Multi-electrode electric field downhole logging tool

Patent metadata

Field	Value
Publication number	US-10254432-B2
Application number	US-201514748839-A
Country	US
Kind code	B2
Filing date	Jun 24, 2015
Priority date	Jun 24, 2014
Publication date	Apr 9, 2019
Grant date	Apr 9, 2019

Abstract

A device can include a housing; external electrodes; circuitry disposed in the housing where the circuitry converts analog signals sensed by the external electrodes to digital signals. Various other apparatuses, systems, methods, etc., are also disclosed.

First claim

What is claimed is:

1. A system comprising:
a surface source loop;
a transmitter that transmits electromagnetic energy to the surface source loop;
surface equipment that controls the transmitter and that analyzes received digital signals associated with electromagnetic energy transmitted by the surface source loop;
a tool that comprises at least two external electrodes for sensing at least a portion of electromagnetic energy transmitted by the surface source loop, two eccentralizers positioned to form a triangle with respect to at least one of the external electrodes to bias the at least one external electrode against a surface of a borehole, and circuitry that converts analog signals sensed by the external two electrodes to digital signals, wherein an angle between the two eccentralizers is approximately 45 degrees with respect to the at least one of the external electrodes; and
a cable that operatively couples the tool to the surface equipment for transmission of the digital signals to the surface equipment for analysis.

2. The system of claim 1 wherein the tool comprises a housing and an insulating sheath that insulates at least a portion of the housing.

3. The system of claim 2 wherein the external electrodes are external to the insulating sheath and electronically coupled to the circuitry.

4. The system of claim 2 wherein the tool comprises a bridle.

5. The system of claim 2 wherein the circuitry comprises preconditioning circuitry that preconditions analog signals prior to digitization of the analog signals.

6. The system of claim 1 wherein the tool comprises two external electrodes.

7. The system of claim 1 , wherein the two eccentralizers are positioned to form a second triangle with respect to at least another one of the external electrodes to bias the at least another one external electrode against the surface of the borehole.

8. The system of claim 7 , wherein an angle between the two eccentralizers is approximately 45 degrees with respect to the at least another one of the external electrodes.

Assignees

• Schlumberger Technology Corp

Inventors

• Cuevas Nestor H
• Denaclara Herve
• Yamazaki Tomohito
• Minto James
• Aoki Ryosei

Classifications

• G01V3/26 Primary

  operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device (with electromagnetic waves G01V3/30) · CPC title

• G01V3/34

  Transmitting data to recording or processing apparatus; Recording data · CPC title