Hot Dry Rock Breaking With Pdc Bit Under Various of Impact Loads

Deep dry hot rock geothermal energy is a new type of clean and renewable energy, which is environmental friendly and abundant. The ROP improvement is one of the bottleneck faced in deep hot dry rock drilling. Regarding to the high temperature, strength and abrasiveness of hot dry rock, the combination of downhole impact drilling tools and PDC bits has become an effective method to increase the ROP of hot dry rock, and the waveform of the impact load generated by the downhole percussive drilling tool is an important factor influencing the ROP of the hot dry rock. Therefore, a three-dimensional full-size PDC bit-hot dry rock model is established, in order to evaluate the ROP improvement rate of dry hot rock under the coupling of impact loads, and the results show that the penetration depth and rock breaking volume depend on the variation of impact loads, the shapes of sine and rectangle load correspond to a high efficient drilling performance. The research results could provide a theoretical basis for the design of rock breaking percussive drilling tools and optimization of drilling parameters for hot dry rock.