Drilling Performance of PDC Bits for Geothermal Well Development in Field Experiments

Abstract

Large amount of cost and long duration required prior to commencement of geothermal power production extremely influence on promotion of the geothermal energy development in Japan. In order to reduce the cost and the duration, JOGMEC (Japan Oil, Gas and Metals National Corporation) has focused on drilling technique and has established a research and development project on the PDC bit with both of high drilling speed and high durability in 2015. In the project, we have studied manufacturing technique of PDC cutters, and have succeeded developing ones with high wear resistance and high toughness. In addition, we have carried out structural analyses to even the loads applied on the PDC cutters and fluid analyses to simulate the movement of the flow of drilling fluid around the PDC cutters on bit face, and then have designed and fabricated several kinds of the PDC bits of 8-1/2 inches in diameter equipped with manufactured PDC cutters of 13.44 mm in diameter. The PDC bits have been used for actual well drilling at several geothermal development sites, and the drilling behavior of the bits has been observed. We will present the drilling performance of the PDC bits obtained from the field experiments.