1,720,983 research outputs found
Very high-resolution seismic profiling shot over exploration seismics routes: neotectonic setting and possible evidence of a recent earthquake offshore Latium region
No full textGeothermal repurposing of depleted oil and gas wells in Italy
Full text linkThe decarbonisation of the energy sector is probably one of the main worldwide challenges of the future. Global changes urge a radical transformation and improvement of the energy-producing systems to meet the decarbonisation targets and a reduction of greenhouse gas emissions. The hydrocarbon industry also contributes to this transition path. In a mature stage of oil and gas fields, the production of hydrocarbons is associated with formation waters. The volume of produced water increases with the maturity of the assets and the geothermal repurposing of depleted oil and gas wells could be an alternative to the mining closure. In the described transition scenario, the geothermal energy seems very promising because of its wide range of applications depending on the temperature of extracted fluids. This flexibility enables us to propose projects inspired by a circular economic vision considering the integration in the territory and social acceptance issues. In Italy, since 1985, 7246 wells have been drilled for hydrocarbon, of which 898 are located onshore with a productive or potentially productive operational status. This paper presents a preliminary investigation of oil and gas fields located onshore in Italian territory based on the available information on temperature distribution at different depths. Then, taking into account the local energy demand, existing infrastructure, and land use of the territory, a conversion strategy for the producing wells is proposed for three case studies
Very high-resolution seismic stratigraphy of Pleistocene eustatic minima markers as a tool to reconstruct the tectonic evolution of the northern Latium shelf (Tyrrhenian Sea, Italy)
No full textThis paper analyzes depth variations of seismically detected lowstand features (i.e., paleo-shelf break and lowstand submerged depositional terraces [LSDTs]), in order to define vertical movements along a continental margin. Narrowly spaced, high-resolution two-dimensional reflection seismic data were used, collected along a segment of the continental shelf of Latium (eastern Tyrrhenian Sea, Italy). Seismostratigraphic analysis allowed us to identify the six most-recent fourth-order depositional sequences formed in the past ~500 k.y. They have a different degree of preservation in the outer and middle shelf, with almost no continuation in the inner shelf. Some wedge-shaped bodies interpreted as LSDTs can be identified in these units. The depth of paleo-shelf break and LSDTs of marine isotope stage 12 (ca. 435 ka) was measured, and gradually varies along the margin between ~220 m and ~131 m below current sea level. Differential subsidence rates have been estimated for the area, varying from 0 to -0.21 mm/a. The spatial variations agree with studies of uplifted coastal terraces on land, controlled by localized volcanic activity along the Latium section of the Tyrrhenian coast. The comparison of deformation onshore and offshore has proven to be a promising approach for understanding the evolution of uplifting continental margins. © 2013 Geological Society of America
Stratigraphical and sedimentological relationships of the Bolognano Formation (Oligocene–Miocene, Majella Mountain, Central Apennines, Italy) revealed by geological mapping and 3D visualizations
Full text linkThe 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 oliaophotic 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 foraminifers 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
Reuse of Oil Wells in Geothermal District Heating Networks: A Sustainable Opportunity for Cities of the Future
No full textClimate 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
Pressure solution inhibition in a limestone–chert composite multilayer. Implications for the seismic cycle and fluid flow
No full textPressure solution seams (PSSs) are frequent features in carbonate rocks undergoing tectonic shortening. In
particular, pervasive, anticline-axis-parallel, bed-normal PSSs are known to develop during layer-parallelshortening
of (marly) carbonate rocks in fold-thrust belts. These pressure solution features can impact
subsequent fracture development, fluid circulation, and strain localization including the seismic cycle. It is here
demonstrated that the occurrence of frequent and continuous chert layers may strengthen a limestone sequence
and inhibit pressure solution under layer-parallel-shortening. Field observations and laboratory determinations
are reported from marly limestone with continuous chert layers of the Scaglia Fm. (Cingoli anticline, northern
Apennines, Italy) exhumed from a depth of c. 1 km. In these outcrops, bed-normal solution seams do not occur
or they occur only where infrequent chert layers have been shortened by small thrusts. In analogy with
laminae-reinforced composite materials, a model is developed explaining the field observations with the
strengthening effect of chert in the chert–limestone composite multilayer. During layer-parallel-shortening,
the composite multilayer deforms under equal strain boundary conditions. In this situation, the tectonic load is
mostly supported by the stiff and frequent chert layers and the strain of the whole chert–limestone composite
remains in the elastic field, so that pressure solution seam development is prevented in the limestone beds.
Our model may be applied down to a depth of a few kilometers in the upper crust that is relevant for the seismic
cycle and fluid flo
Syn-thrusting polygonal normal faults exposed in the hinge of the Cingoli anticline, northern Apennines, Italy
No full textThe Cingoli arcuate anticline is part of the Apennines fold-thrust belt in Italy. The anticline involves sedimentary carbonate strata generally affected by syn-thrusting contractional structures such as bed-normal pressure solution seams, folds, and reverse faults. An exception is constituted by an outcrop in the anticline hinge, where sub-horizontal carbonate and chert beds are affected by joints and intraformational short normal faults. These faults are poorly-systematic and conceivably polygonal in map view. They cut through the carbonate beds while usually stop against the chert layers that are bent and extended along the faults themselves. At the fault tips, the displacement is generally transferred, via a lateral step, to an adjacent similar fault segment. The fault surfaces are often characterized by slickolites, greenish clayey residue, and micro-breccias including chert and carbonate clasts. Fault displacement is partly or largely accommodated by pressure solution. The faults, in effect, are usually accompanied by bed-parallel pressure solution seams in the two contractional quadrants located at the present or past fault tips. The pressure solution features fade away departing from the faults. This evidence and others are analytically explained with fault tip stress distributions. The faults are interpreted as polygonal normal faults syn-tectonically (syn-thrusting) nucleated in response to multi-directional stretching processes occurred at the Cingoli triple-folded anticline extrados. The faults then grew through a four-stage process: (1. stop) the faults stopped at the competent chert beds; (2. shrink) faulting produced shrinkage (pressure solution) of carbonate beds at the fault compressive tips; (3. shrink and step) the faults stepped laterally at the competent chert beds; (4. shatter) the chert beds were shattered along the fault surfaces. The case presented constitutes the first reported one of syn-thrusting non-diagenetic polygonal normal faults
Structural and stratigraphic control on salient and recess development along a thrust belt front. The Northern Apennines (Po Plain, Italy)
No full textThe 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
Central-Eastern margin of the Tyrrhenian basin: an insight from new multichannel seismic profiles
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