| Title | Silica Scaling Mitigation by Brine dilution of two-phase fluids for wells OW-52 & OW-52A, Olkaria East Production Field. |
|---|---|
| Authors | Opondo Kizito, Leech Ndinda Catherine, Ongoma Lilian |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Wells OW-52 and OW-52A were among 12 production wells nominated to provide steam for the development of Olkaria I Unit 6 power plant. Wells OW-52 and OW-52A became almost single-phase steam wells and exhibited “excess enthalpy”. These wells were combined with wells from well pad 731 and conveyed to a common separator. The enthalpy of these wells was ~ 2680 kJ/kg. The evaluation of amorphous silica scaling potential in wells OW-52 and OW-52A was done to provide a basis for the design of mitigation of potential silica scaling. These wells have “excess enthalpy” and high silica concentrations in the small brine fraction. It's contributed by boiling effects. As a result of boiling concentrations of silica of ~1208 mg/kg and 1522 mg/kg respectively (corrected to 10 bar a), in the small amounts of brine wells OW-52 and OW-52A were at high risk of scaling due to high silica concentrations and "excess enthalpy". The potential for silica scaling exists when the silica saturation index (SSI) is > 1. Wells from well pads 52 and 731 were combined to the same central separator. In order to provide a basis for design for mitigation of silica scaling by brine dilution a simple model was used to estimate how much brine from the separator was required to dilute the silica in brine in wells OW- 52 and OW- 52A to or below saturation. The main goal for the above assumptions was to keep silica saturation index to less than 1 and minimise condensation |