Abstract: A well sealing system includes a tailipipe set in a wellbore casing, the annular space between the tailpipe and the casing being sealed by a packer comprising at least two annular seals, and the internal diameter of the tailpipe being sealed by at least two internal seals. Disclosed are also an apparatus and a method for providing a casing in a bore hole for a well an offshore location, comprising the steps of: a) fabricating a casing in a location remote from the offshore well location; b) floating the casing to the location; c) orienting the casing to a substantially vertical position; d) lowering in a drilling assembly; e) operating a drill bit included in the drilling assembly to drill a borehole; f) lowering the casing into the bore hole as required.

Abstract: A method of drilling a second wellbore section (12) from a first wellbore section (10) that is lined with a tubular liner (11) using a remotely controlled electrically powered drilling assembly that is suspended from a cable (1) and of periodically interrupting the drilling operation to extend the tubular liner into the second wellbore section without having to pull the assembly from the wellbore. The drilling assembly comprises an expansion means (2), a traction means (3), and an electrically actuated drill bit (6).