Abstract: A method for improving the permeability in a subterranean formation by acid treatment is disclosed. In this method, an aqueous acidizing solution containing hydrofluoric acid and excess fluoride is injected into the formation. The acidizing solution dissolves siliceous materials and reduces precipitation of dissolved species from the spent acidizing solution. Further, the acidizing solution has lower acidity than presently employed acidizing solutions and thus a reduced tendency to corrode wellbore tubing and equipment.

Abstract: A method for producing hydrocarbons from a subterranean formation which reduces sand packing in a producing well completed in a zone adjacent the hydrocarbon-bearing formation. The method includes the steps of producing a fluid from the formation which contains both a hydrocarbon phase and an aqueous phase, and simultaneously therewith, injecting a sand control agent, such as a quarternized acylated condensed alkanolamine, into the well adjacent the production zone at a rate to obtain a wellhead concentration of the agent in the aqueous phase in the produced fluid effective to flocculate the concomitantly produced sand particles. The sand particles so treated have a reduced tendency to pack in the well bore and are safely produced with the formation fluids. The method may be practiced in conjunction with conventional sand control techniques, or may be employed as the sole means of sand control.