Abstract: The invention is a well radar for detecting, by electromagnetic wave reflection, resistivity horizons in production zones in oil wells. Transmitter and receiver antennas are combined in a tubing string antenna module. Two dipole transmitter antenna are positioned in a first position on either side of the tubing string antenna module. A first directionally sensitive group of four dipole receiver antennas is positioned in a second positioned so that the receiver antennas have even angular separation. Likewise, a second directionally sensitive group of four dipole receiver antennas is positioned in a third position opposite the first directionally sensitive group.

Abstract: A seismic shear wave generator comprising a seismic wave source (3) arranged on a base plate (11) arranged for being placed at the seabed, and a coupling device (1) arranged for coupling the wave source (3) mechanically to the seabed in order for shear waves to be transmitted to the seabed. The novelty of the invention is as follows: a cylindrical skirt (1) closely arranged along the base plate's (11) circumference and extending down from the underside of the base plate (11), and open downwards, and a pump device (2) arranged for pumping water respectably out of, and into, the skirt (1) and form vacuum or overpressure, respectively, in a closed cavity formed by the skirt (1) and the base plate (11) and the seabed (1) is lowered onto the seabed. By means of the device mentioned above the shear wave generator may be suctioned fixed to the sea bed and thus transfer shear waves via the skirt (1) to the seabed.

Abstract: A method for detecting electrical properties in a geological formation in a well which has within it a tubing string comprising the steps of mounting a transmitter antenna outside of the tubing string in a fixed position with respect to the geological formation, mounting a receiving antenna outside of the tubing string in a fixed position with respect to the geological formation, generating a first series of electromagnetic waves at a first time, receiving a first series of reflected electromagnetic waves in the receiver antenna, transforming the first series of reflected electromagnetic waves to form a first registration, generating a second series of electromagnetic waves at a second time, receiving a second series of reflected electromagnetic waves in the receiver antenna, transforming the second series of reflected electromagnetic waves to form a second registration, and comparing the registrations. Also disclosed is a device for accomplishing the method.

Abstract: The invention is a device for measuring and surveillance of resistivity in a petroleum reservoir in a geological formation with an injection-, observation- or production well comprising an electrically conductive metallic well tubing, with the new and inventive being characterized by the following features: a) an electrical energy source; b) at least one inductive transmitter antenna for electromagnetic waves, fixedly arranged in the well, outside of the well tubing's outer metallic surface; c) at least one series of sensors comprising n inductive resistivity sensors (5a, 5b, . . . , 5n) arranged for receiving the electromagnetic waves and generation of measurement signals, fixedly arranged in the well, by the petroleum reservoir and outside the well tubing's outer metallic surface; and d) a signal conductor for the measurement signals.