Shell Oil Comapny

Ronald F Scheuerman

Edwin A Richardson

Charles C Templeton

David C Berkshire

James H Lybarger

Joseph Reisberg

Seth A Silverman

The dissolving of siliceous material in an environment containing corrodable metal and having a temperature exceeding about 300.degree. F. is improved by using an aqueous solution containing an amount of ammonium fluoride equivalent to that in a 2-3 molar solution of hydrogen fluoride and enough weak acid and weak acid salt to provide a pH of near to but less than 7.

Process for acidizing hot siliceous material

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

Production is initiated from a gas well which is kept from producing by the hydrostatic pressure of the liquid it contains, by injecting an aqueous liquid that contains reactants which form nitrogen gas within the wall or reservoir and displaces enough liquid out of the well to lower the hydrostatic pressure to less than the fluid pressure in the adjacent portion of the reservoir and cause fluid to flow from the reservoir to the well.

Method of starting gas production by injecting nitrogen-generating liquid

A carbonate reservoir is acidized slowly by injecting an aqueous solution of a chlorocarboxylic acid salt so that the rate of the acidization is limited to the rate at which an acid is formed by the hydrolyzing of the chlorocarboxylate ions.

Acidizing carbonate reservoirs with chlorocarboxylic acid salt solutions

The clay dissolving capability of an aqueous mud acid solution of weak acid, weak acid salt and fluoride salt (of the type described in the E. A. Richardson U.S. Pat. No. 3,889,753) can be increased by including in the solution a partial salt of an aminopolyacetic acid chelating or complex-forming agent.

Increasing the clay dissolving capability of a buffer-regulated mud acid

The clay-dissolving capability of a self-generating mud acid comprising an aqueous solution or dispersion of a fluoride salt, an ester of a 1-5 carbon atom aliphatic alcohol and a 2-5 carbon atom fatty acid suitable for use at temperatures exceeding about 180.degree. F is improved by adding an effective amount of an aminopolyacetic acid salt chelating or complexing agent.

Increasing the clay-dissolving capability of a relatively high pH

A barium sulfate scale or solid can be dissolved economically by flowing a stream of relatively dilute aqueous solution of aminopolyacetic acid salt chelating agent into contact with and along the surfaces of the scale while correlating the composition and flow rate of the solution so that each portion of solution contains an amount of chelant effective for dissolving barium sulfate and the upstream portions of the scale are contacted by portions of the solution which are unsaturated regarding the barium-chelant complex.

Growing community of inventors

Bellaire, TX, United States of America

Ronald F Scheuerman