WELL RANGING TOOL AND METHOD

摘要

A method and apparatus for active magnetic ranging. A ranging tool includes one or more current-injection electrodes, one or more field-measuring sensors, and one or more expandable isolation packers positioned above and/or below the electrodes and between the electrodes and sensors. The isolation packers stabilize the ranging tool and isolate and insulate the electrodes from the sensors. The electrodes are ideally carried on an expandable electrode packer, which insulates the electrodes, urges them into intimate contact with the earthen formation, and displaces any fluids between the electrodes and the earth.

主权项

1. A method for locating an electrically conductive target within an earthen formation, comprising:
providing an electrode positioned on the outer circumference of a first packer; positioning the first packer and the electrode within a first borehole formed in the earthen formation; expanding said first packer so that the electrode contacts the earthen formation directly; injecting an electrical current into the earthen formation via said electrode so as to generate a field within said earthen formation; and measuring a property of said field by a sensor to locate the target.