Simulation of Single Cutter Experiments in Evaporites through Finite Element Method

Abstract

Abstract Single cutter laboratory experiments are used for evaluating the drill bit - rock interaction mechanisms. These experiments can be simulated through numerical methods in order to analyze particular conditions of each borehole drilling operation. This paper describes the use of Finite Element Method for modeling single cutter experiments in evaporites. The constitutive model of Drucker-Prager, calibrated using results of triaxial compression tests carried out in evaporites, was used to model the rock behaviour. Also, an isotropic damage model was employed for modeling the erosion mechanism that represents the rock-cutter interaction. The model demonstrated good agreement with experimental results. A series of numerical experiments were carried out in order to observe the cutting process under different geometrical conditions. Two-dimensional and three-dimensional simulations were performed to analyze the variation of Mechanical Specific Energy (MSE) required to cut rock by varying three parameters: Depth of Cut (DOC), cutter geometry, particularly the back rake and side rake angles, and confining pressure. It is predicted that MSE decreases when increasing the depth of cut until stabilizing at a certain limit after which it remains substantially constant With regards to the cutter geometry, the results showed that high back rake and side rake angles produce elevated MSE making the process less efficient. The confining pressure analysis showed similar results to the experimental observations found in literature and those performed at our laboratories. The cutting process showed a considerable increase in MSE with the increase of confining pressure.