Geostatistical simulation of transmissivity and flow : simplified case of the linearized diffusion equation in steady state

The calculation of fluid flow by means of numerical codes necessitates the often arbitrary definition of boundary conditions around the domain which can locally significantly modify the flow. The new geostatistical simulation method of joint perturbations of transmissivity, hydraulic head and flow is used, in which the boundary conditions are set at infinity. The simulation method is based on the linearization of the diffusion equation in a simplified case: parallel mean flow, steady state and absence of effective recharge. The usual geostatistical condition- ing procedure allows one to take into account the head, transmissivity or flow data, and if needed the local boundary conditions, giving solutions to the inverse problem. In an example, a comparison is made of the perturbations of head obtained with finite difference calculation.