EVALITA Evaluation of NLP and Speech Tools for Italian - December 17th, 2020

Welcome to EVALITA 2020! EVALITA is the evaluation campaign of Natural Language Processing and Speech Tools for Italian. EVALITA is an initiative of the Italian Association for Computational Linguistics (AILC, http://www.ai-lc.it) and it is endorsed by the Italian Association for Artificial Intelligence (AIxIA, http://www.aixia.it) and the Italian Association for Speech Sciences (AISV, http://www.aisv.it)

The role of stratabound fractures for fluid migration pathways and storage in well-bedded carbonates

Fracture analysis, carried out on two reservoir analogues cropping out at Faito and Chianello Mts. (southern Italy) allowed us to unravel the role of stratabound joint networks for oil migration and storage within well-bedded carbonate successions. The fracture regression analysis pointed out that stratabound fracture aperture increases as a function of bed thickness according to a linear law, independently by the lithological characteristics of the analyzed rock. Furthermore, statistical results suggest that fracture aperture and spacing exhibit, for each bed thickness value, a lognormal probability distribution. The estimation of the stratabound fracture porosity allowed us to identify, in well-bedded sedimentary successions, three classes of multilayer packages: (i) thin beds, characte - rized by a dual role of permeable pathways and oil storage systems; (ii) medium sized beds, showing limited permeability and porosity values and (iii) thick beds, acting as highly permeable pathways and showing a negligible storage capacity. Our results permit a full characterization and modeling of stratabound fracture networks. In particular, they provide a powerful tool for predicting preferential fluid pathways and major oil storage systems based on bed thickness data, within the framework of an analysis that may be further enhanced by the integration of petrophysics data

Early dolomitization in the Lower Cretaceous shallow-water carbonates of Southern Apennines (Italy): Clues about palaeoclimatic fluctuations in western Tethys

A multidisciplinary study of the dolomitized bodies present in the Lower Cretaceous platform carbonates of Mt. Faito (Southern Apennines – Italy) was carried out in order to explore the connection between early dolomite formation and fluctuating climate conditions. The Berriasian-Aptian investigated succession is 466 m thick and mainly consists of shallow-water lagoonal limestones with frequent dolomite caps. The dolomitization intensity varies along the succession and reaches its peak in the upper Hauterivian-lower Barremian interval, where it is present a completely dolomitized interval about 100-m-thick. Field relations, petrography, mineralogy, and geochemistry of the analyzed dolomite bodies allowed identifying two populations of early dolomites, a fine-medium crystalline (FMdol) and a coarse crystalline dolomite (Cdol), both interpreted as the product of mesohaline water reflux. According to our interpretation, FMdol precipitated from concentrated brines in the very early stage of the reflux process, producing typical sedimentary features as dolomite caps. In the successive step of the process, the basin-ward ‘latent’ reflux precipitated Cdol from less concentrated brines. A peculiar feature of the studied succession is the great consistency between stratigraphic distribution of dolomite bodies and their geochemical signature. The completely dolomitized Hauterivian-Barremian interval, in fact, is characterized by geochemical values suggesting an origin from distinctly saltier brines. Considering that the observed near-surface dolomitization process is controlled by physical and chemical parameters reflecting the paleoenvironmental and paleoclimatic conditions during dolomite formation, we propose that the stratigraphically controlled dolomitization intensity reflects periodic fluctuations in the salinity of dolomitizing fluid, in turn controlled by long-term climate oscillations. The present work highlights that the stratigraphic distribution of early diagenetic dolomite may be used as proxy to define the climatic fluctuations that have influenced the sedimentary dynamics in the Early Cretaceous. Moreover, considering that a comparable early dolomite distribution is present also in the Dinaric Platform, we suggest that a regional scale climate control acted on early dolomite formation and distribution. Refining the knowledge of such a key control may have a significative impact on hydrocarbon reservoir characterization and exploration in the Periadriatic area

Pore space properties in carbonate fault rocks of peninsular Italy

The fault cores of extensional faults in Mesozoic limestones and dolostones are examined by mean of combined microstructural, ultrasonic and petrophysical analyses. Grain-supported fault rocks commonly localize in the outer fault cores, whereas matrix-supported fault rocks in their inner portions. Cemented fault rocks, if present, surround the main slip surfaces. All dolomite-rich fault rocks, include elongated pores that show a preferential orientation only in the inner fault core. On the contrary, the pore network of calcite-rich fault rocks is made up of elongated pores in the outer fault core, and of sub-spherical pores in the inner fault core. Despite their different pore network characteristics, the petrophysical values of both grain-supported and matrix-supported fault rocks are quite similar one another, with effective porosity up to 10–12%, and permeability up to 2–5 mD. Differently, these values drop down to host rock values, porosity ∼5% and permeability ∼10−3 mD, in the cemented fault rocks. Experimental data are discussed to establish, for the first time, the relative control exerted by individual cataclastic and diagenetic processes on the present day pore characteristics, and to decipher the fault core permeability structure at depth