Modeling and Analysis of Drill String–Casing Collision under the Influence of Inviscid Fluid Forces

Abstract

The current study aims to study the drill string–casing system operating in an inviscid fluid under imbalanced and rubbing damage types. The Navier–Stokes equations were linearized to establish the hydrodynamic forces surrounding the drill string and resulted in a five-dimensional system of nonlinear differential equations. To ensure the accurate acquisition of friction characteristics in a fluid medium, a nonlinear wavelet synchronized transform (NWSST) technique was enhanced based on the denoised wavelet hard thresholding algorithm to extract the features of the rubbing system. The developed model was verified through various test conditions, and the extracted data tests show that the frictional impact proves sufficient to modify the dynamic behavior of the drill string throughout the energy concentration with a slight shift above and below the resonant frequency. It was shown by simulation that the vibration of the submerged drill string system potentially enhanced highly undesirable hidden vibrational frequencies that led to a disturbed and chaotic 3D orbit pattern vibrational response. The experimental results show how vibration analysis combined with the synchrosqueezed technique can identify the condition of the drill string system even under harsh operating conditions and demonstrate that fluid enables the drill string system to rotate with minimum friction.

Keywords

• axial, lateral, and torsional vibration
• fluid–drill string interaction
• 3D rubbing-caused impact
• rotary drill string systems
• wavelet synchrosqueezed