Chevron Research Company

Andrew Nigrini

Rong J Hwang

Marion G Reed

Liming Hsueh

The present invention relates to an improved method for controlling pH in the liquid and vapor phases of wet steam having such phases formed in a steam generation system from feedwater having therein at least one carbonate species which in the presence of steam forms a vapor phase component tending to lower the pH of the vapor phase of the steam upon condensation and a liquid phase component tending to raise the pH of the liquid phase of the steam. It comprises: (a) converting the feedwater in a steam generation system to steam having a vapor phase and a liquid phase; and (b) adding to the steam generation system, a heterocyclic, multifunctional, nitrogen-containing compound capable of forming a nonvolatile anionic component and a cationic component that, in the presence of said system, yields hydrogen ions for reducing the pH of the liquid phase of said steam and an alkaline component for increasing the pH of the vapor phase of said steam upon condensation.

Method for controlling the pH of steam fluids using heterocyclic,

A method for controlling pH in the liquid and vapor phases of wet steam having such phases formed in a steam generator system from feedwater having therein at least one carbonate species which in the presence of steam forms a vapor phase component tending to lower the pH of the vapor phase of the steam upon condensation and a liquid phase component tending to raise the pH of the liquid phase of the steam, comprising: (a) converting the feedwater in a steam generation system to steam having a vapor phase and a liquid phase; and (b) adding to the steam generation system, a compound, selected from the group of phosphorus, arsenic, antimony, and bismuth containing compounds which are capable of forming a nonvolatile anionic component and a cationic component that, in the presence of the steam, yields hydrogen ions for reducing the pH of the liquid phase of the steam and an alkaline component for increasing the pH of the vapor phase of said steam upon condensation.

Method for controlling the pH of steam fluids

A method of inhibiting the dissolution of the gravel pack and silicate- or carbonate-containing formations subjected to steam-enhanced oil recovery processes while inhibiting the corrosion of mild steel. The method includes the controlled addition of a salt to the steam feed water to maintain the pH of the residual liquid phase in the range of from 8 to 10. Preferred salts are ammonium salts, such as ammonium sulfate and ammonium chloride.

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La Habra Heights, CA, United States of America

Andrew Nigrini