Patent ID: 6533036
Filing Date: 2003-03-18
Classification: E21B

Abstract:
A method of treating the wall of a critical zone in a borehole, the method consisting in reinforcing the wall of the critical zone with a coating obtained from a base fluid which is pumped from the surface to a tool to be projected from an injector against the wall of the critical zone where it forms said coating once it has set, the method being characterized in that it consists in storing at least one additive or activator in liquid form in a reservoir of the tool, and in pumping the base fluid through tubing to a channel which passes through the tool and creating a pressure differential in the terminals of the injector by at least temporarily obstructing the channel of the tool by dropping a projectile from the surface in the tubing and pushing it with base fluid pumped through the tubing to reach the channel of the tool, and stopping the projectile with a retractable retaining means so as to increase the pressure inside the channel of the tool to automatically control the injector and to cause the base fluid and its additive to be projected simultaneously against the wall of the critical zone.