Patent Number: 8,813,873

Title: Enhanced smear effect fracture plugging process for drilling systems

Abstract: This invention relates to drilling a well, particularly an oil or gas well, where casing or liner will be installed to stabilize the wellbore. The present invention is intended to permit more drilling and longer lengths of casing or liner to be installed at one time. The present invention includes a combination of a smear tool and specially sized granular lost circulation material solids in the drilling mud which work together to close and seal leaking formations and fractures whether pre-existing or induced by drilling. By the natural collection of the inventive solids along with the conventional particles in the drilling mud to form a filter cake at the problem areas along the wall of the wellbore and the smear tool arranged to compress the filter cake into the problem areas, lost circulation is minimized. Maintaining circulation naturally allows for longer drilling cycles and potentially fewer liner joints in the well. As such, larger diameter boreholes are located in the hydrocarbon bearing formation and less time is spent installing casing or liner pipe.

Inventors: Beardmore; David H. (Missouri City, TX), Scott; Paul D. (Houston, TX), Watts; Rick D. (Houston, TX)

Assignee: ConocoPhillips Company

International Classification: E21B 17/22 (20060101); E21B 33/13 (20060101)

Expiration Date: 8/26/12018