| 摘要 |
A downhole caliper instrument utilizing a linear or arcuate magneto resistive sensor to determine the position of one or more caliper arms which extend from a carrier tool to touch the surface of a borehole wall. A processor and firmware are included to calculate and plot the borehole radius. A plurality of magneto resistive sensors are provided to calculate the sine, cosine and tangent for accurate motion of each independent arm. The magneto resistive sensors sense the position a precise magnetic ruler linked to the caliper arm. The position of the caliper arm determines the radius of the borehole. Calculation of Radius/Diameter is preferably performed in the computer on surface. The downhole controller's firmware controls the multiplexer switching, A/D conversion and other functions. |
