Modeling And Simulation Of The Dynamic Behavior On Geothermal Drill Rod Train: Case Of Torsion Vibration

Abstract

The goal of this work is to understand the torsional vibration caused by the stick-slip or glue-slip phenomenon. In geothermal drilling operations, problems that hamper work efficiency and cause losses by lengthening the work often remain. Almost all of these problems come from unwanted vibrations which first affect the packing, causing them increased fatigue and causing them to fail prematurely. To better illustrate it, a tool-rock contact model is given. This model is made to observe the parameters that cause vibrations, giving a possibility to avoid them in reality. This model has been treated with a dry friction at the BHA (Bottom Hole Assembly) level. To show the simulation of the stick-slip phenomenon, parameters were given and simulated under MATLAB with the motorization system. In order to escape the dry friction; the combination of varying the three parameters: increasing the speed of the rotary table, reducing the weight on the tool and increasing the dynamic viscosity of the drilling mud allow the stick-slip phenomenon to be canceled. During the drilling operation, all the parameters which directly or indirectly affect the efficiency of the work will be taken into account and should not be excluded from a modification in order to reduce as much as possible the duration of the work. Operation while avoiding material wear, basically minimize the blow of labor.