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Climate change and the energy crisis forced industrialized countries to contain CO2 emissions and use indigenous renewable energy sources. Geothermal energy undoubtedly has great potential, particularly thermal energy, given that 48% of the final energy consumption in the EU20 countries in 2021 was related to heating and cooling systems. The present study verifies and compares the feasibility of realizing district heating systems in two different contexts: (i) depleted hydrocarbon fields with the repurposing of existing hydrocarbon wells into geothermal wells and (ii) areas with documented geothermal resources. The two selected case studies are located, respectively, near Romentino (Northern Italy, province of Novara) and Tuscania (Central Italy, province of Viterbo). Following an assessment of the geothermal resources in the two selected case studies, specific methodological tools have been developed to evaluate the energy demand in the municipalities and determine the projects' economics. Both case studies show positive economic indices assuming heat tariffs aligned with the values recorded in the 2020–2021 period. However, our results show how reusing hydrocarbon wells in geothermal wells constitutes an excellent opportunity to access geothermal resources, significantly reducing the necessary investment and the mining risk and strongly improving the economics of the projects. [ABSTRACT FROM AUTHOR]

The characterization and comprehension of buried reservoirs receive remarkable benefits from detailed studies of outcropping analogues which help to define the architecture of the buried sedimentary units and their petrophysical features. In particular, modern 3D techniques of geological data analysis can better constrain the geological mapping process and reveal the geometry of the sedimentary units with complex lateral and vertical relationships. By means of the 3D Move software, we define the sedimentological and stratigraphical relationships between lithostratigraphic units of the Bolognano Formation, outcropping in the northernmost sector of the Majella Mountain (Central Apennines, Italy). The study area belongs to the Apulian carbonate platform and the Majella Mountain represents the northward outcropping portion of its margin. The sedimentary succession of the Majella Mountain consists of Upper Jurassic to upper Miocene limestone and dolostone deposits. In the investigated area, outcropping deposits mainly belong to the Oligo--Miocene Bolognano Formation characterized by five lithofacies associations and representing a carbonate ramp developed in a warm subtropical depositional environment within the oligophotic to aphotic zone. The Bolognano Fm. represents, due to its specific hydraulic properties (e.g. porosity and permeability), an outcropping analogue of worldwide common reservoirs (i.e. porous calcarenite deposits of a carbonate ramp formed by benthic foraminifera such as lepidocyclinids, nummulitids, red algae, corals). In the study area, several geological units of the Bolognano Fm. are characterized by abundant hydrocarbon (bitumen) occurrences infilled within the high-porosity of the cross-bedded calcarenites ascribed to the Chattian and Burdigalian interval. The geological field mapping of the area and the visualization of the geological data in a 3D environment show that the unit formed by mid-ramp calcarenites (Lepidocyclina calcarenites 2 unit, Chattian--Burdigalian) increases in thickness towards the NE (basinward) direction as a consequence of sediment shedding from inner ramp. Our study illustrates how the geological mapping and the visualization and analysis of geological data in a 3D environment of the northernmost sector of the Majella Mountain confirms depositional models of the Bolognano Formation and represents a valid tool for the characterization of the lateral stratigraphic relationships within this formation, and hence of its potential hydrocarbon occurrences. [ABSTRACT FROM AUTHOR]

Empirical scaling relationships between fault or slip dimensions and earthquake magnitudes are often used to assess the maximum possible earthquake magnitude of a territory. Upon the assumption of the reactivability of any fault, the earthquake magnitudes derived from the surface fault length (FLEM) are compared at the national scale in Italy against catalogued magnitudes. FLEMs are obtained by considering a comprehensive fault dataset regardless of fault age, stress field orientation, strain rate, etc. In particular, (1) a comprehensive catalogue of all known faults is compiled by merging the most complete databases available; (2) FLEM is then derived from fault length; and (3) the resulting FLEMs are compared (i.e. the mathematical difference) with catalogued earthquake magnitudes. Results show that the largest FLEMs as well as the largest differences between FLEMs and catalogued magnitudes are observed for poorly constrained faults, mainly inferred from subsurface data. It is suggested that these areas have to be further characterized to better estimate fault dimension and segmentation and hence properly assess the FLEM. Where, in contrast, the knowledge of faults is geologically well constrained, the calculated FLEM is often consistent with the catalogued seismicity, with the 2 σ value of the distribution of differences being 1.47 and reducing to 0.53 when considering only the Mw≥6.5 earthquakes. Our work highlights areas, in Italy, where further detailed studies on faults are required. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we analyze the Jurassic and Cretaceous evolution of the buried northwards stretch of the Apulia Platform (Southern Italy) (Ombrina-Rospo Plateau – ORP), and adjacent Adriatic Basin. Exploration wells indicate that inner platform carbonate facies across the ORP in the Jurassic and Lower Cretaceous are capped, along a subaerial exposure surface, by Oligocene/Miocene carbonates. A NW-trending intra-platform basin (“Casalbordino Corridor”) was infilled with shallow- to deeper-water sediments in the late Early to Late Cretaceous interval, while platform margins were experiencing tectonic reactivation. The ORP-to-basin transitional belt formed a corner, defining a NW and a NE margin. The NW margin was essentially stationary. A syn- and early post-rift platform-toe bypass wedge formed when late Hettangian–Sinemurian extension produced the platform/basin relief. Export of platform material, coupled with a halt of faulting, made the platform/slope profile continuous in the late Early or early Middle Jurassic (possibly across an ooidal rim). Late Jurassic Ellipsactinia/coral reefs passed downdip into bioclastics. The Maiolica Fm. displays two cycles (M1, M2), where M2 onlaps the slope built by M1. In the Aptian, with lithospheric arching, a high angle fault rejuvenated the margin. Off this margin, a narrow basin, locked between the ORP and a pelagic carbonate platform, was largely infilled with turbidites sourced by the ORP, but the high hampered the dispersal of the sand fraction. The NE margin displays prograding ooidal to bioclastic clinoforms (Middle and Upper Jurassic) downlapping onto the rift basin. In the Lower Cretaceous, the platform recovered after a slow-down of carbonate productivity (M1/2 boundary). The Marne a Fucoidi Fm. thickens at the toe of, and seals, a fault backstepping the margin. Further backstepping occurred ∼5 km platformwards along a (Cenomanian?) normal fault, producing room for a rudist factory. A retreating rocky shoreline sourced breccias, while downdip the shallow water facies graded into the Scaglia Fm. basin along a ramp-like profile with low angle clinoforms, merging with turbidites. [Copyright &y& Elsevier]

We performed geodetic strain rate analyses in southern Italy, using new GPS velocities. Two-dimensional strain and rotation rate fields were estimated and results show that most of the shortening is distributed in the northern Sicily offshore. Extension becomes more evident and comparable with shortening on the eastern side of the same margin, and greater in the eastern Sicily offshore. Principal shortening and extension rate axes are consistent with long-term geological features: seismic reflection profiles show both active compressive and extensional faults affecting Pleistocene strata. We show evidence for contemporaneous extension and transtension in the Cefalù Basin. Combining geodetic data and geological features point to the coexistence of independent geodynamic processes, i.e., the active E-W backarc spreading in the hangingwall of the Apennines subduction zone and shortening along the southern margin of the Tyrrhenian backarc basin operated by the NNW-motion of Africa relative to Eurasia. [ABSTRACT FROM AUTHOR]

New seismic reflection data reveal that the south-eastward prolongation of the Apennine thrust front in the central Adriatic Sea is most likely located in a more external position with respect to the traditional interpretation. In this new interpretation, the Apennine thrust front shows a segmented geometry in correspondence to the Tremiti lithospheric transfer zone. The available data suggest that the north-eastward flexural retreat of the subducting Adriatic lithosphere and the related frontal accretion of the Apennine accretionary prism have acted during the last 5 Ma and may be considered still lively in both the Po plain and in the Central Adriatic domain, north of the Tremiti lineament. By analysing the tectonic evolution of the Apulo-Adriatic areas, it may be argued that the differential slab retreat between the central and southern sectors of the subducting Adriatic plate has been able to induce the segmentation of the Apennine thrust front. [ABSTRACT FROM AUTHOR]

• The research is focused on the evaluation of the geothermal potential stored in the depleted oil & gas fields in Italy. • The volume method has been adopted as methodological approach in geothermal resource evaluation. • Five most promising oil & gas fields have been selected to assess their geothermal potential. • A probabilistic approach has been adopted to obtain a distribution of values of the geothermal technical potential. The target of this work is to produce a vision of the geothermal potential stored in the depleted oil & gas fields in Italy, by using the available information provided by the Ministry of Economic Development, the published data on hydrocarbon fields, and the estimated temperature at depth from the Italian National Geothermal Database. Five most promising fields have been selected and the volume method has been applied to assess their geothermal potential. Then a probabilistic approach has been adopted to obtain not a single value but a distribution of values of the technical potential TP. The results indicate that the available heat in hydrocarbons fields is encouraging and it is fundamental to analyze the production capacities of the existing wells to have a clearer idea of the possible uses of this existing and wasted heat. [ABSTRACT FROM AUTHOR]

Abstract: The Cingoli anticline is a late Messinian thrust-related fold that developed along the northern Apennines front (Italy). This exposed anticline represents a potential analog of hydrocarbon reservoirs located in the nearby Po Plain and Adriatic Sea areas. The folded rock multilayer of the Cingoli anticline includes a heterogeneous, Mesozoic–Cenozoic, marine succession, consisting of massive platform carbonates below, and layered pelagic carbonates on top. This article reports the results of analyses conducted on pelagic micrites cropping out in two exposures located in the anticline backlimb. There, the late Cretaceous–Eocene Scaglia Rossa Fm., which is characterized by thin beds of pelagic limestones and marly limestones, is crosscut by pervasive, closely-spaced, stratabound fractures mostly consisting of pressure solution seams (PSSs) and sheared PSSs. The fractured strata are, in places, crosscut by small-offset fault zones. Field and laboratory structural data are used to define the nature and type of the different fracture sets as well as their temporal evolution and interaction. Seven main sets of stratabound PSSs and sheared PSSs are identified and interpreted as an early background fabric crosscut by or involved in later through-going fault zones. We propose a conceptual model of fault nucleation and growth that envisions the studied faults as late-stage structures, which formed by incorporating and connecting segments of bedding surfaces and early developed PSSs. We discuss our conceptual model in terms of fault and fracture permeability, highlighting the possible role exerted by the documented structures on subsurface fluid flow. [Copyright &y& Elsevier]