Separator control system

Claim 2

Control system for a two-phase subsea separator, including, an input line connected to the subsea separator for introducing a two-phase stream of fluids into the separator, an output gas line connected to the separator, an output liquid line connected to the separator, a valve in the liquid line to control the flow of liquids from the separator, means arranged to detect liquid level in the separator and control the valve in the liquid line to maintain a predetermined range of level in the separator, a valve in the gas line, means sensing the separator pressure and liquid line pressure downstream of the liquid valve to control the valve in the gas line, whereby the gas pressure in the separator is maintained a predetermined amount greater than the downstream liquid line pressure while the separator liquid level is maintained within predetermined range.

Claim 3

The control system of claim 1, wherein the valves are responsive to pressure and the means detecting liquid level in the separator, separator pressure and liquid line pressure generate pressures for control of the valves.

Claim 4

The control system of claim 2, wherein the valve in the gas line is controlled by a pressure generated by the means sensing the separator pressure and the liquid line pressure as a differential of these two pressures and a spring force.

Claim 5

Control system for a subsea oil and gas separator, including, an oil and gas separator vessel positioned at a subsea location to receive the fluids produced from an oil well, an input conduit connected betWeen the oil well and separator vessel with which produced fluids are introduced into the separator vessel, a first output conduit connected to the separator vessel to remove liquids to processing equipment located at the surface, a first valve in the first conduit to control the flow rate of the liquids transmitted from the separator, a second valve in the first conduit controlled to maintain a level of liquid in the separator, means connected to the separator to sense the level of liquid in the separator and control the second valve to maintain liquid level, a second output conduit connected to the separator vessel to remove gas for disposal, a third valve in the second conduit to control the rate of gas removal and therefore the pressure of the separator, and a pressure-actuated operator for the third valve connected to respond to the combination of separator pressure and transmission pressure for the liquid and a spring force, which combination regulates the third valve to maintain separator pressure higher than the transmission pressure for the liquids.

Claim 6

Control system for a subsea oil and gas separator, including, an oil and gas separator vessel positioned at a subsea location to receive the fluids produced from an oil well, an input conduit connected betWeen the oil well and separator vessel with which produced fluids are introduced into the separator vessel, a first output conduit connected to the separator vessel to remove liquids to processing equipment located at the surface, a first valve in the first conduit to control the flow rate of the liquids transmitted from the separator, a second valve in the first conduit controlled to maintain a level of liquid in the separator, means connected to the separator to sense the level of liquid in the separator and control the second valve to maintain liquid level, a second output conduit connected to the separator vessel to remove gas for disposal, a third valve in the second conduit to control the rate of gas removal and therefore the pressure of the separator, and a pressure-actuated operator for the third valve connected to respond to the combination of separator pressure and transmission pressure for the liquid and a spring force, which combination regulates the third valve to maintain separator pressure higher than the transmission pressure for the liquids.

Claim 7

The control system of claim 4, wherein the pressure-actuated operator for the third valve is a piston type of operator with a spring arranged to impose its force on the piston.