An Interactive Drilling Dynamics Simulator for Drilling Optimization and Training

Abstract

Abstract The dynamic behavior of the drill bit is a critical factor in drilling efficiency. It affects ROP, hole conditions and the frequency of bit trips. Improved understanding of this behavior can result is significant improvements in all of these areas. For this reason an interactive PC-based simulator has been developed. This system simulates the dynamic behavior of the drill bit for various drilling conditions. These conditions are defined by numerous downhole and surface factors, such as hook load, RPM, mud properties and flow rate, BHA configuration, drill bit design, borehole parameters, and formation properties. This system allows for accurate simulation of the major drilling dynamic dysfunctions, such as bit bounce, lateral vibrations, BHA / bit whirl, torque shocks, stick-slip and torsional oscillation. The system was developed using field test results and both theoretical and practical knowledge about dynamic behavior of the drillstring, BHA and drill bit under certain drilling conditions. The so-called "System Identification" approach has been used as a basic tool for creating the simulator's internal model. The downhole dynamic and static measurements required for developing such a model were recorded at a high sampling rate during the field test of a prototype of an MWD downhole dynamics tool. The simulator has certain self-learning capabilities and its "smartness" depends upon the amount of data used for developing and training the model. The simulator could be used as a key element in a closed loop drilling system which would allow the driller to be more reactive to any undesirable change in downhole dynamic conditions. By using the simulator "on-line", one could play different scenarios (i.e., drilling ahead based on the existing or anticipated drilling conditions). This could improve the selection of drilling parameters from the surface prior to event occurrence. Therefore, ROP could be optimized while reducing the severity of downhole dynamic dysfunctions. The simulator could also be efficiently used as a training tool for MWD operators and drilling personnel. P. 639