Annulus pressure operated downhole choke and associated methods

A method of controlling fluid flow through a tubular string disposed within a subterranean wellbore, the method comprising the steps of:

• interconnecting a downhole choke in the tubular string;
• positioning the downhole choke within the wellbore;
• flowing fluid axially through the downhole choke;
• actuating the downhole choke to choke fluid flow therethrough;
• and
• establishing steady state flow through the downhole choke after actuating step.

A method of testing a subterranean well which intersects a fluid producing formation, the method comprising the steps of:

• interconnecting a choke and a sample chamber in a tubing string;
• positioning the tubing string within the well;
• actuating the choke to temporarily choke fluid flow through the tubing string;
• establishing steady state flow through the downhole choke after the actuating step;
• and
• acquiring a sample of fluid from the tubing string into the sample chamber while fluid flow through the tubing string is temporarily choked by the choke.

A method of sampling fluid from a subterranean well, the well having a wellbore intersecting a fluid producing formation, the method comprising the steps of:

• interconnecting first and second sample chambers and first and second chokes in a tubing string, the first sample chamber being positioned below the first choke and the second sample chamber being positioned below the second choke;
• disposing the tubing string within the wellbore;
• flowing fluid from the formation through the tubing string to the earth's surface;
• actuating the first choke to restrict fluid flow therethrough;
• acquiring a first sample of fluid from within the tubing string into the first sample chamber;
• actuating the second choke to restrict fluid flow therethrough;
• and
• acquiring a second sample of fluid from within the tubing string into the second sample chamber.