Mathematical modelling of non-isothermal silica transport and deposition in a porous medium

Abstract The problem of transport and deposition of silica in non-isothermal flows, either in a porous medium or a single fracture, is investigated. Analytic solutions are obtained using the method of characteristics for both the one-dimensional problem of constant rate injection into a channel or packed column and the radially symmetric problem of the flow away from a reinjection well. Silica deposition is represented by a first order rate equation. Studies on the temperature effects of reinjection into a hot or cold reservoir are undertaken using the one-dimensional model. The strong dependence of the rate of silica deposition on temperature is confirmed by the model. The radial flow model is applied to some field data from the Otake geothermal field, Japan. The model produces a good match to the permeability decline observed in the wells. Mathematical models of silica deposition resulting from non-isothermal flow in a single fracture are successfully tested against some previously reported numerical results.