Tool for remotely determining the position of a device in an underwater well assembly

In a tool for determining by operations carried out from an operational base at the surface of a body of water whether, in an underwater well assembly equipped with guidance means, a device in the well assembly occupies a specific intended position, the combination of

• support means connectable to a handling string;
• guide means connected to the support and constructed and arranged to coact with the guidance means to maintain the support in a specific position relative to the underwater well assembly as the support approaches the well assembly;
• locator means carried by the support and constructed and arranged to coact with a part of the underwater well assembly in a specific fashion only when the support and said part of the well assembly are in one predetermined positional relationship;
• feeler means mounted on the support for movement from a normal position to an indicating position,
• the feeler means being biased to its normal position and occupying a position on the support relative to the locator means such that the feeler means engages a part of the well assembly and is thereby positively moved to its indicating position only when the device in the wellhead occupies its specific intended position and the locator means coacts with said part of the well assembly;
• an indicator valve unit mounted on the support and comprising
• a body defining an internal chamber and having
• an inlet port connectable to means for supplying pressure fluid to the chamber from the operational base, and
• an outflow port via which pressure fluid can escape from the chamber,
• a valve seat, and
• a movable valve member mounted to coact with the valve seat and biased to a first position relative to the valve seat;
• the valve seat and movable valve member being disposed to control fluid flow via the outflow port;
• the indicator valve occupying a position on the support such that the movable valve member is engaged by the feeler means and moved to a second position relative to the valve seat when the feeler means moves to its indicating position,
• movement of the movable valve member to its second position causing a pressure change in the internal chamber, which change can be observed remotely as a first indication that the device in the well assembly occupies its specific intended position;
• and
• second means carried by the support and coacting with the feeler means to provide a second remotely observable indication that the device in the well assembly occupies its specific intended position.