Downhole fluid control system

A downhole fluid flow control system comprising:

• a fluid control module having an upstream side and a downstream side, the fluid control module including a main fluid pathway in parallel with a secondary fluid pathway each extending between the upstream and downstream sides;
• a valve element disposed within the fluid control module, the valve element operable between an open position wherein fluid flow through the main fluid pathway is allowed and a closed position wherein fluid flow through the main fluid pathway is prevented;
• a viscosity discriminator statically disposed within the fluid control module, the viscosity discriminator having a viscosity sensitive channel that forms at least a portion of the secondary fluid pathway;
• and
• a differential pressure switch operable to shift the valve element between the open and closed positions, the differential pressure switch including a first pressure signal from the upstream side, a second pressure signal from the downstream side and a third pressure signal from the secondary fluid pathway, the first and second pressure signals biasing the valve element toward the open position, the third pressure signal biasing the valve element toward the closed position;
• wherein, a magnitude of the third pressure signal is dependent upon the viscosity of a fluid flowing through the secondary fluid pathway;
• and
• wherein, the differential pressure switch is operated responsive to changes in the viscosity of the fluid, thereby controlling fluid flow through the main fluid pathway, whereby the valve element is caused to move to the closed position when an undesired fluid with an undesired viscosity passes through the viscosity discriminator.