Geochemical Modelling Of An Injection Well

Abstract

A 1-D radial reactive transport model (TOUGHREACT) is set up to investigate the injection capacity decline in a geothermal injection well. Kinetics data from the existing literature, as well as in-field geologic, chemical and production data are used to define the modeling inputs. By considering a relationship between porosity and permeability, it is possible to match the injectivity index decline of the injection well (in t/h/bar). The result suggests that the injection capacity decline is related to the permeability reduction in the near-wellbore formation due to amorphous silica deposition. A sensitivity analysis of the relationship between the porosity and permeability and the influence of the specific reactive surface area has been looked into in the model. Several injection options are simulated and their impacts on injection well performance are compared with conventional analytical solutions.