Patent EP-1748151-A1 (EP)
Inventor: LEMENAGER ERWANN
IPC: H04H60/31
Filed: 2005-07-29
Abstract: The invention provides a method of receiving and/or transmitting information in a well drilled in a geological formation between a first location and a second location, said well comprising a casing communicating with the geological formation, the method comprising: (i) placing a first transducer located at said first location, said first transducer comprising two electrodes, which are first and second downstream electrodes, said first and second downstream electrodes being in electrical contact with the casing; (ii) placing a second transducer located at said second location, said second transducer comprising two electrodes, which are first and second upstream electrodes; (iii) transmitting an electric signal with the first transducer by applying said signal between the first and second downstream electrodes or respectively with the second transducer by applying said signal between the first and second upstream electrodes; (iv) receiving said electric signal with the second transducer by detecting said signal between the first and second upstream electrodes or respectively with the first transducer by detecting said signal between the first and second downstream electrodes. The invention further provides the associated apparatus for receiving and/or transmitting information using the method above, the apparatus comprising: (i) a first transducer located at said first location, said first transducer comprising two electrodes, which are first and second downstream electrodes, said first and second downstream electrodes being in electrical contact with the casing; and (ii) a second transducer located at said second location, said second transducer comprising two electrodes, which are first and second upstream electrodes. 
     In another aspect of the invention, a method to determine the conductivity profile of a formation from a well between a first location at a surface and a second location in a borehole is proposed, the method comprising: (i) placing a first sensor located at said first location, said first sensor detecting electric and/or magnetic field occurring at said first location from the formation; (ii) placing a second sensor located at said second location, said second sensor detecting electric and/or magnetic field occurring at said second location from the formation; (iii) obtaining a first signal by detecting Schumann resonances from said electric and/or magnetic field occurring at said first location with said first sensor; (iv) obtaining a second signal by detecting Schumann resonances from said electric and/or magnetic field occurring at said second location with said second sensor; and (v) combining said first and said second signal to determine the conductivity profile of the formation between said first location and said second location. The associated apparatus to determine the conductivity profile of a formation from a well is also disclosed, said apparatus comprising: (i) a first sensor located at said first location, said first sensor detecting electric and/or magnetic field occurring at said first location from the formation; and simultaneously (ii) a second sensor located at said second location, said second sensor detecting electric and/or magnetic field occurring at said second location from the formation.