Shell Oil Comapny

David C Berkshire

Edwin A Richardson

Ronald F Scheuerman

Jimmie B Lawson

Joseph Reisberg

James H Lybarger

William A McLaughlin

The scaling of a producing well is inhibited by injecting a self-reacting alkaline aqueous solution of a pH-lowering reactant, a compound containing scale-inhibiting anions and a compound containing multivalent cations, which solution subsequently precipitates a slightly soluble scale inhibitor within the reservoir.

Treating wells with self-precipitating scale inhibitor

A backsurge of fluid through perforations in a well casing is chemically induced by injecting into the surrounding reservoir a solution which contains (a) nitrogen gas-generating reactants, (b) a reaction-retarding alkaline buffer, and (c) a pH-reducing reactant that is capable of subsequently overriding the buffer, so that a rapid production of gas and heat causes a backsurging of fluid into the wellbore.

Chemical process for backsurging fluid through well casing perforations

Portions of a subterranean reservoir are temporarily plugged by injecting an aqueous liquid solution which contains nitrogen gas-generating reactants, a foaming surfactant and a pH controlling system arranged so that the solution remains relatively unreactive within the well but forms a relatively immobile foam within the pores or other openings within the reservoir formation.

Temporarily plugging a subterranean reservoir with a self-foaming

The acidizing of a reservoir, particularly one that contains an asphaltenic oil, is improved by using an aqueous solution of strong acid which contains enough sulfosalicylic acid to prevent the formation of iron-asphaltenic solids.

Growing community of inventors

Houston, TX, United States of America

David C Berkshire