A New Evaluation Technique of Rock-Fracture Toughness Using the Drilling Resistance of a Tri-Cone Bit

Abstract

Recently, hydraulic fracturing has been often employed to increase the productivity of geothermal wells. is one of the important parameters in designing hydraulic fracturing jobs. is commonly obtained through fracture toughness tests using rock samples. However, to do toughness test, not only does it take a very long time to measure ,but we also must test many specimens to obtain the borehole profile. To solve these problems, a simple method is described to evaluate the borehole profiles of using drilling resistance of 3-corns bits and sonic andí density logging data. Applying this method to some geothermal wells, we obtained reasonable results with the in-situ profiles corresponding to the geology of the wells. Thereforethis profile can be used in designing hydraulic fracturing parameters and in fracture analysis of geothermal reservoirs.