Custom Pdc Bits Significantly Increase Drilling Performance in Tauhara Geothermal Drilling Project

Abstract

The use of polycrystalline diamond compact (PDC) bits in geothermal applications has always presented challenges in terms of bit durability, directional response, and economic viability of such bits in these applications.
This paper focuses on two sets of challenges associated with designing PDC bits in 20¾ in. and 12¼ in. sizes to drill through hard volcanic and sedimentary formations in the Tauhara geothermal field of New Zealand.
This paper discusses PDC drill bit design, cutter selection, root cause analysis of drilling dysfunctions, and other limitations affecting overall drilling efficiency. It will also demonstrate drilling parameter sensitivity analysis, drilling practices used to reduce bit damage while improving overall drilling performance, and the economics for both sections.
For the above project, two bespoke bits were designed, built, and tested. This paper presents the results of these bit runs, the learnings made, and future iterations. It will show that the tailored bits outperformed all previous bit runs in the Tauhara field and saved the Operator significant drilling time.