Abstract: A downhole tool, for removing sections of metal tubing, said downhole tool comprising at least one conductive element being arranged to corrode a section of metal tubing using an electrolytic process, said conductive element being made of electric conductive material, an apparatus to establish a connection to the metal tubing, and a source of electrical power.

Abstract: A downhole tool, for removing sections of metal tubing, said downhole tool comprising at least one conductive element being arranged to corrode a section of metal tubing using an electrolytic process, said conductive element being made of electric conductive material, an apparatus to establish a connection to the metal tubing, and a source of electrical power.

Abstract: A downhole tool, for removing sections of metal tubing, said downhole tool comprising at least one conductive element being arranged to corrode a section of metal tubing using an electrolytic process, said conductive element being made of electric conductive material, an apparatus to establish a connection to the metal tubing, and a source of electrical power.

Abstract: Pressure amplifier mounted at the lower end of a drill pipe for deep drilling to generate an increased fluid pressure. A piston with a pressure stroke and a return stroke between end positions in a cylinder has a large piston area which during the pressure stroke is subjected to the drilling fluid pressure, a first opposite piston area and a second opposite and small piston area which during the pressure stroke generates an increased pressure in a smaller portion of the drilling fluid flow. A valve arrangement controls drilling fluid flows to and from the piston. For each end position of the piston there is provided at least one moveable valve control element which is adapted to be moved by the piston at either end position, in order to activate the valve arrangement.

Abstract: A pressure amplifier can be mounted above a drill bit at the lower end of a drill pipe for generating an increased fluid pressure in a drilling fluid flow to, for example, obtain an increased drilling effect, A reciprocating piston in a cylinder has at one side (a low pressure side) a large piston area and also has a first opposite piston area and a second opposite and relatively small piston area, which generates an increased pressure. A valve device controls drilling fluid flows to and from the piston. Beyond one end of the cylinder there is provided a hydraulic rotary motor adapted to be driven by the pressure difference between the drilling fluid flows in the drill pipe and an annulus. A transmission mechanism converts the rotation of the hydraulic motor into intermittent movements of the valve device between two operative positions.

Abstract: Pressure amplifier for mounting above the drill bit at the lower end of a drill pipe for generating an increased fluid pressure in a drilling fluid flow, for example for obtaining an increased drilling effect. A reciprocating piston in a cylinder is designed with a large piston area at one end (low pressure side), a relatively small piston area at the opposite end (high pressure side), and an annular surface formed at the transition between the two ends. The pressure converter also includes a control valve, an actuator, and a drilling fluid valve to control drilling fluid flow to and from the cylinder.