Abstract: A packer tool for use in a wellbore having a bottomhole pressure p, the tool comprising: a mandrel assembly; a stabilizer on the mandrel assembly, for releasably engaging the wellbore; a packing element in an annular recess having a floor and two facing walls, the annular recess being transversely compressible into a compressed position and disposed about the mandrel assembly; and a piston assembly for driving compression of the packing element annular recess, the piston assembly having a plurality of pistons connected to act in tandem, the pistons having a total piston face surface area a such that an application of pressure of p? to the piston assembly generates a force f greater than p.

Abstract: A straddle packer tool comprises a mandrel and a housing. Spaced packers are carried by the housing. A plurality of bypass ports are arranged in the mandrel and housing for aligning in several positions: a first downhole position for bypassing fluid around the packers and through the mandrel; an intermediate position wherein the bypass ports are misaligned and a first internal pressure actuates the packers to isolate a zone and a second higher internal pressure releases a stop for enabling relative movement to an uphole position wherein the bypasses are misaligned and the mandrel's bore is opened to isolated zone.

Abstract: Shaped charge liners, typically used in perforating guns, are formed from a zinc alloy of zinc and other metals such as aluminium and magnesium. The liners are formed into desired shapes, for example, by melting ingots and casting the alloy, or by machining bars formed from the alloy, or by stamping strips formed from the alloy, or by pressing powder formed from the alloy.

Abstract: A downhole tool hydraulic firing head includes an automatic drain that is opened when the piston is driven to fire. The automatic drain includes a vent opening from the bore and a sleeve disposed within the bore to move axially with the piston. The sleeve is moveable from a position covering the vent opening to a position clear of the vent opening. A locking collet is disposed between the sleeve and the housing, which locks the sleeve into the position, clear of the vent opening, when the sleeve is moved into that position. This locks the sleeve against returning to the position covering the vent opening when it is urged to move in that direction such as, for example, by venturi forces of the evacuating fluid or by pressure generated from the explosive charges. The firing head is useful to detonate downhole explosive charges, such as those in a perforating gun.