Abstract: A method and system for transmitting signals from a distributed acoustic sensor, DAS, into a well through at least one pin penetrator running from a downhole side to a top side of a subsea wellhead, and without degrading quality of the signals. The method includes: connecting a first assistant recording package, ARP, between the DAS and the at least one pin penetrator on a downhole side of the wellhead; connecting a second ARP between a data acquisition system and the at least one pin penetrator on the topside of the well head; converting DAS signals to electrical signals by the first ARP and performing signal conditioning; transmitting signals received from the DAS sensors, from the first ARP and through the wellhead to the second ARP. The system implements the method.

Abstract: A seismic sensor cable 10 for lowering into a subterranean well 15 for acquiring information about seismic, microseismic and mechanical vibration incidents in the subterranean well 15, where the device comprises a first portion 20 that is elongate and has a first length with a proximal end and a distal end that are to be lowered down into a lower part of the subterranean well 15, the first portion 20 having a plurality of electric or electromechanical multicomponent seismic sensors 25 that are connected and distributed over large parts of its first length, and wherein the seismic profiling device 10 further comprises a second portion 30 that is elongate and has a second length with a proximal end that is to be held above the subterranean well 15 and a distal end that is to be lowered down into the upper part of the subterranean well 15, said second portion 30 comprising an optical fiber 35 that runs along large parts of said second portion 30, and an electric cable 40 for conducting electric power from the pr

Abstract: A method for estimating parameters of a propagating wave field, such as the direction of propagation in 3D space of an acoustic wave from borehole-acoustic data. The estimation technique uses phase delays between recordings made by the individual receivers related to a plane wave travelling across the receiver array. The estimated plane waves include the wave field generated directly by the acoustic source, as well as refracted and reflected components of these fields. The technique can be used with overlapping wave fields. This will provide significant improvements in the quality of formation properties estimated from full-waveform data that are obtained either from wireline or from while-drilling sonic data. The inventive method enables characterization of abnormalities outside multiple casing strings where acoustic signals are transmitted from a source located inside said multiple casing string.

Abstract: A seismic sensor cable 10 for lowering into a subterranean well 15 for acquiring information about seismic, microseismic and mechanical vibration incidents in the subterranean well 15, where the device comprises a first portion 20 that is elongate and has a first length with a proximal end and a distal end that are to be lowered down into a lower part of the subterranean well 15, the first portion 20 having a plurality of electric or electromechanical multicomponent seismic sensors 25 that are connected and distributed over large parts of its first length, and wherein the seismic profiling device 10 further comprises a second portion 30 that is elongate and has a second length with a proximal end that is to be held above the subterranean well 15 and a distal end that is to be lowered down into the upper part of the subterranean well 15, said second portion 30 comprising an optical fibre 35 that runs along large parts of said second portion 30, and an electric cable 40 for conducting electric power from the pr

Abstract: A method for estimating parameters of a propagating wave field, such as the direction of propagation in 3D space of an acoustic wave from borehole-acoustic data. The estimation technique uses phase delays between recordings made by the individual receivers related to a plane wave travelling across the receiver array. The estimated plane waves include the wave field generated directly by the acoustic source, as well as refracted and reflected components of these fields. The technique can be used with overlapping wave fields. This will provide significant improvements in the quality of formation properties estimated from full-waveform data that are obtained either from wireline or from while-drilling sonic data. The inventive method enables characterization of abnormalities outside multiple casing strings where acoustic signals are transmitted from a source located inside said multiple casing string.