Flow control device and method

A production string for transport of hydrocarbons, wherein the production string comprises:

• a base pipe,
• an enclosure arranged at the exterior wall of the base pipe having at least one enclosure input opening, and
• a fluid flow control device for establishing a controllable fluid communication of a fluid flow between an external fluid reservoir and the base pipe, comprising:
• a primary flow path arranged inside a main housing, the primary flow path comprising a primary flow path inlet configured to guide a primary fluid flow constituting a major portion of the fluid flow into the main housing during operation and a primary flow path outlet configured to guide the primary fluid flow from the main housing and into the base pipe during operation,
• a secondary flow path configured to guide a secondary fluid flow constituting the remaining portion of the fluid flow, the secondary flow path comprising a first fluid flow restrictor configured to generate a pressure decrease from a pressure p1 upstream of the first fluid flow restrictor to a pressure p2 downstream of the first fluid flow restrictor, a second fluid flow restrictor arranged downstream of the first fluid flow restrictor and configured to generate a pressure decrease from the pressure p2 upstream of the second fluid flow restrictor to a pressure p3 downstream of the second fluid flow restrictor and a chamber arranged downstream the first fluid flow restrictor and upstream the second fluid flow restrictor and
• a movable valve element arranged inside the main housing and configured to close the primary flow path for fluid flow when exposed to a pressure force from within the chamber exceeding a threshold pressure force,
• wherein the fluid flow control device further comprises:
• a top housing covering the primary flow path inlet of the main housing, the top housing comprising:
• a fluid flow inlet allowing the fluid flow to flow from the external fluid reservoir and at least partly into the primary flow path inlet,
• a swirl inducer inducing a swirl of the fluid flow between the fluid flow inlet and the primary flow path inlet, and
• a secondary flow path inlet configured to guide a secondary fluid flow into the secondary flow path,
• wherein the fluid flow control device is arranged into a through-going hole of the wall of the base pipe within the enclosure such that a controllable fluid communication is obtained between the enclosure and the interior of the base pipe, and
• wherein the enclosure is configured to provide an input chamber covering the at least one enclosure input opening of the enclosure and the fluid flow inlet of the fluid flow control device.

A method of controlling fluid flow based on changes in fluid properties using a fluid flow control device for establishing a controllable fluid communication of a fluid flow between an external fluid reservoir and a base pipe of a production string, comprising:

• a primary flow path arranged inside a main housing, the primary flow path comprising a primary flow path inlet configured to guide a primary fluid flow constituting a major portion of the fluid flow into the main housing during operation and a primary flow path outlet configured to guide the primary fluid flow from the main housing and into the base pipe during operation,
• a secondary flow path configured to guide a secondary fluid flow constituting the remaining portion of the fluid flow, the secondary flow path comprising a first fluid flow restrictor configured to generate a pressure decrease from a pressure p1 upstream of the first fluid flow restrictor to a pressure p2 downstream of the first fluid flow restrictor, a second fluid flow restrictor arranged downstream of the first fluid flow restrictor and configured to generate a pressure decrease from the pressure p2 upstream of the second fluid flow restrictor to a pressure p3 downstream of the second fluid flow restrictor and a chamber arranged downstream the first fluid flow restrictor and upstream the second fluid flow restrictor and
• a movable valve element arranged inside the main housing and configured to close the primary flow path for fluid flow when exposed to a pressure force from within the chamber exceeding a threshold pressure force,
• wherein the fluid flow control device further comprises:
• a top housing covering the primary flow path inlet of the main housing, the top housing comprising:
• a fluid flow inlet allowing the fluid flow to flow from the external fluid reservoir and at least partly into the primary flow path inlet,
• a swirl inducer inducing a swirl of the fluid flow between the fluid flow inlet and the primary flow path inlet, and
• a secondary flow path inlet configured to guide a secondary fluid flow into the secondary flow path, the method comprising:
• guiding the fluid flow into the fluid flow inlet,
• guiding the fluid flow through the swirl inducer arranged between the fluid flow inlet and the primary flow path inlet to generate a swirl of the fluid flow around the primary flow path inlet,
• guiding the primary fluid flow constituting a major portion of the fluid flow through the primary flow path inlet within the fluid control device housing while the fluid flow is swirling;
• and
• guiding the secondary fluid flow through the secondary flow path, the secondary fluid flow constituting a minor portion of the fluid flow.