DRILL STRING INGROUND ISOLATOR IN AN MWD SYSTEM AND ASSOCIATED METHOD

摘要

An inground isolator and associated method can provide an electrically isolated break in a drill string using electrical insulating members/isolators that are supported by a housing. During drill string operations, the isolators are subject only compressive forces responsive to both extension (pushing) and retraction (pulling) by the drill string. The isolators can be formed from an electrically insulating material such as a ceramic material. An interchangeable inground tool system is described which integrally serves to provide an electrically isolating gap in the drill string.

主权项

1. An apparatus for use in combination with a drill string that is electrically conductive and extends from an inground distal end, that includes an inground tool, to a drill rig, said apparatus comprising:
a first group of electrical isolators and a second group of electrical isolators; and a housing defining a through passage along a length thereof and configured to support the first and second groups of electrical isolators in a spaced apart relationship along the through passage and distributed therearound such that, responsive to the drill rig pushing on the drill string, no more than a first one of the first and second groups is subject to a compressive push force and responsive to the drill rig pulling on the drill string no more than the other one of the first and second groups is subject to a compressive pull force to form an electrically isolating break in the drill string.