Indentation Test Implementation for Rock Strength Correlation by Experimental Method and Simulation Using Distinct Element Method

Abstract

Rock strength is an important parameter for the drilling penetration estimation, which is usually determined through standard destructive strength tests, which are known to be sophisticated, expensive, and time-consuming. In addition, the accuracy of these tests has a high standard on the rock sample dimension. As a non-conventional method, the rock indentation test is reviewed and conducted in this study to solve these problems. The sample preparation and test method of the rock indentation test are validated to standardize the test. Based on the stress-strain behavior of the test samples, the correlation between the rock indentation hardness index (IHI) and the rock UCS strength is developed based on different lithology. Then the rock indentation test is simulated in the distinct element method (DEM) in PFC2D software. The robustness of the DEM simulation is validated, and the sample failure pattern is studied. The significance of the process is that it very closely matches with the process a rock fails under the cones of a roller cone drilling bit penetrating the rock.