抄録
Stick-slip is critical problem for offshore drilling, especially scientific drilling, because it will cause crushing or grinding the layer.In order to repress stick-slip, first of all it is necessary to establish a model of the torsional motion of the drill bit and express the stick-slip phenomenon. Therefore, in this paper, the model of the torsional waves in a drill string is established by applying a neutral delay differential equation (NDDE), and then it leads to expression of stick-slip phenomenon for the friction models and a rotation speed that was applied on the uppermost part of the drill string. In addition, utilizing data acquired from the actual drilling operation,stick-slip phenomenon was analyzed and stick-slip level was discussed.
