| 摘要 |
<p>A directional drilling downhole steering and survey tool (100) for detecting ferromagnetic bodies from an off vertical borehole, transmitting the signals from the the downhole sensors (111, 113, 117, 119, 120, 121) to surface equipment while drilling, and for calculation of the range and direction to the detected ferromagnetic body for the use of the directional driller in intercepting or avoiding the ferromagnetic body. In combination with the steering and range and direction to ferromagnetic body capabilities the downhole tool may also include sensors for detecting formation bed interface, apparatus for electric or gamma ray or radioactive logging, neutron density sensor apparatus and other formation evaluation or correlation apparatus. The downhole tools may be packaged in either an electric line transmitted tool or MWD transmitted tool.</p> |
