Reservoir Modelling of a Bioclastic Calcarenite Complex on Favignana, Southern Italy: The Application of Multi-point Statistics

Kil, Robert ¹; Moscariello, Andrea ²
(1) Geotechnology, Delft University of Technology, Delft, Netherlands. (2) Geology and Paleontology, University of Geneva, Geneva, Switzerland.

The island of Favignana provides an exceptional three-dimensional insight of the internal architecture of a Lower Pleistocene complex bioclastic calcarenitic wedge. Field data indicate that these calcarenites consist of foramol association, originated during cool to temperate water conditions in a high-energy, storm dominated, open shelf environment. Predominant sedimentary structures vary from small-scale trough cross bedding, large foresets to large scours filled by structureless massive bioclastic material. Overall a main transport direction to the SE indicates the prograding nature of these deposits. Based on the sedimentological characteristics and reservoir properties, this sedimentary complex is believed to be a relevant analogue for several important hydrocarbon fields worldwide such as the Perla Field in Venezuela.

A detailed reconstruction of facies distribution, and description of sedimentary body dimensions and relative position have been carried out in order to model the reservoir heterogeneity and flow properties of a similar buried sedimentary complex. The rock properties could in fact change significantly during burial, as sedimentary bodies consisting of different primary textural and compositional characteristics could be subject to different type of diagenetic modifications.

The internal architecture of the Favignana calcarenite was thus reconstructed on a 3D geo-cellular model using a multi-point statistics (MPS) approach. For this, the following main types of input data were used:

1) pseudo-well data with stratigraphic and compositional information;

2) probability maps of each facies, created from field data and conceptual model;

3) training images.

The latter in particular, are unique for the MPS approach and allowed us to create an arbitrary three-dimensional image which represents the distribution in space of the different sedimentary facies. Because the large availability of exposures due to both natural outcrops and extensive quarries this case study provide an unique opportunity to test and validate the reliability of the MPS modeling approach on a field scale area (2x3 km).

Overall the results obtained are well representing the overall architecture as described by the conceptual geological model generated from outcrop data. The use of MPS, compared to other geostatistical facies modelling aproaches, is therefore preferable for situation where a solid conceptual geological model, validated by hard data, is available.

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.