construction Systems
Authors: Stringer J. A. , Farley D. B.
Published: December 2013

The common limitation with a casing string is its inability to maintain hole inside diameter (ID) when run through an existing casing string already installed within the wellbore. This instigated development of expandable metal tubulars to maximize the open interval below existing casing, ensuring conventional wellbore designs can be maintained as well as managing unexpected drilling hazards. With the introduction of expandable tubulars, existing wells could now be completed through the ability to include an additional casing without increasing top-hole design or compromising on the planned completion size.

Today’s industry demands further development in technology, with an ability to set a casing and run another casing string without the additional hole-size reduction experienced with conventional casing or standard expandables. A monobore solution is key to allowing operators increased control of the wellbore by isolating intervals, ensuring an efficient fluid-management system, and continuing with the existing tool assemblies. This requirement has led to the development of monobore expandable systems for intervals of the wellbore with common hole sizes of 12-1/4 in., 8-1/2 in., and 6-1/8 in.

Whether in their liner or clad form, isolating the respective interval without a loss in hole diameter provides new economies to operators when accessing deep and more complex reservoirs. Wellbores can now be engineered with contingency solutions without compromising on well objectives. Their ability to isolate intervals while not compromising on post-expansion hole size is providing operators the ability to mitigate drilling hazards, slim tophole casing designs, or increase completion diameters with minimal operational impact on their existing well plans. To date, operators have actively incorporated monobore expandable solutions to mitigate drilling hazards in Norway, Oman, Turkey, Australia, Saudi Arabia, and Azerbaijan, allowing for hazards to be overcome and well objectives achieved. This paper details design and implementation of such monobore expandable systems while providing real results on a global scale of their implementation, advantages, and operational efficiencies.
Drilling and Completion Fluids Design for Horizontal Well Drilling - Case History from Raudatain Field
Authors: Al-Ajmi Hadi Saad , Al-Ajmi Abdullah , Al-Ajmi Khalid , Al-Rushoud Abdul Aziz , Khan Yousef , Barazi Nasser Al , Merza Abdullah , Sotomayor Ghery , Jadhav Prakash
Published: December 2013

This paper presents drilling and completion fluids design for drilling long lateral / horizontal wells in a North Kuwait field and its field application on well RA-492, RA-493 and RA-499. The offset wells were reviewed to identify the issues from drilling a challenging trajectory through troublesome reactive formations that showed serious wellbore stability issues and stuck pipe incidents.

The customized drilling and completions fluids system was designed for different intervals, taking the following objectives in consideration: Improved hole stability through stressed and reactive formationsEnhanced hole-cleaning efficiency at critical anglesMinimized risk of stuck pipe across depleted formations with high porosity and permeabilityMinimized / no induced losses to formation by utilizing unique wellbore-strengthening techniqueMinimal damage to reservoir section during drilling phaseNear-wellbore damage remediation during completion phase

This paper describes the customized drilling and completions fluids performance as compared to offset wells. A comprehensive engineered approach addressed the challenges of drilling horizontal wells by using a revolutionary bridging technology to strengthen the wellbore and improve wellbore stability to reduce nonproductive time (NPT) related to losses, stuck pipe, etc. This paper also describes the completions fluids design to minimize reservoir damage and utilize Mesophase technology to remediate near-wellbore damage and improve reservoir producibility. The lessons learned on these wells were incorporated in drilling subsequent wells to continue improve on performance.
Confirmation of Water Saturation and Rock Fluid Properties Across the Transition Zone for a Major Carbonate Reservoir
Authors: Serry Amr Mohamed , Budebes Sultan , Al-Marzouqi Mariam , Hashimura Tadashi , Tan Willy , Ramamoorthy Raghu , Desport Olivier
Published: December 2013

Proper petrophysical evaluation of carbonate formations, offshore Abu Dhabi is a difficult process considering the number of challenges to resolve. Lithology mainly consists of a combination of dolomite and calcite but also contains anhydrite which must be accounted for to get an accurate porosity. Resistivity measurements are affected by invasion and by the very high shoulder bed resistivity so computing formation resistivity can only be done through resistivity modeling and inversion, and once formation porosity and resistivity are properly computed, it is possible to compute an accurate formation saturation only if the Archie parameters cementation and saturation exponents m and n are properly defined. We will show how to resolve these challenges by acquiring and integrating in an advanced workflow a modern suite of logs including density-neutron-resistivity-gamma ray along with a multi-frequency dielectric measurement. We will also show how to confirm the formation saturation in selected zone in an Archie independent manner by combining the dielectric log and pump-out formation tester. The integration of the log data with core analysis results in a very comprehensive petrophysical evaluation of the formations encountered.
Creating a Culture of Safety and Reliability in the Offshore World
Authors: Matthews Teg
Published: December 2013

Most organizations in the offshore oil industry have squeezed all of the performance they can get from traditional approaches to procedures, rules, and other administrative controls. Adding more programs to an already overtaxed workforce is not only undesirable and costly but can actually be detrimental to safety, environmental, and cost performance. Operators don’t need more things to do but a way to get more out of what they are already doing. Operational reliability and execution are the keys to effective performance. And this means developing a safety culture that engages people at all levels to fully commit to doing the right thing at the right time in the right way. This paper will discuss research findings that demonstrate how a strong safety culture leads to operational reliability and is the leading factor that sets the very best performers in offshore drilling apart from their counterparts.