bluuebunny/crossref_metadata_2025_split huggingface dataset:
Targets for hydrogen-peroxide-induced damage to suspension and biofilm cells of Streptococcus mutans
Authors: Baldeck Jeremiah D. , Marquis Robert E. 
Published: October 2008

Hydrogen peroxide (H2O2) is considered a major endogenous source of oxidative stress to oral bacteria and also is widely used in oral care products. Our study objectives were to identify specific targets for H2O2-induced damage to cells of Streptococcus mutans in suspensions and monospecies biofilms and to differentiate bacteriostatic and bactericidal actions of the peroxide. Streptococcus mutans was grown in suspension cultures and fed-batch biofilms for assessing relative sensitivities of viability, glycolysis, and protein synthesis to H2O2 damage. Biofilm cells were found to have essentially the same peroxide sensitivity as cells in suspensions. H2O2 at low concentrations of about 16.3 mmol/L was highly inhibitory for glycolysis and mainly bacteriostatic. The most sensitive target detected for glycolytic inhibition was glyceraldehyde-3-phosphate dehydrogenase with IC50 (50% inhibitory concentration) values of ca. 2.2 mmol/L for suspension cells and 2.3 mmol/L for biofilms with 15 min treatments. The phosphoenolpyruvate:glucose phosphotransferase pathway was less sensitive with an IC50 of ca. 10 mmol/L. Aldolase was not inhibited at bacteriostatic concentrations of the peroxide. For suspensions and biofilms, acidification somewhat diminished peroxide sensitivity, while increased temperature enhanced sensitivity. At concentrations above about 30 mmol/L, H2O2 became mainly bactericidal but not mutagenic for S. mutans. A major target for bactericidal damage was protein synthesis, thus rendering cells incapable of repairing or replacing oxidatively damaged proteins.
Film coating of seeds with Bacillus cereus RS87 spores for early plant growth enhancement
Authors: Jetiyanon Kanchalee , Wittaya-Areekul Sakchai , Plianbangchang Pinyupa 
Published: October 2008

The plant growth-promoting rhizobacterium Bacillus cereus RS87 was previously reported to promote plant growth in various crops in both greenhouse and field trials. To apply as a plant growth promoting agent with practical use, it is essential to ease the burden of routine preparation of a fresh suspension of strain RS87 in laboratory. The objectives of this study were to investigate the feasibility of film-coating seeds with B. cereus RS87 spores for early plant growth enhancement and to reveal the indoleacetic acid (IAA) production released from strain RS87. The experiment consisted of the following 5 treatments: nontreated seeds, water-soaked seeds, film-coated seeds, seeds soaked with vegetative cells of strain RS87, and film-coated seeds with strain RS87 spores. Three experiments were conducted separately to assess seed emergence, root length, and plant height. Results showed that both vegetative cells and spores of strain RS87 significantly promoted (P ≤ 0.05) seed emergence, root length and plant height over the control treatments. The strain RS87 also produced IAA. In conclusion, the film coating of seeds with spores of B. cereus RS87 demonstrated early plant growth enhancement as well as seeds using their vegetative cells. IAA released from strain RS87 would be one of the mechanisms for plant growth enhancement.
Multidisciplinary stochastic impedance inversion: integrating geological understanding and capturing reservoir uncertainty
Authors: Rowbotham P. S. , Marion D. , Lamy P. , Insalaco E. , Swaby P. A. , Boisseau Y. 
Published: October 2008

Stochastic (or geostatistical) impedance inversion techniques have great potential in addressing key questions in reservoir characterization. They work at the vertical scale of reservoir models and, therefore, at higher resolution than the seismic data. They produce multiple equiprobable results which provide an assessment of, the uncertainties, and they are ideally suited for integrating non-seismic information in the inversion process. However, two issues have slowed the acceptance of stochastic impedance inversion techniques. First, there is suspicion of‘ unconstrained random noise generators’, which appear to offer extra information for free, and, secondly, managing and extracting value from multiple realizations is difficult. For these reasons, faster deterministic inversion approaches, resulting in a single lower-resolution impedance volume, with less quantified uncertainty, are more commonly used when building reservoir models.
To address the first issue, we have developed ways of integrating 3D constraints from sedimentary modelling with the geostatistical impedance inversion method, since these two approaches bring complementary information on reservoir properties. The resulting high-resolution multiple realizations of impedance are combined with uncertainties from petrophysical regression analysis to produce multiple realizations of reservoir properties (e.g. porosity), and from each an estimate of total pore volume. We illustrate the benefits of this multiple realization work flow applied to data from a shallow marine siliciclastic reservoir. A comparison of the seismic/sedimentologically constrained reservoir models with those constrained by well data only has demonstrated more accuracy and better control on the spatial variability of reservoir properties. In this example, however, adding more constraints results in a broader range of possible reservoir models and a more meaningful uncertainty assessment. We conclude that our models constrained by well data only were derived with unrealistic simulation parameters and an over-optimistic assessment of a priori uncertainty.
Overview of global 4D seismic implementation strategy
Authors: Waal Hans de , Calvert Rodney 
Published: October 2008

For many Shell-operated fields around the world, time-lapse reservoir monitoring (4D) is now an integral part of field management and some 25 dedicated 4D surveys were acquired for this purpose by the end of 2002. This widespread application is the result of a focused implementation effort aimed at global deployment to maximize the value extracted from the surveys in terms of saved costs, increased production, increased recovery and improved HSE management, where effective implementation is achieved through a combination of global operatorship and technology capability.
Apart from ensuring global deployment, there is the challenge to extend the range of 4D applicability. To achieve this the project has three application portfolios:

today's‘ proven’ 4D technology portfolio, which is about monitoring fluid movements in thick clastic oil reservoirs offshore. Results come largely from comparing reservoir simulator output with difference maps derived from repeat 4D streamer surveys;

a‘ stretch’ portfolio where the technology is applied to gas reservoirs, land data, stacked reservoirs, carbonate fields and to the monitoring of pressure changes;

a‘ tomorrow's technology’ portfolio, which has the potential to increase the application base even further. The new technologies are about the use of permanent arrays, downhole acquisition, passive listening and ‘smart fields’ where semi-continuous 4D monitoring provides eyes and ears between the wells.

More and more value is realized as 4D becomes fully integrated with subsurface work flows and modelling tools. Benefits from 4D technology for individual fields can be in the tens or hundreds of millions of dollars. A large fraction of these come from 4D surprises, illustrating that we tend to underestimate our uncertainties and suggesting different approaches to field management.
The Rotliegend reservoir in Block 30/24, UK Central North Sea: including the Argyll (renamed Ardmore) and Innes fields
Authors: Heward Alan P. , Schofield Paul , Gluyas Jon G. 
Published: October 2008

Rotliegend Auk Formation sandstones form the second most productive reservoir in the 30/24 fields and the major source of aquifer pressure support. In the Argyll Field, where the Zechstein oversteps beyond the Rotliegend on to Devonian continental sandstones, there were initial difficulties distinguishingbetween the Rotliegend and the Devonian.
Four facies associations are present in the Rotliegend Auk Formation: aeolian slipface sands, aeolian wind-ripple sands, water-lain Weissliegend sands and other water-lain conglomerates, breccias and sands. Five reservoir zones consist of different proportions of these facies which infill topography and onlap the Argyll high. Their distribution and character reflect periods of sediment supply, subsidence and fluctuating climatic conditions towards the margin of an interior continental basin.
The Auk Formation as a whole forms a high quality reservoir at depths of 3000–4000 m. The best intervals, with Darcy permeabilities, consist of coarse-grained Weissliegend sands. Two of the four initial wells in the Ardmore (Argyll) Field redevelopment are planned to target the Rotliegend reservoir.
The complexity of a ramp–flat–ramp fault and its effect on hanging-wall structuring: an example from the Njord oil field, offshore mid-Norway
Authors: Ehrlich Ralf , Gabrielsen Roy H. 
Published: October 2008

The Njord oil field of the mid-Norwegian continental margin comprises a hydrocarbon trap structure, which is delineated by segments of master faults with complex geometry. The Vingleia Fault Complex includes the major fault segments that delineate the Njord structure to the southeast and east. Three master fault segments with a change in strike orientation are recognized. Reflection seismic sections reveal that these segments show strong variations in fault plane geometry. The central part is characterized by a pronounced ramp–flat–ramp geometry, which diminishes both southwestward and northeastward, so that the northeastern and southwestern segments have a more listric geometry. Hence, an along-strike profile shows an antiform-like culmination in the master fault surface.
To the characteristic deformation of ramp–flat–ramp faults, additional deformation in the Njord Field is obvious and marked by extensional horses, extensive roll-over folding, varying strata rotation, characteristic fault bending and variable influence of synthetic and antithetic faults. The occurrence of the style of deformation and geometrical variations in fault pattern are closely related to the structural position above the detachment fault. The following steps in the development of the Vingleia Fault Complex and the associated deformation of the hanging-wall fault block are proposed. (1) Initiation of the master faults in early Triassic. This stage was characterized by slow, extensional displacement. The positions of the master fault segments were possibly influenced by basement in homogeneities marked by a magnetic/gravity anomaly. (2) It is likely that the ramp–flat–ramp had already become established at this stage and that the master fault geometry and a proposed weak salt layer promoted this. (3) During accelerating extension in mid to late Jurassic, the master fault segments became connected by one-sided, lateral linking of fault tip and fault plane or by mutual curved linking of the fault tips. (4) Simultaneously, a roll-over anticline developed within the hanging wall of the master fault. Its relatively large amplitude is produced by a differential movement on the fault surface in combination with a dip-parallel shift of the vertical displacement maximum, which is positioned above a change in the footwall dip.
Calibration improves uncertainty quantification in production forecasting
Authors: McVay Duane A. , Lee W. John , Alvarado Martin G. 
Published: October 2008

Despite recent advances in uncertainty quantification, the petroleum industry continues to underestimate the uncertainties associated with reservoir production forecasts. This paper describes a calibration process that can improve quantification of uncertainties associated with reservoir performance prediction.
Existing methods underestimate uncertainty because they fail to account for all, and particularly unknown, factors affecting reservoir performance and because they do not investigate all combinations of reservoir parameter values. However, the primary limitation of existing methods is that their reliability cannot be verified because the testing of an estimate of uncertainty from existing methods yields only one sample for what is inherently a statistical result. Verification and improvement of uncertainty estimates can be achieved with calibration – comparison of actual performance with previous uncertainty estimates and then using the results to scale subsequent uncertainty estimates.
Calibration of uncertainty estimates can be achieved with a more frequent, if not continuous, process of data acquisition, model calibration, model prediction and uncertainty assessment, similar to the process employed in weather forecasting. Improved ability to quantify production forecast uncertainty should result in better investment decision making and, ultimately, increased profitability.
Seismic evidence for gas hydrates in the North Makassar Basin, Indonesia
Authors: Jackson B. A. 
Published: October 2008

This paper describes the distribution, seismic characteristics and potential volume of gas hydrates in the eastern part of the North Makassar Basin, Indonesia. Identification of the gas hydrates depends entirely on the presence of extensive bottom simulating reflectors (BSR) which are distributed primarily within the offshore extension of the West Sulawesi Fold Belt. Turbidite deposition within the fold belt mini-basins provides a reservoir and a source of organic material for the production of biogenic methane gas. Several seismic examples are shown, including a suspected palaeo-BSR on the crest of an eroded anticline, a submarine mud volcano and an occurrence of rotated slump blocks and debris flows that glide along the hydrate/free gas interface.

Geothermal gradients derived from the BSR database averaged 4.7°C/100 m, whilst derived heat flow values varied from 20 mW m
−2
to 60 mW m
−2
, comparing favourably with regional heat flow data. Gas-in-place estimations for the most contiguous accumulation of gas hydrates (
c
. 8000 km
2
) yielded an estimated 1.89×10
12
m
3
(67×10
12
SCF) of methane gas. Free gas in place below the hydrate zone within the same area was estimated to be 379×10
9
m
3
(13×10
12
SCF).
Mapping and characterization of thin chalk reservoirs using data integration: the Kraka Field, Danish North Sea
Authors: Klinkby Lone , Kristensen Lars , Nielsen Erik B. , Zinck-Jørgensen Kim , Stemmerik Lars 
Published: October 2008

The integration of 3D seismic data, well logs and synthetic seismic data has been used to identify an additional Intra Danian seismic horizon in the chalk reservoir of the Kraka Field, Danish North Sea. Mapping of this seismic horizon has allowed production of a separate thickness map for the main reservoir unit, the Danian Porous, in the greater Kraka area. The unit is less than 25 m thick in most areas and, to produce reliable reservoir maps, it has been necessary to use well data to guide the seismic interpretation. It is impossible, however, to resolve the reservoir stratigraphy properly in areas where the Danian Porous is thinner than
c.
15 m due to tuning effects.

The lateral porosity distribution has been mapped using a combination of well log data and seismic data inverted for acoustic impedance. The Danian Porous unit is characterized by average porosities over 28% and shows no evidence of depth-related porosity reduction. Rather, the impedance data indicate the presence of positive porosity anomalies both over the crest and downflank towards the southeast. Comparison of impedance-derived porosities with those derived from well data indicates that the seismic-based data reflect the variations in porosity but underestimate the highest porosity by 3–4%.
Faults and fractures are important for production of the Kraka Field. Detailed mapping of seismic horizons, supplemented with seismic attribute mapping, has proved useful for outlining areas with high fault intensity in the northwestern part of the field but has been unsuccessful in identifying individual faults as recognized from log data.
Sequence stratigraphically controlled diagenesis governs reservoir quality in the carbonate Dehluran Field, southwest Iran
Authors: Taghavi Ali Asghar , Mørk Atle , Emadi Mohammad Ali 
Published: October 2008

The Sarvak Formation (late Albian–early Turonian) is one of the major oil and gas reservoir units in southwestern Iran and was deposited in a wide carbonate ramp marine setting. Three major transgressive–regressive sequences are interpreted in the upper part of the Sarvak Formation in the Dehluran Field. Sequence boundaries are recognized from facies shifts and diagenetic effects related to sea-level fall, whereas maximum flooding episodes are indicated by deep-water facies characterized by abundant bioturbation and high gamma-ray log responses.
Diagenesis is the main controlling factor on reservoir quality and plays both a constructive and a destructive role. Permeability is decreased by cementation, which fills primary porosity and disconnects pore throats, while compaction decreases porosity by establishing tighter intergrain contacts. Conversely, the dissolution of unstable minerals (mainly aragonite) is the major process that improves porosity and then permeability by enlarging pores and pore throats. Dolomitization, when associated with dissolution, creates the best reservoir intervals in the Sarvak Formation, although this is not a widespread phenomenon.
These diagenetic processes are controlled by sea-level fluctuations, and thus the sequence stratigraphic development. Dissolution, early cementation and exposure-related dolomitization took place during falling sea-levels, mainly in the uppermost, regressive parts of the major sequences. Dolomitization is recognized in the transgressive and in the regressive systems tracts. Stylolitization and fracturing are independent of sea-level fluctuations and are most likely to have formed through a combination of compaction and tectonic events.
The Aquitaine Basin
Authors: Biteau Jean-Jacques , Le Marrec Alain , Le Vot Michel , Masset Jean-Marie 
Published: October 2008

The Aquitaine Basin is located in the southwest of France, between the Gironde Arch in the north and the Pyrenean Mountain Chain in the south. It is a triangular-shaped domain, extending over 35 000 km
2
. From north to south, six main geological provinces can be identified: (1) the Medoc Platform located south of the Gironde Arch; (2) the Parentis sub-basin; (3) the Landes Saddle; (4) the North Aquitaine Platform; (5) the foreland of the Pyrenees (also known as the Adour, Arzacq and Comminges sub-basins); and (6) the Pyrenean fold-and-thrust belt. Only the Parentis sub-basin, the foreland of the Pyrenean Chain and a minor part of the fold-and-thrust belt itself are proven hydrocarbon provinces.

The Aquitaine Basin, in turn, is subdivided into four sub-basins – the Parentis, Adour–Arzacq, Tarbes and Comminges areas. The lozenge shape of these depocentres is related to the Hercynian tectonic framework of the Palaeozoic basement, reactivated during Early Cretaceous rifting. This rift phase aborted at the end of the Albian (prior to the development of an oceanic crust) in response to the beginning of the subduction of the Iberian plate under the European plate. During the Upper Cretaceous, continued subduction led to the creation of northwards-migrating flexural basins. In the Eocene, a paroxysmal phase of compression was responsible for the uplift of the Pyrenean Mountain Chain and for the thin-skinned deformation of the foreland basin. The resulting structuration is limited to the south by the internal core of the chain and to the north by the leading edge of the fold-and-thrust belt, where the Lacq and Meillon gas fields are located.
Four main petroleum provinces have been exploited since the Second World War: (1) the oil-prone Parentis sub-basin and (2) salt ridges surrounding the Arzacq and Tarbes sub-basins; and (3) the gas-prone southern Arzacq sub-basin (including the external Pyrenean fold-and-thrust belt and the proximal foreland sub-basin) and (4) Comminges sub-basin. Two major distinct vertically drained petroleum systems (PS) can be identified: the Upper Kimmeridgian–Barremian is the main PS, based on Type II shaly-carbonate source rocks; and the Lias PS based on Type II–III source rocks. The latter is restricted to the Comminges and Tarbes sub-basins. Reservoirs consist of fractured and diagenetically modified carbonates, and clastics. Shaly-marly deposits of regional extent associated with transgressive systems provide the main seals.

Formation of petroleum traps results from a complex polyphase geodynamic evolution. They are developed mainly along Palaeozoic inherited palaeostructures. Oil and gas migration took place from Albian times up to the present, depending on the respective structural position and histories of the traps. These petroleum provinces of the Aquitaine Basin have been exploited since 1939 and a total of 11.5×10
12
SCF of gas and 470×10
6
BBL oil recoverable reserves have been proven to date (the total amount is in the order of 2.5×10
9
BOE).
Modelling the effects of stratigraphical uncertainty on fault seal and trap-fill in faulted structures
Authors: Clarke S. M. , Littler M. , Burley S. D. , Williams G. D. , Hughes D. , Coogan S. 
Published: October 2008

A three-dimensional approach to migration modelling through faulted structures is described that allows the effects of stratigraphical uncertainty on potential hydrocarbon accumulations to be assessed. Deterministic, three-dimensional fault seal analysis typically produces results that are extremely sensitive to input parameters such as structural architecture and stratigraphical variation. These parameters can be amongst the most poorly defined of modelling inputs because subsurface structural detail and stratigraphical variation are often below the limit of seismic resolution and are not sampled by well data.
The new technique is fully integrated with three-dimensional fault seal analysis and hydrocarbon flow pathway modelling to give a workflow that predicts the likelihood of fault-controlled hydrocarbon accumulations, given these uncertainties. Multiple deterministic realizations of the model are used to highlight specific uncertainties in stratigraphy to which predicted hydrocarbon accumulations are sensitive. The results of these realizations are incorporated into, and used to condition, a stochastic model to risk predicted accumulations based on their likelihood of occurrence and volume.
This technique has many advantages over either purely deterministic or purely stochastic approaches. A single deterministic realization places over-optimistic faith in the accuracy of the geological model because of the high sensitivity of fault seal analysis to input parameters. Multiple realizations allow specific input parameter uncertainties to be investigated, and the resulting common traps can be considered low risk, but accumulations exclusive to individual realizations cannot be risked. Moreover, a purely stochastic simulation based on all uncertainties will, at best, reduce efficiency by modelling uncertainties to which the result is insensitive or, at worst, may bias results with geologically implausible, stochastically-generated trials.