INFLUENCE OF PORE FLUID CHEMISTRY ON THE STATE OF STRESS IN SEDIMENTARY BASINS

Abstract

In order to accommodate growth of a grain, an equivalent volume of the surrounding material must be removed by deformation, displacement, or diffusion. Under certain conditions of stress, fluid pressure, and pore fluid saturation, the process known as pressure solution can occur in reverse, the grains moving apart as solute diffuses into the grain contacts and precipitates there. In this paper the horizontal stress required to prevent lateral spreading of a rock due to reverse pressure solution is shown to be equal to the fluid pressure, plus an extra term dependent on the saturation level of the pore fluid. Results of numerical modeling suggest that the contribution of this term can be significant, equivalent to the horizontal stress required to resist expansion due to overpressure. Such interaction between chemistry and stress may have significant consequences for the stress state within sedimentary basins.