| Title | PDC Bits Outperform Conventional Bit in Geothermal Drilling Project |
|---|---|
| Authors | Raymond, David; Knudsen, Steven; Blankenship, Doug; Bjornstad, Steve; Barbour, Joel; Schen, Aaron |
| Year | 2012 |
| Conference | Geothermal Resources Council Transactions |
| Keywords | Chocolate Mountains; drilling; geothermal; PDC Bit; Roller Cone; granite |
| Abstract | Geothermal drilling is hampered by the challenges of hard rock, fractured formations, and high temperatures. This drilling difficulty has traditionally been a point of distinction between geothermal and oil and gas applications yet recently this difference is less pronounced as the oil and gas industry targets more challenging formations for sustained production. This synergy can benefit the geothermal industry as technology developed for oil and gas, backed by significant research and testing, can be adapted for use in geothermal drilling. The work described herein demonstrates the use of mature oil and gas drilling technologies on an actual geothermal well construction project. The principal objective is to develop and demonstrate Enhanced Geothermal Systems (EGS) drilling solutions based upon mature, proven rock penetration systems that have been used in the oil and gas industries to penetrate hard rock formations. Polycrystalline diamond compact (PDC) bits are routinely used in the oil and gas industry fo r drilling medium to hard rock but have not been adopted for geothermal drilling, largely due to past reliability issues and higher purchase costs. The Sandia Geothermal Research Department has recently completed a field demonstration of the applicability of advanced synthetic diamond drill bits for production geothermal drilling. Two commerciallyavailable PDC bits were tested in a geothermal drilling program in the Chocolate Mountains in Southern California. These bits drilled the granitic formations with significantly better Rate of Penetration (ROP) and bit life than the roller cone bit they are compared with. Drilling records and bit performance data along with associated drilling cost savings are presented herein. The drilling trials have demonstrated PDC bit drilling technology has matured for applicability and improvements to geothermal drilling. This will be especially beneficial for development of Enhanced Geothermal Systems whereby resources can be accessed anywhere within the continental US by dril ing to deep, hot resources in hard, basement rock formations. |