Abstract:

In view of the problem that the wellbore trajectory fitting deviates from the true drilling trajectory caused by the changeable wellbore trajectory shape and the single inclination mode, this study proposes a method of wellbore trajectory segmentation and pattern recognition based on characteristic parameters. On the basis of sufficient theory, the cubic b-spline function of well inclination and azimuth with well depth is established, and the curve characteristic parameters which can determine the adjacent shape of a certain point of the well trajectory are obtained. According to the characteristic parameters, and combined with the characteristic parameters of various models, the wellbore pattern recognition evaluation index and segmentation index are constructed, and the wellbore trajectory model that best matches the actual drilling is selected. In order to verify the effectiveness of this method, a prototype is designed to simulate the actual drilling experiment. The results show that the wellbore trajectory pattern recognition and segmenting method based on characteristic parameters can significantly improve the accuracy of wellbore trajectory fitting.

Key words: wellbore trajectory, morphology and changeful, single trajectory mode, well inclination, characteristic parameters, trajectory subsection, track pattern recognition, cubic b-spline