A Multiphase Separation System

A method of controlling an interface level in a liquid-liquid separator, comprising:

• receiving a separated liquid into the liquid-liquid separator;
• regulating the interface level in the liquid-liquid separator by adjusting a speed of an oil pump with an adjustable speed and a speed of a water pump with an adjustable speed, wherein the oil pump is configured to pump a separated oil from the liquid-liquid separator and wherein the water pump is configured to pump a separated water from the liquid-liquid separator;
• determining the interface level using signals from at least one interface level detector, wherein the signals are transmitted by at least one invert action split range controller to the oil pump and to the water pump, the at least one invert action split range controller output for the speed of the oil pump is configured to be the inverse of a controller output for the speed of the water pump;
• and
• tuning the at least one invert action split range controller to a critically damped or overdamped condition to maintain the interface level in the liquid-liquid separator at a set-point value, the critically damped condition having a damping ratio of one and the overdamped condition having a damping ratio of greater than one.

A multiphase separation system, comprising:

• a gas-liquid separator;
• a liquid control valve positioned between the gas-liquid separator and a liquid-liquid separator in a flow line comprising separated liquid from the gas-liquid separator;
• a liquid-liquid separator positioned downstream of the gas-liquid separator and configured to receive the separated liquid from the gas-liquid separator;
• an oil pump with an adjustable speed configured to pump a separated oil from the liquid-liquid separator;
• a water pump with an adjustable speed configured to pump a separated water from the liquid-liquid separator;
• an oil control valve positioned downstream of the liquid-liquid separator and the oil pump in a flow line comprising the separated oil;
• a water control valve positioned downstream of the liquid-liquid separator and the water pump in a flow line comprising the separated water;
• and
• at least one invert action split range controller of the oil pump, the oil control valve, the water pump, and the water control valve configured to receive signals from at least one interface level detector,
• wherein the at least one interface level detector determines the interface level in the liquid-liquid separator and is configured to transmit signals of a measured value of the interface level in the liquid-liquid separator to the at least one invert action split range controller,
• wherein the speed of the oil pump and actuation of the oil control valve are adjusted to operate inversely from the speed of the water pump and actuation of the water control valve based on signals transmitted from the at least one invert action split range controller.

An inverse operating control system for a liquid-liquid separator, comprising:

• a first pump with an adjustable speed configured to pump a first flow line from the liquid-liquid separator;
• a second pump with an adjustable speed configured to pump a second flow line from the liquid-liquid separator;
• and
• at least one invert action split range controller of the first pump and the second pump configured to receive signals from at least one interface level detector,
• wherein the at least one interface level detector determines the interface level in the liquid-liquid separator and is configured to transmit signals to the at least one invert action split range controller,
• wherein the speed of the first pump is adjusted to operate inversely from the speed of the second pump based on signals transmitted from the at least one invert action split range controller, and
• wherein the at least one invert action split range controller is tuned to a critically damped or overdamped condition to maintain the interface level in the liquid-liquid separator at a set-point value, the critically damped condition having a damping ratio of one and the overdamped condition having a damping ratio of greater than one.

A control system for a gas-liquid separator, comprising:

• a liquid control valve positioned between the gas-liquid separator and a liquid-liquid separator in a flow line comprising a separated liquid;
• an oil control valve positioned downstream of the liquid-liquid separator and an oil pump in a flow line comprising a separated oil;
• a water control valve positioned downstream of the liquid-liquid separator and a water pump in a flow line comprising a separated water;
• and
• a control loop to transmit signals to the liquid control valve, the oil control valve, and the water control valve to regulate a liquid level in the gas-liquid separator, wherein the control loop is tuned to a critically damped or an overdamped condition.