Sandstone compaction by intergranular pressure solution

F. K. Lehner , Y. M. Leroy (1)

1 LMS - Laboratoire de mécanique des solides

This chapter discusses sandstone compaction by intergranular pressure solution and presents the theoretical means for exploring problems of stress-sensitive dissolution and coupled macroscopic deformation and transport. The simple one-dimensional compaction model discussed in this chapter represents only a first exploratory study of the behavior of the proposed model. Despite carrying out a numerical study for only one-layer thickness and a single set of initial and boundary conditions, the results obtained for this case have yielded some basic insights into the behavior of the compaction model that can also point the way for future studies. When precipitation was inhibited, the exceedingly slow diffusive transport over 5,000 m of layer thickness was found to lead to the build-up of high (possibly unrealistic) supersaturations, approximately 1.5 times the equilibrium concentration, which slowed down intergranular dissolution to extremely low rates. However, because this low-rate limit in compaction behavior is likely to be attained only in the absence of any significant advective influx of undersaturated fluid through the base of the layer, the role of the prevailing hydrological regime in compacting sedimentary layers is immediately apparent. This observation suggests that in a sedimentary column that is open only at its top, macroscopic advection will be activated only if there exist local sinks—the free faces—on the grain scale, where the material at a nearby grain boundary can be deposited.

Domaines: Mécanique [physics.med-ph]

F. K. Lehner, Y. M. Leroy. Sandstone compaction by intergranular pressure solution. Mechanics of fluid saturated rocks, pp.115-168, 2004, ⟨10.1016/S0074-6142(03)80019-0⟩. ⟨hal-00112505⟩