The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 11, 2001
Filed:
Dec. 20, 1999
Jean-François Argillier, Saint Cloud, FR;
Philippe Roche, Nanterre, FR;
Institut Francais du Petrole, Rueil-Malmaison Cedex, FR;
Abstract
A process for circulating an aqueous foam in a wellbore includes the steps of forming a foam from an aqueous composition having a determined pH value, injecting the foam into a well so that it circulates from the surface to the well bottom and then back from the well bottom to the surface, and then changing the pH value of the foam when it returns to the surface. The aqueous composition from which the foam is made includes at least one ionic surfactant whose charge does not practically depend on the pH value and a polyampholytic polymer whose global charge depends on the pH value. This composition gives the foam the property that when the pH of the foam is varied at the surface of the well, the charge of the polyampholytic polymer is modified and the foam becomes destabilized and breaks more readily.