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Three-Dimensional Characterization of Diagenetic Geobodies


Predicting the distribution of reservoir heterogeneities is important for the prediction of reservoir performance, essential both for hydrocarbon production and carbon dioxide storage. Reservoir heterogeneity is influenced by the nature and distribution of depositional facies, diagenetic products and structural elements, and these are presented as geobodies in subsurface modeling. We focus here on diagenetic geobodies, and to gain a better insight in the distribution and dimension of such geobodies, outcrop analogues are investigated. The current study presents research on dolomite geobodies in Picos de Europa (northern Spain). The goal is to develop a methodology to capture and present the distribution and dimension of diagenetic geobodies and to derive meaningful correlations, which could later be implemented in subsurface models. The documented geobodies occur in Carboniferous host rock of the so-called “Caliza de Montaña” (Barcaliente and Valdeteja Formations) and the Picos de Europa Formation. The study area is near Fuente Dé, the southern part of the Picos de Europa Province. Although terrestrial LIDAR scanning could provide more detailed 3D information on the geobodies, it would also come with a significant additional cost. Hence, we developed a methodology based on remote sensing data, complemented by field pictures, field GPS tracing and mapping and laser rangefinder and tape measurements. We propose new calculation methods to derive height and width of diagenetic bodies documented by laser rangefinder measurements of inaccessible cliff faces. Our results show that the dolomite bodies in the Picos de Europa Formation (recorded on hilly terrain) have a principal length axis oriented WNW-ESE, similar to the main faults in the area. A length/width ratio of 1.8 is apparent, whereas correlation between height and width is less pronounced. For the dolomite bodies in the Montaña beds (captured on steep cliff faces), length of the bodies could not be documented. No correlation was apparent between width and height of the bodies. Dimensions of the geobodies in the Montaña beds are significantly greater than those in the Picos de Europa Formation. Our findings on the dimensions are interpreted in the context of the fracture network, and thus the tectonic history, fluid flow, and depositional lithologies. This study is part of the Qatar Carbonates and Carbon Storage Centre funded jointly by Qatar Petroleum, Shell and the Qatar Science & Technology Park.