Fractured Reservoir Parameters from Borehole Image Analysis

The success of borehole imaging is widely due to the need, expressed by reservoir modelers, for fracture detection and quantification. The way geologists describe fractures through clustering in different sets, mainly addresses the timing of the structural evolution. This is not necessary the best approach for reservoir modeling that requests more quantification of the fracture network. As a borehole image is both a virtual outcrop, and a high resolution measurement of the resistivity, it can feed both approaches. In favorable cases images provide orientation, density, aperture and even an estimation of the fracture length and height. They also provide the relationship between fractures and bedding or between different fracture sets. These parameters directly constrain the fracture network properties at reservoir scale: density, permeability and connectivity. Images can also be interpreted in terms of structural models from bed boundary dips. These models provide valuable information on relationships between structures and fracture networks.