Method and system for real-time estimation of at least one parameter linked with the behavior of a downhole tool

摘要

The present invention relates to a system and method of estimation of the actual behavior of a drilling tool attached to the end of a drill string and driven in rotation in a well by drive means located at the surface, in which it uses a physical model non-linear of the drilling process based on general equations of the mechanical. In the method, the following steps: & br / - are identified and it calculates the parameters of the model taking into account the parameters of said well and of the said liner, & br / - the model is linearized about a point of operation, & br / - it reduces the model is linearized by retaining only some of the natural modes of the state matrix of the model, & br / - is calculated in real time, the displacement of the drilling tool or the force applied to the tool, with the aid of the reduced model and of at least one parameter measured at the surface.