Vibration Analysis Of The Bottom Hole Assembly Containing A Strap-down Automatic Vertical Drilling System

Drill string vibration has been one of important reasons affecting the safety of drilling.On the basis of consulting a large number of literature,this paper studies the vibration of the bottom hole assembly containing a strap-down automatic vertical drilling system in combination with the practical situation of engineering.In reference to previous studies on drill string vibration,this paper combines the size of the data of the bottom hole assembly containing a dtrap-down automatic vertical drilling system in field engineering application by the drilling technology research institute of Shengli petroleum engineering company,applies ABAQUS finite element software engineering,established the strap-down automatic vertical drilling system vibration analysis model that is called AVDS-BHA model.It simulates the actual working condition of static analysis for the AVDS-BHA model.This simulation got the conclusion that the stability load of BHA in the drilling doesn’t pose a direct damage to the drill string.Based on the static analysis for the AVDS-BHA model,the frequency modal analyzes the frequency modality of AVDS-BHA modal and the influences that the stability load makes to the modal frequency.Compared with the natural frequency of the free viberation and the viberation under the condition of stability loading,it is concluded that the longitudinal load makes greater impact on the natural frequency of transverse vibration,and as well as the constant torque of bit on torsional vibration.In the correct analysis of drill string vibration during drilling,the influence cannot be ignored.Based on the frequency modal analysis under the condition of stable loading and the enough modal frequency extraction,this paper analyzes the dynamic response influence that drilling tool combination structure(the number of stabilizer)and the drilling parameters(the drilling speed)makes on AVDS-BHA model.According to the results of the analysis and puts forward the corresponding measures of vibration reduction.This paper considers the buoyancy of drilling fluid to the drill string,but the other effects,such as the dynamic effect of drilling fluid and the interaction between drill string and borehole wall and so on,need to be further studied.