Packing tool apparatus for sealing well bores

摘要

An improved packing tool (P1) for sealing spaces between the wall (10) of a wellbore and means (12) defining an elongate member (e.g. tubing) disposed longitudinally in the well bore including a sealing mechanism supportable peripherally about the elongate member and including at least one element (27) containing a shape memory alloy material which maintains a radially contracted condition at below a predetermined temperature-corresponding to the transition temperature of the shape memory alloy-to enable introduction of the sealing mechanism into the well bore and which responds to the temperature by transforming into a radially expanded condition to make sealing contact with the wall of the well bore, establishing a tight metal to metal seal therethrough.