Performance Evaluation of Polycrystalline Diamond Cutter (PDC) Bits Used in the Production Interval of Well AW-01 in the Akiira Ranch Field, East African Rift Valley, Central Kenya

摘要

Inherent to geothermal drilling are many challenges, which might be distinct from traditional oil and gas drilling. These include harder rock formations, total losses, high temperature, and, typically, a limited budget. These downhole conditions and monetary differences have led to drilling geothermal wells with 'fit for purpose' equipment and technology chosen to perform best under these conditions and constraints. One of the most important pieces of drilling equipment is the drill bit: up until recently the tricone bit (also called roller cone) had been the only choice in bits, for the vast majority of geothermal wells. However, as evidenced by the results of the first Akiira Geothermal LLC ("AGL" or "Akiira") exploration well, PDC bits have some advantages over the tricone bits in specific applications, and this widely available technology is worth consideration in geothermal environments. The aim of this paper is to compare the performance of both PDC and tri-cone bits used while drilling the production interval of vertical exploration well AW-01, in the Akiira Ranch Field, East African Rift Valley, Central Kenya. Also, and as part of the technical analysis carried out, this paper highlights specific drilling parameters and values related to each bit used, such as footage drilled, drilling time and the average rate of penetration (ROP).