Autonomous flow control device and method

A valve assembly for integration within a wellbore string disposed within a subterranean reservoir, comprising:

• a valve housing comprising a tubular wall defining a fluid passage therethrough and having injection ports extending through the tubular wall;
• an inner barrel mounted within the valve housing and comprising a fluid channel adapted to establish fluid communication between the fluid passage and the injection ports, the fluid channel having a channel inlet and being configured to create a fluid flowrate restriction between the fluid passage and the injection ports, each injection port being aligned with respective portions of the fluid channel to define respective flow path lengths extending between the channel inlet and the injection ports, each flow path length defining respective degrees of flowrate restriction;
• and
• a flow adjuster operatively connectable to the valve housing and comprising:
• an outer barrel slidably coupled about the tubular wall and having an outlet in fluid communication with the reservoir, the outer barrel and the tubular wall defining a fluid chamber therebetween adapted to allow fluid flow therein, the outer barrel being adapted to shift along the tubular wall downhole upon pressurization of the fluid chamber to align the outlet with one of the injection ports and enable fluid communication between the fluid passage and the reservoir through the corresponding injection port;
• and
• a biasing element operatively connected to the outer barrel and being adapted to bias the outer barrel along the tubular wall uphole,
• wherein the valve assembly is configurable between:
• an installation configuration, where the outer barrel is releasably secured to the tubular wall in an installation position where the outlet is occluded by the tubular wall, the injection ports are occluded by the outer barrel, and the fluid chamber is fluidly sealed from the fluid channel to prevent fluid communication between the fluid passage and the reservoir and facilitate pressurization of the fluid chamber;
• a closed configuration, where the outer barrel is shifted to a closed position, where the outlet is occluded by the tubular wall, the injection ports are occluded by the outer barrel and the fluid chamber is in fluid communication with the fluid channel;
• and
• an open configuration, where the outer barrel is shifted to one of a plurality of open positions, where each open position includes the outlet being in fluid communication with a corresponding one of the injection ports such that fluid flow is restricted by a corresponding degree of flowrate restriction, the outer barrel occluding the other injection ports, and the fluid chamber being in fluid communication with the fluid channel to enable fluid communication between the fluid passage and the reservoir at an injection rate;
• the flow adjuster being configured to autonomously shift the outer barrel from the installation position to the closed position, between the closed position and the open positions, and between different open positions based on a pressure differential between an internal pressure (Pi) of the fluid chamber and an external pressure (Pe) of the reservoir, wherein shifting the outer barrel between the different open positions maintains the injection rate between the fluid passage and the reservoir substantially constant.