Evaluation and characterization of hydraulic pulsing drilling tools and potential impacts on penetration rate.

Abstract

Hydraulic pulse tools are one of the well-known tools to create vibrational forces in drill-strings. It is known that these vibrational forces applied behind the bit can affect the drilling rate in medium strength formations. This thesis investigates the action of these types of tools behind the bit through the series of Distinct Element Method (DEM) simulations. Two types of hydraulic pulse tools are evaluated and characterized in this thesis. The Valved-flow tool (AGT) and the Hydropulse tool. A unique simulation scenario was designed to simulate these tools in the DEM environment. Then this scenario combined with simulation of drilling process to simulate the drilling with the AGT and the Hydropulse tool. Results of the simulations showed significant increase in drilling performance when the AGT was used in the process. Simulation results of the two types of tools were analyzed and compared to each other. The results showed that the AGT tool with accompanying shock tool has better performance than the integrated Hydropulse tool and drilling bit. The shock tool produces axial compliance in the drill-string. Results of additional simulations revealed the effect of compliance on drilling performance. These results showed that if the AGT is deployed without accompanying shock tool, it can have strong negative effect on drilling rate. On the other hand, the results suggested the use of shock tool in Hydropulse tool assembly since the drilling performance improved when shock tool was used in combination with the Hydropulse tool. It was observed from the iii simulation results that the drilling performance of the Hydropulse tool was increase by more than 100 % when shock tool was used in the assembly.