Abstract: A tool assembly and method are for performing formation stress testing in an openhole section of a borehole, wherein the openhole section of the borehole is to be provided with, or already have been provided with, a perforation tunnel generated by a series of electrically induced focused acoustic shock waves. The tool assembly has at least two borehole isolation means arranged with an axial distance therebetween for forming an isolated section at the openhole section of the borehole; a pump device for altering a pressure within the isolated section; a pressure sensor for measuring a pressure within the isolated section; a control unit for controlling a testing sequence; an acoustic shock wave device for generating the series of acoustic shock waves to excavate the perforation tunnel; and an acoustic shock wave sub for actuating the acoustic shock wave device.

Abstract: A tool assembly and method are for performing formation stress testing in an openhole section of a borehole, wherein the openhole section of the borehole is to be provided with, or already have been provided with, a perforation tunnel generated by a series of electrically induced focused acoustic shock waves. The tool assembly has at least two borehole isolation means arranged with an axial distance therebetween for forming an isolated section at the openhole section of the borehole; a pump device for altering a pressure within the isolated section; a pressure sensor for measuring a pressure within the isolated section; a control unit for controlling a testing sequence; an acoustic shock wave device for generating the series of acoustic shock waves to excavate the perforation tunnel; and an acoustic shock wave sub for actuating the acoustic shock wave device.

Abstract: A device is for perforation of a downhole formation. The device has an electronically induced acoustic shock wave generator; and an acoustic shock wave focusing member. The device is adapted to focus generated acoustic shock waves onto an area of a borehole in order to disintegrate the downhole formation within said area. The device is adapted to generate a plurality of consecutive focused acoustic shock waves in order to gradually excavate a perforation tunnel, or to improve an already existing perforation tunnel, extending from said borehole and into said formation.

Abstract: A device is for perforation of a downhole formation. The device has an electronically induced acoustic shock wave generator; and an acoustic shock wave focusing member. The device is adapted to focus generated acoustic shock waves onto an area of a borehole in order to disintegrate the downhole formation within said area. The device is adapted to generate a plurality of consecutive focused acoustic shock waves in order to gradually excavate a perforation tunnel, or to improve an already existing perforation tunnel, extending from said borehole and into said formation.