The Analysis Of Mechanism And Dynamics Simulation On COmpund Drilling Technology

Abstract: Nowadays the compound drilling technique with screw drilling tool combined with PDC bit has become a main current technology in drilling. Practical application shows that it can seriously improve the drilling rate, shorten drilling period and reduce drilling comprehensive cost. But as compound drilling technique further generalized and drilling demands more elevated, the problem of applying the compound drilling technique to drill fast in complex formation without inclination is more and more serious. It restricts the improvement of drilling efficiency. So analysing compound drilling technique mechanism and optimizing the main parameters and adopting efficient BHA is very significant to drill fast with deviation controlled.This paper mainly analyses the problems of deviation controlling and fast drilling in compound drilling in Tamtsay. At first it analyses the effect of screw drilling tool under the condition of compound drilling to discern the mechanical properties of screw drilling tool and the speed elevation mechanism of compound drilling. Compared to normal drilling it analyses the correlation of compound drilling technique characters and well bore quality, then discuss the mechanism of controlling deviation in screw drilling. With the method of finite analysis it simulates the contact status between drill string and borehole wall and combines the dynamics theory of drill string, calculates and simplifies the drill string frame,boundary condition and external load via ANSYS , then it establishes the finite analysis model of whole string. According to the actual well log data it takes the T19-117 well as an example to analyse. The calculating result is mainly accordant with actual engineering situation which proves the correctness of this calculation method. It further studies the effect on well quality made by bit weight and rotary speed, makes finite buckling analysis of BHA which indicates that the reasonable application of stabilizer would inflect side stress of bit. In the actual experiment of T21-79-1 well the predicted well trajectory is mainly agree with the actual one which validates the feasibility of the adopted method. Finally, on the basis of compound drilling mechanism research it proposed an assumption of double-stage and double-speed PDC bit, which provides a new idea in this field, makes some basic analysis of its infrastructure and mechanism. It provides a new perspective for the development of compound drilling.