EXPERIMENTAL STUDIES OF ENERGY TRANSFER DRILL STRING FUNCTIONS IN DIRECTIONAL WELL

Abstract

of the directional well are described in this article. Experimental stands designs, the methods of mathematic simulation, experimental procedure, similarity criteria for drill string models and the results of researches in the form of graphic dependences are considered. According to the results of the researches, the authors determined the dependences of drill string idle capacity change on its extension force change, the intensity of wellbore and inclination angle deviation, which can be used for any of its real designs. It has been established that the dominant factor of idle capacity increase is axial extension force, caused by weight of its lower part and the intensity of wellbore deviation. Extension of experimental possibilities through taking into consideration pipe joints, extension forces, wellbore deviation intensity increase accuracy of research results and provide better presentation of real process under laboratory conditions.
The results received from the experimental studies of drill string idle capacity in the deviated wellbore were compared with analytical data that were calculated according to the known mathematical models for SBT 114.3 pipes. The divergence was established at about 8%. The drill string energy transfer methods and means of experimental study offered extend possibilities of improvement of their designs and service conditions. It allows to correct the methods of design and the choice of drill string design for directional and horizontal wells.