bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and Validation of the Emotional Self‐Awareness Questionnaire: A Measure of Emotional Intelligence
Authors: Killian Kyle D.
Published: May 2011

This study examined the psychometric characteristics of the Emotional Self‐Awareness Questionnaire (ESQ), a self‐report measure of emotional intelligence. The ESQ, Emotional Intelligence Scale, and measures of alexithymia, positive negative affect, personality, cognitive ability, life satisfaction, and leadership aspirations were administered to 1,406 undergraduate psychology students. The ESQ was reduced from 118 to 60 items via factor and reliability analyses, retaining 11 subscales and a normal score distribution with a reliability of .92. The ESQ had significant positive correlations with the Emotional Intelligence Test and positive affect, significant negative correlations with alexithymia and negative affect, and an insignificant correlation with cognitive ability. The ESQ accounted for 35% of the variance in life satisfaction over and above the Big Five, cognitive ability, and self‐esteem, and demonstrated incremental validity in explaining GPA and leadership aspirations. The significance of emotional intelligence as a unique contributor to psychological well‐being and performance, and applications for the ESQ in assessment and outcome research in couple and family therapy are discussed.
Evaluation of a portable glucose meter for use in cattle and sheep
Authors: Katsoulos Panagiotis D. , Minas Anastasios , Karatzia Maria A. , Pourliotis Konstantinos , Christodoulopoulos Georgios
Published: May 2011

Background: In farm animal practice, determination of blood glucose concentration under field conditions is often necessary.

Objective: As there is no portable glucose meter device developed for use in farm animals, the analytical accuracy of a portable glucometer designed for people was evaluated for its use in cattle and sheep.

Methods: Blood samples from 90 cattle and 101 sheep were used in the study. Glucose concentration was determined in whole blood immediately after blood collection from the jugular vein with the One Touch Vita portable glucometer and in serum with an enzymatic colorimetric method. The agreement between methods was assessed by Passing and Bablok regression analysis. The precision and the accuracy of the measurements were determined using the concordance correlation coefficient.

Results: There was a strong linear relationship between the glucose values obtained using the portable glucometer and those obtained by the bench method in both cattle and sheep. Precision was 95% for cattle and 88% for sheep, whereas accuracy was 92% and 99%, respectively. The mean glucose values obtained using the portable glucometer were significantly lower by 8.3% in cattle and 3.2% in sheep than those determined by the bench method.

Conclusion: The One Touch Vita portable glucometer can be used in clinical practice to determine blood glucose concentrations in cattle and sheep, but reference intervals (RI) must be corrected to allow for negative bias. Based on these equations the RI for blood glucose in cattle and sheep using the portable glucometer were corrected to 1.84–4.17 and 2.41–4.35 mmol/L, respectively.
Frequency of dog erythrocyte antigen 1.1 expression in dogs from Portugal
Authors: Ferreira Rui R. F. , Gopegui Rafael R. , Matos Augusto J. F.
Published: May 2011

Background:Dog erythrocyte antigen (DEA) 1.1 is the antigen considered most responsible for severe hemolysis owing to incompatible blood transfusions in previously sensitized dogs. Few reports describe the frequency of DEA 1.1 expression in European dogs, and there are no reports in dogs from Portugal.

Objective:The aims of this study were to identify the frequency of DEA 1.1 expression in Portuguese dogs, to examine the relationship between phenotypic traits and expression of this blood group, and to assess the risk of transfusing blood that is not typed or cross‐matched.

Methods:Expression of DEA 1.1 was determined in 274 dogs using a migration gel test. Weight, sex, breed, and hair length and color were recorded for each dog. Results were analyzed by descriptive statistical analysis, probabilistic analysis, and χ2‐tests.

Results:Of 274 dogs, 56.9% were DEA 1.1‐positive and 43.1% were DEA 1.1‐negative. All Boxers, German Shepherds, and Dobermans were DEA 1.1‐negative, whereas all Saint Bernards, 88.9% of Golden Retrievers, 88.2% of Rottweilers, and 61.4% of mixed breed dogs were DEA 1.1‐positive. A significant relationship between DEA 1.1 expression and phenotypic traits was not found. The probability of sensitization of recipient dogs following first‐time transfusion with blood that was not typed or cross‐matched was 24.5%; the probability of an acute hemolytic reaction following a second transfusion with blood from any other donor in the absence of pretransfusion compatibility testing was 6%.

Conclusion:The frequency of DEA 1.1 expression in dogs in Portugal is high, and there is a potential risk of sensitization following transfusion with blood that is not typed or cross‐matched. Breed‐related frequencies may help predict DEA 1.1‐positivity, but the best practice is to type and cross‐match blood before transfusion.
Superfluous or Mischievous: Evaluating the Determinants of Government Defeats in Second Chambers
Authors: FISK DAVID
Published: May 2011

Governments often extol the policy refining functions of second chambers, but in bicameral parliamentary systems, governments must balance these policy refinement functions with their ability to pass legislation in the second chamber. I examine government defeats in the second chamber, suggesting they are a function of the cost and the likelihood of defeat. Using an original dataset, I find that strong veto authority creates incentives for governments to act strategically to avoid defeats (even when facing a friendly chamber), while opposition majorities and a weaker ability to sanction members who deviate from their party's position increase the likelihood of defeat.
States of Citizenship: Contexts and Cultures of Public Engagement and Citizen Action
Authors: Cornwall Andrea , Robins Steven , Von Lieres Bettina
Published: May 2011

Drawing on case studies from the Citizenship Development Research Centre, this paper contends that mechanisms aimed at enhancing citizen engagement need to be contextualised in the states of citizenship in which they are applied. It calls for more attention to be focused on understanding trajectories of citizenship experience and practice in particular kinds of states. It suggests that whilst efforts have been made by donors to get to grips with history and context – such as DFID's Drivers of Change analyses or Sida's Power Studies – less attention has been given to exploring the implications of the dissonance between the normative dimensions of global narratives of participation and accountability, and the lived experience of civic engagement and the empirical realities of ‘civil society’ in diverse kinds of states. By exploring instantiations of citizenship in different kinds of states, the paper reflects on what citizen engagement comes to imply in these contexts. In doing so, it draws attention to the diverse ways in which particular subject‐positions and forms of identification are articulated in the pursuit of concrete social and political projects.
Integrating Least Square Support Vector Regression and Mode Pursuing Sampling Optimization for Crashworthiness Design
Authors: Wang Hu , Shan Songqing , Wang G. Gary , Li Guangyao
Published: May 2011

Many metamodeling techniques have been developed in the past two decades to reduce the computational cost of design evaluation. With the increasing scale and complexity of engineering problems, popular metamodeling techniques including artificial neural network (ANN), Polynomial regression (PR), Kriging (KG), radial basis functions (RBF), and multivariate adaptive regression splines (MARS) face difficulties in solving highly nonlinear problems, such as the crashworthiness design. Therefore, in this work, we integrate the least support vector regression (LSSVR) with the mode pursuing sampling (MPS) optimization method and applied the integrated approach for crashworthiness design. The MPS is used for generating new samples which are concentrated near the current local minima at each iteration and yet still statistically cover the entire design space. The LSSVR is used for establishing a more robust metamodel from noisy data. Therefore, the proposed method integrates the advantages of both the LSSVR and MPS to more efficiently achieve reasonably accurate results. In order to verify the proposed method, well-known highly nonlinear functions are used for testing. Finally, the proposed method is applied to three typical crashworthiness optimization cases. The results demonstrate the potential capability of this method in the crashworthiness design of vehicles.
INFEASIBILITY OF QUANTUM CRYPTOGRAPHY WITHOUT EAVESDROPPING CHECK
Authors: YANG WEI , HUANG LIUSHENG , SONG FANG , WANG QIYAN
Published: May 2011

Secure key distribution is impossible in pure classical environment. Unconditional secure key distribution is available when quantum means are introduced, assisted by a classical communication channel. What is possible when a quantum key distribution scheme is without classical communication? We present a general model with this constraint and show that quantum key distribution without classical eavesdropping check is in principle impossible. For an adversary can always succeed in obtaining the secret key via a special case of man-in-the-middle attack, namely intercept-and-forward attack without any risk of being captured.
WEYL CORRESPONDENCE FORMALISM FOR DESCRIBING ELECTRON UNDER UNIFORM MAGNETIC FIELD STUDIED BY VIRTUE OF THE ENTANGLED STATE REPRESENTATION
Authors: ZHOU NAN-RUN , HU LI-YUN , FAN HONG-YI
Published: May 2011

Based on the entangled state representation for describing electron's coordinates under uniform magnetic field, we establish a one-to-one correspondence between quantum Hamiltonian and its classical Weyl function through the introduction of Wigner operator. We also study some new important properties of Wigner function of electron's quantum states, such as its upper bound, and its relation with electron's wave function. These discussions demonstrate the beauty and elegance of the entangled state representation.
CONTINUOUS-VARIABLE QUANTUM TELEPORTATION OF MULTIPARTITE ENTANGLED COHERENT STATES
Authors: SUN YONG , SUN BEN-JIN , SHI MEI-LI , MAN ZHONG-XIAO , XIA YUN-JIE
Published: May 2011

We investigate the problem of teleportation of tripartite entangled coherent state (ECS) using linear optical devices such as beam splitters, phase shifters, and two-mode number measurements. The scheme is based on the maximally four-partite ECS with bipartite maximal entanglement as the quantum channel to teleportation tripartite ECS. Our scheme is efficient in the sense that for mean number of photons equal to 2, the minimum of average fidelity (MAF) for teleportation an arbitrary tripartite entangled state is 1-2.3 × 10-7. We also generalize the tripartite scheme into multipartite case and calculate the MAF for the schemes in multipartite cases.
ASYMPTOTIC TRANSITION FROM COSSERAT ROD TO STRING MODELS FOR CURVED VISCOUS INERTIAL JETS
Authors: ARNE WALTER , MARHEINEKE NICOLE , WEGENER RAIMUND
Published: May 2011

This work deals with the modeling and simulation of slender viscous jets exposed to gravity and rotation, as they occur in rotational spinning processes. In terms of slender-body theory, we show the asymptotic reduction of a viscous Cosserat rod to a string system for vanishing slenderness parameter. We propose two string models, i.e. inertial and viscous-inertial string models, that differ in the closure conditions and hence yield a boundary value problem and an interface problem, respectively. We investigate the existence regimes of the string models in the four-parametric space of Froude, Rossby, Reynolds numbers and jet length. The convergence regimes where the respective string solution is the asymptotic limit to the rod turn out to be disjoint and to cover nearly the whole parameter space. We explore the transition hyperplane and derive analytically low and high Reynolds number limits. Numerical studies of the stationary jet behavior for different parameter ranges complete the work.
REDUCED BASIS A POSTERIORI ERROR BOUNDS FOR THE STOKES EQUATIONS IN PARAMETRIZED DOMAINS: A PENALTY APPROACH
Authors: GERNER ANNA-LENA , VEROY KAREN
Published: May 2011

We present reduced basis approximations and associated rigorous a posteriori error bounds for the Stokes equations in parametrized domains. The method, built upon the penalty formulation for saddle point problems, provides error bounds not only for the velocity but also for the pressure approximation, while simultaneously admitting affine geometric variations with relative ease. The essential ingredients are: (i) dimension reduction through Galerkin projection onto a low-dimensional reduced basis space; (ii) stable, good approximation of the pressure through supremizer-enrichment of the velocity reduced basis space; (iii) optimal and numerically stable approximations identified through an efficient greedy sampling method; (iv) certainty, through rigorous a posteriori bounds for the errors in the reduced basis approximation; and (v) efficiency, through an offline-online computational strategy. The method is applied to a flow problem in a two-dimensional channel with a (parametrized) rectangular obstacle. Numerical results show that the reduced basis approximation converges rapidly, the effectivities associated with the (inexpensive) rigorous a posteriori error bounds remain good even for reasonably small values of the penalty parameter, and that the effects of the penalty parameter are relatively benign.
STOCHASTIC MEAN-FIELD LIMIT: NON-LIPSCHITZ FORCES AND SWARMING
Authors: BOLLEY FRANÇOIS , CAÑIZO JOSÉ A. , CARRILLO JOSÉ A.
Published: May 2011

We consider general stochastic systems of interacting particles with noise which are relevant as models for the collective behavior of animals, and rigorously prove that in the mean-field limit the system is close to the solution of a kinetic PDE. Our aim is to include models widely studied in the literature such as the Cucker–Smale model, adding noise to the behavior of individuals. The difficulty, as compared to the classical case of globally Lipschitz potentials, is that in several models the interaction potential between particles is only locally Lipschitz, the local Lipschitz constant growing to infinity with the size of the region considered. With this in mind, we present an extension of the classical theory for globally Lipschitz interactions, which works for only locally Lipschitz ones.
L2-GLOBAL TO LOCAL PROJECTION: AN APPROACH TO MULTISCALE ANALYSIS
Authors: BABUSKA IVO , LIPTON ROBERT
Published: May 2011

The paper introduces a new global–local method for recovering the microscale features of gradient fields inside heterogeneous media. The approach is based upon the L2-projection of the homogenized solution onto function spaces spanned by solutions of local problems. The projection framework introduced is general and applies to local domains ω on the interior of the domain of interest as well as those touching the boundary. Within this new framework it is shown that the difference between the actual solution and the L2-projection of the homogenized solution as measured in the energy norm over ω is the same order as the error between the homogenized solution and the actual solution as measured by the L2-norm over a slightly larger domain. In light of the classic results from periodic homogenization this is the best one can do see A. Besounssan, J. L. Lions and G. C. Papanicolau, Asymptotic Analysis for Periodic Structures (North-Holland, 1978).
H(div)-CONFORMING FINITE ELEMENTS FOR THE BRINKMAN PROBLEM
Authors: KÖNNÖ JUHO , STENBERG ROLF
Published: May 2011

The Brinkman equations describe the flow of a viscous fluid in a porous matrix. Mathematically the Brinkman model is a parameter-dependent combination of both the Darcy and Stokes models. We introduce a dual mixed framework for the problem, and use H( div )-conforming finite elements with the symmetric interior penalty Galerkin method to obtain a stable formulation. We show that the formulation is stable in a mesh-dependent norm for all values of the parameter. We also introduce a postprocessing scheme for the pressure along with a residual-based a posteriori estimator, which is shown to be efficient and reliable for all parameter values.
RANKING VALID TOPOLOGIES OF THE SECONDARY STRUCTURE ELEMENTS USING A CONSTRAINT GRAPH
Authors: AL NASR KAMAL , RANJAN DESH , ZUBAIR MOHAMMAD , HE JING
Published: May 2011

Electron cryo-microscopy is a fast advancing biophysical technique to derive three-dimensional structures of large protein complexes. Using this technique, many density maps have been generated at intermediate resolution such as 6–10 Å resolution. Although it is challenging to derive the backbone of the protein directly from such density maps, secondary structure elements such as helices and β-sheets can be computationally detected. Our work in this paper provides an approach to enumerate the top-ranked possible topologies instead of enumerating the entire population of the topologies. This approach is particularly practical for large proteins. We developed a directed weighted graph, the topology graph, to represent the secondary structure assignment problem. We prove that the problem of finding the valid topology with the minimum cost is NP hard. We developed an O(N2 2N) dynamic programming algorithm to identify the topology with the minimum cost. The test of 15 proteins suggests that our dynamic programming approach is feasible to work with proteins of much larger size than we could before. The largest protein in the test contains 18 helical sticks detected from the density map out of 33 helices in the protein.
Influence of complex formation with tetraantraquinoporphyrazines and tetrasulphophthalocyanine on thermal stability of bovine serum albumin
Authors: Lebedeva Natalia , Popova Tatyana , Kozbial Malgorzata , Wszelaka-Rylik Malgorzata , Gubarev Yuri , Gierycz Pavel
Published: May 2011

Interaction between bovine serum albumin (BSA) and tetraantraquinoporphyrazines (TAP) and tetrasulphophthalocyanine (Pc) aluminum hydroxide was studied by means of electron absorption spectroscopy, IR spectroscopy, fluorescence spectroscopy and differential scanning calorimetry. It was found that the complex formation of BSA with the TAPs results in increase of thermal stability of the protein while Pc does not have remarkable influence on the protein thermal denaturation.
Global petroleum systems in space and time
Authors: May S. , Kleist R. , Kneller E. , Johnson C. , Creaney S.
Published: May 2011

Each of the Earth's approximately 900 sedimentary basins is a unique result of geologic, hydrologic, atmospheric and biologic processes. The interaction of these processes results in complex histories that are palaeogeographically linked within tectonic provinces. Process-based genetic analysis provides the fundamental framework for predicting the distribution and character of petroleum systems. New technologies enable the exploitation of this predictability and are themselves the origin of new ideas and improved systems understanding. Petroleum geoscience embraces both forward modelling of processes as well as observation, calibration and inverse modelling. This approach of forward and inverse modelling promotes a general scientific methodology of simulation, prediction, testing and learning that allows us to describe the genetics of sedimentary basins. Genetic analysis can be applied to the spectrum of resource types from hydrocarbon to groundwater to mineral systems and across the range of scales from regional to play to prospect. Like the study of evolution through the fossil record, fundamental characteristics of petroleum systems can be recovered from the patterns of their distribution within the framework provided by plate motion, palaeogeography and palaeoclimate. These fundamental drivers control regional tectonics, subsidence, fill history and deformation that result in the phenotypic expression of individual basins and their fluid systems. Genetic analysis results in a taxonomic hierarchy that facilitates prediction and guides resource exploration. Although genetic analysis provides a framework for understanding the distribution and nature of petroleum systems, that framework itself is insufficient to address the challenges now facing the petroleum industry. New technologies are required to enable exploration in frontier settings, to identify new opportunities in mature basins, to maximize recovery from existing fields, and to unlock the potential of unconventional resources. Future success in all of these areas is fundamentally dependent on our ability to conceptualize new ideas.
From thrust-and-fold belt to foreland: hydrocarbon occurrences in Italy
Authors: Bertello F. , Fantoni R. , Franciosi R. , Gatti V. , Ghielmi M. , Pugliese A.
Published: May 2011

Italy is the most hydrocarbon endowed country of southern Europe, with total discovered reserves (produced+remaining) of 1840 million barrels of oil and 30 trillion ft
3
of gas. The production of oil amounts to 43.2 million barrels per year, about 75% of which comes from the Val d'Agri Field in the southern Apennines. The production of gas is 340 billion ft
3
per year, most of it coming from the northern Adriatic Sea. Hydrocarbon occurrences derive from a variety of petroleum systems which are the result of a complex geological history. At least five important source rocks have been recognized which are distributed in age from Mesozoic through Pleistocene. Three of them were deposited during Mesozoic crustal extension and are mainly oil-prone. Hydrocarbon occurrences associated with these sources are usually found in complex carbonate structures along the Apennines thrust-and-fold belt and in the foreland. Villafortuna–Trecate (Po Plain), Val d'Agri/Tempa Rossa (southern Apennines) and Gela (Sicily) fields represent the largest oil accumulations pertaining to these systems. Two other important sources rocks were deposited in the foredeep terrigenous units of the foreland basins which formed during the Cenozoic orogenesis. The older source is thermogenic gas-prone and is found in the highly tectonized Oligo-Miocene foredeep wedges: gas occurrences associated with this source are mainly concentrated along the northern Apennines margin (e.g. Cortemaggiore Field), in Calabria (e.g. Luna Field) and Sicily (e.g. Gagliano Field). The younger source is biogenic gas-prone and is situated in the outer Plio-Pleistocene foredeeps. The most important gas fields of Italy, located in the eastern Po Plain and northern Adriatic sea (Barbara and other gas fields), have originated from this source. Hydrocarbon exploration in Italy is overall mature, especially for gas, whose residual potential is estimated to be 6.0 trillion ft
3
of reserves. The remaining potential of oil is estimated to be 800 million barrels.
Upper Jurassic reservoir sandstones in the Danish Central Graben: new insights on distribution and depositional environments
Authors: Johannessen P. N. , Dybkjær K. , Andersen C. , Kristensen L. , Hovikoski J. , Vosgerau H.
Published: May 2011

Recently available well data from the northern part of the Danish Central Graben have been analysed to further understand the basin development, biostratigraphy, depositional models and palaeogeography of Upper Jurassic reservoir sandstones, which are the primary exploration targets in this basin. Notably, the discovery of the Hejre accumulation in 2001, where oil has been encountered in Upper Jurassic good reservoir quality sandstones at a depth of more than 5000 m, triggered renewed interest in the Upper Jurassic High Temperature–High Pressure sandstone play in the area.

Overall the Danish Central Graben was transgressed from east to west during the Late Jurassic. During the Late Kimmeridgian, marginal and shallow marine sandstones assigned to the Heno Formation were deposited at the margin of the Feda Graben, and on the Gertrud and Heno Plateaus and constitute the reservoirs in the Freja and Hejre discoveries. The sandstones are analogues to the UK Fulmar and Norwegian Ula Formations encountered in several hydrocarbon fields.

During the Early Volgian, the transgression continued westwards across the Outer Rough Basin along the margin of the Mid North Sea High, where shoreface sandstones with excellent porosities and permeabilities were deposited close to similar sandstones of the Fulmar Formation in the British Fergus, Fife and Angus fields.

During this overall westward transgression, the eastern and central parts of the Danish Central Graben continued to subside and offshore mudstones accumulated, locally intercalated with gravity-flow sandstones. In the easternmost Danish Central Graben, in the Tail End Graben, Upper Kimmeridgian gravity-flow sandstones of the Svane-1 well have proved the presence of gas at
c
. 6 km depth.

Hydrocarbon-bearing Upper Jurassic sandstone reservoirs at significant depths (deeper than 5 km) may form the future exploration targets in the northern part of the Danish Central Graben.
Sedimentology and sequence stratigraphy of the Hugin Formation, Quadrant 15, Norwegian sector, South Viking Graben
Authors: Kieft R. L. , Jackson C. A.-L. , Hampson G. J. , Larsen E.
Published: May 2011

The Middle Jurassic Hugin Formation has been the target of exploration within Quadrant 15 of the Norwegian South Viking Graben since the 1960s. The Hugin formation comprises shallow-marine and marginal-marine sediments deposited during the overall transgression and southward retreat of the ‘Brent Delta’ systems. Sedimentological analysis of cores across the quadrant has identified six facies associations: bay-fill, shoreface, mouth bar, fluvio-tidal channel-fill, coastal plain and offshore open marine. These facies associations are arranged in a series of parasequences bounded by flooding surfaces, several of which are correlated regionally using biostratigraphic data. Within this stratigraphic framework, facies association distributions and stratigraphic architectures are complicated, reflecting the spatial and temporal interaction of various physical processes (e.g. waves and tides) with an evolving structural template produced by rift initiation and salt movement. The overall transgression was highly diachronous, becoming younger from north to south. The northern part of the study area (Sigrun–Gudrun area) is characterized by a series of backstepping, linear, north–south-trending barrier shorelines and sheltered bays. The central part of the study area (Dagny area) contains stacked, backstepping strandplain shorelines that fringed syn-depositional topographic highs. Local angular unconformities are developed around these highs, implying that they formed above fault-block crests and salt-cored structures. The southern part of the study area (Sleipner area) contains stacked deltaic shorelines that were modified by both waves and tides. Sandbody geometry is closely related to depositional regime and syn-depositional tectonic setting within the basin; a robust understanding of both is critical to successful exploration of Hugin Formation reservoirs.
Overcoming multiple uncertainties in a challenging gas development: Chiswick Field UK SNS
Authors: Nesbit R. , Overshott K.
Published: May 2011

Twenty-three years after BP discovered the Chiswick Field in 1984, first gas production was achieved by Venture Production. During its long period of appraisal and development, this asset has passed between five different operators and a large number of co-venturers. Prior to development, the field represented one of the largest undeveloped gas volumes present in the UK Southern North Sea. Key uncertainties include reservoir compartmentalization, low net/gross ratios and poor reservoir permeability, uncertainties in structural mapping and gas–water contact depths, as well as a widely varying Carboniferous subcrop and significant lateral changes in fluviatile sandstone architecture. Drilling and completion during the first phase of development were a significant challenge, with ambitious long and deep fracture-stimulated horizontal wells. The installation comprised a five-slot minimum facilities well-head platform with production tied back via the Venture-operated Markham J6A Platform with gas landed in Den Helder, Holland. As part of Phase II development a further three wells are being planned to accelerate recovery and access the remaining undeveloped reserves in both the primary Carboniferous and secondary Rotliegend reservoirs in the Chiswick Field.
Locating the remaining oil in the Nelson Field
Authors: Gill C. E. , Shepherd M.
Published: May 2011

The Nelson Field has been in production since 1994 and is at the mid-mature stage of field life. The current management strategy has focussed on identifying infill well locations with the aim of recovering bypassed oil. An increasingly detailed reservoir description is required in order to locate these opportunities and to help screen them for their economic viability. A systematic workflow has been followed through to localize those areas of the Nelson Field where the target oil volumes are most likely to be found. This workflow is given the name ‘locate the remaining oil’ within Shell. The aim of this workflow is to understand the relationship between sweep and the geological framework of the reservoir. On this basis, drainage cells are defined within the reservoir. Rather than behaving as a single ‘tank’ of oil with a common rising oil–water contact, the Nelson Field produces from nine discrete drainage volumes, each with separate producing oil–water contacts. The drainage cells have been defined on the basis of sedimentology, oil and water geochemistry in combination with quantitative volumetric analysis. Screening of the nine drainage cells in the reservoir has identified four cells that contain significant remaining volumes of mobile oil. These have then been investigated in further detail with a view to locating any stranded oil volumes that are unlikely to be produced by the existing well stock, and to determine if these are large enough to justify infill well drilling.
The Scott Field: revitalization of a mature field
Authors: Brook G. R. , Wardell J. R. , Flanagan S. F. , Regan T. P.
Published: May 2011

The Scott Field, located in the UK Central North Sea, is in a mature stage of development. The Scott platform has been on production since 1993, when the Scott Field came on stream, followed in by the subsea tie-back of the Telford Field development, located to the south of Scott. By 2005 the Scott Field had produced 400×10
6
boe cumulative production. However, the field was producing at water cuts approaching 90% and the previously completed 2002–2004 infill drilling campaign had not met expectations. A change in strategy was undertaken in the subsequent 2005–2007 Scott drilling campaign, which yielded positive results, adding reserves and significantly increasing platform export rates. The focus moved from peripheral targets towards the edge of the field to lower risk targets closer to existing well control. Success was also attributed to focusing on the seismic interpretation of block bounding faults in poorly imaged areas of the field, allowing identification of small fault-bound targets. The recent drilling has demonstrated that significant value can be found in small and often complex accumulations within an extensively drilled mature field.
Tilting oil-water contact in the chalk of Tyra Field as interpreted from capillary pressure data
Authors: Fabricius I. L. , Rana M. A.
Published: May 2011

The Tyra Field in the central North Sea is located in Palaeogene and Upper Cretaceous chalk. It contains a natural gas zone underlain by an oil leg. Based on analysis of logs and core data from ten wells drilled prior to the field being put into production, normalized water saturation depth-trends from logs were compared with normalized water saturation depth-trends predicted from capillary pressure core data. The ten wells lie close to a SW–NE cross section of the field. For the gas–oil contact, a free contact measured in one well corresponds to a practically horizontal contact interpreted from logging data in the remaining wells. A westerly dipping oil–water contact was found from logging data. Comparison of the depth-wise trends in normalized water saturation among the different wells indicates a regional pattern: in the western side of the field, the trends correspond to a situation of imbibition, where the free water level overlies an interval of residual oil, whereas in the eastern part of the field, the depth-wise trends in normalized water saturation correspond to a situation of drainage. The free water level apparently dips to the east due either to hydrodynamic action or to pressure inequilibrium in the aquifer following tectonic tilting.
Investigating fault-sealing potential through fault relative seismic volume analysis
Authors: Dutzer J.-F. , Basford H. , Purves S.
Published: May 2011

Accurate fault interpretation is key to building a robust and reliable reservoir model, and is essential for further study of fault-seal behaviour and reservoir compartmentalization. Conventional fault interpretation defines faults as planar features. Although the concept of fault damage zones (FDZ) is well established, manual delineation of FDZ from subsurface imaging data is difficult and rarely attempted. In this work we are using the concept of a seismic fault distortion zone (SFDZ). The SFDZ differs from the geological FDZ and is the 3D extent of the regions where the presence of a fault has perturbed the seismic image. The SFDZ represents an area of significant uncertainty within the seismic volume where the signal is distorted either by changes in geology associated with faulting or by imaging problems due to the presence of the fault. Delineation of the SFDZ is a key step in further analysing 3D seismic data to provide information regarding variations in seismic attributes across a fault that can be used to indicate how juxtaposition of strata influences a potential sealing fault. The SFDZ is delineated using an adaptive region growing algorithm and produces a set of detailed 3D SFDZ geobodies. The delineated SFDZ is then used as the input to a set of analysis techniques that examine 3D volumetric juxtaposition of seismic attributes, and properties relative to the fault. The techniques involve automated statistical measurement along seismic structure relative to the fault itself. The workflow has been applied and its utility assessed on an underground gas storage dataset. Initial results suggest that by taking account of the 3D geometry of the SFDZ and subsequently analysing 3D frequency and acoustic impedance volumes relative to these structures, an improved understanding of the juxtaposition of layers across the fault and the lateral variability, juxtaposition can be determined at seismic resolution, and subsequently used to assess the potential for fault seal and fluid migration.
4D acquisition and processing: a North Sea case study on the relative contributions to improved 4D repeatability
Authors: Rushmere E. C. , Dyce M. , Campbell S. , Hill A. J.
Published: May 2011

Using a case study from the Mungo Field in the Central North Sea, we investigate the relative impact of acquisition and processing improvements on 4D seismic repeatability. The results show that, while advancements in both have helped to reduce 4D noise, significant noise reduction can be attributed to processing alone. 4D noise can be thought of as any non-production-related amplitudes that are observable on a 4D difference section, and has both random and coherent components. Both are undesirable as they can mask any real 4D signal. A great deal of effort is employed to reduce noise levels by optimizing acquisition and processing between the 3D surveys, which are differenced to highlight the 4D signal. This paper studies the changes introduced by acquisition and processing improvements using the calibrated difference in reflectivity measure.
3D seismic mapping and porosity variation of intra-chalk units in the southern Danish North Sea
Authors: Abramovitz T. , Andersen C. , Jakobsen F. C. , Kristensen L. , Sheldon E.
Published: May 2011

Deposition of the Upper Cretaceous–Danian Chalk Group in the Salt Dome Province of the southern Danish Central Graben took place during a tectonic period dominated by post-rift subsidence, halokinesis and structural inversion. This resulted in highly variable chalk distribution with >1300 m of chalk located in synclines and <200 m preserved on inversion highs and salt structures. The area is mature with respect to exploration with most of the chalk fields located in structural traps discovered in the 1970s. However, the Halfdan discovery in 1999 illustrates the existence of off-structural traps, leading to renewed exploration interest. To locate additional off-structural traps, a detailed geological model is necessary for prediction of chalk intervals with reservoir potential. To unravel basin development, we combine 3D seismic interpretation, well log correlation and 2D seismic inversion to estimate acoustic impedance along selected profiles. The 2D acoustic impedance profiles are converted to total porosity and used to identify areas with potential untargeted reservoirs. A prominent high-amplitude reflection is interpreted as a regional unconformity separating two distinctly different chalk deposition patterns. Nannofossil biostratigraphy suggests a latest Campanian to early Maastrichtian age for the unconformity. It corresponds to an increase in acoustic impedance and decrease in porosity in wells. The Tor Formation contains porous intervals while the underlying Hod Formation contains less porous chalk. The Hod Formation has a maximum porosity of <20% based on well log and inversion data. In contrast, inversion data indicate that the Tor Formation comprises reservoir-grade porosity at several locations on downflank structures. In several areas, the inversion-based maximum porosity is predicted to be higher than expected, compared with porosity/depth trends derived from well data. Therefore, the spatial porosity variation in chalk is complex and controlled by factors other than burial depth.
Seismic imaging of variable water layer sound speed in Rockall Trough, NE Atlantic and implications for seismic surveying in deep water
Authors: Jones S. M. , Sutton C. , Hardy R. J. J. , Hardy D.
Published: May 2011

Natural variation in sound speed within ocean water can degrade sub-seabed images from 2D, 3D and 4D seismic reflection datasets. Degrading effects include vertical offset of reflections between adjacent or intersecting sail lines and difficulties in suppressing multiples from water layer reverberations. Here we investigate water layer variability in Rockall Trough, offshore Ireland, in water depths ranging from 200 m to 3.5 km. A compilation of vertical sound speed profiles, calculated from temperature and salinity profiles obtained by probes lowered from ships, shows that the mean sound speed in the water layer mostly varies between 1490 and 1500 m s
−1
. Vertical offsets of up to about 15 ms two-way travel time are predicted at seismic line intersections. A significant amount of the total observed sound speed variability can occur along a single seismic sail line. These effects result mainly from spatial and temporal fluctuations in the thicknesses of, and vertical sound speed gradients within, an upper layer of North Atlantic Central Water and a mid-depth layer of Mediterranean Outflow Water. Seismic sections across Rockall Trough commonly show lateral variability in reflectivity within these same two water layers. Some reflective packages contain lens-shaped structures consisting of reflective rims and transparent cores and with diameters between 10 and 50 km. Other reflective packages have abrupt, almost vertical boundaries and no distinct transparent core. We infer that the lateral boundaries of the reflective packages are likely to be associated with significant variations in average water layer sound speed. When processing 2D, 3D and 4D seismic surveys of regions of high oceanic variability, such as Rockall Trough, it is necessary to employ techniques that can solve for and then remove the effect of significant fluctuations in water layer sound speed over time periods as short as a few hours and distances as short as a kilometre.
New aeromagnetic and gravity compilations from Norway and adjacent areas: methods and applications
Authors: Olesen O. , Brönner M. , Ebbing J. , Gellein J. , Gernigon L. , Koziel J. , Lauritsen T. , Myklebust R. , Pascal C. , Sand M. , Solheim D. , Usov S.
Published: May 2011

The Geological Survey of Norway (NGU) has produced new aeromagnetic and gravity maps from Norway and adjacent areas, compiled from ground, airborne and satellite data. Petrophysical measurements on core samples, hand specimens and on
in situ
bedrock exposures are essential for the interpretation of these maps. Onshore, the most prominent gravity and magnetic anomalies are attributed to lower crustal rocks that have been brought closer to the surface. The asymmetry of the gravity anomalies along the Lapland Granulite Belt and Kongsberg–Bamble Complex, combined with the steep gradient, points to the overthrusted high-density granulites as being the main source of the observed anomalies. The Kongsberg–Bamble anomaly can be traced southwards through the Kattegat to southern Sweden. This concept of gravity field modelling can also be applied to the Mid-Norwegian continental shelf and could partially explain the observed high-density rocks occurring below the Møre and Vøring basins and in the Lofoten area. Extrapolations of Late-Caledonian detachment structures occurring on the mainland can be traced on aeromagnetic and gravimetric images towards the NW across the continental margin. Subcropping Late Palaeozoic to Cenozoic sedimentary units along the mid-Norwegian coast produce a conspicuous magnetic anomaly pattern. The asymmetry of the low-amplitude anomalies, with a steep gradient and a negative anomaly to the east and a gentler gradient to the west, relates the anomalies to gently westward dipping strata. Recent aeromagnetic surveys in the Barents Sea have revealed negative magnetic anomalies associated with shallow salt diapirs. Buried Quaternary channels partly filled with gravel and boulders of crystalline rocks generate magnetic anomalies in the North Sea. The new maps also show that the opening of the Norwegian–Greenland Sea occurred along stable continental margins without offsets across minor fracture zones, or involving jumps in the spreading axis. A triple junction formed at 48 Ma between the Lofoten and Norway Basins.
Charging the giant gas fields of the NW Siberia basin
Authors: Fjellanger E. , Kontorovich A. E. , Barboza S. A. , Burshtein L. M. , Hardy M. J. , Livshits V. R.
Published: May 2011

The West Siberia basin is the largest petroleum province in Russia, with 80% of the country's gas resources in the Cenomanian Pokur Formation. Significant undiscovered gas resources have been assessed as on trend with the giant gas fields. However, the origin of the large amounts of dry, isotopically light gas is still an enigma, albeit extensively addressed in the literature. This study aims at quantifying the gas contribution from all relevant thermal sources. The West Siberia Basin is the world's largest intracratonic basin, comprising up to 12 km of Mesozoic and Cenozoic clastic rocks. The Basement is composed of Palaeozoic accretionary crust. Northward-trending Permian–Triassic rifts were filled by fluvial–deltaic sediments from the south and east, punctuated by marine transgressions from the north. Cenozoic basin inversion formed traps for petroleum. A regional high-resolution 3D basin simulation was used to model the thermal evolution of the northern West Siberia basin. Geostatistical modelling was applied to assess source rock richness and quality. Basal heat flow was modelled by calibration to bottom-hole temperature and vitrinite measurements. Hydrocarbon generation kinetic parameters were derived from measurements performed on West Siberia rock samples. Thermal gas charge expelled from the hydrocarbon kitchen drainage areas of key fields were compared with the gas volumes accumulated in these fields. The study found that Cretaceous terrestrial sources can generate sufficient early thermal gas to charge accumulations in the South Kara Sea area, and additional Jurassic sources can charge the remaining accumulations of the study area if favourable conditions apply. Biogenic gas is likely to have contributed to the gas accumulations. Mixing of thermal and biogenic gas could explain the observed isotopic composition. Sensitivity analyses show that the timing of structuring and uplift is the most critical factor of the assessment. Variations in glaciation, heat flow and source kinetics show less effect on the hydrocarbon accumulation.
Integrated petroleum systems and play fairway analysis in a complex Palaeozoic basin: Ghadames-Illizi Basin, North Africa
Authors: Dixon R. J. , Moore J. K. S. , Bourne M. , Dunn E. , Haig D. B. , Hossack J. , Roberts N. , Parsons T. , Simmons C. J.
Published: May 2011

The Ghadames–Illizi Basin system is a highly productive petroleum province with a long exploration history in Algeria, Libya and Tunisia (from the late 1950s to present day). Ongoing exploration success in all three countries suggests that it will continue to provide attractive exploration targets in the future. The basin has a long (Cambrian to Plio-Pleistocene) and complex geological evolution characterized by multiple phases of subsidence punctuated by significant regional uplift events. Two ‘world-class’ petroleum source rocks of different geological age are present (Lower Silurian and Upper Devonian) with similar depositional environments and geochemical characters. Both source horizons have generated significant volumes of oil and gas. Migration is strongly influenced by the stratigraphic architecture of the basin fill, notably distribution of regional seals and the complex patterns of subcrop and onlap across regional unconformities. Multiple reservoir–seal combinations are presented by Late Ordovician glaciogenic sediments and younger Silurian through to Carboniferous paralic sequences. Integrating the stratigraphic relationships with the complex burial history of the basin (timing of uplift, degree of tilting, amount of section removed by erosion) is not a trivial task, but is key to exploration success in such a complex basin. With the aid of 3D basin reconstruction and fluid flow modelling software, we can attempt to capture the stratigraphic and structural complexity and make exploration predictions. If basin modelling techniques are to be optimally applied in such settings, a fully integrated and geologically realistic approach involving sedimentologists, structural geologists, geophysicists and geochemists is required. A modelling approach, workflow and some results are presented.