Quantifying aperture, spacing and fracture intensity in a carbonate reservoir analogue: Crato Formation, NE Brazil

Miranda, Tiago Siqueira de; Santos, Reginaldo; Barbosa, José Antônio; Gomes, Igor Fernandes; Alencar, Márcio Lima; Correia, O.J.; Falcão, Thiago C.; Gale, Julia; Neumann, Volker

doi:10.1016/j.marpetgeo.2018.07.019

Cited by 56 publications

(24 citation statements)

References 37 publications

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“…This aperture is obtained for an effective stress always below

-

8 MPa in the large fracture scenario, and it would correspond to a maximum aperture

b_{\max}

of 4.6 mm at zero stress (equation , Table ). Fractures with such large aperture are rare but have been observed in the field (e.g., Miranda et al, ; Reyer et al, ). Our results indicate that permeability changes of 2 to 3 orders of magnitude indeed occurred at St. Gallen (Table ).…”

Section: Discussionmentioning

confidence: 99%

Hydromechanical Modeling of Fault Reactivation in the St. Gallen Deep Geothermal Project (Switzerland): Poroelasticity or Hydraulic Connection?

Zbinden¹,

Rinaldi²,

Diehl³

et al. 2020

Geophysical Research Letters

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In 2013, fluid injection during the St. Gallen deep geothermal project, Switzerland, induced hundreds of seismic events, including a ML 3.5 earthquake on a fault hundreds of meters away from the well. Recent studies have suggested the direct pressure effect through permeable hydraulic connections and poroelastic effects as possible mechanisms for inducing seismicity on distant faults. In St. Gallen, operational, seismic, and earthquake data are available to investigate the underlying physical mechanisms using a numerical model. The results show that Coulomb stress changes at the fault can be 3 orders of magnitude greater when a hydraulic connection is present. Combining this with several field observations, we conclude that the direct pressure effect was more likely the predominant mechanism behind the seismicity induced in St. Gallen. The detection of hydraulic connections may be important for future projects as pressure can be driven far from the well and reactivate remote faults.

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“…This aperture is obtained for an effective stress always below

-

8 MPa in the large fracture scenario, and it would correspond to a maximum aperture

b_{\max}

Section: Discussionmentioning

confidence: 99%

Hydromechanical Modeling of Fault Reactivation in the St. Gallen Deep Geothermal Project (Switzerland): Poroelasticity or Hydraulic Connection?

Zbinden¹,

Rinaldi²,

Diehl³

et al. 2020

Geophysical Research Letters

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“…Indeed, Miranda et al . (2018) described a set of shear and extensional fractures, joints and stylolites, indicating the laminites of the Crato Formation as a potentially Pre‐Salt reservoir analogue.…”

Section: Discussionmentioning

confidence: 99%

“…This makes the time-equivalent successions of the north-eastern Brazilian interior basins the best correlate deposits with the Pre-Salt (Bahniuk et al, 2015;Catto et al, 2016). Indeed, Miranda et al (2018) described a set of shear and extensional fractures, joints and stylolites, indicating the laminites of the Crato Formation as a potentially Pre-Salt reservoir analogue. The Aptian Cod o Formation (Parna ıba Basin), also in the north-eastern Brazilian interior, bears carbonate deposits that can be correlated with those of the Crato Formation (Varejão et al, 2016).…”

Section: Implications For a Pre-salt Analoguementioning

confidence: 95%

“…Therefore, the brittle–ductile SSDS at the top of FA‐4 are interpreted to be seismites ( sensu Seilacher, 1969). Other SSDS were previously identified in FA‐4 (Martill et al ., 2008; Miranda et al ., 2018; Alencar et al ., 2020), suggesting early extensional and compressional tectonics during sedimentation (Miranda et al ., 2018; Alencar et al ., 2020) of the strata below those described here. This tectonic event probably had some effect on the variation of the isotope values of this bed, which is accompanied by less evaporative conditions.…”

Section: Facies Associationsmentioning

confidence: 99%

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Mixed siliciclastic–carbonate sedimentation in an evolving epicontinental sea: Aptian record of marginal marine settings in the interior basins of north‐eastern Brazil

et al. 2021

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The Aptian evaporitic transitional sequence (sag phase) of the Brazilian marginal basins records the first connection between the Central and South Atlantic oceans in the equatorial area. During this phase, lacustrine carbonate reservoirs and giant salt deposits developed in the southern basins of Santos and Campos, forming world-class petroleum reservoirs. The sag succession is also well-preserved in the interior rift basins of north-eastern Brazil, where upper Aptian strata are represented by a continuous section. This contribution presents an interpretation of the evolution of a third-order depositional sequence comprising lacustrine limestones, marine siliciclastic facies and evaporite deposits of the intracontinental Araripe Basin. The Lowstand Systems Tract is characterized by fluvial deposits filling accommodation generated during the syn-rift phase. The overlying deposits comprise marine facies with preservation of dinoflagellates and marine ichnotaxa, evidencing marine deposition in bayhead delta settings. The transgressive surface is represented by limestones, including the Konservat-Lagerst€ atte laminites, onlapping the basement rocks. Above, tide-dominated bay deposits with distinct subtidal, intertidal and supratidal portions are recorded. The Maximum Flooding Surface is a dark shale below foreshore to shoreface facies, marking the beginning of the Highstand Systems Tract, culminating with deposition of evaporites (gypsum and anhydrite). The stratigraphic architecture and palaeocurrents measured in different facies associations suggest that marine waters reached the basin from the south. The data unequivocally records late Aptian marine ingressions of an incipient South Atlantic Ocean over the interior basins of north-eastern Brazil, while lacustrine conditions were still prevailing in the Pre-Salt sag units of the Santos and Campos basins.

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“…The latter is of growing interest in environmental geosciences, as it is less time-consuming and more cost-effective. The fields of application are wide and they include analysis of: slope stability and landslides (Fernández et al 2016;Salvini et al 2017; Barlow et al 2017;Casagli et al 2017); structural geology (Cawood et al 2017;Nesbit et al 2018); cultural heritage and archeology (Spanò et al 2018); geomorphology (Silva et al 2017); bathymetry (Bandini et al 2018); and reservoir characterization (Miranda et al 2018). Moreover, UAV setups permit the application of multispectral imaging and other tools for data collection (e.g., thermal sensors).…”

Section: Introductionmentioning

confidence: 99%

Integration of photogrammetry from unmanned aerial vehicles, field measurements and discrete fracture network modeling to understand groundwater flow in remote settings: test and comparison with geochemical markers in an Alpine catchment

Binda¹,

Pozzi²,

Spanu³

et al. 2021

Hydrogeol J

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Fast and cost-effective techniques for hydrogeological modeling are of broad interest for water resources exploitation, especially in remote settings, where hydrogeological measurements are difficult to perform. Unmanned aerial vehicles (UAV)-based techniques are potentially useful for these aims, but their application is still limited. In this study, a field-based approach and UAV-based approach are integrated for the computation of a discrete fracture network model of a fractured aquifer in the Central Alps. Then, calculated directions of the hydraulic conductivity components were compared with a geostatistical analysis of geochemical markers from sampled spring waters, to infer a conceptual model of groundwater flow. The comparison of field-based and UAV-based fracture measurements confirmed a good matching for fracture orientations and recognized a more reliable estimation of fracture dimensions for the UAV-based dataset. Nonetheless, an important variable for hydrogeological modeling—fracture aperture—is not measurable using UAV, as this requires field measurements. The calculated directions of the main conductivities fit well with the analyzed geochemical markers, indicating the presence of two partially separated fractured aquifers and describing their possible groundwater flow paths. The adopted integrated approach confirms UAV-based measurements as a potential tool for characterization of fracture sets as the input for hydrogeological modeling and for a fast and effective surveying tool, reducing time and cost for other following measurements.

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Quantifying aperture, spacing and fracture intensity in a carbonate reservoir analogue: Crato Formation, NE Brazil

Cited by 56 publications

References 37 publications

Hydromechanical Modeling of Fault Reactivation in the St. Gallen Deep Geothermal Project (Switzerland): Poroelasticity or Hydraulic Connection?

Hydromechanical Modeling of Fault Reactivation in the St. Gallen Deep Geothermal Project (Switzerland): Poroelasticity or Hydraulic Connection?

Mixed siliciclastic–carbonate sedimentation in an evolving epicontinental sea: Aptian record of marginal marine settings in the interior basins of north‐eastern Brazil

Integration of photogrammetry from unmanned aerial vehicles, field measurements and discrete fracture network modeling to understand groundwater flow in remote settings: test and comparison with geochemical markers in an Alpine catchment

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