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The tectonic evolution of rift basins can strongly influence the petrophysical properties of its sedimentary infills at various scales and, therefore, influence the characteristics of present resources. Understanding the tectonic evolution of a rift basin is therefore decisive, as it can have consequences for the parameters that influence the planning of geothermal doublets. In this framework, this study gives a detailed interpretation of the syn- and post-rift episodes in the West Netherlands Basin, since Jurassic times. Despite multiple studies on the geotectonic setting of the West Netherlands Basin, a detailed understanding of its syn- and post-rift phases in the context of geothermal exploration is still fundamentally lacking. With a renewed interpretation of a seismic 3D cube, covering a large portion of the onshore section of the basin, we identified two important Jurassic rifting episodes and one Cretaceous inversion event. Rifting caused compartmentalisation of the main producing geothermal target in the area; the Late Jurassic Nieuwerkerk Formation. Yet, the central portions of the half-grabens show good potential for geothermal exploration. Subsequent inversion could have caused local breaching of the aquifer, forming a potential risk. Therefore, only non to moderately inverted areas should be considered for geothermal exploration. This study provides a better understanding of the multi-phase rifting history in the West Netherlands Basin, providing important constraints on the reservoir-seal integrity and with that, the amount of heat that can be safely produced from a geothermal reservoir rock. Aiming to contribute to the energy transition, this study provides an integrated picture of the West Netherlands Basin and shows how a basin’s geological history can affect its geothermal resources.

Delft University of Technology, The Netherlands (1); PanTerra Geoconsultans (2); CGG The Hague (3) Heat production from low permeability reservoirs is believed to be significantly aided by the presence of open natural fractures (e.g. Upper Rhine Graben). However, in hot sedimentary aquifer studies these structural features are rarely included when estimating their economic viability. Therefore, we present a case study which assesses the impact of natural fractures on heat extraction from the tight Main Buntsandstein Subgroup targeted by the recently drilled NLW-GT-01 well (West Netherlands Basin (WNB)). We integrate: 1) reservoir property characterisation using petrophysical-analysis and geostatistical-inversion, 2) image log- and core interpretation, 3) large-scale seismic fault extraction and characterisation, 4) Discrete Fracture Network (DFN) modelling and permeability upscaling, and 5) fluid-flow and temperature modelling. First, the results of the petrophysical analysis and geostatistical inversion indicate that the Triassic reservoir layers have almost no intrinsic porosity or permeability. Second, the image-log interpretation shows predominately NW-SE orientated fractures having log-normal length - and negative-power-law aperture behaviour, respectively. Third, the seismic fault analysis depicts pattern which is to be expected from the structural setting of WNB. Fourth, inspection of the reservoir scale 2D DFN’s and upscaled permeability models suggest that if open, natural fractures significantly enhance the effective permeability (up to 500 mD). Finally, the performed 2D fluid-flow/temperature simulations indicate that open natural fractures significantly increase in the geothermal heat extracted from the normally tight reservoir rock. However, while the presented results are positive, it should be noted that the prediction and characterisation of natural fractures in the sub-surface is a relatively uncertain process.

Studies on mechanical stratigraphy of shallow-water carbonates have shown that the distribution of fractures can be controlled by depositional facies, sedimentary cycles/sequences, and diagenesis. Understanding the role of these sedimentary controls is therefore crucial in the characterization of matrix-tight reservoirs, where fractures may represent the main conduits for fluid flow. Nonetheless, the relation between fracture distribution and sedimentary controls is not always investigated at scales that are relevant to reservoir and fluid-flow characterization. In this dissertation, is provided a solution to this problem by integrating sequence stratigraphic analysis with the multi-scale fracture characterization of two carbonate platform exposures outcropping in the Sorrento Peninsula (southern Italy). These outcrops represent the surface analogue of subsurface hydrocarbon reservoirs of the Basilicata region (southern Italy), and consist of nearly vertical cliffs (hundreds of meters wide and high) exposing shallow-water limestones and dolostones, crossed by several sub-vertical fractures ranging in height from few centimetres up to few tens of metres. Due to the partial inaccessibility of this cliff, field measures have been combined with remote sensing on virtual outcrop models. The study allowed to identify the key control exerted by sedimentary sequences on the thickness of mechanical units and the position of their boundaries, which implies that sequence stratigraphy can be used to predict the distribution of large-scale fractures. The applicability of this concept has been tested on a subsurface dataset from the Basilicata region. Performing a sequence stratigraphic analysis on image logs calibrated with core data, the main mechanical boundaries were predicted in a portion of fractured stratigraphic units. The thickness of predicted mechanical units showed a clear relation to the distribution of fractures. Indeed, in the investigated stratigraphic interval, an increase in the mean thickness of mechanical units corresponds to an increase in the mean spacing of fractures, of a comparable order of a magnitude. The main outcome of this study is the proposal of a new approach to estimate large-scale fracture intensity in carbonate reservoirs, based on the evaluation of the thickness of mechanical units through sequence stratigraphy.

The shelf life of spices is traditionally extended by drying. Fresh herbs, due to their high water content, undergo microorganism growth and adverse biochemical reactions. On the other hand drying may result in a lot of physical and chemical alterations. Air and oven-dehydration are the main methods used to stabilize spices. During oven drying, in general, losses of volatile compounds are directly dependent on the temperature and time used. This paper deals with the effect of different drying temperatures and air fluxes on the volatiles in rosemary (Rosmarinus officinalis L.) and thyme (Thymus officinalis L.) cultivated in Sardinia. Fresh leaves were collected and soon divided in two batches, which were subjected to hydro distillation and GC-MS analysis, the first batch as fresh, the second one after drying in a laboratory pilot dryer. Three drying temperatures were used, 30, 38 and 45°C, and for each one two airflow rates were set. The fresh and dried plant material were hydro distilled for 4 hours using a Clevenger-type apparatus (Italian Official Pharmacopeias X). The oils (liquid and light yellow) were recovered directly from above the distillate without adding any solvent and stored at –20°C before analyses, which were carried out on two replicates of each sample by gas chromatography, using a flame ionization detector. The diluted samples were injected using a split/splitless automatic injector (using 2,6-dimethylphenol as internal standard). Qualitative analysis was done by GC/Mass and mass units were monitored from 10 to 450 at 70 eV. Results of the influence of the different drying conditions on volatile compounds of the two herbs will be reported.

Fault zones can often display a complex internal structure associated with antithetic faults, branch and tip points, bed rotations, bed-parallel slip surfaces, and subordinate synthetic faults. We explore how these structural complexities may affect the development of fault-related fractures as displacement accumulates. We analysed in detail an incipient fault zone within well-bedded, shallow-water carbonates of the southern Apennines thrust belt (Italy). The fault zone crops out with quasi-complete exposure at a reservoir scale on an inaccessible sub-vertical cliff face, and fault and fracture mapping were carried out on a 3D virtual outcrop model of the exposure built for this study using photogrammetry. Comparing the structure of the fault zone and the density of 9444 mapped fractures allowed us to unravel their spatial relationships. Our results show that the areas of denser fractures coincide with: (i) rock volumes bounded by antithetic faults developed within the fault zone, (ii) branch points between these antithetic faults and fault zone-bounding fault segments, (iii) fault zone-bounding fault segments associated with significant displacement gradients, and (iv) relay zones between subordinate synthetic faults. These findings may aid locating sub-seismic resolution volumes of dense fracturing and associated enhanced permeability within faulted reservoirs.

In this work, we present a Google Earth (GE) based virtual field mapping exercise, designed for master’s and bachelor’s students of geology and aimed at supporting or replacing field mapping training courses. The exercise consists of mapping geological limits and faults in a poorly vegetated area of the Lurestan region (Zagros thrust and fold belt). The occurrence of cliff- forming and recessive formations allows students to recognise directly on GE the first order geological structures of the area, which include faults and folds with wavelengths of many kilometers. The provided input data includes a stratigraphic description of the exposed formations, field photographs, and a set of field checkpoints. The material can be provided entirely or partly, depending on the students’ level and workload required. The full dataset is intended for undergraduate students with little or no field experience, while master students are expected to complete the exercise with limited input data. Additionally, the exercise can be limited/focused on sub-areas or extended on the entire area. This virtual mapping exercise is expected to empower students’ ability to visualize, understand and reconstruct 3D geological surfaces; providing an essential tool for future scholars and practitioners.

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.

Through-going joints cutting across beds are often invoked to match large-scale permeability patterns in tight carbonate reservoirs. However, despite the importance of these structures for fluid flow, only few field studies focused on the understanding and estimation of through-going joint dimensional parameters, including spacing and vertical extent in relation to stratigraphy. Recent improvements in the construction of digital models of outcrops can greatly help to overcome many logistic issues, favouring the evaluation of relationships between jointing and stratigraphy at the reservoir scale. In this study, we present the results obtained from integrating field measurements with a digital outcrop model of a carbonate platform reservoir analogue in the Sorrento peninsula (Italy). The outcrop consists of a nearly vertical cliff exposing a monocline of alternating gently-dipping shallow-water limestones and dolostones, crossed by several vertical joints of different size. This study allowed us to define how major through-going joints pass across thick beds (bed thickness > 30 cm), while they arrest against packages made of thinly stratified layers. In essence, through-going joints arrest on “weak” levels, consisting of thinly bedded layers interposed between packages made of thick beds, in the same manner as bed-confined joints arrest on less competent interlayers.