Appraisal of the volumes of fluid in a carbonate reservoir will typically require a reliable predictive model. This can be achieved by combining studies of well‐exposed carbonate successions with 3D ...models in order to obtain reliable quantitative data. In this paper, we present a detailed outcrop study and a 3D porosity model of a well‐exposed Oligocene carbonate ramp (Salento Peninsula, southern Italy) to investigate the nature of small‐scale facies and porosity heterogeneities. Porosity and permeability in the ramp carbonates appear to be controlled by the original mineralogy of skeletal components and by depositional textures. The aims of the study were therefore to identify the factors controlling porosity development in an undeformed carbonate ramp; to model the scale‐dependent heterogeneities characteristic of the facies associations; and finally to produce a 3D model of the porosity distribution.
The upper Chattian Porto Badisco Calcarenite which crops out along the coast of the Salento Peninsula consists of six lithofacies ranging from inner ramp deposits to fine‐grained outer ramp calcarenites. The lithofacies are: inner ramp small benthic foraminiferal wackestone‐packstones associated with (i) sea grass meadows (SG) and (ii) coral mounds (CM) consisting of coral bioconstructions with a floatstone/packstone matrix; middle ramp (iii) large rotaliid packstones to wackestone‐packstones (LR), (iv) rhodolith floatstone‐rudstones (RF), and (v) large lepidocyclinid packstones (LL); and (vi) outer ramp fine‐grained bioclastic calcarenites (FC). A total of 38 samples collected from six stratigraphic sections (A, B, D, J, E, LO), measured in the Porto Badisco ravine, were investigated to discriminate the types of porosity. Effective and total porosity was measured using a helium pycnometer. The 3D porosity modelling was performed using PETREL™ 2016 software (Schlumberger).
Four main types of porosity were recognized in the carbonates: interparticle, intraparticle, vuggy and mouldic. Primary porosity (inter‐ and intraparticle) is limited to middle ramp lithofacies (LL and LR) and outer ramp lithofacies (FC), whereas secondary porosity (vuggy and mouldic) was present in both inner ramp lithofacies (CM and SG) and middle ramp red algal lithofacies (RF).
In the Porto Badisco carbonates, stratigraphic complexity and the distribution of primary porosity are controlled by lateral and vertical variations in depositional facies. Significant secondary porosity was produced by the dissolution of aragonitic and high‐magnesium calcite components, which are dominant in the sea‐grass and coral mound facies of the inner ramp and in the rhodolith floatstone‐rudstones of the middle ramp.
3D models were developed for both effective and total porosity distribution. The porosity models show a clear correlation with facies heterogeneities. However of the two models, the effective porosity model shows the best correlation with the 3D facies model, and shows a general increase in effective porosity basinwards in the middle ramp facies.
This work is the result of detailed geological mapping and stratigraphic analysis of the Lepidocyclina Limestone in the northern sector of the Majella Mountains (Central Apennines). The Lepidocyclina ...Limestone represents an informal member of the Bolognano Formation (Chattian to Messinian in age).
Four main lithofacies have been recognized: planar cross-bedded grainstone (FA); moderate-angle, cross-bedded grainstone to packstone (FB); sigmoidal cross-bedded grainstone (FC); and bioturbated marly packstone to wackestone (FD).
A detailed description of the recognized lithofacies and facies association of the Lepidocyclina Limestone is given in this work, together with an interpretation of the corresponding depositional setting and a discussion of the related larger-scale processes.
In summary, the depositional profile of the Lepidocyclina Limestone is consistent with a carbonate ramp, where most of the sediments appear to be parautochthonous in the middle ramp environment and autochthonous-dominated in the outer ramp environment.
Palaeocurrent patterns indicate a strong, generally north–west basin-ward direction that affected the middle ramp environment and developed a wide, down-slope migrating dune field.
Considering that the warm Oligocene climate of the Mediterranean area was favorable to tropical cyclone development, both in terms of frequency and intensity, it is suggested that return currents generated by strong winds or storms were common on the “Lepidocyclina” carbonate ramp, thus favoring the development of the observed dune field.
This work illustrates the evolution the Lower Jurassic shallow-water carbonates known as the Calcare Massiccio Formation in the Central Apennines (Italy). The Calcare Massiccio is characterized by ...lateral and vertical variability in the facies associations, related to an articulated physiography of the Triassic to Lower Jurassic carbonate platform and to its tectonic evolution. This work documents the depositional environment changes during the platform evolution. Quantitative analysis on samples collected from three stratigraphic sections were performed through the Calcare Massiccio succession allowed up to the overlying Pliensbachian pelagites. Two type of carbonate sedimentation have been recognized: in the peritidal and shallow subtidal environments (Calcare Massiccio A) the carbonate production is dominated by microbial activity, while the carbonate sedimentation in a deeper environment of middle to outer ramp (Calcare Massiccio B), is dominated by a bioclastic sedimentation.
The evolution from the Calcare Massiccio A to the B can be interpreted as the product of increase of accommodation that in turn produced a backstepping of carbonate facies belt, the photic microbial dominated peritidal facies developed on the persistent Latium-Abruzzi Platform while the bioclastic carbonate production factory settled on the structural highs resulting from the dismembering of the platform by syn-sedimentary tectonic.
The bioclastic carbonate factory was not efficient in filling the available accommodation space produced by Sinemurian extensional tectonic. This inefficiency was amplified by the restricted area available for this factory in the small structural highs. These conditions were sufficient to predispose the platform to the drowning without invoke change in the trophic resource or change in the palaeoceanography.
•In the Calcare Massiccio shallow photic microbial vs deep aphotic bioclastic sedimentation.•Evolution from photic to aphotic production as product of backstepping of facies belt.•Drowning produced by tectonic without changes in the trophism or palaeoceanography.
Nowadays, many database systems are available but they may not be optimized for storing time series data. Monitoring DIRAC jobs would be better done using a database optimised for storing time series ...data. So far it was done using a MySQL database, which is not well suited for such an application. Therefore alternatives have been investigated. Choosing an appropriate database for storing huge amounts of time series data is not trivial as one must take into account different aspects such as manageability, scalability and extensibility. We compared the performance of Elasticsearch, OpenTSDB (based on HBase) and InfluxDB NoSQL databases, using the same set of machines and the same data. We also evaluated the effort required for maintaining them. Using the LHCb Workload Management System (WMS), based on DIRAC as a use case we set up a new monitoring system, in parallel with the current MySQL system, and we stored the same data into the databases under test. We evaluated Grafana (for OpenTSDB) and Kibana (for ElasticSearch) metrics and graph editors for creating dashboards, in order to have a clear picture on the usability of each candidate. In this paper we present the results of this study and the performance of the selected technology. We also give an outlook of other potential applications of NoSQL databases within the DIRAC project.
The CLARO8 chip has been designed for single-photon counting in the upgraded RICH detector of the LHCb experiment at CERN. The chip has 8 channels with 5ns peaking time and a recovery time better ...than 25ns. Each channel is made of a charge amplifier with 2-bit settable attenuation, plus a comparator with a 6-bit settable threshold, and the configuration register is protected against Single Event Upsets by triple modular redundancy. In order to ensure stable operation of the upgraded RICH detectors over the expected lifetime of the experiment after the upgrade, the performance of the CLARO8 in high radiation fields has been assessed. These chips will be exposed, during the whole upgrade running phase, to a total ionizing dose of 200krad, a neutron fluence of 3×1012 1MeVneq/cm2 and a high energy hadrons fluence of 1.2×1012cm−2. Systematic irradiation campaigns have been performed using ions, protons and mixed-field high-energy hadron beams. This paper describes the radiation hardness campaign of the CLARO8 chips and the main results of its extensive characterisation.
The CLARO-CMOS is a prototype ASIC that allows fast photon counting with 5 ns peaking time, a recovery time to baseline smaller than 25 ns, and a power consumption of less than 1 mW per channel. This ...chip is capable of single-photon counting with multi-anode photomultipliers and finds applications also in the read-out of silicon photomultipliers and microchannel plates. The prototype is realized in AMS 0.35 micron CMOS technology. In the LHCb RICH environment, assuming 10 years of operation at the nominal luminosity expected after the upgrade in Long Shutdown 2 (LS2), the ASIC must withstand a total fluence of about 610 super(12) 1 MeV n sub(eq)/cm super(2)neq/cm2 and a total ionizing dose of 400 krad. A systematic evaluation of the radiation effects on the CLARO-CMOS performance is therefore crucial to ensure long term stability of the electronics front-end. The results of multi-step irradiation tests with neutrons and X-rays up to the fluence of 10 super(14) cm super(-2) and a dose of 4 Mrad, respectively, are presented, including measurement of single event effects during irradiation and chip performance evaluation before and after each irradiation step.
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