Analogical Model of the Deformation of Sandy Submarine Channels in Shaly Pelagic Sediments

The grassemargins are affected by strong deformation due to the increase of the sedimentary cover, the eventual basement tilt and the resulting gravity gliding. These movements affect the entire sedimentary sequence including the sandy channels often present in the shaly or silty pile. As a result, the channel shape changes with time, faults may appear that will break the sand continuity and therefore affect the petroleum reservoir quality of these channels. In this paper we document the brittle deformation of a channel through analogical models. The channel is embedded in ductile series where gravity sliding induces multi-directional extension. Results show that the channel is progressively deformed and cut by faults. These ones are systematically perpendicular to the channel borders, do not affect the meanders and are poorly dependent on the regional dip

Analysis of analogue models by helical X-ray computed tomography

The aim of analogue model experiments in geology is to simulate structures in nature under specific imposed boundary conditions using materials whose rheological properties are similar to those of rocks in nature. In the late 1980s, X-ray computed tomography (CT) was first applied to the analysis of such models. In early studies only a limited number of cross-sectional slices could be recorded because of the time involved in CT data acquisition, the long cooling periods for the X-ray source and computational capacity. Technological improvements presently allow an almost unlimited number of closely spaced serial cross-sections to be acquired and calculated. Computer visualization software allows a full 3D analysis of every recorded stage. Such analyses are especially valuable when trying to understand complex geological structures, commonly with lateral changes in 3D geometry. Periodic acquisition of volumetric data sets in the course of the experiment makes it possible to carry out a 4D analysis of the model, i.e. 3D analysis through time. Examples are shown of 4D analysis of analogue models that tested the influence of lateral rheological changes on the structures obtained in contractional and extensional settings