Geothermal wells, acidizing acid additives

Deep and geothermal wells are inherently hot and are well served by aluminum phosphate formulations (see Chapter 11). The dynamic temperature in these wells is 250 °F (121°C) or higher, and the static temperature is >350 °F (235°C). For these wells, berlinite-based CBPC works well with its maximum solubility at 244 °F (118°C) of alumina and phosphoric acid solution. As we have seen in Chapter 11, this reaction takes place at 302 °F (150°C) that is in the range of the temperatures of deep and geothermal wells [7]. Even at these temperatures, the solubility of aluminum oxide is too low, but addition of a small amount of microcrystalhne or amorphous aluminum hydroxide aids in increasing the soluble ions in the solution. With its large surface area, alumina provides the necessary solubility at the given downhole temperamre. 

Resistance to steam and aqueous acidic media in addition to the other previously mentioned oil well environments is necessary. Steam is mandatory for well enhancement and in geothermal conditions. These conditions prove too severe for most medium-rated elastomers. 

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