Enhancement of processing capabilities of oriented bottomhole assemblies

Abstract

The article considers how performance of oriented bottomhole assemblies (BHA) with downhole motors (PDM) (combined drilling) can be improved. The international practices of design, selection and application of oriented BHA are analyzed in conjunction with the subject of the article. The mathematical model was developed to calculate the static characteristics of influence, affecting steering effort at bit and turn angle, from the performance parameters. Such model was developed with consideration of geometrical specifics of the oriented assemblies with bent PDM and serves to define the influence of design parameters of oriented BHA and bottomshole parameters on the static characteristics of their interaction with well walls and down hole. Results of analytic studies for designs of unsupported assemblies show that inclusion of bend angle between housing and bearing assembly of the PDM into calculation leads to special interaction between bit and well walls and down hole. It is also established that the presence of bend angle creates significant advantage for the oriented unsupported BHA in comparison with non-oriented assembly. Such design advantage allows stabilize inclination angle in combined drilling. The further research is planned to expand on the findings.