Schlumberger Technology Corporation

Prad Research and Development Nv

Services Petroliers Schlumberger

Schlumberger Holdings Limited

Schlumberger Oilfield Assistance Limited

Henri Budan

Emmanuel Legendre

Matthieu Simon

Mehdi Hizem

Alexandre Abellan

Laurent Mosse

Sofiane Ellouz

Medhi Hizem

The present disclosure introduces an apparatus for downhole measurement of a formation resistivity. The apparatus includes a probe having a button electrode, a first guard electrode insulated from the button electrode, a second guard electrode insulated from the first guard electrode, and a return electrode positioned external to the second guard electrode. The apparatus also includes an electrical source for setting a voltage drop between the second guard electrode and the return electrode, a first impedance (R) electrically coupled between the button electrode and the second guard electrode, and a second impedance (R) electrically coupled between the first guard electrode and the second guard electrode.

Dual-guard imager probe

A probe for measuring electromagnetic properties of a subsurface formation includes a pad having a face adapted for engagement with a borehole wall, a pair of transmitting antennas, and two pairs of receiving antennas. The transmitting antennas and receiving antennas are mounted in the face of the pad, and each of the two pairs of receiving antennas include a first and second antenna distributed on opposite sides of the pair of transmitting antennas. The probe further includes an electronic arrangement having a transmitter module and a receiver module. The transmitter module is arranged to operate the pair of transmitting antennas in either a broadside mode or an endfire mode by applying an excitation signal modulated by two or more frequencies, and the receiver module is arranged to determine an attenuation and a phase shift of each reception signal provided by each receiving antenna relatively to the excitation signal.

Electromagnetic probe for measuring properties of a subsurface formation

Growing community of inventors

Clamart, France

Henri Budan