Downhole flow control devices and methods

A method for controlling fluid flow when injecting fluids into a formation, comprising:

• providing a well tubular having one or more flow control devices for injecting fluid into a formation or for producing fluid from a formation, each of the one or more flow control devices including
• a body locatable with a tubular,
• a flow regulator, housed within the body, the flow regulator defining a flow path through the body to accommodate flow between internal and external locations of a tubular in use,
• the flow regulator comprising a valve arrangement forming part of the flow path, and a biasing mechanism configured to urge the valve arrangement towards an open configuration from a restricted configuration in which fluid flow through the flow path is restricted, wherein the biasing mechanism and flow path through the flow control device are configured such that a differential pressure acting across the flow regulator, in excess of a particular threshold, moves the valve arrangement from the open configuration towards the restricted configuration in order to limit flow through the flow control device, wherein the biasing mechanism is provided with a shroud arrangement, the shroud arrangement comprising a plurality of shroud members,
• wherein each of the shroud members comprise an axial extension, such that when the shroud members are configured to cooperate in sliding arrangement, the axial extensions of the shroud members overlap to maintain a tortuous path in a labyrinth configuration that inhibits fluid/debris entering the biasing mechanism;
• controlling each device and restricting flow through each device when a differential pressure acting across that device is in excess of a particular threshold, such that each device is configured to move from the open configuration to the restricted configuration.

A method for controlling fluid flow when injecting fluids into a formation, comprising:

• locating one or more flow control devices for injecting fluid into a formation or producing fluid from a formation with a well tubular, wherein each of the one or more flow control devices is locatable with the tubular via a body;
• housing a flow regulator and a biasing mechanism within a cavity defined within the body of each of the one or more flow control devices;
• providing the well tubular in a formation;
• controlling each device and restricting flow through each device via the flow regulator when a differential pressure acting across that device is in excess of a particular threshold, wherein the flow regulator defines a flow path through the body to accommodate flow between internal and external locations of the tubular in use, the flow regulator further comprising a valve arrangement forming part of the flow path;
• biasing the valve arrangement towards an open configuration from a restricted configuration in which fluid flow through the flow path is restricted via the biasing mechanism, wherein the biasing mechanism and flow path through the flow control device are configured such that a differential pressure acting across the flow regulator, in excess of a particular threshold, moves the valve arrangement from the open configuration towards the restricted configuration in order to limit flow through the flow control device, and wherein the biasing mechanism is provided with a shroud arrangement, the shroud arrangement comprising a plurality of shroud members,
• wherein each of the shroud members comprise and axial extension, such that when the shroud members are configured to cooperate in sliding arrangement, the axial extensions of the shroud members overlap to maintain a tortuous path in a labyrinth configuration that inhibits fluid/debris entering the biasing mechanism;
• and
• sealing the biasing mechanism from the flow path with a shroud arrangement.