Abstract: An apparatus T.sub.1 for sealing a well tubing 12 including a housing 20, 21, 22 which has a channel 68 communicating with the bore of tubing 12 and a chamber 43 connected with channel 68. A seal 62 is slidably mounted in the housing and is disposed in a retracted open condition in chamber 43 to enable fluid flow through channel 68. AN actuator 41, 42 also disposed in chamber 43, includes a shape memory alloy material which is responsive to the temperature thereof rising to a predetermined level corresponding to the transition temperature of the shape memory alloy for transforming in shape to extend the seal into an extended condition within channel 68, thereby blocking fluid flow therethrough.

Abstract: Subsurface safety valve assembly (16) for oil wells comprising a valve element (57) and a temperature responsive operator comprising multiple coil springs (69, 70), made of shape memory material, operable in opposing directions for opening and closing the valve element and a ratchet locking mechanism comprising wickers (79) for locking the valve in its open position after removal of the heating which causes shape memory effect movement to such position.

Abstract: 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.