Michael Rainbolt

US Patent:

6935426, Aug 30, 2005

Filed:

Feb 4, 2003

Appl. No.:

10/357943

Inventors:

Michael F. Rainbolt - Plano TX, US
Andrew W. Tullis - Cedar Hill TX, US

Assignee:

Encana Oil & Gas (USA) Inc. - Dallas TX

International Classification:

E21B043/27

US Classification:

166279, 166300, 166307, 1663082

Abstract:

Embodiments provide systems and methods in which a non-viscous fluid, having a heavy concentration of an appropriate breaker, is pumped into a well in front of viscosified fluid, such as a cross-linked polymeric fracturing fluid, to saturate permeable media with a breaker agent. When a polymer filter cake is subsequently formed on the surfaces of the media the breaker is provided good communication with the polymer filter cake for its breakdown and removal. Communication between the breaker and the polymer filter cake is substantially controlled by an operator in that the breaker remains saturated in the permeable media until such time as the operator decreases hydraulic pressure within the well to a point at which the hydraulic pressure of the media forces the breaker back into the well.