Study on the Error Analysis and Correction Method of Well Deviation Angle Measurement

In the actual drilling process, the accurate measurement of deviation angle is a crucial issue. Due to the error of measuring instrument and wellbore trajectory calculation method, the description and prediction of wellbore trajectory are deviated. In order to reduce the deviation angle error of measurement while drilling and avoid the uncertainty of wellbore trajectory, this paper will analyze the source of deviation angle error, which is one of the key parameters of wellbore trajectory calculation, and study the corresponding correction method for each error source. Combined with the existing error correction method, a set of methods that can improve the accuracy of measuring well deviation angle is established. The research shows that the error of the deviation angle measurement mainly comes from the tool measurement error and the BHA deflection, which leads to the stress deformation of the bottom hole drilling tool. The deviation angle error can be well corrected by the tool measurement error correction and the deviation angle SAG correction. The error of the tool itself can be checked before use, and the sag of the gravity sensor position can be corrected to correct the deviation angle error. The example analysis shows that the deviation is related to the deviation angle. The closer the deviation angle is to the horizontal, the greater the deviation is. When the deviation angle is greater than 45°, SAG correction is recommended, which has significant engineering significance for accurately determining the actual wellbore trajectory.