A simulation framework for evaluating intelligent control of continuum drillstring dynamics.

ABSTRACT: Intelligent drilling control systems depend on accurate models of drilling dynamics to avoid destructive behaviors and boost operational efficiency. While lower-fidelity models offer rapid run-times and straightforward analysis, they suffer from some drawbacks. Specifically, lower-complexity models may lack the fidelity required to capture drill-string nonlinear behavior and multi-degree-of-freedom dynamics. This work proposes the use of a co-simulation environment, PyAnsys, to create a computationally efficient yet high-fidelity framework enabling realistic simulation across varying drilling scenarios. The framework uses both Ansys Parametric Design Language (APDL) and Python within a single programming interface to study drillstring behavior. Ansys finite element (FE) software captures essential behavior such as higher mode drilling dynamics and bit-rock frictional interactions. Python enables the integration and real-time adaptation of control schemes based on evolving downhole conditions. The co-simulation environment can also model the communication delays often encountered in field operations. In this paper, we show how the PyAnsys workflow enables rapid implementation of physical drillstring characteristics, drilling operational parameters, and a velocity weakening bit-rock model into the simulation. Subsequent simulations utilize varying control algorithms to study system stability and achieve stick-slip suppression of the FE model. Preliminary results illustrate the framework's potential for capturing higher order dynamic behaviors. This can provide a valuable tool for performing advanced dynamic analysis and control scheme evaluation in challenging drilling scenarios.