Analysis of Neutralization Reaction in a Geothermal Well

Abstract

Geothermal wells producing acidic fluid have been abandoned because of high corrosion potential on casing and surface pipeline even though their high productivity. Injecting alkaline solution into the wellbore at a depth of feedzone can be an effective method for neutralizing acid fluid. This study aims to develop a numerical wellbore model for simulating steam-water two-phase flow and equilibrium chemical reactions. The model consists of two-phase flow incorporated with mass action and mass balance equations with respect to chemical components.

The model was first verified by analyzing chemical data of the discharged fluid and steam-water flowrates measured at the wellhead of Well N13-SZ-4, and chemical conditions at the feedzone was estimated. Then, the effects of injecting sodium hydroxide (NaOH) solution quantitatively on neutralization of fluid and pH profiles along the wellbore were analyzed with the model.