Effect of contact obstacles on fluid flow in rock fractures

Abstract

Rock fractures have both conductive areas and impermeable obstacles, where the two rock surfaces are in contact. This paper aims at a better understanding of the effect of contact obstacles on fluid flow. Finite element simulations through rock fractures with conductive and contact areas were conducted to test validity of the theoretical equation. The contact correction term (1–2c) was modified to (1–2.4c), yielding better estimates when compared with measured hydraulic apertures, especially at a high fractional contact area. The modified correction term (1–2.4c) reflects a strong impact on fluid flow at high fractional contact areas. As some void areas surrounded by contact regions do not contribute to fluid flow, incorporation of these areas into contact areas leads to the better calculation of fluid flow through rough fractures with contact obstacles.