In fractured rocks, production optimisation, deep storage safety and pollution control require hydrodynamic models that involve the representation of discrete fractures. This representation cannot be based only on a traditional stochastic approach since field analyses show that each fracture network is organised in a specific way. Predicting the properties of each fracture network requires a unified geometric-mechanical analysis integrating an exhaustive geometric description and the tectono-mechanics of fracture system formation. The challenge is to understand, and thereby explicitly represent and predict, the physical behaviour of a mechanically heterogeneous medium that has undergone a complex geological history. This difficult challenge can be addressed because only a limited number of the many potential physical parameters that control fracture system genesis and present day behaviour seem to be crucial. Our goal is to identify these crucial parameters using a multi-disciplinary approach including field and borehole studies, physical (both analogue and numerical) modelling.

Physical modelling at the heart of integrated research

The methods used to study fracture network initiation, evolution and present day behaviour cannot be based exclusively on rock mechanics or material science methods because of geological complexity and the scaling requirements (one cannot reproduce the deformation and fracturing of a massif in a small rock sample). Therefore, modelling is indispensable.

Numerical modelling is the most frequently used method and we are involved in application and improving the current models of dynamic fracturing. On the other hand, analogue modelling may provide a more powerful approach to study generation and interaction of a large number of fractures in heterogeneous 3D medium.

Geo-FracNet has well-developed skills in many analogue experimental techniques and is actively developing new ones. We use these experimental techniques in combination with numerical modelling and field or borehole studies, to give new insights into fracturing. This  gives further constraints to the prediction of fracture geometries and dynamic behaviour within the predictive tools.

Working together : flexibility

In recent years, collaborations between academia and industry have become the mutually beneficial norm for the research of fracture systems. Geo-FracNet is a group of leading academics with experience of the priorities, needs and work practices of industrial groups such as Elf E-P, Shell Int., TotalFina, I.F.P. ANDRA, etc. The Geo-FracNet work philosophy of continued feedback between co-workers and clients is extremely flexible and easily adapted to the specific needs of individual clients.
 
 
LastEdited Pascal 17:30 01/12/00