Amorphous silica scales deposited in a geothermal well at Olkaria, Kenya

摘要

Amorphous silica scale deposits have been encountered in the utilization of fluids at Olkaria, especially in the separated waters. In Olkaria scale deposition has mainly been experienced in drains and conditioning ponds at the wellhead separators, and to some extent in valves and orifices. Five scales collected from different points of well OW-34 wellhead equipment were studied by FTIR, XRD, EDAX SEM, ICP and UV. The results showed mainly that the scales formed were composed of groups associated with amorphous and opaline silica in the FTIR, and are mainly amorphous to X-rays. The major composition in the EDAX SEM was silicon and oxygen. The fifth scale formed under different flow conditions from the others, and showed some traces of Fe in the EDAX SEM and a quartz peak in the XRD. The scales formed both before and after separation of fluids in the wellhead equipment.