bluuebunny/crossref_metadata_2025 huggingface dataset:
Preclinical Studies of Pf-04849285, An Interferon-α8 Fusion Protein for the Treatment of HCV
Authors: Flores M Victoria , Hickling Timothy P , Sreckovic Sasha , Fidock Mark D , Horscroft Nigel , Katragadda Madan , Savic Boris , Rawal Jaiessh , Delpuech-Adams Oona E , Robas Nicola , Corey Thomas , Nelms Linda , Lawton Michael , Marcek John , Stubbs Makeida , Westby Michael , Ciaramella Giuseppe
Published: April 2012

Background

This study presents preclinical data of a novel interferon (IFN)-α8 fusion protein, PF-04849285, and compares it with IFN-α2 and pegylated IFN-α2; the latter being the current standard of care for HCV.

Methods

The antiviral properties were evaluated in vitro using the HCV replication assay (replicon) and the general encephalomyocarditis virus assay. The binding affinity to both IFNR-subunits was assessed using surface plasmon resonance. Ex vivo experiments using cynomolgus monkey and human blood were used for the evaluation of induction of IFN-inducible biomarkers (interferon inducible protein 10 [IP-10], 2′-5′-oligoadenylate synthetase [OAS2] and interleukin-6 [IL-6]). The molecule was tested intravenously and subcutaneously in cynomolgus monkey in a single dose study for two weeks at 0.01, 1, 5 and 20 mg/kg. Each route and dose combination was given to a single male animal, blood samples were collected for evaluation of biomarkers and pharmacokinetics. The compound was also tested in cynomolgus monkey in a multiple dose study for four weeks, with a twice-a-week dosing prior to a three-week wash-out period for toxicokinetics, pharmacokinetics, and biomarker evaluation at 20, 50 or 100 mg/kg subcutaneously and 20 mg/kg intravenously.

Results

The molecule is 10x more potent than the pegylated IFN-α2a, with potency similar to the unmodified IFN-α2a. No unanticipated findings were observed in cynomolgus monkey when dosed up to 20 mg/kg, >10,000-fold margin over the anticipated efficacious human dose.

Conclusions

The biomarker and toxicological findings were consistent with a potent IFN molecule. The potency and pharmacokinetic properties of the molecule are consistent with dosing at least twice daily with the potential for monthly dosing.
Vitamin D Levels and Il28B Polymorphisms are Related to Rapid Virological Response to Standard of Care in Genotype 1 Chronic Hepatitis C
Authors: Petta Salvatore , Ferraro Donatella , Cammà Calogero , Cabibi Daniela , Di Cristina Antonietta , Di Marco Vito , Di Stefano Rosa , Grimaudo Stefania , Mazzola Alessandra , Levrero Massimo , Scazzone Concetta , Craxì Antonio
Published: April 2012

Background

Genotype 1 (G1) chronic hepatitis C (CHC) patients achieving a rapid virological response (RVR) on pegylated interferon (PEG-IFN) plus ribavirin have a high chance of sustained virological response (SVR), influenced by IL28B status, viral load, fibrosis and insulin resistance. We assessed whether 25-hydroxyvitamin D (25[OH]D) serum levels are linked to RVR and can be used together with IL28B to construct a pretreatment model to predict RVR.

Methods

A total of 117 consecutive patients with G1 CHC were evaluated by biopsy and anthropometric and metabolic measurements. 25(OH)D serum levels were measured by HPLC. IL28B rs12979860 and rs8099917 polymorphisms were also evaluated. All patients underwent antiviral therapy with PEG-IFN-α2a plus ribavirin. HCV RNA was assessed at baseline, week 4, week 12, at the end of therapy and after 6 months of follow-up.

Results

Mean ±sd 25(OH)D serum levels were 26.3 ±10.6 μg/l (range 8.0–58.0) and 31 (26.5%) patients had the rs12979860 CC polymorphism. RVR was achieved in 35 (29.9%) patients, and 32 (91.4%) of them had an SVR, compared to 26 of 82 (31.7%) without RVR. The rs12979860 CC polymorphism (OR 4.575, 95% CI 1.761, 11.889; P=0.002) and higher 25(OH)D levels (OR 1.055, 95% CI 1.010, 1.101; P=0.01) were independently associated with the achievement of RVR by multivariate analysis. The likelihood of RVR progressively increased from patients in the worst class (vitamin D<26.8 μg/l and TT/TC polymorphism; RVR 14.2%), to those with only one positive predictor (RVR 29.7% and 37.5%), and to those in the best class (vitamin D≥26.8 μg/l and rs12979860 CC polymorphism; RVR 73.3%).

Conclusions

In patients with G1 CHC, 25(OH)D serum levels and IL28B status are independently associated with the likelihood to achieve RVR and SVR. When incorporated into a pretreatment predictive model they can assist in further discriminating patients with a high likelihood of achieving RVR and SVR.
Monnaie et crise bancaire dans une petite économie ouverte
Authors: Cheng Jin
Published: April 2012

Résumé Cet article développe un modèle intégrant le rôle de la monnaie et des flux de capitaux internationaux afin d’examiner la fragilité du système bancaire d’une petite économie ouverte dans un contexte de crise financière internationale. Le modèle met l’accent sur les décalages de maturité et de devises au niveau du bilan des banques et illustre comment la contraction du crédit sur le marché financier international, via les banques commerciales, impacte la monnaie et l’activité d’une petite économie. Les effets stabilisants du capital bancaire et du ratio minimal de capital sur le système bancaire sont également examinés. Par ailleurs, le modèle souligne qu’un secteur informel de dimension importante est un facteur défavorable à la stabilisation de la valeur de la monnaie et du système financier. Classification JEL : G2, E4, F34
Évaluation de l'activité physique chez l'enfant en surcharge pondérale après un programme de réadaptation : le questionnaire contre l'accélérométrie
Authors: Vanhelst Jérémy , Béghin Laurent , Bui-Xuân Gilles , Mikulovic Jacques
Published: April 2012

Résumé Objectif  : Le but de l’étude est de comparer la mesure de l’activité physique (AP) en utilisant un questionnaire individuel d’activité physique et un accéléromètre. Méthodes  : La mesure de l’activité physique a été relevée chez vingt-huit jeunes obèses avec un accéléromètre RT3 et le questionnaire international d’activité physique, avant et après un programme d’intervention. Les temps d’AP passés dans la tranche « modérée à vigoureuse » (MVPA) ont été comparés. Résultats  : Avant l’intervention, les participants ont passé un temps de 116.1 minutes en moyenne en MVPA pendant une semaine, évaluées par accélérométrie, et 210.2 minutes évaluées par le questionnaire. Après l’intervention, les jeunes obèses ont passé 210.3 minutes versus 316.1 minutes par semaine en MVPA évaluée respectivement par accélérométrie et par questionnaire. Une différence significative a été trouvée entre les deux méthodes, avec une surestimation pour la technique subjective en comparaison avec la mesure objective. Conclusions  : Bien que les questionnaires soient simples d’utilisation et facilement administrables pour évaluer l’AP, leur utilisation a des limites. Des méthodes alternatives doivent être prises en compte pour mesurer l’AP chez les enfants et adolescents obèses.
Création de l'ENEP à Paris en 1933 et formation des enseignants d'éducation physique sous la IIIe République
Authors: Fouquet Gérard , Peter Jean-Michel
Published: April 2012

Résumé Le but de cette étude est de décrire quelques aspects de la formation des enseignants d’éducation physique. Dans un premier temps, il s’agit de rappeler à grands traits quelles étaient ses caractéristiques du milieu du XIX e  siècle jusqu’aux années 1920. Puis, à partir des procès-verbaux du conseil d’administration de la première École normale d’éducation physique créée en 1933, d’en montrer les changements, les innovations mais aussi les difficultés.
Endoscopic management of biliary injuries and leaks
Authors: Chandrasekar T. S. , Hussain Hameed , Murugesh M.
Published: April 2012

Bile duct injuries and subsequent leaks can occur following laparoscopic and open cholecystectomies and also during other hepatobiliary surgeries. Various patient related and technical factors are implicated in the causation of biliary injuries. Over a period of twenty five years managing such patients of biliary injuries our team has found a practical approach to assess the cause of biliary injuries based on the symptoms, clinical examination and imaging. Bismuth classification is helpful in most of the cases. Immediate referral to a centre experienced in the management of bile duct injury and timely intervention is associated with improved outcomes. Resuscitation, correcting dyselectrolytemia, aspiration of undrained biloma and antibiotics take the priority in the management. The goal is to restore the bile conduit, and to prevent short and longterm complications such as biliary fistula, intra-abdominal abscess, biliary stricture, recurrent cholangitis and secondary biliary cirrhosis. Endoscopic therapy by reducing the transpapillary pressure gradient helps in reducing the leak. Endoscopic therapy with biliary sphincterotomy alone or with additional placement of a biliary stent/nasobiliary drainage is advocated. In our tertiary care referral unit, we found endoscopic interventions are useful in situations where there is leak with associated CBD calculus or a foreign body, peripheral bile duct injury, cystic duct stump leak and partial bile duct injury with leak/narrowing of the lumen. Endotherapy is not useful in case of complete transection (total cut off) and complete stricture involving common hepatic or common bile ducts. In conclusion, endoscopic treatment can be considered a highly effective therapy and should be the first-line therapy in such patients. Though less successful, an endoscopic attempt is warranted in patients suffering from central bile duct leakages failing which surgical management is recommended.
Endoscopic management of pancreatic fluid collections
Authors: Rana Surinder S. , Bhasin Deepak K.
Published: April 2012

Pancreatitis, both acute and chronic, can lead on to various types of fluid collections that include pseudocysts, organized or walled off pancreatic necrosis (WOPN), and pancreatic abscess and these have been traditionally treated by surgery. The advancement in the endoscopic technology and instruments including the availability of therapeutic endoscopic ultrasound (EUS) has opened up an era of minimally invasive, safe and effective endoscopic drainage of pancreatic fluid collections (PFC). Endoscopic drainage is to be done only in symptomatic patients and it can be accomplished either through the transpapillary, transmural, or using a combination of these two routes. The decision to use one approach over the other depends on the size of the PFC, its proximity to the stomach or duodenum, presence of solid necrotic debris and the ability to enter the pancreatic duct and/or reach the area of disruption. EUS guided drainage should be considered in patients with non-bulging fluid collections, high pretest probability of bleeding, prior failed transmural entry using non-EUS guided technique and, collections inaccessible by standard technique like those located at the tail end of the pancreas.
Endoscopic management of recurrent pancreatitis
Authors: Lehman Glen A.
Published: April 2012

Endoscopic therapy is a well-established, valuable alternative to surgery for the treatment of a variety of biliary tract diseases. Applications of similar techniques to the pancreas continue to develop. Encouraged by the recognition of the relative safety of ERCP and endoscopic sphincterotomy (ES) for gallstone pancreatitis, endoscopic therapy is now being applied in the setting of acute pancreatitis of other etiologies, chronic pancreatitis, complications of acute or chronic pancreatitis, and pancreas divisum.
Prevention of post endoscopic retrograde cholangiopancreatography pancreatitis
Authors: Guda Nalini M.
Published: April 2012

Post ERCP pancreatitis (PEP) is a common problem. Knowledge of patient and procedure related risk factors along with appropriate measures aimed at reduction of risk have been successful in reducing both the incidence and the severity. Prophylactic pancreatic duct stenting has definitely reduced the incidence and the severity of PEP in high risk patients. There are some emerging data on the use of non steroidal anti inflammatory agents though this is not widely adapted in practice. Key is to avoid procedures with marginal indications and use of non invasive/less invasive procedures.
Particle backscatter and relative humidity measured across cirrus clouds and comparison with state-of-the-art cirrus modelling
Authors: Brabec M. , Wienhold F. G. , Luo B. , Vömel H. , Immler F. , Steiner P. , Peter T.
Published: April 2012

Abstract. Advanced measurement and modelling techniques are employed to determine the partitioning of atmospheric water between the gas phase and the condensed phase in and around cirrus clouds, and thus to identify in-cloud and out-of-cloud supersaturations with respect to ice. In November 2008 the newly developed balloon-borne backscatter sonde COBALD (Compact Optical Backscatter and AerosoL Detector) was flown 14 times together with a CFH (Cryogenic Frost point Hygrometer) from Lindenberg, Germany (52° N, 14° E). The case discussed here in detail shows two cirrus layers with in-cloud relative humidities with respect to ice between 50% and 130%. Global operational analysis data of ECMWF (roughly 1° × 1° horizontal and 1 km vertical resolution, 6-hourly stored fields) fail to represent ice water contents and relative humidities. Conversely, regional COSMO-7 forecasts (6.6 km × 6.6 km, 5-min stored fields) capture the measured humidities and cloud positions remarkably well. The main difference between ECMWF and COSMO data is the resolution of small-scale vertical features responsible for cirrus formation. Nevertheless, ice water contents in COSMO-7 are still off by factors 2–10, likely reflecting limitations in COSMO's ice phase bulk scheme. Significant improvements can be achieved by comprehensive size-resolved microphysical and optical modelling along backward trajectories based on COSMO-7 wind and temperature fields, which allow accurate computation of humidities, ice particle size distributions and backscatter ratios at the COBALD wavelengths. However, only by superimposing small-scale temperature fluctuations, which remain unresolved by the NWP models, can we obtain a satisfying agreement with the observations and reconcile the measured in-cloud non-equilibrium humidities with conventional ice cloud microphysics.
An isotopic (Δ14C, δ13C, and δ15N) investigation of particulate organic matter and zooplankton biomass in Lake Superior and across a size-gradient of aquatic systems
Authors: Zigah P. K. , Minor E. C. , Werne J. P. , Leigh McCallister S.
Published: April 2012

Abstract. Food webs in aquatic systems can be supported both by carbon from recent local primary productivity and by carbon subsidies, such as material from terrestrial ecosystems or past in situ primary productivity. The importance of these subsidies to respiration and biomass production remains a topic of debate, but they may play major roles in determining the fate of organic carbon and in sustaining upper trophic levels, including those contributing to economically important fisheries. While some studies have reported that terrigenous organic carbon supports disproportionately high zooplankton production, others have suggested that phytoplankton preferentially supports zooplankton production in aquatic ecosystems. Here we apply natural abundance radiocarbon (Δ14C) and stable isotope (δ13C, δ15N) analyses to show that zooplankton in Lake Superior selectively incorporate recently-fixed, locally-produced (autochthonous) organic carbon even though other carbon sources are readily available. Estimates from Bayesian isotopic modeling based on Δ14C values show that the average lakewide median contributions of recent in situ algal, terrestrial, sedimentary, and bacterial organic carbon to the bulk POM in Lake Superior were 23%, 28%, 15%, and 25%, respectively. However, the isotopic modeling estimates show that recent in situ production (algae) contributed a disproportionately large amount (median, 40–89%) of the carbon in zooplankton biomass in Lake Superior. Although terrigenous organic carbon and old organic carbon from resuspended sediments were significant portions of the available basal food resources, these contributed only a small amount to zooplankton biomass (average lakewide median, 2% from sedimentary organic carbon and 9% from terrigenous organic carbon). Comparison of zooplankton food sources based on their radiocarbon composition showed that terrigenous organic carbon was relatively more important in rivers and small lakes, and the proportion of terrestrially-derived material used by zooplankton correlated with the hydrologic residence time and the ratio of basin area to water surface area.
Quality assessment concept of the World Data Center for Climate and its application to CMIP5 data
Authors: Stockhause M. , Höck H. , Toussaint F. , Lautenschlager M.
Published: April 2012

Abstract. The preservation of data in a high state of quality and suitable for interdisciplinary use is one of the most pressing and challenging current issues in long-term archiving. For high volume data such as climate model data, the data and data replica are no longer stored centrally but distributed over several local data repositories, e.g. the data of the Climate Model Intercomparison Project No. 5 (CMIP5). The most important part of the data is to be published as DOI according to the World Data Center for Climate's (WDCC) application of the DataCite regulations. The integrated part of WDCC's data publication process, the data quality assessment, was adapted to the requirements of a federated data infrastructure. A concept of a distributed and federated quality assessment procedure was developed, in which the work load and responsibility for quality control is shared between the three primary CMIP5 data centers: Program for Climate Model Diagnosis and Intercomparison (PCMDI), British Atmospheric Data Centre (BADC), and WDCC. This distributed quality control concept, its pilot implementation for CMIP5, and first experiences are presented.
Joint statistical correction of clutters, spokes and beam height for a radar climatology in Southern Germany
Authors: Wagner A. , Seltmann J. , Kunstmann H.
Published: April 2012

Abstract. Extensive corrections of radar data are a crucial prerequisite for radar derived climatology. This kind of climatology demands a high level of data quality. Little deviations or minor systematic underestimations or overestimations in single radar images become a major cause of error in statistical analysis. First results of radar derived climatology have emerged over the last years, as data sets of appropriate extent are becoming available. Usually, these statistics are based on time series lasting up to ten years as storage of radar data was not achieved before. We present a new statistical post-correction scheme, which is based on seven years of radar data of the Munich weather radar (2000–2006) that is operated by DWD (German Weather Service). The typical correction algorithms for single radar images, such as clutter corrections, are used. Then an additional statistical post-correction based on the results of a climatological analysis from radar images follows. The aim of this statistical correction is to correct systematic errors caused by clutter effects or measuring effects but to conserve small-scale natural variations in space. The statistical correction is based on a thorough analysis of the different causes of possible errors for the Munich weather radar. This robust analysis revealed the following basic effects: the decrease of rain rate in relation to height and distance from the radar, clutter effects such as remaining clutter, eliminated clutter or shading effects from obstacles near the radar, visible as spokes, as well as the influence of the Bright Band. The correction algorithm is correspondingly based on these results. It consists of three modules. The first one is an altitude correction, which minimizes measuring effects. The second module corrects clutter effects and the third one realizes a mean adjustment to selected rain gauges. Two different radar products are used. The statistical analysis as well as module one and module two of the correction algorithm are based on frequencies of occurrence of the so-called PX-product with six reflectivity levels. For correction module 3 and for the validation of the correction algorithm rain rates are calculated from the 8-bit-depth so-called DX-product. An application (2004–2006) and a validation (2007–2009) of this correction algorithm with rain gauges show a much higher conformity for radar climatology after the statistical correction. In the years 2004 to 2006 the Root-Mean-Square-Error (RMSE) decreases from 262 mm to 118 mm excluding those pair of values where the rain gauges are situated in areas of obviously corrupted radar data. The results for the validation period 2007 to 2009 are based on all pairs of values and show a decline of the RMSE from 322 mm to 174 mm.
Synchrony Relationships between the Left Ventricle and a left Ventricular Assist Device: An Experimental Study in Pigs
Authors: Heredero Angeles , Perez-Caballero Ramon , Otero Javier , Rodríguez-Martínez Daniel , Quintana-Villamandos Begoña , Rodríguez-Bernal Guillermo , González-Pinto Ángel , Ruiz-Fernandez Manuel , Del Cañizo Juan F.
Published: April 2012

Background:

Synchronization between the left ventricle and a left ventricular assist device (LVAD) may be important for ventricular unloading and coronary perfusion. We assessed the synchrony between cardiac and LVAD cycles by increasing delays in steps of 100 msec throughout the cycle, under conditions of total and partial left ventricular support.

Methods:

We studied 7 healthy minipigs weighing 30–40 kg. A 60–cc Berlin Heart Excor LVAD was implanted and connected to a BCM 1200 console, making it possible to synchronize the LVAD systole and the EKG signal with a prefixed delay. We recorded hemodynamic parameters (including aortic, pulmonary, and left ventricular pressure) and LVAD flow for each delay.

Results:

Intraventricular pressure during LVAD systole was minimized with delays of around 40–80% of one cycle. In addition, total flow was higher under these conditions.

Conclusions:

This study shows that the synchronous mode of LVAD operation is feasible. Moreover, a delay in device contraction until the second half of the cardiac cycle optimizes ventricular unloading and may eventually improve myocardial recovery.
Factors Influencing the Transfer of Porcine Endogenous Retroviruses across the Membrane in Bioartificial Livers
Authors: Shi Xiao-Lei , Han Bing , Tan Jia-Jun , Yuan Xianwen , Zhang Yue , Xiao Jiang-Qiang , Gu Zhong-Ze , Ding Yi-Tao
Published: April 2012

Objectives:

to investigate the factors influencing the transfer of porcine endogenous retroviruses (PERVs) across the membrane in a new bioartificial liver (BAL).

Methods:

A new BAL containing 2 circuits was constructed using plasma component separators with membrane pore sizes of 10 nm, 20 nm, 30 nm, and 35 nm, or a plasma filter with a membrane pore size of 500 nm. Cocultured cells of porcine hepatocytes and mesenchymal stem cells or single porcine hepatocytes were incubated in the bioreactors, and the BAL worked for 72 hours, with supernatant samples in internal and external circuits collected every 12 hours. PERV RNA, reverse transcriptase (RT) activity, and in vitro infectivity of the supernatant were detected.

Results:

With the plasma filters, the results of PERV detection were the same in both circuits. With plasma component separators, PERV RNA was found in the external circuits, but no positive RT activity or HEK293 cell infection was found. The time at which the PERV RNA was first detected varied with the pore size of membrane; the larger the membrane pore size was, the earlier the RNA was detected. The PERV RNA level in the external circuits was reduced significantly compared with that in the internal circuits at any detecting time.

Conclusions:

The plasma component separators with membrane pore size ≤35 nm could significantly reduce the passage of infectious PERVs. And the membrane pore size, the treatment duration, and the viral level in the internal circuit were potential factors influencing the transfer of PERVs across the membrane in a BAL. In addition, a low risk of PERV transmission from porcine hepatocytes to human cells was found.
Computational Modeling of Effects of Mechanical Shaking on Hemodynamics in Hollow Fibers
Authors: Kim Jeong Chul , Garzotto Francesco , Cruz Dinna N. , Clementi Anna , Nalesso Federico , Kim Ji Hyun , Kang Eungtaek , Kim Hee Chan , Ronco Claudio
Published: April 2012

Introduction:

Blood-membrane interaction during hemodialysis develops a secondary protein layer on the dialysis membrane surface, resulting in reduction of hemodialyzer performance. Wall shear stress at the surface of the hollow-fiber membrane is one of the determinant factors able to influence dialysis efficiency. Shaking of hemodialyzer during treatment could increase the wall shear stress of the membrane, which could enhance hemodialyzer performance.

Methods:

In this study, hemodynamic changes in hollow fibers were analyzed using computational fluid dynamics software for various shaking conditions of hemodialyzer (longitudinal, transverse, rotational motions).

Results:

Longitudinal motion induced reverse flow, while transverse motion induced symmetric swirling inside the hollow fiber. During rotational motions, nonuniform vortices were developed according to the rotational radius of the hollow fiber. These changes in flow pathlines induced by different shaking profiles increased the relative motion of blood, transmembrane pressure, and wall shear stress on dialysis membrane surfaces. Both longitudinal and transverse shaking profiles showed a linear relationship between shaking velocity (the product of amplitude and frequency) and wall shear stress.

Conclusion:

Performance of hemodialyzer can be enhanced with simple mechanical shaking motions, and optimal shaking profiles for clinical application can be investigated and predicted with the computational fluid dynamics model proposed in this study.
RESERVOIR MODELING OF DEEPWATER CLASTIC SEQUENCES: MESOSCALE ARCHITECTURAL ELEMENTS, ASPECT RATIOS AND PRODUCIBILITY
Authors: COSSEY STEPHEN P.J.
Published: April 2012

The geoscientist is usually the provider of semi-quantitative data on deepwater clastic architectural elements in the integrated reservoir modeling process. These data can take the form of aspect ratios, vertical and lateral frequencies, or orientations. The arrangement and internal variability of the elements determines the ratio of vertical to horizontal permeability (KV/KH), lateral continuity, and connectivity of the full reservoir model. These three factors ultimately determine the reservoir behavior or producibility. In high net/gross deepwater clastic systems, connectivity of the reservoir is not usually a problem. The size and distribution of architectural elements such as high permeability zones and permeability barriers affect the KV/KH and lateral continuity of reservoirs. Permeability barriers may take the form of shale, concretionary layers, and sandstone that is poorly-sorted. However, in low net/gross systems the lateral continuity of the reservoir “beds” and the presence, absence, and abundance of sedimentary injection features and bioturbation are critical to the connectivity and behavior of the reservoir.

Stochastic models rely on the accuracy of the input variables, where knowledge of the aspect ratios of architectural elements is essential. Stochastic reservoir models of two fields are used as examples of how individual architectural elements might affect the reservoir performance.
FIELD DEVELOPMENT, DEPOSITIONAL MODEL, AND PRODUCTION PERFORMANCE OF THE TURBIDITIC “J” SANDS AT PROSPECT BULLWINKLE, GREEN CANYON 65 FIELD, OUTER-SHELF GULF OF MEXICO
Authors: Holman William E. , Robertson Stephen S.
Published: April 2012

The Green Canyon 65 Field (GC 65) is located approximately 150 miles southwest of New Orleans, Louisiana in the Gulf of Mexico. The field was developed between 1988 and 1990 from a single 60-slot conventional platform in 1,353 feet of water. GC 65 is expected to produce in excess of 90 MMBO and 170 BCF, 90% of which is contained within the prolific “J” sand sequence. The field’s daily production has consistently exceeded 50,000 BO and 90 MMCFG from 19 producing wells since full scale production began in 1991.

The field lies along the margin of a Plio-Pleistocene salt withdrawal mini-basin. Salt had some influence on “J” sand deposition; however, the primary trap is stratigraphic onlap against a broad lowstand valley. The “J” package consists of numerous interconnected turbidite sheet and channel sands (“J1,” “J2,” “J3,” “J4”). Grain size and bedding style indicate that depositional energy increased upward within the package; the upper surface of the package is defined by multiple erosional unconformities, reflecting sediment bypass as the basin filled.

Integration of multiple 3D seismic surveys, well control, evolving geologic models, produce-while-drilling data, and reservoir simulations optimized the development of Bullwinkle, one of the Gulf of Mexico’s premier oil reservoirs.

Our understanding of the “J” sand reservoirs continues to evolve as production data are incorporated into the subsurface model, reservoir simulator, and compared with seismic/well control. Production has confirmed extensive lateral continuity within individual sands as well as intercommunication between sand members. Aquifer/pressure support is also greater than anticipated. Understanding the reservoir architecture of both the “J” sand package as well as its individual members is considered fundamental in developing an effective reservoir management scheme.
RESERVOIR GEOMETRY AND ARCHITECTURE OF PRODUCTIVE UPPER CRETACEOUS MUD-RICH AND SAND-RICH SUBMARINE-FAN SYSTEMS, SACRAMENTO BASIN, CALIFORNIA
Authors: Nilsen Tor H. , Imperato Douglas P. , Moore Donald W.
Published: April 2012

The Forbes Formation (Santonian and lower Campanian) and Winters Formation (upper Campanian and lower Maastrichtian) are highly productive turbidite reservoirs in the Sacramento forearc basin of northern California. However, their reservoir geometries and architectures differ markedly, chiefly as a result of differences in sediment supply and orientation of sediment input into the basin.

The Forbes Formation has been penetrated by thousands of wells and is productive in about 50 gas fields. It consists, in ascending stratigraphic order, of four major architectural elements that can be distinguished in well logs, seismic-reflection data, and outcrop: (1) a basal massive, concretionary basinwide mudstone, the Dobbins Shale Member, interpreted to be a condensed section deposited during a sea-level highstand; (2) an interval of shale with abundant laterally continuous thin-bedded and fine-grained turbidites interpreted to be a basin-plain succession; (3) a thick interval of mudstone with interbedded sandy and silty turbidites, interpreted to be a mud-rich submarine fan dominated by meandering channel-levee complexes that form the principal reservoir units; and (4) an upper interval of mostly mudstone with laterally discontinuous sandstone bodies incised into south-sloping clinoforms, interpreted to be a muddy slope succession containing abundant sandstone-filled gullies. The deep-marine system was fed by a south-prograding fluvial-dominated delta, the Kione Formation. Both units are overlain by a second basinwide massive mudstone, the Sacramento Shale. The meanderform, ribbon-shaped channel-levee complexes, oriented subparallel to the structural axis of the basin, produce from a variety of traps.

The overlying Winters Formation in the central and southern Sacramento basin has also been penetrated by thousands of wells, and produces from about 40 gas fields. It overlies the Sacramento Shale, interpreted to have been deposited as a condensed section during a long sea-level highstand. The Winters Formation consists, in ascending stratigraphic order, of (1) an interval of mostly shale interpreted to be a basin-plain succession, (2) a complex of pod-shaped sandstone bodies interpreted to have been deposited as sand-rich submarine fans dominated by suprafan-type sandstone bodies that form the principal reservoir units, and (3) muddy slope deposits that contain southwest-dipping clinoforms incised by prominent sandstone-filled submarine canyons. The deep-marine system was fed by a complex of west- and southwest-prograding wave-dominated deltas of the Starkey Formation. The small, pod-shaped submarine fans and pod-shaped suprafan sandstone bodies produce from a variety of traps, and provide a model for other sand-rich, delta-fed submarine-fan systems deposited in restricted basins with modest amounts of shelf accommodation space.
STRATIGRAPHIC AND STRUCTURAL COMPARTMENTALIZATION OBSERVED WITHIN A ‘MODEL TURBIDITE RESERVOIR,’ PENNSYLVANIAN UPPER JACKFORK FORMATION, HOLLYWOOD QUARRY, ARKANSAS
Authors: SLATT ROGER M. , JORDAN DOUGLAS W. , STONE CHARLES G. , WILSON MICHAEL S.
Published: April 2012

Hollywood Quarry is a 600 X 375 X 150 ft. (200 X 125 X 50m) excavation which provides a window into lower Pennsylvanian Jackfork Formation turbidite stratal architecture along the crest of a faulted anticlinal fold. A variety of turbidite facies are present, including: (a) lenticular, channelized sandstones, pebbly sandstones, and conglomerates within shale, (b) laterally continuous, interbedded thin sandstones and shales, and (c) thicker, laterally continuous shales. The sandstone and shale layers are broken by several strikc-slip and reverse faults, with vertical displacements of up to several feet. This combination of facies and structural elements has resulted in a highly compartmentalized stratigraphic interval, both horizontally and vertically, along the anticlinal flexure.

The quarry can be considered analogous to a scaled-down turbidite reservoir. Outcrop gamma-ray logs, measured sections, a fault map, and cross sections provide a database which is analogous to what would be available for a subsurface reservoir. Thus, the quarry provides an ideal outdoor geologic and engineering ‘workshop’ venue for visualizing the potential complexities of a combination stnictural-stratigraphic (turbidite) reservoir. Since all forms of compartmentalization are readily visible in the quarry, problems related to management of compartmentalized reservoirs can be discussed and analyzed first-hand while standing in the quarry, within this ‘model reservoir’. These problems include: (a) the high degree of stratigraphic and structural complexity that may be encountered, even at close well spacings, (b) uncertainty in well log correlations and log-shape interpretations, (c) variations in volumetric calculations as a function of amount of data available, and (d) potential production problems associated with specific ‘field’ development plans.
REGIONAL SEQUENCE STRATIGRAPHIC SETTING OF THE MISSISSIPPI FAN COMPLEX, NORTHERN DEEP GULF OF MEXICO: IMPLICATIONS FOR EVOLUTION OF THE NORTHERN GULF BASIN MARGIN
Authors: Weimer Paul , Dixon Barrett T.
Published: April 2012

The Mississippi Fan Complex is a large submarine fan unit in the deep northern Gulf of Mexico. This complex comprises two distinct submarine fans: the Western and Eastern Fan. Regional mapping of the continental slope and deep basin have further refined the interpretation for the evolution of this area in the Gulf of Mexico. The Western Fan consists of seventeen depositional sequences that were deposited during the late Miocene (5.5 Ma) to the Present. At least seven discrete submarine canyons located in the Ewing Bank, Green Canyon, and Mississippi Canyon lease areas can be traced downslope to their terminus in the equivalent channel-levee systems. The Eastern Fan consists of eight depositional sequences that are coeval to sequences 8-11, 13-16 in the Western Fan. The submarine canyons that fed diese channel-levee systems are located immediately due east of the modem Mississippi bird-foot delta.

Internally, the depositional sequences of the Western and Eastern Fans had similar stratigraphie evolution. Erosional surfaces (sequence boundaries) are at the base of most sequences in the Western Fan amd are overlain by mass transport complexes. In the Eastern Fan, there is generally less erosion at die base of die sequences and mass transport complexes arc generally absent. Channel-levee systems comprise the bulk of the sediments in both fans and can be mapped in both fans. However, the channels in die Eastern Fan are considerably smaller in dimensions than the Western Fan; the eastern channels also have less lateral migration, less sinuosity, and fewer downfan avulsion of channels than the coeval channels in die Western Fan. Large portions of diree sequences in die Eastern Fan consist of in situ slides.

The correlation of die coeval fan sequences between the Eastern and Western Fans lends further evidence of the eustatic control on die timing of these depositional sequences. Compilation of regional work from the slope and shelf areas has also led to the refinement of the age dates of the Mississippi Fan Complex sequences. Sequences 14-17 are now recognized to be 70,000 years to the Present. Sequences 6-13 are interpreted to be 1.9 to 0.40 Ma. Sequences 1-5 are interpreted to be 5.5 to 3.0 Ma. Two major stacked condensed sections are present in the fan: 3.0 to 1.9 Ma, and 0.4 to 0.07 Ma. The development of die condensed sections reflects major avulsions and shifts in the position of the feeding deltaic systems on the continental shelf.
Analysis of Gravity-Flow Depositional Systems From 3-D Seismic Data: Neogene Deposits of the Niger Delta Slope
Authors: Armentrout John M. , Kanschat Katherine A. , Meisling Kristian E. , Tsakma Jerome J. , Antrim Lisa , McConnell Dennis R.
Published: April 2012

Gravity-flow depositional systems of a portion of the Niger delta slope are imaged and documented in seismic amplitude extraction and coherency displays from a large 3-D seismic volume. The displays are extracted immediately above regionally significant sequence boundaries. Interpretation of the 3-D seismic reflection volume demonstrates the strength of combining seismic sequence stratigraphic analysis methodology with the turbidity system architectural element framework.

Each of the gravity-flow systems consists of confined-flow channel-form elements grading down slope into less confined flow, lobe-to sheet-form elements. The Niger slope depositional systems are confined to slope-valley and slope-basin bathymetric lows. The valleys are bounded by densely faulted, structurally complex zones clearly imaged on coherency processed 3-D time slices but poorly imaged on 2-D profiles where they have been previously interpreted as zones of shale diapirism.

Restoration of the valley systems suggests that they had very low relief paleo-bathymetric profiles similar to those observed on the present sea floor. Lower slope basins are “piggy-back” basins above toe thrusts linked to deep-seated gravity-driven, extensional failure of the slope.

Each gravity-flow depositional system consists of three architectural segments: (1) upper slope, small-scale channel elements converging down slope into, (2) singlechannel and nested-channel elements with linear to sinuous map patterns, grading farther down slope into, (3) slope basin lobe and sheet elements. Three types of channel elements are observed: (1) erosional, (2) erosional-depositional, and (3) depositional. The depositional channel elements have geometries strongly suggestive of channel-levee-overbank complexes, indicating that transport must include turbidity-flow processes. In one case, the gradation from mapped channel to lobe to fan elements occurs over less than 1 km (0.65 mi). Within the sheets, lateral accretion of depositional elements suggests compensation sedimentation composed of amalgamated depositional events.

Mapped amplitude patterns of the sequences suggest switching of the inferred sand-prone depositional system from one slope valley to another through time. This is interpreted to reflect both the lateral shifting of the fluvial sediment supply on the shelf, and the local tectonic modification of valley system bathymetry.

The 3-D seismic reflection volume resolves the depositional systems formed by gravity-flow processes through all mapped sequences of the study area. These depositional systems occur within the stratigraphic interval immediately above seismic sequence boundaries and consist of depositional elements known to occur in other modern and ancient turbidite systems.
Geological Heterogeneities and Reservoir Model Based on Facies Architecture of Middle Mississippian Salem Grainstone Shoal, Illinois Basin
Authors: Ahmad Nadeem , Saller Arthur H.
Published: April 2012

Internal architecture, three scales of reservoir heterogeneity, and porosity-permeability compartments can be reconstructed for Middle Mississippian Salem Limestone reservoirs of the Illinois Basin by integrating bedform architecture, depositional fabrics, and trends of porosity development. In sawed quarry walls of south-central Indiana, excellent exposures of the Salem Limestone allow detailed mapping of a wide range of bedforms representative of an extremely dynamic hydrographic regime similar to that of the shoreface zones of siliciclastic shelves. Echinoderm- and bryozoa-rich grainstones and fossiliferous oolitic grainstones are the predominant depositional facies and were deposited as subtidal shoals in an upper shore-face setting. Vertical and spatial relationships of facies and bedforms reveal hierarchies of depositional units and bounding surfaces that have been used to reconstruct four architectural packages (AP’s) of the scale of mesoforms.

AP-I is a channelized mesoform that defines a NNE-SSW intrashoal channel. AP-II is a large storm-deposited sandwave complex that filled the channel. AP-III is a dark-gray grainstone/packstone that grades laterally into packstones and was deposited in a relatively low energy setting. AP-IV consists of oscillatory trough cross-stratified megaripples of oolitic grainstones. Numerous stylolites occur and add to the mesoscale heterogeneity. Together, microfacies, bedforms, and bounding surfaces compartmentalize porosity and permeability and lead to micro- and mesoscale heterogeneities within the mesoform scale architectural packages.

Lessons learned from such outcrop models can be applied to the producing Salem reservoirs in the subsurface. Here, in the distal parts of the inner ramp, the shoal complex is even more compartmentalized because each AP is represented by a “complete” suite of upward-shallowing facies: a basal outer shelf sponge-spicular wackestone, a main shoal grainstone, and an overlying restricted marine lagoonal wackestone. When integrated with mercury-injection capillary-pressure and production data, these packages and respective scales of reservoir heterogeneity help delineate flow units for reservoir characterization and simulation purposes and determine how the reservoir facies will drain during primary and secondary recovery. The results can also be used to reduce uncertainty (geologic risk) during the pre-drill economic assessment, field appraisal, and development phases.
Bayfill Successions in the Lower Jurassic Åre Formation, Offshore Norway: Sedimentology and Heterogeneity Based on Subsurface Data from the Heidrun Field and Analog Data from the Upper Cretaceous Neslen Formation, Eastern Book Cliffs, Utah
Authors: Kjærefjord J. M.
Published: April 2012

Interdistributary bays form a major sedimentary subenvironment within many delta systems. These interdistributary bays occur as open bodies of water that are typically open to the sea. They may cover large areas of the lower delta plain and are normally surrounded by marsh and distributary-channel features. The interdistributary bay deposits in the Åre Formation of Heidrun field, offshore Norway, and in the Neslen Formation, Utah, occur as shallow, 2- to 7-km-wide features that were deposited in brackish to marine waters. Within these bays, low-energy wave action reworked a large proportion of the sedimentary features, such as crevasse splays, bayhead deltas, and distributary-mouth bars. The resulting wave-influenced bayfill lithofacies association (WLA) shows a relatively similar vertical development of lithofacies in both the Åre and the Neslen Formations. Normally the WLA is 2 to 8 m thick and contains a basal mudstone overlain by a wave-influenced lenticular and/or wavy-bed-ded heterolithic unit. The upper few meters consists of wave-rippled and small-scale hummocky cross-laminated sandstone with good reservoir qualities. Roots or coal or both are present at the top. Within the sandstone, mud drapes or heterolithic layers are common. In the Neslen Formation these drapes seem to be concentrated along gently dipping clinoform surfaces. Laterally, along the depositional strike and landward, the reservoir quality changes abruptly as the WLA passes into the bayhead delta, marsh, sub-bay/lake, and distributary-channel-fill lithofacies associations. Although individual bayfill successions are relatively thin, continuing subsidence and repetition of similar processes resulted in a stacking of one bayfill succession on top of another, building an 80-m-thick package of lower delta plain deposits.
Knowledge Capture and Reuse in Geological Modeling
Authors: Bryant D. , Kaufman P. S. , McCormick D. S. , Tilke P. G.
Published: April 2012

Geologists have always used analogy to assist their interpretations, and until recently, this has meant that a considerable period was required for geologists to develop interpretation expertise in a new geographic region or a new field of geology. The advent of modern graphical workstations offers the opportunity for geologists to gain access to knowledge outside of their previous personal experience by accessing online geological knowledge. This knowledge, gained from previous expert interpretation of analogous outcrops or fields, is then explicitly used to rigorously constrain the interpretation of 3D geometries of depositional units or structural elements.

We illustrate our approach to knowledge capture and reuse by showing how interpretations may be stored in association with the parameters required to build 3D interpretations from well and seismic data. We show how digital images from analogous outcropping formations, cores, borehole imaging tools, and seismic horizon displays may be stored in an archive database and subsequently retrieved using an intuitive query tool. Once these interpretations have been retrieved, they may be readily compared with new data by using a common viewing environment to visualize all data types. Visual comparison of the new data with the previously interpreted data is augmented by consistency checks using associated data stored in the database. In this way, interpretation expertise may be captured and reused by less experienced interpreters to construct 3D digital hypotheses of subsurface reservoir geometries.