bluuebunny/crossref_metadata_2025 huggingface dataset:
P2Y12 receptor gene mutation associated with postoperative hemorrhage in a Greater Swiss Mountain dog
Authors: Boudreaux Mary K. , Martin Monica
Published: May 2011

Abstract: A novel hereditary disorder of platelets was identified across 5 generations of a family of Greater Swiss Mountain dogs. The first dog identified with the mutation bled excessively following routine ovariohysterectomy and required multiple transfusions. Coagulation screening assays, platelet counts, and von Willebrand factor antigen activity were within reference intervals. Flow cytometric studies indicated that platelets from the affected dog expressed normal levels of glycoproteins IIb and IIIa and responded to 2 platelet‐activating agents, convulxin and platelet‐activating factor, but not to ADP. Based on DNA studies, a 3 base‐pair deletion predicted to result in elimination of a serine from the extracellular domain was identified in the gene encoding P2Y12, an ADP receptor protein located on platelet membranes. Flow cytometric analysis of platelets and studies of DNA performed concurrently on 2 unrelated Greater Swiss Mountain dogs were unremarkable. The mutation was subsequently identified in the sire, the maternal grand‐dam, a maternal great grandparent, a paternal great grandparent, and a great‐great grandparent. The sire was homozygous, but had not yet been identified as having a hemostatic disorder; the other 4 dogs were carriers. This is the first report of a mutation in the gene encoding the ADP receptor P2Y12 in a domestic animal. P2Y12 is the same receptor targeted by ticlopidine and clopidogrel, platelet inhibitors used in lieu of aspirin in people at risk for cardiovascular disease; thus, spontaneous bleeding is not expected unless there are other contributing factors. This disorder is particularly troublesome because spontaneous hemorrhage is absent to mild in affected dogs; however, following routine surgical procedures or trauma, excessive bleeding could occur and have possible fatal consequences.
Oil Red O‐positive lipid in peritoneal fluid from a horse with a rectal tear
Authors: Brown Jennifer S. , Johnson Mark C. , Sims Will P. , Boone Lindsey H. , Swor Tamara M. , Weeks Bradley R.
Published: May 2011

Abstract:A 4‐year‐old Quarter Horse mare was presented to the Texas A&M University Veterinary Medical Teaching Hospital for evaluation of a rectal tear. On initial evaluation, rectal palpation and colonoscopy revealed a grade IIIb rectal tear. Analysis of peritoneal fluid revealed a modified transudate. Preliminary supportive care included fluid therapy and mineral oil administration via nasogastric tube. Approximately 48 hours after presentation, a second abdominocentesis was performed, and cytologic examination of the fluid revealed a marked suppurative exudate. Round clear nonrefractile material observed within neutrophils and macrophages and in the background stained bright pink to red with Oil Red O, confirming the material as lipid, likely from leakage of mineral oil through the rectal tear. The condition of the mare deteriorated and euthanasia was elected due to the poor prognosis. At necropsy, gross and histologic findings included peritoneal effusion and a full‐thickness rectal tear with transmural necrotizing pyogranulomatous colitis and fibrinous peritonitis. To the authors' knowledge, this is the first reported case of Oil Red O‐positive lipid vacuoles in the peritoneal fluid of a horse from presumed leakage of mineral oil through a transmural rectal perforation. The frequency of this occurrence in horses is unknown, but it is important for cytopathologists to be familiar with the appearance and significance of lipid‐type droplets in phagocytic cells in cytologic fluid analysis specimens.
Development, validation and application of a patient satisfaction scale for a community pharmacy medicines-management service
Authors: Tinelli Michela , Blenkinsopp Alison , Bond Christine
Published: May 2011

Objective

To develop, validate and apply a scale to measure patient satisfaction in a randomised controlled trial of community pharmacy service.

Methods

Published scales were reviewed to inform development of the patient satisfaction scale. Questionnaires were sent to patients in the control (n = 500) and intervention (n = 941) groups of a randomised controlled trial of community pharmacy-led management of coronary heart disease at baseline and 12-month follow-up. Any underlying main factors were assessed with exploratory factor analysis. Reliability and construct validity were tested. The 15-item scale was used to compare patient satisfaction across arms with their most recent pharmacy visit.

Results

Response rates were 92% (461/500) for control and 96% (903/941) for intervention groups at baseline and 85% control (399/472) and intervention (810/941) at follow-up. At baseline satisfaction was very similar in the intervention and control groups (median scores of 42). At follow-up mean satisfaction had significantly improved for the intervention compared with the control (median scores of 46 compared with 43; P < 0.01); intervention females were more likely to be satisfied with the service than males (49 compared with 44; P < 0.01). Three main factors explained the majority of the data variance. Cronbach's alpha was 0.7–0.9 for both groups over time for all factors and total scale. An increase in the overall satisfaction corresponding to a decrease in subjects wanting that particular service to be provided during their next visit indicated construct validity of the scale.

Conclusion

A new scale of patient satisfaction with community pharmacy services was developed and shown to be reliable and valid. Its application showed increased satisfaction in the intervention group receiving a new pharmacy service.
Provision of advice on alcohol use in community pharmacy: a cross-sectional survey of pharmacists' practice, knowledge, views and confidence
Authors: McCaig Dorothy , Fitzgerald Niamh , Stewart Derek
Published: May 2011

Objective

Community pharmacists are well placed to provide advice to clients on public health issues such as alcohol use. The aim of the study was to characterise community pharmacists' current level of activity and views on providing such advice in Scotland.

Method

A postal questionnaire survey, covering provision of advice, knowledge and views on alcohol issues, was sent to all community pharmacies in Scotland (n = 1098).

Key findings

The response rate was 45% (497/1098). Knowledge of recommended alcohol-intake limits was high (79 and 84% correct for male and female limits, respectively), but few respondents (5%) currently advised clients on alcohol consumption once a week or more and 29% had never done so. Around a quarter were confident in explaining alcohol limits, binge drinking and confidentiality issues, but about 40% lacked confidence in screening and providing a brief intervention on alcohol. Respondents expressed mixed views on the appropriateness of pharmacist involvement in discussing alcohol use with clients. Attitudes to harmful or hazardous drinkers varied: some 20% of respondents felt uncomfortable with this group, whereas another 20% felt they could work with this group as well as with any other.

Conclusion

Community pharmacists in Scotland provide little advice on alcohol use, have a reasonable knowledge of recommended limits but lack the knowledge and confidence to provide a brief intervention. Implementation of a brief alcohol intervention in community pharmacy, therefore, would need to be underpinned by an appropriate training programme. Such a programme needs to provide factual knowledge but must also address pharmacists' attitudes to clients and promote confidence in service delivery.
Design and Verification of a Sensing Device for Deformation Measurement of High Temperature Pipes
Authors: Jia J. H. , Hu X. Y. , An Z. L. , Xuan F. Z. , Tu S. T.
Published: May 2011

In this paper, a sensing device specifically for measuring deformations of high temperature pipes is designed, and its applicability is verified both experimentally and theoretically. First, the design procedure and the working principle of the sensing device are described in detail. Then, experiments are carried out to prove the accuracy and the long-term stability of the sensing device. To verify the accuracy of the device, numerical simulation of the deformation of a pipe model is carried out using finite element method. Results from the experimental measurements are in good agreement with results from the numerical simulation. The long-term stability of the device is validated by monitoring the deformation. Conclusions are drawn that the designed sensing device has high accuracy and excellent stability and can be used for measuring deformations of high temperature pipes in power plants.
An Enhanced Bayesian Based Model Validation Method for Dynamic Systems
Authors: Zhan Zhenfei , Fu Yan , Yang Ren-Jye , Peng Yinghong
Published: May 2011

Validation of computational models with multiple correlated functional responses requires the consideration of multivariate data correlation, uncertainty quantification and propagation, and objective robust metrics. This paper presents an enhanced Bayesian based model validation method together with probabilistic principal component analysis (PPCA) to address these critical issues. The PPCA is employed to handle multivariate correlation and to reduce the dimension of the multivariate functional responses. The Bayesian interval hypothesis testing is used to quantitatively assess the quality of a multivariate dynamic system. The differences between the test data and computer-aided engineering (CAE) results are extracted for dimension reduction through PPCA, and then Bayesian interval hypothesis testing is performed on the reduced difference data to assess the model validity. In addition, physics-based threshold is defined and transformed to the PPCA space for Bayesian interval hypothesis testing. This new approach resolves some critical drawbacks of the previous methods and adds some desirable properties of a model validation metric for dynamic systems, such as symmetry. Several sets of analytical examples and a dynamic system with multiple functional responses are used to demonstrate this new approach.
PARAMETER-DEPENDENT DISPERSION AND TRANSMISSION IN A NOVEL TUNABLE PHOTONIC CRYSTAL FIBER
Authors: XU XUN , XIONG GUIGUANG , XU DI
Published: May 2011

Depending on the properties of photonic band gap materials, a novel photonic crystal fiber (PCF), formed by lithium niobate and liquid crystal, has been studied numerically. Dispersion relationships and transmission spectra of the PCF are calculated by methods of the full-vector modal and the finite difference time domain, respectively. The parameter-dependent dispersion and transmission of the PCF have been found. It is shown that the design of the novel photonic crystal fiber could be supported by the theoretical analysis in the paper.
STABILITY RESULTS FOR THE TIME-HARMONIC MAXWELL EQUATIONS WITH IMPEDANCE BOUNDARY CONDITIONS
Authors: HIPTMAIR RALF , MOIOLA ANDREA , PERUGIA ILARIA
Published: May 2011

We consider the time-harmonic Maxwell equations with constant coefficients in a bounded, uniformly star-shaped polyhedron. We prove wavenumber-explicit norm bounds for weak solutions. This result is pivotal for convergence proofs in numerical analysis and may be a tool in the analysis of electromagnetic boundary integral operators.
LANGEVIN MOLECULAR DYNAMICS DERIVED FROM EHRENFEST DYNAMICS
Authors: SZEPESSY ANDERS
Published: May 2011

Stochastic Langevin molecular dynamics for nuclei is derived from the Ehrenfest Hamiltonian system (also called quantum classical molecular dynamics) in a Kac–Zwanzig setting, with the initial data for the electrons stochastically perturbed from the ground state and the ratio M of nuclei and electron mass tending to infinity. The Ehrenfest nuclei dynamics is approximated by the Langevin dynamics with accuracy o(M-1/2) on bounded time intervals and by o(1) on unbounded time intervals, which makes the small [Formula: see text] friction and o(M-1/2) diffusion terms visible. The initial electron probability distribution is a Gibbs density at low temperature, motivated by a stability and consistency argument. The diffusion and friction coefficients in the Langevin equation satisfy the Einstein's fluctuation–dissipation relation.
NONLINEAR WAVES IN NEWTON'S CRADLE AND THE DISCRETE p-SCHRÖDINGER EQUATION
Authors: JAMES GUILLAUME
Published: May 2011

We study nonlinear waves in Newton's cradle, a classical mechanical system consisting of a chain of beads attached to linear pendula and interacting nonlinearly via Hertz's contact forces. We formally derive a spatially discrete modulation equation, for small amplitude nonlinear waves consisting of slow modulations of time-periodic linear oscillations. The fully nonlinear and unilateral interactions between beads yield a nonstandard modulation equation that we call the discrete p-Schrödinger (DpS) equation. It consists of a spatial discretization of a generalized Schrödinger equation with p-Laplacian, with fractional p > 2 depending on the exponent of Hertz's contact force. We show that the DpS equation admits explicit periodic traveling wave solutions, and numerically find a plethora of standing wave solutions given by the orbits of a discrete map, in particular spatially localized breather solutions. Using a modified Lyapunov–Schmidt technique, we prove the existence of exact periodic traveling waves in the chain of beads, close to the small amplitude modulated waves given by the DpS equation. Using numerical simulations, we show that the DpS equation captures several other important features of the dynamics in the weakly nonlinear regime, namely modulational instabilities, the existence of static and traveling breathers, and repulsive or attractive interactions of these localized structures.
ON THE DISJOINTNESS OF ALGEBRAICALLY CONSTRUCTED COSTAS ARRAYS
Authors: DRAKAKIS KONSTANTINOS , GOW ROD , RICKARD SCOTT
Published: May 2011

Is it possible for a particular Costas array to be generated by two different constructions of the Golomb and Welch families? Experimental data suggests that this does not happen (except for trivially small orders), and a (partial) proof of this fact is offered herein through a case-by-case study of all possible pairs of constructions that can potentially produce Costas arrays of equal order.
AN AXIOMATIC SETUP FOR ALGORITHMIC HOMOLOGICAL ALGEBRA AND AN ALTERNATIVE APPROACH TO LOCALIZATION
Authors: BARAKAT MOHAMED , LANGE-HEGERMANN MARKUS
Published: May 2011

In this paper we develop an axiomatic setup for algorithmic homological algebra of Abelian categories. This is done by exhibiting all existential quantifiers entering the definition of an Abelian category, which for the sake of computability need to be turned into constructive ones. We do this explicitly for the often-studied example Abelian category of finitely presented modules over a so-called computable ring R, i.e. a ring with an explicit algorithm to solve one-sided (in)homogeneous linear systems over R. For a finitely generated maximal ideal 𝔪 in a commutative ring R, we show how solving (in)homogeneous linear systems over R𝔪 can be reduced to solving associated systems over R. Hence, the computability of R implies that of R𝔪. As a corollary, we obtain the computability of the category of finitely presented R𝔪-modules as an Abelian category, without the need of a Mora-like algorithm. The reduction also yields, as a byproduct, a complexity estimation for the ideal membership problem over local polynomial rings. Finally, in the case of localized polynomial rings, we demonstrate the computational advantage of our homologically motivated alternative approach in comparison to an existing implementation of Mora's algorithm.
The GeoControversies debates
Authors: Underhill J. R.
Published: May 2011

An opportunity to discuss and publically debate three critical issues of concern to oil company geologists was introduced into the Petroleum Geology Conference (PGC) programme for the first time in 2009. The debates selected focused on whether “peak oil” was already upon us; the relative role of National Oil Companies (NOCs) versus that of International Oil Companies (IOCs) and whether North Sea Exploration was finished. In each case, the arguments were delivered by two experts, who presented the case for and against each motion before answering questions and facing a vote by the audience, who showed coloured cards to indicate their support for what they had heard. All three debates proved to be extremely popular and were very well attended for all three days. The novel concept was deemed a great success and added significant value to the PGC.
North Sea hydrocarbon systems: some aspects of our evolving insights into a classic hydrocarbon province
Authors: Erratt D. , Thomas G. M. , Hartley N. R. , Musum R. , Nicholson P. H. , Spisto Y.
Published: May 2011

A review is given of the development of the understanding of the structure and stratigraphy of a classic petroleum province through 35 years of NW European Petroleum Geology Conferences, using new examples to illustrate the interplay between tectonics and sedimentation in the development of some of the major hydrocarbon plays. Cimmerian tectonics is discussed, with regard to the evidence for regional-scale truncation beneath the Mid Cimmerian unconformity, and the stratal motifs characteristic of rifting associated with the Early and Late Cimmerian events. New data revealing the structural geometries associated with polyphase rifting in the East Shetland Basin are presented. The seismic and sequence stratigraphy of Jurassic and Cenozoic sequences are reviewed and new data presented, with a discussion of generic play controls in North Sea Jurassic deepwater reservoirs. The development of integrated hydrocarbon system studies is reviewed, and the remaining challenges to predictive capabilities discussed. The impact of advances in geoscience and technology on North Sea creaming curves is discussed.
Source rock quality and maturity and oil types in the NW Danish Central Graben: implications for petroleum prospectivity evaluation in an Upper Jurassic sandstone play area
Authors: Petersen H. I. , Nytoft H. P. , Vosgerau H. , Andersen C. , Bojesen-Koefoed J. A. , Mathiesen A.
Published: May 2011

The principal exploration targets in the northwestern part of the Danish Central Graben have been Upper Jurassic sandstone reservoirs. The presence and effectiveness of the oil-generating rocks of the Upper Jurassic–lowermost Cretaceous marine shales of the Farsund Formation has generally not been considered as a significant risk. This study provides an evaluation of the source rock quality, maturity and distribution and of the oils in this area. The kerogen in the Farsund Formation is algal-derived, and kerogen type ranges from Type II to Type III. Generally the source rock quality is fair to excellent, but the petroleum generation potential varies considerably. In most wells the uppermost part of the Farsund Formation (Bo Member) consists of highly oil-prone shales. However, the presence of oil-prone kerogen may be masked by kerogen of poorer source quality. Favourable conditions for oil-prone kerogen preservation were present during the time of deposition of upper parts of the Farsund Formation, but exceptions are not unusual. Similar vitrinite reflectance gradients indicate a uniform thermal regime over the area. The oil window occurs from
c
. 3800–4000 to 4800 m, i.e. spanning approximately 800–1000 m. A general decrease in the generation potential from the top towards the base of the formation is caused by both generation and deterioration of kerogen quality. The Gertrud Graben and Feda Graben constitute the main kitchen areas, and oil compositions indicate sourcing from marine shales. In the shallow parts of the Outer Rough Basin the shales are mostly immature and the sourcing is dependent on kitchen areas outside the area or on Palaeozoic rocks. Mature Zechstein is indicated by a minor oil show probably locally sourced.
Architecture of an Upper Jurassic barrier island sandstone reservoir, Danish Central Graben: implications of a Holocene-Recent analogue from the Wadden Sea
Authors: Johannessen P. N. , Nielsen L. H. , Nielsen L. , Møller I. , Pejrup M. , Andersen T. J.
Published: May 2011

An unusually thick (
c
. 88 m), transgressive barrier island and shoreface sandstone succession characterizes the Upper Jurassic Heno Formation reservoir of the Freja oil field situated on the boundary of Denmark and Norway. The development and preservation of such thick transgressive barrier island sands is puzzling since a barrier island typically migrates landwards during transgression and only a thin succession of back-barrier and shoreface sands is preserved. Investigation of the development and geometry of the Freja reservoir sandstones is problematic since the reservoir is buried
c.
5 km and seismic resolution is inadequate for architectural analysis. Description of the reservoir sandstone bodies is thus based on sedimentological interpretation and correlation of seven wells, of which five were cored. Palaeotopography played a major role in the position and preservation of the thick reservoir sandstones. Using the nearest maximum flooding surface above the reservoir as a datum for well-log correlations, the base of the barrier island succession in the wells is reconstructed as a surface with steep, seaward-dipping palaeotopography. The relief is
c
. 270 m over a distance of
c
. 8 km and dips WNW.

As a complementary approach to investigation of the reservoir architecture, a Holocene–Recent barrier island system in the Danish part of the NW European Wadden Sea has been studied and used as an analogue. The barrier island of Rømø developed during a relative sea-level rise of
c.
15 m during the last
c.
8000 years and is up to 20 m thick. To unravel the internal 3D facies architecture of the island, an extensive ground penetrating radar (GPR) survey of 35 km line length and seven cores,
c.
25 m long, was obtained. Although the barrier island experienced a rapid relative sea-level rise, sedimentation kept pace such that the island aggraded and even prograded seawards and became wider and longer due to the large surplus of sand.
The Huntington discoveries: efficient exploration in the UK Central North Sea
Authors: Hollywood J. M. , Olson R. C.
Published: May 2011

The Huntington discoveries are an unusual exploration success in that two oil accumulations were tested in separate syn- and post-rift reservoirs with a single well. The discoveries are located 205 km east of Aberdeen in the East Central Graben some 35 km east of Forties Field in 300 ft of water. The 22/14-5 discovery well, drilled in May 2007, encountered a 122 ft oil column in the Paleocene Forties Sandstone and also a 136 ft oil column in the Upper Jurassic Fulmar Sandstone. Both the Forties and the Fulmar contain high-quality oil, 41 and 39° api gravity, respectively. Aggregate flow rates from the two zones exceeded 11 000 boepd on test. Appraisal drilling of the Forties was completed in late 2007 with first oil targeted for 2011. The Fulmar appraisal programme is currently in progress. The Forties reservoir is a high net to gross sandstone containing stacked channel sequences deposited in a submarine fan system. The Fulmar reservoir also contains a thick sand package deposited in a shallow marine shelf setting. Pre-drill mapping based on reprocessed 3D seismic indicated a structural closure on both horizons at the location tested by the well. At both the Forties and Fulmar targets, however, the oil column height exceeded the pre-drill prognosis. This overview will focus on pre-drill perceptions of the prospect relative to actual drilling results.
Prospectivity of the T38 sequence in the Northern Judd Basin
Authors: Rodriguez J. M. , Pickering G. , Kirk W. J.
Published: May 2011

A seismic amplitude anomaly has been identified at the Upper Paleocene T38 level in the northern Judd Basin and will be tested by the drillbit in 2009. Prospectivity at shallower levels has been largely ignored due to the fact that the main regional seal in the area was recognized to be the T35/T36 mudstones below the Kettla Tuff. Seismo-stratigraphic analysis of the T38 sequence directly above the tuff marker has identified the potential for a new play type, especially adjacent to fault zones where these mudstones are breached, allowing hydrocarbons to migrate from the Upper Jurassic source kitchen into any traps identified above the seal. In this area, the T38 is represented by a series of northerly prograding low-angle clinoforms representing the final marine infill of sediments into the basin from the south. Erosion of top sets in a more marginal setting is observed, along with deposition of basin floor fans at the toe of the prograding clinoforms. The overlying seals are basinal sediments as well as mudstones and siltstones of subsequent progradational sequences. Mild structural modification of potential stratigraphic traps in the Judd Basin occurred during the Oligo-Miocene inversion associated with continued opening of the North Atlantic. Drilling seismic amplitude anomalies in the West of Shetlands area has often been unsuccessful. Therefore, a fully integrated geophysical and geological evaluation was carried out on the T38 anomaly comprising rock physics, amplitude variation with offset analysis, fault seal analysis and the acquisition of a CSEM survey which, supported by a valid geologic model, have reduced the risk from high to moderate. The results indicate that the anomaly has the potential to be sand-bearing and contain oil and gas. It is proposed that an integrated evaluation can reduce the level of uncertainty associated with an anomaly much more effectively and so improve the chance of exploration success.
Can stratigraphic plays change the petroleum exploration outlook of the Netherlands?
Authors: Van Hulten F. F. N.
Published: May 2011

Fifty years after the discovery of the giant Groningen gas field, good insight into the remaining hydrocarbon exploration potential of the Netherlands is of great interest due to the aging infrastructure. In a review of prospective areas, the stratigraphic element of Dutch play areas has been summarized for conventional and unconventional formations. This is to answer the question of whether stratigraphic traps can contribute to future exploration. Complex faulting, very common in the Dutch subsurface, makes structural definition generally the highest prospect risk. With increase in 3D coverage over the country, many structures have now been drilled successfully. The success of structural traps has left the stratigraphic plays and prospects under-explored. Most hydrocarbon reserves in the Netherlands have been discovered in Permian Rotliegend and Triassic Bunter sandstone reservoirs, which are not prone to much stratigraphic trapping as a consequence of very gradual facies changes. Other prospective horizons and hydrocarbon reservoirs in the country range in age from Carboniferous to Cenozoic and can be found in clastic and carbonate rocks. They share an overall comparable basin setting but the varying interplay at basin margins creates varying stratigraphic elements. Rifting creates new facies variation during the Mesozoic. Salt movement is another factor that creates stratigraphic components in trapping. The various erosional events create other possibilities for stratigraphic trapping. This, combined with varying relative sea-levels through time, creates very distinct stratigraphic intervals often correlatable over large distances. The very limited contribution of stratigraphic traps to present-day gas finds may change in the future because of improved seismic. Risking of prospects needs better understanding of stratigraphic elements in various plays. This includes the stratigraphic aspects of reservoir sealing in dominantly structural traps and the nature of source horizons.
Laggan; a mature understanding of an undeveloped discovery, more than 20 years old
Authors: Gordon A. , Younis T. , Bernard-Graille C. , Gray R. , Urruty J.-M. , Ben-Brahim L. , Navarre J.-C. , Paternoster B. , Evers G.
Published: May 2011

Laggan, located in the west of Shetland, was discovered in 1986. There is now an improved understanding of Laggan, thanks to innovative and fully integrated geoscience studies and a successful appraisal campaign. Development studies are well advanced, with the discovery of Tormore in 2007 providing the potential for a combined development project. Laggan and Tormore are Paleocene gas condensate discoveries in approximately 600 m water depth. The traps are both mixed, stratigraphic with updip closure against bounding faults. The reservoir comprises sand-rich turbidite channelized lobes and lobes. Reservoir properties are good (permeability range 30–300 mD) due to the presence of chlorite and pre-sorting on the shelf. The geoscience evaluation of Laggan has matured over the last four years with the help of fully integrated studies using 3D seismic and well data. The depositional model has been defined on the basis of an evaluation of cores and seismic and supported by analogue studies. Seismic inversion studies have also helped constrain the reservoir architecture. Of particular value has been the application of AVO to quantify net gas sand, recognized as the principal static uncertainty. The main dynamic uncertainty is the risk of compartmentalization. This risk has been reduced through an improved definition of the fault configuration by re-processing the seismic and detailed seismic attribute analysis. The potential of Tormore was recognized by applying the geoscience understanding of Laggan to help de-risk the prospect. In particular, it was recognized that Laggan could be used as an analogue for the Tormore trapping configuration and reservoir potential and that AVO could be used to help define the Gas–Water Contact. The exploration well, drilled in 2007, was successful in finding a similar reservoir to that encountered in Laggan. The fluid encountered was a gas condensate, approximately three times richer than Laggan.
Maximizing production and reserves from offshore heavy oil fields using seismic and drilling technology: Alba and Captain Fields, UKNS
Authors: Hampson J. M. , Walden S. F. , Bell C.
Published: May 2011

Chevron North Sea Limited operates Alba and Captain, two large, mature, heavy oil fields in blocks 16/26 and 13/22a of the UK sector of the North Sea, respectively. Although the fields are structurally and stratigraphically different, their development schemes have been similar. Common components to both fields are that they are marine sandstone reservoirs; have one steel jacket, plus subsea templates; are under water injection for pressure support; utilize long horizontal development wells; use pilot holes and logging while drilling (LWD) geosteering tools to optimize well locations; and have seismic resolution issues. New technologies and techniques have been developed and adopted to maximize production and reserves from the fields. The benefits to both Alba and Captain of previous and new technologies are reviewed below.
The Buzzard Field: anatomy of the reservoir from appraisal to production
Authors: Ray F. M. , Pinnock S. J. , Katamish H. , Turnbull J. B.
Published: May 2011

The Buzzard oil field in the Outer Moray Firth, Central North Sea was discovered in 2001 and rapidly appraised during 2001–2002. Pre-production development drilling began in 2005 and the field was brought on stream in January 2007 by operator Nexen Petroleum UK Ltd. The Buzzard reservoir consists of Upper Jurassic deep marine turbidites within the Kimmeridge Clay Formation. Sands were derived from the shelf to the west and the resulting mass flow deposits were contained within a fault-bounded basin, whose margins were prone to mass wastage. The deposits pinchout to the west and thicken eastwards into the basin and hydrocarbon source kitchen. Following appraisal drilling, the high net-to-gross reservoir was interpreted as well connected. Interbedded shale layers were thought unlikely to control flow through the reservoir. However, a biostratigraphic review indicated that a consistent biostratigraphic event, indicative of reworking, could be identified field-wide. This shale layer is interpreted as a large-scale, muddy slump, extensive enough to form a significant vertical barrier to flow. Subsequent production data, modelling and chemostratigraphy studies suggest greater subdivision and vertical baffling within the main reservoir. Interpretation of these data has led to a move away from early models of Buzzard as a tank-like reservoir to a model dominated by compensationally stacked lobes, where hydraulic flow is influenced by sand body geometry and extensive shales. A comprehensive understanding of the Buzzard Field has only been possible through full integration of core, log and dynamic data, benefiting from a high density of well control, an extensive data acquisition programme and early reservoir monitoring. Ongoing reservoir management, involving continuous update of both the geological and dynamic models in response to new data, has enabled an evolving understanding of the Buzzard reservoirs, and placed the operator in an excellent position to proactively address future development challenges.
An old field in a new landscape: the renaissance of Donan
Authors: Reekie R. R. A. , Davies E. L. , Hart N. J. , McInally A. T. , Todd J. R. , McAteer J. R. , Franoux L. , Ferguson E. L. M.
Published: May 2011

The Donan Field was discovered in 1987 by BP well 15/20a-4. Oil is reservoired in Paleocene Lower Balmoral Sandstones of the Lista Formation. First oil was achieved from Donan on 28 April 1992 via two crestal producers to the Single Well Oil Production System (SWOPS) vessel
O.P.V. Seillean
. Peak production rates of 15 mstb/day were achieved before high well watercuts caused a significant drop in gross rates. Further attempts at development proved unsuccessful at the time. No further infill attempts were made as the field continued to be produced until it reached its economic limit in 1997. The field had produced 15.3×10
6
stb. Subsequently, block 15/20a was awarded to a partnership led by Kerr–McGee (North Sea) UK Ltd (now Maersk Oil North Sea UK Limited) in 2002 as part of the twentieth licensing round. Drilling results whilst testing the prospectivity on the block led to a focus towards Donan redevelopment. A combination of Rock Physics modelling and AVO, calibrated by appraisal drilling, and the integration of high-resolution biostratigraphy, played a significant role in the successful first phase of the ‘Dumbarton Project’, consisting of five horizontal producers and one produced water reinjection well. ‘Second oil’ from Donan was achieved on 19 January 2007 to the Global Producer III FPSO. Early production performance was in line with expectations with the field producing 20×10
6
stb within the first two years. In 2008 and 2009 further phases of development drilling took place on Donan with 2009 also expected to deliver two development wells in the Lochranza Field, a smaller, structurally distinct field to the east of Donan.
Role of the Chalk in development of deep overpressure in the Central North Sea
Authors: Swarbrick R. E. , Lahann R. W. , O'Connor S. A. , Mallon A. J.
Published: May 2011

A high magnitude of overpressure is a characteristic of the deep, sub-Chalk reservoirs of the Central North Sea. The Upper Cretaceous chalk there comprises both reservoir and non-reservoir intervals, the former volumetrically minor but most commonly identified near the top of the Tor Formation. The majority of non-reservoir chalk has been extensively cemented with average fractional gross porosity of 0.08, and permeability in the nano- to microDarcy range (10
−18
–10
−21
m
2
), and sealing properties comparable to shale. Hence deeply buried chalk is comparable to shale in preventing dewatering and allowing overpressure to develop. Direct pressure measurements in the Chalk are restricted to the reservoir intervals, plus in rare fractured chalk, but reveal that Chalk pressures lie on a pressure gradient which links to the Lower Cenozoic reservoir above the Chalk and the Jurassic/Triassic reservoir pressures below. Hence a pore pressure profile of constantly increasing overpressure with increasing depth is indicated. Mud weight profiles through the Chalk, by contrast, show many borehole pressures lower than those indicated by these direct measurements, implying wells are routinely drilled underbalanced. The Chalk is therefore considered the main pressure transition zone to high pressures in sub-Chalk reservoirs. In addition to its role as a regional seal for overpressure, the Base Chalk can be shown to be highly significant to trap integrity. Analysis of dry holes and hydrocarbon discoveries relative to their aquifer seal capacity (the difference between water pressure and minimum stress) shows that the best empirical relationship exists at Base Chalk, rather than Base Seal/Top Reservoir, where the relationship is traditionally examined. Using a database of 65 wells from the HP/HT area of the Central North Sea, and extending the known aquifer gradients from the Fulmar reservoirs via Base Cretaceous to Base Chalk, leads to a risking threshold at 5.2 MPa (750 psi) aquifer seal capacity. Discoveries constitute 88% of the wells above the threshold and 36% below, with 100% dry holes where the aquifer seal capacity is zero (i.e. predicted breached trap). This relationship at Base Chalk can be used to identify leak points which control vertical hydrocarbon migration as well as assessing the risk associated with drilling high-pressure prospects in the Central North Sea.
Applying time-lapse seismic methods to reservoir management and field development planning at South Arne, Danish North Sea
Authors: Herwanger J. V. , Schiøtt C. R. , Frederiksen R. , If F. , Vejbæk O. V. , Wold R. , Hansen H. J. , Palmer E. , Koutsabeloulis N.
Published: May 2011

At South Arne a highly repeatable time-lapse seismic survey (normalized root-mean-square error or NRMS of less than 0.1) allowed us to reliably monitor reservoir production processes during five years of reservoir depletion. Time-lapse AVO (amplitude v. offset) inversion and rock-physics analysis enables accurate monitoring of fluid pathways. On the crest of the field, water injection results in a heterogeneous sweep of the reservoir, whereby the majority of the injected water intrudes into a highly porous body. This is in contrast to a pre-existing reservoir simulation model predicting a homogeneous sweep. On the SW flank, time-lapse AVO inversion to changes in water saturation Δ
S
w
reveals that the drainage pattern is fault controlled. Time-lapse seismic data furthermore explain the lack of production from the far end of a horizontal producer (as observed by production logging), by showing that the injected water does not result in the expected pressure support. On the highly porous crest of the reservoir compaction occurs. Time-lapse time shifts in the overburden are used as a measure for compaction and are compared with predictions of reservoir compaction from reservoir geomechanical modelling. In areas where compaction observations and predictions disagree, time-lapse seismic data give the necessary insight to validate, calibrate and update the reservoir geomechanical model. The information contained in time-lapse seismic data can only be fully extracted and used when the reservoir simulation model, the reservoir geomechanical model and the time-lapse seismic inversion models are co-visualized and available in the same software application with one set of coordinates. This allows for easy and reliable investigation of reservoir depletion and gives deeper insight than using reservoir simulation or time-lapse seismic individually.
Synchronous exhumation events around the Arctic including examples from Barents Sea and Alaska North Slope
Authors: Green P. F. , Duddy I. R.
Published: May 2011

In many areas of the Arctic, sedimentary sequences have been exhumed from significantly greater depths during the Cenozoic, with 2 km of section or more removed in some areas. Implications for exploration include enhanced maturity levels, possible loss of reservoired hydrocarbons as a result of seal breach, and phase changes due to pressure reduction. While the importance of Cenozoic exhumation to hydrocarbon prospectivity in individual basins is widely recognized, less well recognized is the regional synchroneity in the main phases of Cenozoic exhumation over wide areas of the Arctic and North Atlantic. Thermal history reconstruction studies in the Barents Sea and the Alaskan North Slope, based on application of apatite fission track analysis and vitrinite reflectance, reveal three main episodes of exhumation, in Paleocene, Eocene–Oligocene and Miocene times, and correlative exhumation episodes have been identified in a number of published studies in these and other areas. Previous attempts to explain these episodes of exhumation have been focussed on local mechanisms. However, our results reveal a pattern of regionally synchronous exhumation over a wide region, not only of the Arctic but also in many areas around the European North Atlantic margin, suggesting that events in each area are a regional response to events at plate boundaries, perhaps coupled to imbalances of crustal forces at continental boundaries. To date, no convincing mechanism has been put forward for producing such regional exhumation episodes, despite the fact that in many areas they exert critical control on regional hydrocarbon prospectivity. We suggest that serious attention should be directed to investigating the underlying mechanisms.
The hydrocarbon prospectivity of the Egyptian North Red Sea basin
Authors: Gordon G. , Hansen B. , Scott J. , Hirst C. , Graham R. , Grow T. , Spedding A. , Fairhead S. , Fullarton L. , Griffin D.
Published: May 2011

Recent work by a multi-disciplinary team has led to a significantly better understanding of the prospectivity of the North Red Sea. New regional biostratigraphic and environmental analysis from north to south through the Gulf of Suez and into the Red Sea have placed the Nubian sequences into a regional chronostratigraphic framework. The Nubian Upper Cretaceous pre-rift sandstones are observed in the field on both the Egyptian and Saudi Arabian side of the North Red Sea. This regionally extensive sequence was deposited in a continental to shallow marine setting fringing the Mesozoic Tethys Ocean, which lay further north. Extensive onshore fieldwork and mapping of sediment input points, fault orientations and fault linkages have helped to develop an understanding of the expected controls on syn-rift sandstone and carbonate deposition offshore. Thick halite with interbedded evaporite and clastics in the Late Miocene sequences of the Red Sea pose seismic imaging challenges. Recent reprocessing and newly acquired seismic data have produced a step change improvement in imaging of the prospective pre-rift section. Petroleum systems modelling incorporating new information on rift timing and crustal thinning as well as onshore core analysis for source rock properties and temperature variation through time indicates that oil expulsion occurs in the inboard section of North Red Sea – Block 1. This is supported by hydrocarbon shows in the drilled offshore wells which can be typed to pre-rift source rocks from stable isotope and biomarker data. All the key elements of the Gulf of Suez petroleum system exist in the North Red Sea. An integrated exploration approach has enabled prospective areas in the North Red Sea – Block 1 to be high-graded for drilling in early 2011.
Properties and distribution of lower crustal bodies on the mid-Norwegian margin
Authors: Reynisson R. F. , Ebbing J. , Lundin E. , Osmundsen P. T.
Published: May 2011

Anomalously high velocity and high density bodies have been detected in the lower crust on the mid-Norwegian margin. The lower crustal bodies (LCB) are pronounced on the Møre and Vøring margins segments and have mainly been interpreted as either magmatic or high-grade metamorphic in origin. Evolutionary models of the whole margin are heavily affected by the interpretation of the LCB and so are estimates of vertical movements and thermal structure in the area. A 3D gravity and magnetic model of the mid-Norwegian margin was constructed to map the main geological features of the margin and acquire the distribution of the LCB. The model utilizes the most recent potential field compilations on the margin and is constrained by extensive reflection seismic data and published refraction profiles. Further constraints on the model were attained from studying the isostatic state of the lithosphere. We present a map showing the distribution of the different LCB and discuss the implications for the structural and thermal evolution of the margin. The properties of the LCB vary across the margin and at least three different processes may be responsible for their existence. The LCB is commonly interpreted as igneous rock either intruded into the lower crust or underplated beneath it. The distribution of the LCB along the Vøring margin has an apparent correlation with the offshore prolongations of major onshore detachments stemming from Late Caledonian orogenic collapse. This may point towards some relation between the LCB and these old zones of weakness and that the LCB represents high-grade metamorphic rocks. Detailed modelling on the Møre margin shows a spatial link between parts of the LCB and extremely thin crustal thickness, suggesting a serpentinized exhumed mantle origin.
Source-to-sink systems on passive margins: theory and practice with an example from the Norwegian continental margin
Authors: Martinsen O. J. , Sømme T. O. , Thurmond J. B. , Helland-Hansen W. , Lunt I.
Published: May 2011

Source-to-sink system analysis involves a complete, earth systems model approach from the ultimate onshore drainage point to the toe of related active deepwater sedimentary systems. Several methods and techniques have evolved in recent years, from experimental and numerical modelling through analysis of modern and recent systems, to analysis of ancient systems. A novel method has been developed, bridging between the previous approaches and dividing and analysing source-to-sink systems based on linked geomorphic segments along the source-to-sink profile. This approach builds on uniformitarian principles. The method is driven by the need to understand ancient, subsurface systems and still has high uncertainty but is an original, first-order approach to source-to-sink system analysis. In modern systems, entire onshore-to-offshore systems can be analysed with a higher degree of confidence than in ancient systems and semi-quantitative relationships can be established. Application in ancient systems is much more challenging but, in some cases, antecedent morphologies have been preserved onshore that can be matched with offshore known occurrences of, for instance, sandy submarine fan systems. Along the Norwegian North Sea and Norwegian Sea margins the Paleocene deep-marine reservoir of the giant Ormen Lange gas field is such an example. There, antecedent onshore drainage patterns which formed the feeder system to the offshore, deepwater fan system can be interpreted and aligned with onshore palaeogeomorphological evidence. Understanding the palaeogeomorphic development of basement regions such as the Fennoscandian shield is of high importance for understanding the offshore presence of deepwater sandstones.