Acoustic subsea test tree and method

A well string, comprising:

• a pipe string including a plurality of connected pipe segments with acoustic couplers connected between adjacent pipe segments, said acoustic couplers being separate from any mechanical connecting means connecting said adjacent pipe segments;
• transmitting means, connected to an upper portion of said pipe string, for transmitting an acoustic command signal down said pipe string through said acoustic couplers;
• a subsurface device to be actuated by said acoustic command signal transmitted down said pipe string through said acoustic couplers;
• signal receiving means connected to said pipe string for receiving said acoustic command signal transmitted down said pipe string through said acoustic couplers;
• and
• actuator means, operably associated with said signal receiving means, for actuating said subsurface device in response to said acoustic command signal transmitted down said pipe string through said acoustic couplers.

A method of testing a subsea well, said method comprising the steps of:

• assembling a pipe string from at least a first and a second pipe segment, said first segment being attached to said second segment;
• connecting an acoustic coupling means between said first and second pipe segments;
• connecting a subsea test tree to said pipe string;
• lowering said pipe string and said subsea test tree from a surface structure to said subsea well;
• connecting said subsea test tree to a blowout preventor stack of said well;
• transmitting an acoustic command signal from said surface structure down said pipe string through said first pipe segment, then through said acoustic coupling means, and then through said second pipe segment;
• receiving said acoustic command signal at said subsea test tree;
• and
• actuating a closure valve means of said subsea test tree to move said closure valve means to one of an open and a closed position in response to said acoustic command signal.

A method of transmitting an acoustic signal through a pipe string, said method comprising the steps of:

• assembling said pipe string from at least a first and a second pipe segment, said first segment being attached to said second segment;
• connecting an acoustic coupling means between said first and second pipe segments, said acoustic coupling means being separate from any mechanical connecting means connecting said first and second pipe segments;
• and
• transmitting said acoustic signal through said first pipe segment, then through said acoustic coupling means, and then through said second pipe segment.