Modelling of Scaling in a Tauhara Production Well

Abstract

The nature of output decline in Tauhara well TH06 has been investigated using a numerical simulation. The scaling of the well is thought to be due to a combination of deposition at the flashpoint in the wellbore and deposition within the formation at the major feed zone. The numerical model aims to confirm the possibilities of formation scaling. A preliminary 1-D radial kinetic TOUGHREACT model representing the major feed zone was constructed and production simulated using chemical and production field data as input. The model was then simulated for a number of years under a production scenario, and changes in mineral abundance observed. Calcite, illite, pyrite, quartz and epidote were all shown to be oversaturated and had volume fraction changes large enough to influence the porosity and hence flowrate and output of the well. More modelling is required to improve the models match to the true mechanisms driving the calcite deposition.