| 摘要 |
A method and apparatus for protecting a sensor from impact and abrasion while drilling a borehole including a drill collar having a section of electrically non-conductive material, such as a composite material. The electrically non-conductive material has a rugged structural strength for conveying required drilling operation torque and load. The sensor which, for example, induces an RF field, is located inside the drill collar within the section of electrically non-conductive material wherein the sensor is protected from impact and abrasion while drilling a borehole without interference to the electromagnetic energy. The sensor is located, for example, within a load bearing section of the drill collar. Alternatively, the sensor is located inside a removable probe positioned inside the fluid channel through the drill collar. Stabilizers are used for stabilizing the probe within the channel. Preferably, metallic tool joints are connected to the section of electrically non-conductive material for coupling the drill collar to a drilling assembly. Hardfacing can also be embedded on an outer surface of the drill collar for providing additional abrasion protection.
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