Eccentricity Correction Algorithm for Borehole Shape and Tool Location Computations from Caliper Data

A system, comprising:

• a caliper tool;
• and
• a caliper measurement device operably coupled to the caliper tool and having a memory and a processor, wherein the memory comprises commands which, when executed by the processor, cause the caliper measurement device to:
• acquire field measurements from the caliper tool;
• apply an eccentricity correction algorithm to one or more standoff samples from the obtained field measurements, wherein the eccentricity correction algorithm produces a shape fitted curve that represents a measured borehole with a least number of points outside of the shape fitted curve and a least amount of error;
• determine eccentricity-corrected borehole coordinates with the applied eccentricity correction algorithm;
• determine a borehole shape from the eccentricity-corrected borehole coordinates;
• and
• determine tool location coordinates relative to the borehole with the determined borehole shape,
• wherein, when applying the eccentricity correction algorithm, the commands which, when executed by the processor, further cause the caliper measurement device to:
• determining a number of points out of the shape fitted curve for each transducer firing;
• determining a number of errors of the shape fitted curve for each transducer firing;
• determine a hole center of the shape fitted curve with a least number of points out of the shape fitted curve and a least number of errors;
• and
• determine a hole radius of the shape fitted curve with a minimized sum of the number of points out of the shape fitted curve for all transducer firings and a minimized sum of the number of errors for all transducer firings.

A non-transitory computer-readable medium storing instructions which, when executed by a processor, cause a computer to:

• acquire field measurements from a caliper tool deployed into a borehole penetrating a subterranean formation;
• apply an eccentricity correction algorithm to one or more standoff samples from the obtained field measurements, wherein the eccentricity correction algorithm produces a shape fitted curve that represents the borehole with a least number of points outside of the shape fitted curve and a least amount of error;
• determine eccentricity-corrected borehole coordinates with the applied eccentricity correction algorithm;
• determine a borehole shape from the eccentricity-corrected borehole coordinates;
• and determine tool location coordinates relative to the borehole with the determined borehole shape,
• wherein the instructions which, when executed by the processor, further cause the computer to perform operations to apply the eccentricity correction algorithm, the operations comprising:
• determine a number of points on an intact section of the shape fitted curve and an non-intact section of the shape fitted curve for a predetermined number of firings;
• determine a number of errors of the shape fitted curve for the predetermined number of firings;
• determine a hole center of the shape fitted curve based on the determined number of points on the shape fitted curve and the determined number of errors of the shape fitted curve;
• and
• determine a hole radius of the shape fitted curve based on a sum of the determined number of points and a sum of the determined number of errors for a plurality of transducer firings in a depth interval.