Patent ID: 8205689
Filing Date: 2012-06-26
Classification: E21B

Abstract:
1. A drilling system in a drill string for enlarging a borehole in a subterranean formation, comprising: a drill bit located at an end of the drill string; a first expandable reamer located above the drill bit in the drill string, the first expandable reamer comprising a tubular body having a longitudinal axis and a drilling fluid flow path therethrough, a plurality of generally radially and longitudinally extending blades carried by the tubular body, a first triggering device carried by the tubular body for receiving a first actuation device introduced into the tubular body of the first expandable reamer through the drilling fluid flow path and initially retaining the blades of the plurality in a retracted or initial position, and a cutting structure carried by at least one blade of the plurality of blades, wherein at least one blade of the plurality of blades is movable outwardly, with respect to the longitudinal axis upon application of fluid pressure after the first triggering device is triggered by the first actuation device; a second expandable reamer located above the first expandable reamer in the drill string, the second expandable reamer comprising a tubular body having a longitudinal axis and a drilling fluid flow path therethrough, a plurality of generally radially and longitudinally extending blades carried by the tubular body, a second triggering device carried by the tubular body for receiving a second actuation device introduced into the tubular body of the second expandable reamer through the drilling fluid flow path and initially retaining the blades of the plurality in a retracted or initial position, and a cutting structure carried by at least one blade of the plurality of blades, wherein at least one blade of the plurality of blades is movable outwardly, with respect to the longitudinal axis upon application of fluid pressure after the second triggering device is triggered by the second actuation device; an expandable stabilizer axially spaced from the second expandable reamer in the drill string, the expandable stabilizer comprising a tubular body having a longitudinal axis and a drilling fluid flow path therethrough, a plurality of generally radially and longitudinally extending bearing pads carried by the tubular body, and a third triggering device carried by the tubular body for receiving a third actuation device introduced into the tubular body of the expandable stabilizer through the drilling fluid flow path and initially retaining the bearing pads of the plurality in a retracted or initial position, wherein at least one bearing pad of the plurality of bearing pads includes an up-hole cutting structure carried thereupon and is movable outwardly with respect to the longitudinal axis upon application of fluid pressure after the third triggering device is triggered by the third-actuation device; and a fixed blade stabilizer located above the drill bit and below the first expandable reamer; wherein the second triggering device of the second expandable reamer is non-responsive to passage of the first actuation device for the first expandable reamer therethrough and wherein the third triggering device of the expandable stabilizer is non-responsive to passage of the first actuation device and the second actuation device therethrough.