Method for plugging subterranean formations with siliceous gels

摘要

A high pH solution containing a silica material and an inorganic fluoride salt which hydrolyzes to form hydrofluoric acid are introduced into a subterranean zone where the pH is reduced by the acid whereby the silica material forms a gel and plugs the subterranean zone. The pH at which gelling occurs can be increased by adding a soluble inorganic salt to the solution.