Subsidence and capillary effects in chalks

Pierre Delage (1) , Christian Schroeder (2) , Yu-Jun Cui (1)

1 CERMES - Centre d'enseignement et de recherche en mécanique des sols
2 LGIH - Engineering geology laboratory

Based on the concepts of the mechanics of unsaturated soils where capillary phenomena arise between the wetting fluid (water) and the non-wetting one (air), the subsidence of chalks containing oil (non-wetting fluid) during water injection (wetting fluid) is analysed. It is shown that the collapse phenomenon of unsaturated soils under wetting provides a physical explanation and a satisfactory prediction of the order of magnitude of the subsidence of the chalk. The use of a well established constitutive model for unsaturated soils allows a description of the hydro-mechanical history of the chalk, from its deposition to the oil exploitation.

Mots clés: Reservoir Chalk; Subsidence; Oilfield; Unsaturated Soils; Capillarity; Collapse; Water Flooding

Domaines: Matériaux et structures en mécanique [physics.class-ph]; Matériaux et structures en mécanique [physics.class-ph]

Pierre Delage, Christian Schroeder, Yu-Jun Cui. Subsidence and capillary effects in chalks. ISRM International symposium, Sep 1996, Torino, Italy. pp.1291-1298. ⟨hal-00261639⟩