Orienting whipstock seat, and method for seating a whipstock

A method of landing a whipstock onto an expandable seat for seating a whipstock along the inner surface of a cased wellbore, the whipstock having an orientation member, and the expandable seat comprising:

• an outer surface having a diameter which is less than the inner diameter of the casing within the wellbore;
• an inner surface having a diameter dimensioned to receive a whipstock;
• a top edge;
• and
• a keyway for receiving the orientation member of the whipstock after said seat has been expanded and set within the cased wellbore;
• the method comprising the steps of:
• releasably attaching the expandable seat to an expander tool;
• running the expandable seat and the expander tool to a selected depth within the wellbore;
• activating the expander tool so as to expand a portion of the expandable seat into contact with the inner surface of the cased wellbore;
• reciprocating the expander tool within the expandable seat so as to release the releasable connection therebetween, and so as to expand the remaining portions of the length of the expandable seat into contact with the inner surface of the cased wellbore;
• removing the expander tool from the wellbore;
• and
• lowering a whipstock into the wellbore until the orientation member is seated in the keyway of the expandable seat.