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We exploit the concept of the geothermal favourability, widely used for hydrothermal and EGS systems, to present an innovative methodology for assessing geopressured-geothermal resources occurring in terrigenous units in sedimentary basin plays. Geopressured-geothermal systems are an unconventional resource for power trigeneration exploiting three forms of energy from hydrocarbons, hydrothermal fluids, and well-head overpressure. This paper is intended to be a practical analytical framework for the systematic integration of the relevant data required to assess geopressured-geothermal resources. For this purpose, innovative parameters were also implemented in the methodology. The final result is the favourability map for identifying prospective areas to be further investigated for the appraisal of the geopressured-geothermal potential. We applied our methodology to the foredeep-foreland domains of the Apennines thrust belt in the Abruzzo region (central Italy). We analysed hundreds of deep hydrocarbon wells in order to create 3D geological and thermo-fluid dynamic models at a regional scale as well as to obtain information on the pressure regimes and on the chemistry of the system. The final favourability map for the Abruzzo case study is a first attempt at ranking these kinds of unconventional geothermal resources in a region that has been historically explored and exploited mostly for hydrocarbons. [ABSTRACT FROM AUTHOR]

Abstract: The external part of the Northern Apennines accretionary wedge in northern Italy is buried beneath its fast subsiding and asymmetric foreland basin in the Po Plain. It is characterized by a diffused noncylindrical geometry resulting in salients and recesses in the study area, namely, the Cremona salient, the Parma recess, and the Ferrara salient. The interpretation of borehole and seismic reflection data suggests that the thrust belt is characterized by thin‐skinned tectonic style. Two main décollement levels have been identified: a basal décollement located in the Upper Carnian units (San Giovanni Bianco Clay and Raibl Group) and a shallow décollement located in the late Eocene‐Oligocene formations (Gallare Marls). The décollement surfaces dip SSW toward the hinterland of the accretionary prism, parallel to the steep (>10°) regional monocline. The geometry of the seismically active Northern Apennines system of salients and recesses is essentially controlled by the interplay of two factors: (i) the lateral facies variations of the stratigraphic units hosting and controlling the location and depth of the décollement levels and (ii) the slope of the basal décollement. Salients occur where, due to the inherited variable stratigraphy of the Mesozoic‐Cenozoic Tethyan passive margin, the shaly formations hosting the two décollements are well developed allowing larger forward propagation of the thrust wedge. Recesses are instead associated to erosional‐nondepositional areas. Moreover, salients are more pronounced where the flexural behavior of the Adriatic subducting slab has generated a steeper geometry of the foreland monocline and consequently of the basal décollement. [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 deep structure of the southern Apennines (SA) accretionary wedge is still debated since industrial seismic reflection and well data provide reliable constraints only to a depth of about 10 km. As a consequence, two directly linked questions regard (1) the shortening in the accretionary prism (particularly within the buried Apulian thrust units) and (2) the degree of involvement of the lower plate basement (i.e., the Apulian crystalline basement). To address these issues, we have constructed a regional section along a recently released deep seismic reflection profile (CROP-04) which intersects the entire SA. The resulting cross section, adequately constrained to a depth of about 15 km, has been framed in a geodynamic scenario characterized by the eastward roll-back of the westward subducting Apulo-Adriatic lithosphere. On the basis of this section we speculate on the deep structure, building both thin- and thick-skinned thrust models. A cross-check of these end-members models against documented tectonic, geophysical, and geochemical features shows that the thin-skinned model is generally more consistent with the available data. The development of basement slices with thicknesses of tens of kilometers is unlikely, while it remains possible that the Apulian basement could have been involved with its upper few kilometers. In the thin-skinned model, the total shortening of the allochthonous units (i.e., Apennine and Apulian carbonate platforms and Lagonegro basin) is estimated to be greater than 280-300 km. Some 90 km of shortening can be attributed to the Apulian thrust units. [ABSTRACT FROM AUTHOR]

Along representative cross sections of the Apennines and the Northern Barbados accretionary prisms, we measured the area, the décollement depth, the angle α of the upper envelope and the angle β of the dip of the regional monocline. The continental sections of the Apennines accretionary prism have a deeper décollement than the oceanic sections of the Northern Barbados, 6-10 km depth and <1 km depth, respectively, because the sediment pile is thinner on the incoming Barbados plate and its denser oceanic structure is more easily subducted. Considering the frontal 50 km, the Apennines have an average cross-sectional area of 500 km2 and the Northern Barbados Ridge of 100 km2. The total area is a function of the depth of the décollement plane. Therefore, at a given amount of subduction, the deeper the décollement depth is, the bigger the area of the wedge will result, assuming negligible compaction and erosion. As a consequence, the larger area/volume and higher elevation of the Apennines with respect to the Barbados is determined by the Apenninic deeper décollement. Despite these differences, the geometry of both décollements is, in some cases, comparable, in particular, close to the boundary between the crystalline crust and the sediment pile, where the main density and strength contrasts are concentrated. Variations in depth of the décollement occur moving along strike in both accretionary prisms. The geometry of the prisms is further controlled by the different values of α and β, their sum, and the distance of the accretionary prism relative to the subduction hinge. [ABSTRACT FROM AUTHOR]