Modeling Friction Performance of Drill String Torsional Oscillation Using Dynamic Friction Model

Abstract

Drill string torsional and longitudinal oscillation can significantly reduce axial drag in horizontal drilling. An improved theoretical model for the analysis of the frictional force was proposed based on microscopic contact deformation theory and a bristle model. The established model, an improved dynamic friction model established for drill strings in a wellbore, was used to determine the relationship of friction force changes and the drill string torsional vibration. The model results were in good agreement with the experimental data, verifying the accuracy of the established model. The analysis of the influence of drilling mud properties indicated that there is an approximately linear relationship between the axial friction force and dynamic shear and viscosity. The influence of drill string torsional oscillation on the axial friction force is discussed. The results indicated that the drill string transverse velocity is a prerequisite for reducing axial friction. In addition, low amplitude of torsional vibration speed can significantly reduce axial friction. Then, increasing the amplitude of transverse vibration speed, the effect of axial reduction is not significant. In addition, by involving general field drilling parameters, this model can accurately describe the friction behavior and quantitatively predict the frictional resistance in horizontal drilling.

Vibration Technologies for Friction Reduction to Overcome Weight Transfer Challenge in Horizontal Wells Using a Multiscale Friction Model

“…The changes of slope with a low ROP were sharper than the changes of slope with greater ROPs. This was different from the results reported in Reference [10]. As discussed, this was due to the fact that the asperity deformation and the drill string motion were on the millimeter-scale.…”

“…This cyclical extension of the Shock Tool mandrel creates the axial oscillation motion which spreads through the drill string, both above and below the DAS [17]. The type of axial vibration motion is considered to be sine or cosine [10]. …”

“…This value can be determined from the following equation: Figure 11. Changes in general asperities deformation at consecutive phases of sliding and vibration of the drill string [10]. The blue dotted line is virtual projected element in the calculation process, the dark red solid line is real projected element at end of time step.…”

“…The simulation work adopted the parameters reported in a previously published article [10,13]. These parameters are listed in Table 1.…”

“…Some articles have described mechanical torque and drag reduction methods in a certain drilling field [10,11], such as an axial oscillation tool. These works promoted the application of vibration technologies in the field.…”