Instrument Performance Models and Their Application to Directional Surveying Operations

Abstract

Summary When planning, monitoring, or checking the results from a directional surveying program, one must be able to predict the probable errors associated with the different survey tools used. An "instrument performance model" is a mathematical algorithm that, when combined with a set of independently validated parameters describing the particular survey instrument in question and information about the well, enables the directional uncertainty to be computed at any point in a survey run. Randomization caused by axial rotation of the tool significantly affects the size of the predicted errors. The analysis accounts for rotation and incorporates a new depth-measurement-error treatment. Performance models have many practical uses in survey operations management and wellsite quality control. They enable research to be focused accurately and objective comparisons to be made between different instruments.