A METHOD AND APPARATUS FOR A DOWNHOLE NMR MWD TOOL CONFIGURATION

摘要

A 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 t he 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 a NMR sensor. A stabilizer is activated to stabilize the rotating NMR sens or located on the drilling collar in the bore hole. The permanent magnets and receiving and transmitting antennas are located on a non-rotating sleeve tha t is clamped against the borehole wall to decouple the permanent magnets and receiving and transmitting antennas from drilling vibrations.