Method and apparatus for a downhole NMR MWD tool configuration

US6739409B2 · kind B2 · utility

Assignee

• Baker Hughes Holdings LLC · US

Inventors

• Thomas Kruspe · Braunschweig, DE
• Robert Slade · Abingdon, GB
• Martin Blanz · Culham, GB
• Peter Rottengatter · Celle, DE
• Hartmut Schrader · Bad Doberan, DE
• Rob Hawkes · Northstowe, GB

Key dates

• Filing date: Jan 29, 2002
• Grant date: May 25, 2004
• Expiry date: Jan 29, 2022

Classification

• Technology area (CPC E): Fixed Constructions
• CPC primary: E21B2200/22
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An NMR device is presented that includes a drill collar having non-rotating sleeve containing permanent magnets. The non-rotating sleeve is clamped against a borehole wall and decoupled from drilling vibrations during NMR measurements. The transmitter and receiver are located on the rotating part of the drill collar. Alternatively the permanent magnets and the RF receiver antenna and/or receiver electronics are placed on the non-rotating sleeve which is clamped against the borehole wall and decoupled from drilling vibrations, with the transmitting antenna located on the rotating drill collar. Alternatively a non-rotating stabilizer is provided above or below an NMR sensor. A stabilizer is activated to stabilize the rotating NMR sensor located on the drilling collar in the bore hole. The permanent magnets and receiving and transmitting antennas are located on a non-rotating sleeve that is clamped against the borehole wall to decouple the permanent magnets and receiving and transmitting antennas from drilling vibrations.