Foam Drilling Fluid Technology for Ultra-high Temperature Geothermal Wells.

A high temperature additive, HT-1, was developed to improve the performance of foam drilling fluid used for ultra-high temperature geothermal wells. The addition of HT-1 into foam drilling fluids to some extent enhances the high temperature performance of foaming agents from 180 ℃ to 240 ℃. HT-1 is insensitive to the contamination caused by calcium and chloride ions, and will thus not affect the contamination tolerance of the original foaming agents used. For field operation, HT-1 is cost effective and is easy to use.