Integrated Fractured Reservoir Characterization: A Case Study in a North Africa Field

Abstract

Summary In fractured reservoirs, data directly related to fractures are scarce and 1D (e.g., core and image-log data). Other types of data are more widespread (e.g., seismic data) but generally are related only indirectly to fracture distribution. In such reservoirs, it is necessary to understand and then to model the fracture network on a field-wide scale by integrating all available data. We propose a methodology to achieve this objective. The methodology establishes relationships between the fracturing and other sources of data in a systematic workflow that goes from static 1D data to a 3D dynamic model. The methodology is described and illustrated with a case study from north Africa. In this field, fracture data from image logs and cores are related to (1) 3D seismic attributes (e.g., amplitude, coherency), (2) fault patterns, and (3) other types of well data (e.g., interval thickness, lithology index, and porosity). Production data also are used to quantify the contribution of each fracture set to flow, which then can be mapped on a reservoir basis with the more widely distributed log and seismic data. The resultant set of maps then is entered into a dynamic reservoir model. The methodology has been validated with a new well, the fracture network of which was accurately predicted in the reservoir by the model.

Calibrating discrete fracture-network models with a carbonate three-dimensional outcrop fracture network: Implications for naturally fractured reservoir modeling

“…Capturing Fracture-network Heterogeneity Using One-Dimensional Well Data Three-dimensional fracture networks generally display strong spatial heterogeneity, often linked to geological drivers, such as faults, folds, stress fields, lithological trends or bed thickness distributions (Gauthier et al, 2002b;Bourbiaux et al, 2002). These geological drivers impact the large-scale trends of fracture networks.…”

“…Three-dimensional modeling of highly heterogeneous subsurface km-scale fractured reservoirs is a major challenge as usually only 1D well data are available, sometimes steered by geological drivers (Gauthier et al, 2002b). As our 3D DFN models are considered accurate representations of the fracture network within the quarry, we can use them to calibrate a similar subsurface NFR analog.…”

Fast and Efficient Modeling and Conditioning of Naturally Fractured Reservoir Models Using Static and Dynamic Data

“…Though fracturing should be related to geomechanical (strain and stress) conditions, fracture orientations, types and densities generally result from successive poorly known tectonic episodes, which are difficult to identify hence to model. Relating fracture densities to seismic attributes has also been the purpose of research work (Zheng 2006, Zeidouni & van Kruijsdijk 2006, Pearce 2003, Gauthier et al 2002c). If valuable information may be expected from seismic data, the availability of good quality seismic data must come along with specific processing algorithms to extract relevant attributes.…”

“…The spatial distribution of fracture densities being necessarily uncertain, a probabilistic approach should also be preferred, that relies on multivariate statistical analysis, for relating fracture density to explicative variables, and on geostatistics for addressing the spatial variability issue. Such an approach has been proposed by Gauthier et al (2002aGauthier et al ( , 2002bGauthier et al ( and 2002c where it proved efficient on different case-studies. It is the one presented later in this article.…”

Fractured reservoir modeling: From well data to dynamic flow. Methodology and application to a real case study in Illizi Basin (Algeria)

“…Several studies have focused on surface and subsurface fractures characterization in Algeria encompassing different methodologies and approaches (Gauthier et al, 2002;Guehria et al, 2005;Zazoun, 2008;Panien et al, 2010). The increasing interest in fractured reservoir modeling in Algeria is mainly due to the observations that well performances are strongly influenced by the presence of faults and fractures in the subsurface.…”