| 摘要 |
<p>An insulating segment for a drill string electrode structure is presented. The insulating segment of the drill string includes a drill string segment having a recess along an axial length thereof with a first sleeve of insulating material in the recess on the recessed surface of the drill string segment and a second sleeve of insulating material on the first sleeve of insulating material. The first end second sleeves of insulating material are of different hardnesses, with the second sleeve being harder than the first sleeve. A plurality of electrode are embedded in the second sleeve.</p> |
