Abstract: A sonic transmitter assembly for use in logging-while-drilling includes stacks of piezoelectric crystals that extend outwardly from a nodal plate member, and a generally tubular assembly that contains such stacks and has end portions that are sealingly mounted in diametrically opposed holes in a pipe member that forms a pan of the drill string. Spring mass isolator systems are employed to inhibit transmission of acoustic waves to the pipe member. Balanced mounting forces and the bilateral symmetry of the construction also inhibit transmission of acoustic waves to the pipe member, particularly waves which are asymmetric with respect to the longitudinal axis of the pipe member.

Abstract: The invention is directed to a locking mechanism for locking a tool to an anchor seat located in the tubing of a well, the locking mechanism comprising keys which are radially movable relative to the axis of the tool, the keys emerging via apertures in the body of the tool to engage in a groove of an anchor seat located in the well conduit. The groove of the anchor seat has an internal diameter smaller than the internal diameter of the well conduit. Each key is axially movable within the aperture between a high position and a low position. Structure is provided for retaining the keys in the high position, positioning the keys in a radially retracted position, so that the keys do not cause the tool to be secured in the anchor seat. Structure is also provided for positioning the keys in a radially extended position, causing the keys to contact the groove of the anchor seat, thereby locking the tool to the anchor seat.

Abstract: The invention relates to a tool suitable for closing a production column (100) of a well when the tool is located in a connector of enlarged diameter (101). The tool is lowered on the end of a cable (76) and includes a tilting valve member (60) which is oblong in shape and which is oriented longitudinally to pass through the corresponding oblong orifice of a valve seat (69) fixed to the connector, and is then oriented transversely in order to co-operate with said seat in order to close the production column when a traction force (F) is applied to the cable (76).