Calculating Borehole Geometry from Standard Measurements of Borehole Inclinometry

This report describes two new methods for computing borehole geometry from discrete measurements of borehole inclination ( θ ) and azimuth ( α ). In the first method θ and α are assumed to vary linearly with arc length. This results in an analytic model of the borehole that is continuous but not smooth. The second model, which takes θ and α to vary quadratically with arc length between three measuring points, improves the smoothness of the model but the analysis must be carried out numerically. These models were applied to the borehole inclinometry data collected at DYE-3, Greenland. The methods were found convenient to use and it is claimed that the results represent physically reasonable approximations to the borehole geometry.