Sequential remote control plug release system

A sequential remote control plug release system, comprising:

• plug container having a chamber for receiving two cementing plugs;
• a first plug release plunger, connected to said plug container so that said first plug release plunger can be extended into said chamber to support a lower cementing plug received in said chamber and further so that said first plug release plunger can be retracted out of said chamber to allow the lower cementing plug to drop;
• a second plug release plunger, connected to said plug container so that said second plug release plunger can be extended into said chamber to support an upper cementing plug received in said chamber and further so that said second plug release plunger can be retracted out of said chamber to allow the upper cementing plug to drop;
• a first manifold valve connected to said plug container below said first plug release plunger;
• second manifold valve connected to said plug container in between said first and second plug release plungers;
• a third manifold valve connected to said plug container above said second plug release plunger;
• remote control means, adapted to be operated at a location spaced remotely from said plug container, for controlling the retracting of said first and second plug release plungers and the opening of said first, second and third manifold valves, said remote control means including:
• first valve means for providing an actuating signal for said first manifold valve;
• second valve means for providing an actuating signal for said first plug release plunger;
• third valve means for providing an actuating signal for said second manifold valve;
• fourth valve means for providing an actuating signal for said second plug release plunger;
• fifth valve means for providing an actuating signal for said third manifold valve;
• first conductor means for conducting said actuating signal for said first manifold valve to said first manifold valve;
• second conductor means for conducting said actuating signal for said first plug release plunger to said first plug release plunger;
• third conductor means for conducting said actuating signal for said second manifold valve to said second manifold valve;
• fourth conductor means for conducting said actuating signal for said second plug release plunger to said second plug release plunger;
• fifth conductor means for conducting said actuating signal for said third manifold valve to said third manifold valve;
• and
• sequencing means, connected to said second, third, fourth and fifth valve means and said second, third, fourth and fifth conductor means, for preventing said actuating signal for said second manifold valve from opening said second manifold valve through said third conductor means until after said actuating signal for said first plug release plunger is provided through said second conductor means to retract said first plug release plunger, and for preventing said actuating signal for said second plug release plunger from retracting said second plug release plunger through said fourth conductor means until after said actuating signal for said second manifold valve is provided through said third conductor means to open said second manifold valve, and for preventing said actuating signal for said third manifold valve from opening said third manifold valve through said fifth conductor means until after said actuating signal for said second plug release plunger is provided through said fourth conductor means to retract said second plug release plunger.

A method for controlling the use of a plug container connected to a well during a cementing job, which plug container includes two stacked plugs and two fluid inlet valves, said method comprising:

• releasing the lower plug into the well;
• completing a first control signal circuit in response to releasing the lower plug into the well;
• opening one of the two fluid inlet valves, including sending a control signal through the completed first control signal circuit;
• completing a second control signal circuit in response to sending a control signal through the completed first control signal circuit,
• releasing the upper plug into the well, including sending a control signal through the completed second control signal circuit;
• completing a third control signal circuit in response to sending a control signal through the completed second control signal circuit;
• and
• opening the other fluid inlet valve, including sending a control signal through the completed third control signal circuit.