Patent ID: 8196664
Filing Date: 2012-06-12
Classification: E21B

Abstract:
1. A plug for controlling fluid flow in a well bore at a packer or other sealing element, the plug comprising a substantially cylindrical body adapted for connection to the packer or sealing element, the body including an axial bore through a portion thereof thereby creating a barrier and providing isolation from production zones, wherein the body comprises a plurality of radial ports for passage of fluid from the bore to an outer surface of the body, an actuating member moveable relative to the body so as to cover each of the plurality of radial ports in a first position and uncover each of the plurality of radial ports in a second position wherein movement of the actuating member is controlled by an actuating mechanism, wherein the actuating mechanism comprises first and second pistons; the first piston including a damping element for delaying movement of the first piston relative to the second piston under the applied pressure: the second piston acting on a retaining element; the retaining element adapted to hold the second piston in an intermediate position when the applied pressure is within the predetermined range and allow movement of the first piston to a final position: the retaining element allowing the second piston to move to a secondary position when the applied pressure is above the predetermined range; a locking element which prevents movement of the first piston when the second piston is in the secondary position; and a securing element for retaining the actuating member in the first position until released by virtue of the first piston reaching the final position, whereby the actuating member moves to the second position and opens the plug, the actuating mechanism being operable under pressure in the well bore to set the plug in a first natural state wherein the actuating member is in the first position for a pressure under a predetermined pressure range; a second closed state wherein the actuating member is locked in the first position regardless of the pressure being greater or less than the predetermined pressure range or within the predetermined pressure range following an initial increase in pressure greater than the predetermined pressure range or the pressure being within the predetermined pressure range for a period of time less than a predetermined time; and a third open state wherein the actuating member is moved to the second position on increasing the pressure to the predetermined pressure range and holding the pressure in the predetermined pressure range for the predetermined time.