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Core descriptions provide an essential element of ground truth to subsurface reservoir characterizations, but adequate core characterization and interpretation require a significant time commitment from geoscientists because they are usually done manually. Moreover, core characterizations and interpretations often are inconsistent because they are made at different times by different people. We have used deep-learning segmentation networks, trained using worldwide data sets labeled by specialists, to infer lithofacies and structural features on core images. These networks are not intended to provide perfect core descriptions, but rather to provide high-level fully digital characterizations that can be quickly checked for quality and manually fixed if needed. This ensures that all available and relevant data can be used and relieves geoscientists from the most repetitive characterization tasks to allow them to focus on more complex and value-adding integration and interpretation. We test the previously trained networks in legacy public data from a UK field as an example. There are more than 1300 m of released core images in the field, together with multiple vintages of fault interpretations, that significantly differ from one another. Integrating core and seismic-scale structural characterizations is critical because the best reservoir facies are the most prone to deform via permeability-reducing processes. Detailed structural characterization and identification of individual structural features achieved through deep learning provide an unprecedented amount of data to highlight areas where the seismic-scale fault interpretations and core-scale structural interpretations are inconsistent, yielding valuable insights to validate fault interpretation.

[Sand and sediment transfer to deep water in Icehouse continental margins is quantified departing from an original model of the Brazos fluvio‐deltaic system (USA). Short‐term variability due to local process is superimposed to long‐term trends and masks the base level signal. However, for entire base level cycle sand transferred to deep water is mainly controlled by the proportion of time in which the delta remains docked at the shelf‐edge. , Abstract Sequence stratigraphy for clastic continental margins predicts the development of sand‐rich turbidite deposits during specific times in relation to base‐level cycles. It is now widely understood that deltas can extend to the shelf‐edge forced by high sediment flux and/or base level, providing a direct connection to transfer sediment and sand to the slope and basin floor even during high base level periods. Herein, we build a stratigraphic forward model for the last 120 kyr of the fluvio‐deltaic to deep‐water Brazos system (USA) where sediment partitioning along an Icehouse continental margin can be evaluated. The reduced‐complexity stratigraphic forward model employs geologically constrained input parameters and mass balance. The modelled architecture is consistent with the location of depositional units previously mapped in the shelf. Sand bypasses the shelf and upper slope between 35 to 15 kyr before present and only about 20%–30% of all the sediment and sand supplied to the system is transferred to deep water. Several scenarios based on the initial Brazos model investigate the relationships between base level and deep‐water sand ratio (DWSR). DWSR is defined as the relative amount of sand transferred to the deep‐water portions of the system subdivided by the total sand input to the model. Linear correlations between DWSR and base level change rates or base level are very poor. Short‐term variability due to local processes (for example avulsions) is superimposed to the long‐term trends and mask the base level signal. DWSR for an entire base‐level cycle is mainly controlled by the proportion of time the delta stays docked at the shelf‐edge. Stratigraphic forward models are useful to complement field observations and quantify how different processes control stratigraphy, which is important for making predictions in areas with limited information.]

Carbonate platforms grow through the precipitation, transport, and final deposition of carbonate sediment out of seawater. Quantifying the relative contributions of initial production versus subsequent transport in determining the growth rates and geometries of platforms remains a significant challenge. In this study, stratigraphic forward modeling is used to quantify the roles of sediment production, transport, and deposition during each growth stage of a Permian-Triassic carbonate platform with a complex growth history. Parameter optimization and sensitivity analysis show that, within the range of reasonable values, the morphology of the platform is most sensitive to sediment transport, moderately sensitive to maximum carbonate production rate, and least sensitive to the productivity-depth curve. The ramp-to-high relief, steep-sloped platform transition during Early Triassic time can be explained by any factor that limits sediment transport from shallow water areas of high production to the slope and basin. Reefs may play a role in limiting sediment transport on many platforms but other processes, such as early marine cementation or carbonate production along the slope, may be equally capable of yielding this shift in platform geometry. In this particular case, early lithification of ooid and skeletal shoals on the platform margin, perhaps facilitated by unusually high carbonate saturation state of seawater, may have inhibited sediment transport into the basin prior to the development of a reef on the platform margin. Later, Anisian progradation of the platform margin can be explained by the development of a slope factory rather than requiring increased sediment transport from the platform top. The development of an escarpment margin in the Ladinian is mainly influenced by accommodation in the slope profile created by antecedent Anisian topography. A general implication from the model results is that the growth of steep-sloped carbonate platforms lacking slope factories may often be limited by transport of sediment from the platform top to accommodation on the slope rather than by the intrinsic production capacity of the platform top factory.

A novel reduced-complexity approach to 3D forward modeling of siliciclastic stratigraphy is presented for the simulation of erosion, transport, and sedimentation in continental, transitional, and marine depositional domains. The numerical model is based on defining centerlines that connect sediment input points to the shoreline. For each centerline, erosional and depositional surfaces bound depositional domains, and sand and mud proportions are assigned to each domain. The position of each depositional surface follows a set of geologic rules and ensures mass balance with sediment input. The numerical model is tested by simulating the basin-fill architecture of the XES02 laboratory experiment run at the University of Minnesota, which generates stratigraphy mimicking a passive-margin basin fill. Automatic calibration is used to test multiple combinations of uncertain model input parameters to find those that produce scenarios consistent with the experimental stratigraphy. Calibrated models accurately reproduce shoreline and mass-balance centroid migration, marine sediment proportions, and shoreline trajectories measured in the XES02 experiment. The models also provide reasonable approximations of sand distribution. Of interest, falling shoreline trajectories in the experiment and the calibrated models develop coeval to topset aggradation or topset incision depending on rate of base-level fall. The results reported herein validate the numerical approach for simulating sand distribution in an experimental basin, representing a first step towards the application of the numerical model in fluvio-deltaic settings. For field applications, analogue data can be used to independently constrain the geometry of surfaces bounding depositional domains and their composition. The simplicity of the numerical model then enables multiple realizations by quickly varying uncertain boundary conditions, allowing probabilistic predictions in settings with limited data constraints.

Terrestrial laser scanning is an effective method for digitally capturing outcrops, enabling them to be visualized, analyzed, and revisited in an office environment without the limitations of fieldwork (such as time constraints, weather conditions, outcrop accessibility, repeatability, and poor resolution of measurements). It is common practice in geological interpretation of digital outcrops to use visual identification and manual digitization of pointsets or polylines in order to characterise geological features using 3D CAD-like modules. Other recent and less generic approaches have focused on automated extraction of geological features by using segmentation methods, mostly based on geometric parameters derived from the point cloud, but also aided by attributes captured from the outcrop (intensity, RGB). This paper presents a workflow for the supervised and automated identification and reconstruction of near-planar geological surfaces that have a three-dimensional exposure in the outcrop (typically bedding, fractures, or faults enhanced by differential erosion). The original point cloud is used without modifications, and thus no decimation, smoothing, intermediate triangulation, or gridding are required. The workflow is based on planar regressions carried out for each point in the point cloud, enabling subsequent filtering and classification to be based on orientation, quality of fit, and relative locations of points. A coarse grid preprocessing strategy is implemented to speed up the search for neighboring points, permitting analysis of multimillion point clouds. The surfaces identified are organized into classes according to their orientations and regression quality parameters. These can then be used as seeds for building outcrop reconstructions or further analyzed to investigate their characteristics (geometry, morphology, spacing, dimensions, intersections, etc.). The workflow is illustrated here using a synthetic example and a natural example from a limestone outcrop, in which surfaces corresponding to bedding and three fault orientations were reconstructed.

Understanding and predicting reservoir presence and characteristics at regional to basin scales is important for evaluating risk and uncertainty in hydrocarbon exploration. Simulating reservoir distribution within a basin by a stratigraphic forward model enables the integration of available prior information with fundamental geologic processes embedded in the numerical model. Stratigraphic forward model predictions can be significantly improved by calibrating the models to independent constraints, such as thicknesses from seismic or well data. A three-dimensional basin-scale stratigraphic forward-modeling tool is coupled with an inversion algorithm. The inversion algorithm is a modification of the neighborhood algorithm (a type of genetic algorithm), which is designed to sample complex multimodal objective functions and is parallelized on computer clusters to accelerate convergence. The process generates a set of representative geological models that are consistent with prior ranges for uncertain parameters, calibration constraints, and associated tolerance thresholds. The workflow is first demonstrated on two data sets: a synthetic example based on a clastic passive margin and a real hydrocarbon exploration example for slope and basin-floor stratigraphic traps in the Neocomian (Lower Cretaceous) of the West Siberian Basin. The analysis of calibrated models provides constraints on stratigraphic controls, and allows prediction of locations with higher potential to develop stratigraphic traps. These locations are related to complex interactions between paleobathymetry, subsidence, eustatic fluctuations, characteristics of sediment-input sources, and sediment-transport parameters. Results show the potential of stratigraphic forward modeling combined with inverse methods as an additional tool to support conventional play-based exploration and reservoir-presence prediction.

Forecasting coal resources and reserves is critical for coal mine development. Thickness maps are commonly used for assessing coal resources and reserves; however they are limited for capturing coal splitting effects in thick and heterogeneous coal zones. As an alternative, three-dimensional geostatistical methods are used to populate facies distribution within a densely drilled heterogeneous coal zone in the As Pontes Basin (NW Spain). Coal distribution in this zone is mainly characterized by coal-dominated areas in the central parts of the basin interfingering with terrigenous-dominated alluvial fan zones at the margins. The three-dimensional models obtained are applied to forecast coal resources and reserves. Predictions using subsets of the entire dataset are also generated to understand the performance of methods under limited data constraints. Three-dimensional facies interpolation methods tend to overestimate coal resources and reserves due to interpolation smoothing. Facies simulation methods yield similar resource predictions than conventional thickness map approximations. Reserves predicted by facies simulation methods are mainly influenced by: a) the specific coal proportion threshold used to determine if a block can be recovered or not, and b) the capability of the modelling strategy to reproduce areal trends in coal proportions and splitting between coal-dominated and terrigenous-dominated areas of the basin. Reserves predictions differ between the simulation methods, even with dense conditioning datasets. Simulation methods can be ranked according to the correlation of their outputs with predictions from the directly interpolated coal proportion maps: a) with low-density datasets sequential indicator simulation with trends yields the best correlation, b) with high-density datasets sequential indicator simulation with post-processing yields the best correlation, because the areal trends are provided implicitly by the dense conditioning data.

Riassunto Obiettivi Nella preparazione cavitaria per un restauro estetico diretto di IV Classe, il bordo smalteo viene di solito modificato per aumentare l’area di adesione con un bisello o con un chamfer. Scopi del presente contributo sono stati: a) verificare se la trasformazione clinica di un bisello smalteo a 45° dell’estensione di 1 mm in un chamfer con gli stessi lati e la curvatura di 1/4 di cerchio generi l’aumento di area atteso in teoria (dimostrato in un precedente contributo); b) verificare se, in presenza di tale aumento, ci siano margini di variabilita legati agli aspetti clinici. Materiali e metodi Sulle corone di 12 incisivi estratti sono state condotte: a) scansione CAD/CAM per ottenere un’immagine 3D e il calcolo dell’area della superficie coronale b) rimozione dell’angolo mesiale per riprodurre una IV Classe di media entita, preparazione di un bisello a 45° con estensione di 1 mm, scansione CAD/CAM per ottenere l’immagine 3D e il calcolo dell’area del bisello; c) trasformazione del bisello a 45° in un chamfer che, mantenendo i bordi del bisello, aveva una concavita di 1/4 di cerchio, scansione CAD/CAM per ottenere l’immagine 3D e il calcolo dell’area del chamfer. Risultati e discussione Sono state ottenute: aree dei biselli espresse, in millimetri quadrati (Gruppo A); aree teoriche dei chamfer attese, ammettendo che per ogni bisello trasformato in chamfer vi fosse un incremento dell’11,03%, come dimostrato in precedenti contributi (Gruppo B); aree dei chamfer, espresse in millimetri quadrati, riscontrate sperimentalmente dopo preparazione clinica (Gruppo C). In media, l’area dei biselli era di 12,56 mm2, quella dei chamfer da essi ottenuti era di 14,013 mm2 e quella attesa in teoria di 13,95 mm2. La percentuale di incremento nella trasformazione da bisello a chamfer sperimentale raggiungeva l’11,54% (rispetto alla teorica dell’11,03%). L’analisi statistica dei Gruppi A e C conferma che la trasformazione di un bisello in un chamfer avente gli stessi lati produce un aumento di area altamente significativo; l’analisi statistica dei Gruppi B e C indica che le aree del chamfer attese in teoria non differiscono significativamente da quelle ottenute con la metodica clinica utilizzata. Conclusioni E stato dimostrato sperimentalmente che l’applicazione di una metodica clinica codificata e ripetibile nella trasformazione di un bisello smalteo a 45° in un chamfer avente gli stessi lati e curvatura di 1/4 di cerchio comporta un aumento di superficie altamente significativo ma che non differisce statisticamente da quello atteso in teoria (incrementi dell’11,54% rispetto all’11,03%).

Riassunto Obiettivi Nella preparazione cavitaria per un restauro estetico diretto di Classe IV, il bordo smalteo puo essere lasciato a taglio netto (butt-joint) oppure modificato con un bisello o con un chamfer per aumentare l'area di adesione. Poiche tale aumento non e mai stato dimostrato ne quantificato, scopo del presente contributo e quello di calcolare teoricamente le differenze nell'area smaltea destinata all'adesione ottenuta con la preparazione a butt-joint, a bisello a 45° e a chamfer di ¼ di sfera dello stesso margine cavitario; cio al fine di permettere all'operatore di comparare il vantaggio conseguibile nell'adesione utilizzando l'una o l'altra preparazione. Viene inoltre esaminata la difficolta nell'utilizzo dei valori dell'angolo cavo superficiale (Cavosurfacial Angle, CSA) a tale riguardo. Materiali e metodi Essendo noti lo spessore dello smalto e l'estensione lineare del margine cavitario, vengono calcolate e confrontate percentualmente le aree di smalto disponibili per l'adesione a seguito dei tre tipi di preparazione. Successivamente si calcola quanto la variazione dei suddetti dati influisca percentualmente sulle aree disponibili. Risultati e discussione Ponendo lo spessore smalteo a 1 mm e l'estensione lineare del margine cavitario a 10 mm, risulta che l'area di smalto disponibile aumenta del 41% con il bisello a 45° e del 57% con il chamfer di 7 4 di sfera rispetto al butt-joint. La trasformazione del bisello a 45° in chamfer di ¼ di sfera porta a un aumento relati v o dell'11,03%. N e la variazione dell'estensione lineare del margine ne la variazione (con importanti limitazioni cliniche) dello spessore dello smalto, mantenendo il taglio del bisello a 45°, influenzano i suddetti risultati percentuali. Conclusioni L'angolo smalteo di una cavita non appare correttamente definito dal CSA, che si riferisce anche alle pareti dentinali: si propone, quindi, di considerare il solo angolo di smalto residuo (Enamel's Residual Angle, ERA), che sara di 90° nel butt-joint e di pendenze minori nei biselli con interessamenti progressivamente maggiori della superficiesmaltea. L'aumento di area smaltea disponibile per l'adesione con l'uso di bisello o chamfer rispetto al butt-joint e accertabile con semplici calcoli geometrici. Viene dimostrato che, in teoria, la trasformazione di un bisello smalteo a 45° dell'estensione di 1 mm in un chamfer con gli stessi lati e il disegno di ¼ di sfera comporta un aumento percentuale di superficie disponibile pari all'11,03%. In letteratura non sono riportate medie universalmente accettate per lo spessore smalteo degli elementi anteriori, il che richiede nuovi studi e/o l'ideazione di apparecchiature utilizzabili sperimentalmente e clinicamente per tale scopo.

The structure of the Eocene Ainsa basin is dominated by kilometre-scale thrusts and folds that have trends at c . 70° to that of the main Pyrenean structures. Late uplift and erosion provide excellent exposure of this fold-and-thrust system and its growth strata. Field observations integrated with 2D seismic and well data support the 3D reconstructions presented in this paper. Structural reconstructions of pre- and syn-growth geometries contribute substantial improvements to the understanding of the structure of the area and provide a unique insight into the timing of Pyrenean structures. This study demonstrates that oblique features in the Ainsa basin can be grouped into two main systems: the La Fueba thrust system, an oblique-lateral ramp to one of the main Pyrenean thrusts, and the kilometre-scale folds of the Sobrabe system, a set of anticlines that grew as part of a relaying system of folds. In this study we propose a chronology of deformation based on the geometry of the basin fill, which has been used to frame the general tectonosedimentary evolution of the Ainsa basin. The relative timing of structures indicates that the La Fueba structures predate the Sobrarbe structures, which originated as orogen-parallel structures, and obliquity developed during the growth of these structures through clockwise vertical-axis rotation.

Sedimentary facies is a key control on petrophysical properties within subsurface reservoirs and facies modelling is a critical aspect of reservoir modelling. Several modelling methods exist and selecting the best approach for a specific case is challenging and time-consuming. Outcrop analogues provide detailed information on architecture, geometry and facies connectivity that is not directly available in the subsurface. By modelling outcrop data it is possible to test and compare different modelling strategies systematically in a case where the geology is well constrained. The Eocene aged, Sant Llorenc del Munt fan-delta complex (NE Spain) is a well exposed, transgressive–regressive fan-delta. Outcrop data were used to test a variety of modelling strategies in which the density of conditioning wells, stratigraphic subdivision, modelling algorithm and trends were all varied. The results of these modelling exercises were compared against themselves and against a close-to-deterministically built Base Case reconstruction using a series of static measures including the distribution of fan-delta front reservoir facies, directional connectivity and reservoir-to-well connectivity. The results highlight the following: (a) the impact of the conditioning well density on improving the stratigraphic architecture reproduction in the different modelling approaches; (b) that surface-based modelling subdivisions including the maximum flooding surface to separate independent grids for modelling the transgressive and regressive sequence sets can be detrimental when compared to using only the top and base of the composite sequence unless additional constraints are included; (c) that an algorithm combining a linear trend and a Gaussian field is the most suitable algorithm for reproducing this type of architecture, but requires defining a 3D trend; and (d) the need for using trends to reproduce the architecture when well data are sparse. These results provide guidelines for modelling analogue fan-delta reservoirs in the subsurface.

This study uses one-dimensional convolution seismic models to better understand which features of slope turbidite systems can (or cannot) be observed on real seismic data, aiming to improve subsurface seismic interpretation. Synthetic seismic sections and cubes were built from reservoir-scale three-dimensional facies models of the outcropping Ainsa turbidite system. This turbidite system developed in a foredeep and wedge-top depositional setting within a slope system. The turbidite system consists of laterally and vertically stacked sandstone- and debrite-dominated channel fills, grading into heterolithic and mudstone units, with intercalations of slump-deformed mudstone-rich units. Typical petrophysical values for subsurface Cenozoic sediments were assumed for the seismic models, which are presented at 25-, 50-, and 75-Hz resolution. Seismic models enabled the comparison between architectural and facies distributions observed in the outcrops and the geological models to their possible seismic expression in the subsurface. Comparisons show how seismic expression degrades when seismic resolution decreases. By using models at different geological scales, the effects of each heterogeneity scale are identified. Precise delineation of the internal architecture and facies distribution within channel complexes is beyond the reach of all seismic frequencies. The position of channel complex tops and margins is uncertain because of their gradual character. Differentiating between sandstone- and debrite-filled channels is not straightforward, and bed-scale heterogeneities within the sandstone-dominated channels are barely distinguishable in the seismic data. The net-to-gross predictive capability of root-mean-square amplitude extractions varies depending on the seismic frequency and unit thickness

The Eocene Sant Llorenc del Munt fan-delta complex developed in the Ebro foreland basin. The stratigraphy of this succession, about 1000 m thick, has been described as made up of several transgressive–regressive composite sequences, each composed of a stack of fundamental sequences, in turn made up of a transgressive systems tract and an overlying regressive systems tract. Systems tracts are composed of several facies belts: proximal alluvial fan, distal alluvial fan, fan-delta front, carbonate platform, and fan-delta slope and prodelta. A 3D facies model of a 130 m thick stratigraphic succession was built using outcrop data from one of the composite sequences. The modelling followed a hierarchical approach. A deterministic method was used to reconstruct the surfaces bounding fundamental sequences and their constituent systems tracts. Data input was outcrop traces digitized on photorealistic terrain models. The stacking trend and interfingering of adjacent facies belts within each systems tract was added by means of a geostatistical algorithm and was conditioned to measured stratigraphic logs. The analysis of the resultant 3D facies distributions allows revising the architectural interpretation of the studied interval, leading to the conclusion that the observed arrangements are accommodation, not supply-driven. Furthermore, the 3D models were flow simulated in two injector-producer scenarios: up-depositional and down-depositional dip waterflooding. Flow simulation results show that the depositional architecture of the studied succession controls potential recovery efficiencies, in that a considerable proportion of moveable oil is trapped at the dead-ends in depositional pinch-outs of the main potential reservoir (fan-delta front deposits). Also that up-dip waterflooding predicts better recovery efficiencies than down-dip. The dataset, methods, and results herein make the Sant Llorenc del Munt complex a ready-for-application analogue for marine-transitional reservoirs.

Valid representations of geological heterogeneity are fundamental inputs for quantitative models used in managing subsurface activities. Consequently, the simulation of realistic facies distributions is a significant aim. Realistic facies distributions are typically obtained by pixel-based, object-based or process-based methods. This work presents a pixel-based geostatistical algorithm suitable for reproducing lateral gradual facies transitions (LGFT) between two adjacent sedimentary bodies. Lateral contact (i.e. interfingering) between distinct depositional facies is a widespread geometric relationship that occurs at different scales in any depositional system. The algorithm is based on the truncation of the sum of a linear expectation trend and a random Gaussian field, and can be conditioned to well data. The implementation introduced herein also includes subroutines to clean and geometrically characterize the obtained LGFT. The cleaned sedimentary body transition provides a more appropriate and realistic facies distribution for some depositional settings. The geometric measures of the LGFT yield an intuitive measure of the morphology of the sedimentary body boundary, which can be compared to analogue data. An example of a LGFT obtained by the algorithm presented herein is also flow simulated, quantitatively demonstrating the importance of realistically reproducing them in subsurface models, if further flow-related accurate predictions are to be made.

Simulation of flow and solute transport through aquifers or oil reservoirs requires a precise representation of subsurface heterogeneity that can be achieved by stochastic simulation approaches. Traditional geostatistical methods based on variograms, such as truncated Gaussian simulation or sequential indicator simulation, may fail to generate the complex, curvilinear, continuous and interconnected facies distributions that are often encountered in real geological media, due to their reliance on two-point statistics. Multiple Point Geostatistics (MPG) overcomes this constraint by using more complex point configurations whose statistics are retrieved from training images. Obtaining representative statistics requires stationary training images, but geological understanding often suggests a priori facies variability patterns. This research aims at extending MPG to non-stationary facies distributions. The proposed method subdivides the training images into different areas. The statistics for each area are stored in separate frequency search trees. Several training images are used to ensure that the obtained statistics are representative. The facies probability distribution for each cell during simulation is calculated by weighting the probabilities from the frequency trees. The method is tested on two different object-based training image sets. Results show that non-stationary training images can be used to generate suitable non-stationary facies distributions.

Facies reconstructions are used in hydrogeology to improve the interpretation of aquifer permeability distribution. In the absence of sufficient data to define the heterogeneity due to geological processes, uncertainties in the distribution of aquifer hydrofacies and characteristics may appear. Geometric and geostatistical methods are used to understand and model aquifer hydrofacies distribution, providing models to improve comprehension and development of aquifers. However, these models require some input statistical parameters that can be difficult to infer from the study site. A three-dimensional reconstruction of a kilometer scale fine-grain dominated Cenozoic alluvial fan derived from more than 200 continuously cored, closely spaced, and regularly distributed wells is presented. The facies distributions were reconstructed using a genetic stratigraphic subdivision and a deterministic geostatistical algorithm. The reconstruction is only slightly affected by variations in the geostatistical input parameters because of the high-density data set. Analysis of the reconstruction allowed identification in the proximal to medial alluvial fan zones of several laterally extensive sand bodies with relatively higher permeability; these sand bodies were quantified in terms of volume, mean thickness, maximum area, and maximum equivalent diameter. These quantifications provide trends and geological scenarios for input statistical parameters to model aquifer systems in similar alluvial fan depositional settings.

Building reservoir-scale facies models of outcrops is a practice that improves the three-dimensional geological modelling of subsurface analogues. Facies modelling of outcrops can be achieved either with geostatistical or object-based methods, which in most cases requires conditioning to field-measured sedimentary logs. DEVLOGS assists in producing input files from field logs to be loaded into standard reservoir modelling packages. This is achieved by using a number of georeferenced nodes along the log trace, and placing intermediate bed boundaries according to true thickness recorded in the field log. Moreover, a number of operations to enable the correct loading of sedimentary logs are also performed. The main benefit of DEVLOGS is to facilitate the loading of non-vertical logs. By using non-vertical logs, the conditioning of outcrop models it is not limited to favourable outcropping settings such as very step exposures or non-dipping strata.

Using data from an outcrop characterization of a sandstone-rich turbidite channel fill (the so-called Quarry outcrop in the Ainsa basin), several stochastic facies models were constructed at bed-scale resolution (cells 2.5 m [8 ft] wide and 0.05 m [2 in.] thick). Several industry-standard reservoir-modeling algorithms were employed: truncated Gaussian simulation, sequential indicator simulation, multiple-point geostatistics, and object-based methods with varying degrees of complexity. The degree of similarity (i.e., realism) between realizations and the outcrop characterization was quantified through the use of several responses: (1) static connectivity, (2) effective permeability, and (3) recovery efficiency from waterflood simulations. Differences in the responses measured from the outcrop and facies models were observed: these are mostly algorithm related, instead of caused by soft data or different stochastic realizations. Differences increase greatly when the permeability of the heterolithic packages and mudstone beds (Ht-M) decreases and reflect the methods' ability to model the inclined and undulating Ht-M packages and beds that occur in the outcrop. These packages and beds can drape scours and sandstone beds with depositional topography and pinch-outs, producing sandstone thinning and dead ends. Object-based methods capable of introducing highly undulating Ht-M beds provided the most realistic models. Variogram-based and simple object-based methods failed to capture and reproduce the whole length of undulating beds. Multiple-point geostatistics provided realizations with responses intermediate between variogram-based and simple object-based methods and the more successful advanced object-based methods. The conditioning-to-hard-data capabilities of multiple-point geostatistics are higher than those of the object-based methods, which give them an added advantage.

The external and internal geometry of four turbidite systems outcropping around the Buil syncline (Ainsa basin, Spanish Pyrenees) has been reconstructed with reservoir-scale resolution in three dimensions (3-D). The irregular geometry of the syncline and the resolution required for the reconstruction cannot be resolved with cross sections. Therefore, reconstruction has been carried out with a new methodology that applies a 3-D dip-domain geometrical model and 3-D restoration techniques to achieve reservoir-scale resolution in kilometric-scale reconstructions. This methodology is aimed at resolving 3-D geometries in folded areas and regions with variable thickness stratigraphy.The 3-D reconstruction of the Buil syncline reveals the synsedimentary growth of an intrabasinal anticline and the foreland lithospheric flexure associated with tectonic loading north of the Ainsa basin.

Objectives. In the cavity preparation for direct aesthetic restoration of Class IV, the edge of enamel may be left to butt-joint or modified with a bevel or a chamfer to increase the adhesion area. Since this increase has never been demonstrated and quantified, the purpose of this paper is to theoretically calculate the differences in the enamel area intended for adhesion obtained by preparing a butt-joint, a 45 � bevel and a 1/4 ball chamfer of the same cavity margin, in order to enable the operator to compare the advantage obtainable in the adhesion by using one or the other of the preparations. The difficulty of using the values of the Cavosurfacial Angle (CSA) in this

Point clouds acquired with terrestrial LIDAR are used as a digital support to accurately and precisely georeference outcrop characterizations; as well as to resolve accessibility problems, and improve outcrop characterizations. The LIDAR data allows for an efficient visualization and analysis of the outcrop in the computer, and is also useful for revisiting field data in the office or for teaching purposes. The common practice for virtual outcrop interpretation is visual identification and manual digitalization of pointsets or polylines by using 3-D CAD-like modules. Other, less generic, approaches are oriented towards the automated or semi-automated extraction of geological features, either based on the processing of intensity or other attributes of the virtual outcrop (RGB, hyperspectral) or on geometric parameters calculated from positions. In this presentation, we propose a workflow for the automatic characterization of planar surfaces (typically stratigraphic bedding or fractures) from LIDAR data. The workflow directly uses the point cloud; therefore no decimation, smoothing, intermediate triangulated or gridded surface are required; and is designed aiming to minimize user interaction to allow for a simple, fast, objective and semi-automated use. The result of the workflow is the reconstruction of planar surfaces identified in the point cloud by means of TIN surfaces, organized into families according to their orientations. These surfaces can be used as seeds for building surface-based models of the outcrop, or can be further analysed to investigate their characteristics (geometry, morphology, spacing, dimensions, intersections, etc.). The workflow is based on planar regressions carried out for each point in the point cloud. Which allow the subsequent filtering of points based on normal vector orientation, planar regression quality, relative locations of points or their relative normal vectors differences. This is aimed at individualizing planar patches with geological signification. A coarse grid search strategy is implemented to speed up neighbouring points searches and allow handling multimillion point clouds. The workflow is illustrated using synthetic and natural examples.

Outcrop-scale reconstruction of depositional geometries and facies distribution of carbonate systems improves our knowledge on their heterogeneity distribution, stacking patterns and stratal architecture. The collected data and derived models can be used as analogues for characterizing and modelling potential subsurface reservoirs. Traditional sedimentological analyses in cropping out carbonate systems have limited accuracy depending on exposure conditions, accessibility or past erosive processes. On the other hand, there is a need to complement classical sedimentological approaches with quantitative characterizations and models of sedimentary bodies. In this respect, processing of three-dimensional (3D) point clouds captured by terrestrial LIght Detection And Ranging (LIDAR) technology combined with real-time kinematic global positioning system offers to field geologists the possibility to construct virtual 3D digital outcrop models (DOMs), which allow for more accurate analyses, reconstructions and quantification of the outcropping facies distribution than conventional digital terrain models. We present a LIDAR 3D DOM of an Aptian flat-topped non-rimmed carbonate platform margin from the western Maestrat Basin (Spain). The DOM served as a departing point to perform a 3D reconstruction that shows the relationship between depositional architecture and facies distribution of the carbonate system. The reconstruction not only highlights the value of digital outcrop models to characterize virtual attributes not observable in the outcrops due to the limitations of the 2D views of the exposures, but also allows to refine outcrop-scale sequence stratigraphic analyses. In addition, the 3D sequence stratigraphic approach obtained together with the 3D facies distribution model generated can be used as an analogue for the characterization of subsurface carbonate reservoirs with similar depositional profiles. The workflow of this study followed these steps: 1) Acquisition of the outcrop 3D point data set using a ground-based terrestrial LIDAR equipped with a differential GPS; 44 overlapping scans were needed to cover the entire outcrops of the flat-topped non-rimmed carbonate system characterized, each scan has associated a high-resolution photograph. 2) Mapping stratigraphic surfaces and pseudowells describing 5 lithofacies onto each individual photograph using a CAD-based tool, the mapping is carried directly onto the photographs because manipulating the images and interpreting the details is easier than directly digitizing onto the point-cloud. 3) The features mapped onto the photographs are projected into the corresponding point-cloud in order to georeference them. 4) Locally georeferenced individual point-clouds and attached interpretations were globally georeferenced by means of the UTM coordinates of each scan. 5) The stratigraphic boundaries mapped are used reconstruct the surfaces bounding stratigraphic units. 6) Population of the internal facies distribution conditioned to the pseudowells. This methodology allows to efficiently extracting information from point clouds, and resulted in the construction of a high-resolution 3D geological model displaying the stratal architecture and facies heterogeneity of sedimentary bodies, confined within a 3D sequence stratigraphical framework.

Coal exploration and mining in extensively drilled and sampled coal zones can benefit from 3D statistical facies interpolation. Starting from closely spaced core descriptions, and using interpolation methods, a 3D optimum and robust facies distribution model was obtained for a thick, heterogeneous coal zone deposited in the non-marine As Pontes basin (Oligocene-Early Miocene, NW Spain). Several grid layering styles, interpolation methods (truncated inverse squared distance weighting, truncated kriging, truncated kriging with an areal trend, indicator inverse squared distance weighting, indicator kriging, and indicator kriging with an areal trend) and searching conditions were compared. Facies interpolation strategies were evaluated using visual comparison and cross validation. Moreover, robustness of the resultant facies distribution with respect to variations in interpolation method input parameters was verified by taking into account several scenarios of uncertainty. The resultant 3D facies reconstruction improves the understanding of the distribution and geometry of the coal facies. Furthermore, since some coal quality properties (e.g. calorific value or sulphur percentage) display a good statistical correspondence with facies, predicting the distribution of these properties using the reconstructed facies distribution as a template proved to be a powerful approach, yielding more accurate and realistic reconstructions of these properties in the coal zone.

For a property measured at several locations, interpolation algorithms provide a unique and smooth function yielding a locally realistic estimation at any point within the sampled region. Previous studies searching for optimal interpolation strategies by measuring cross-validation error have not found consistent rankings; this fact was traditionally explained by differences in the distribution, spatial variability and sampling patterns of the datasets. This article demonstrates that ranking differences are also related to interpolation smoothing, an important factor controlling cross-validation errors that was not considered previously. Indeed, smoothing in average-based interpolation algorithms depends on the number of neighbouring data points used to obtain each interpolated value, among other algorithm parameters. A 3D dataset of calorific value measurements from a coal zone is used to demonstrate that different algorithm rankings can be obtained solely by varying the number of neighbouring points considered (i.e. whilst maintaining the distribution, spatial variability and sampling pattern of the dataset). These results suggest that cross-validation error cannot be used as a unique criterion to compare the performance of interpolation algorithms, as has been done in the past, and indicate that smoothing should be also 26 coupled to search for optimum and geologically realistic interpolation algorithms.

Field trips can be improved by integration of new technologies. Among these, virtual outcrops allow for improved, fast and accurate, perception of geological features. Visualization of other complementary information, like terrain models draped with geology and static and dynamic reservoir models, are also important at providing contextual and across-discipline information. All these techniques are independent of accessibility, weather or light conditions, and together render fieldtrips optimal in terms of learning, safety, costs, and organization.

The Eocene aged, Sant Llorenc del Munt fan-delta complex is a well exposed, transgressive–regressive fan-delta, which crops out in NE Spain. Outcrop data were used to test a variety of modelling strategies in which well conditioning, stratigraphic subdivision, modelling algorithm and trends were all varied. The results of these modelling exercises were compared against themselves and against a close-to-deterministically built Base Case reconstruction using a series of static measures including the distribution of fan-delta front reservoir facies, directional connectivity and reservoir-to-well connectivity. The results highlight how well conditioning improves the reproduction of the stratigraphic architecture in the different modelling approaches. That stratigraphic subdivisions including the maximum flooding surface to separate independent grids for modelling the transgressive and regressive sequence sets can actually be detrimental unless additional constrains are included. That an algorithm combining a linear trend and a Gaussian field is the most suitable algorithm for reproducing this type of architecture, but requires defining a three-dimensional trend. And finally, the need for using trends to properly reproduce the architecture when well data are sparse. These results provide guidelines for modelling analogue fan-delta reservoirs in the subsurface.