Patent Number: 6,167,961

Title: Small diameter run in whipstock and method for setting in large diameter casing

Abstract: A whipstock assembly 10 for setting within a casing C on an anchor A diverts a cutting mill M to cut a window in the casing. The whipstock assembly is passed through a restriction positioned above the location where the whipstock assembly is set, is lowered past the restriction in a run in position, and is set within the casing in a set position. The whipstock assembly includes an upper whipstock body 20 having a ramp surface 22, 26, a middle lower whipstock body 60 having a concave guiding face 72, and a lower whipstock body 110 having a concave whipstock diversion face 112. A lower hinge member 118 is provided for positioning the concave whipstock diversion face for diverting the cutting mill, and at least one whipstock positioning member 80, 100 engages the casing when in the set position for positioning the middle whipstock body guiding face. Accordingly the method of the invention, the cutting mill and at least a portion of the a downhole motor may be positioned adjacent the guiding face of the middle whipstock body when initiating rotation of the cutting mill. The whipstock and method of the present invention are particularly well suited for conducting a thru tubing operation, with the tubing OD being less than the ID of the casing which the whipstock assembly is set.

Inventors: Pollard; Michael E. (Houston, TX), Braddick; Britt O. (Houston, TX)

Assignee: TIW Corporation

International Classification: E21B 23/01 (20060101); E21B 7/04 (20060101); E21B 7/06 (20060101); E21B 23/00 (20060101); E21B 29/00 (20060101); E21B 29/06 (20060101); E21B 007/08 (); E21B 029/16 ()

Expiration Date: 01/02/2018