Mineral scaling potential of geothermal fluids in well MW01A in Menengai, Kenya

Abstract

The Menengai geothermal field was drilled in 2011. Some of the wells that have been discharging have recorded a decrease in productivity over time. In this study, geothermal water was sampled from well MW 01A in Menengai to determine the scaling potentials of calcite, amorphous silica, and anhydrite to understand the possible areas where scaling could occur. Simulations for fluids’ scaling potential was done for the reservoir fluid, discharge and reinjection by adiabatic boiling and conductive cooling by use of the WATCH program. Two conceptual models for these minerals’ saturation in the fluids are used. The results of simulations shows that calcite is expected to cause some scaling problems at the well during initial boiling and does not cause any problem at production, utilization, and reinjection. Amorphous silica may deposit during utilization especially if the water lowered below 100°C during discharges and reinjection. Anhydrite has no possibility of scaling in both boiling and cooling at any stage. Measures should be taken to avoid calcite mineral scaling at the well and amorphous silica deposition by saturated water at temperatures < 150°C during utilization.