Digital-hydraulic well control system

A system for controlling at least three well tools located downhole in a wellbore, comprising:

• hydraulic pressure means located at the wellbore surface for selectively pressurizing a fluid;
• at least two hydraulic lines engaged with said hydraulic pressure means and with each well tool for selectively conveying fluid pressure to each well tool;
• and
• hydraulic control means engaged between each hydraulic line and each well tool, wherein each hydraulic control means is operable in response to selective pressurization of one or more hydraulic lines by said hydraulic pressure means, and wherein operation of a well tool through the pressurization of one hydraulic line displaces fluid which is conveyed through another hydraulic line.

A system for controlling at least three well tools located downhole in a wellbore comprising:

• hydraulic pressure means for selectively pressurizing a fluid;
• at least two hydraulic lines engaged with said hydraulic pressure means and with each well tool for selectively conveying fluid pressure to each well tool;
• and
• hydraulic control means engaged between each hydraulic line and each well tool, wherein each hydraulic control means is operable in response to selective pressurization of one or more hydraulic lines by said hydraulic pressure means, and wherein operation of a well toll through the pressurization of one hydraulic line displaces fluid which is conveyed through another hydraulic line;
• and
• a controller for detecting said displaced fluid conveyed through a hydraulic line during operation of a well toll, wherein said controller is capable of measuring the displaced fluid conveyed through said hydraulic line.

A system for controlling at least three well tools located downhole in a wellbore, comprising:

• hydraulic pressure means for selectively pressurizing a fluid;
• at least two hydraulic lines engaged with said hydraulic pressure means and with each well tool for selectively conveying fluid pressure to each well tool;
• and
• hydraulic control means engaged between each hydraulic line and each well tool, wherein each hydraulic control means is operable in response to selective pressurization of one or more hydraulic lines by said hydraulic pressure means, and wherein operation of a well tool through the pressurization of one hydraulic line displaces fluid which is conveyed through another hydraulic line, wherein the number of hydraulic lines engaged with said hydraulic pressure means and with each well tool is equal to the number of well tools located downhole in the wellbore.

A system for controlling at least three well tools located downhole in a wellbore, comprising:

• hydraulic pressure means for selectively pressurizing a fluid, wherein said hydraulic pressure means is capable of reducing hydraulic pressure for a pressurized fluid below a selected pressure;
• at least two hydraulic lines engaged with said hydraulic pressure means and with each well tool for selectively conveying fluid pressure to each well tool;
• and
• hydraulic control means engaged between each hydraulic line and each well tool, wherein each hydraulic control means is operable in response to selective pressurization of one or more hydraulic lines by said hydraulic pressure means, wherein operation of a well tool through the pressurization of one hydraulic line displaces fluid which is conveyed through another hydraulic line, and wherein each hydraulic control means is capable of preventing further movement of the corresponding tool following pressure reduction by said hydraulic pressure means of the pressurized fluid below said selected pressure.