Rock Drilling. Numerical modeling of rock cutting

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Edwin Johnson
5 years ago
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1 Rock Drilling 1

The Project Modeling of Evaporite Drilling under High Pressure was developed in conjunction with Baker Hughes Company from august 2009 to march 2013 and aimed to study the rock cutting process on

2 The Project Modeling of Evaporite Drilling under High Pressure was developed in conjunction with Baker Hughes Company from august 2009 to march 2013 and aimed to study the rock cutting process on evaporite rocks. The survey was motivated by recent discovery of big oil reserves under pre-salt layers. This event increased the importance of studies related to the drilling process optimization in Brazilian fields. Analytic models are used to predict rate of penetration and efficiency of drilling process based on operational parameters, and the evaluation of Mechanical Specific Energy is the most used for this purpose. The Mechanical Specific Energy (MSE) is the amount of work required to cut a volume of rock. Studies on the parameters that influence the amount of MSE in a drilling process have been developed through field tests like full-scale (Balci et al., 2004; Pessier and Fear, 1992) and through laboratory tests like single cutter (Kaitkay and Lei, 2005; Rafatian et al., 2010). The single cutter test is a useful and advantageous laboratory test to evaluate the rock- -cutter interaction. It eliminates the influence of parameters and grandeurs generated during a field test (like torque generated along the column and vibrations), which facilitates the study of a specific parameter and its influence on cutting efficiency.the experiment consists of a single polycrystalline diamond cutter (PDC) that cuts a groove as a sample of rock rotates at certain angular velocity against it. Several passes over the same groove (single track) occur as drilling progresses. These experiments can be simulated through numerical methods to analyze the effects of changing relevant conditions affecting drilling efficiency. This project aimed to develop numerical simulations to represent the cutting mechanism during a single cutter test using the Discrete Element Method (DEM) and the Finite Element Method (FEM). 2

3 Numerical modeling through Finite Element Method was developed using the software ABAQUS. From the results of simulations with two-dimensional and three-dimensional models, analysis of different parameters and their influence on cutting could be made, like: depth of cut, cutter inclination and confinement pressure. The objective was to evaluate the influence of each parameter on specific energy generation and hence on cutting efficiency. Figure 1 presents a two-dimensional and three-dimensional modeling view at Abaqus. Figure 2 and 3 present results and data processed from the simulations using FEM. 3 Figure 1. Two-dimensional and three-dimensional modeling view at Abaqus - FEM.

4 4 Figure 2. Numerical modeling results with 2D and 3D - FEM

5 Fx (kn/m) Deslocamento (m) Numerical modeling through Discrete Element Method was developed using the software PFC. As in the FEM modeling, simulations using DEM aimed to analyze the influence of certain parameters on cutting efficiency. The parameters selected for the study were: depth of cut, back-rake angle, the friction between cutter and rock and confinement pressure. Figure 4 presents the cutting view to two and three-dimensional models. Figure 5 presents the results processed in a two-dimensional modeling. 5 Energia Específica Mecânica- ε- (MPa) Profundidade de Corte 0.18mm 0.37mm 0.55mm Deslocamento (m) Figura 3. Processed results - FEM

6 6 Figure 4: cutting view to 2D and 3D modeling DEM. Figure 5: Processed results DEM. Another project is under development that aims to develop numerical modeling of rock cutting on carbonates.

7 References: BALCI, C., Demercin, M.A., Copur, H., Tuncdemir, H. Estimation of optimum specific energy based on rock properties for assessment of roadheader performance. The Journal of the South African Institute of Mining and Metallurgy. December, DETOURNAY, E., Defourny, P. A phenomenological model for drilling action of drag bits. International Journal of Rock Mechanics & Mining Sciences and Geomechanics, volume 29, number JIANYONG, P. Interpretation of Single Cutter Tests for Rock Mechanical Properties. ARMA TH US Rock Mechanics / Geomechanics Symposium held in Chicago, IL, USA, June KAITKAY, P., Lei, S. Experimental study of rock cutting under external hydrostatic pressure. Journal of Materials Processing Technology, Number 159. Manhattan, PESSIER, R.C., Fear, M.J. Quantifying common drilling problems with mechanical specific energy and bit-specific coefficient of sliding friction. Paper SPE 24584, presented at the 67th Annual Technical Conference and Exhibition of the Society of Petroleum Engineers. Washington, DC, October 4-7, 1992 RAFATIAN, N., Miska, S., Ledgerwood III, L.D., Ahmed, R. Yu, M., Takach, N. Experimental study of MSE of a single PDC cutter interacting with rock undar simulated pressurized conditions. Journal SPE Drilling & Completation, volume 25, number 1. March, ZHANG, W.; Whipple, G. R.; Lindner, E. N.; Thornton, J. D. The initial Single Cutter Test of the NETL Ultra Deep Drilling Simulator. ARMA , 45th U.S. Rock Mechanics / Geomechanics Symposium, San Francisco, CA,

Rock Cutting Analysis Employing Finite and Discrete Element Methods

Journal of Mechanics Engineering and Automation 6 (2016) 100-108 doi: 10.17265/2159-5275/2016.02.006 D DAVID PUBLISHING Rock Cutting Analysis Employing Finite and Discrete Element Methods Carla Massignani