Abstract
The pre-salt reserves offshore from Santos basin represent a great opportunity and probably the most important recent oil discovery in Brazil. These carbonate reservoirs are currently drilled with various types of drill bits, and have proven to be a challenging environment. Since their discovery, there has been an incessant search for the development of drill bits that are able to drill these hard and, in some cases, very abrasive formations in a single run and with optimized drilling rates. In this way, the costs for wells construction would be increasingly reduced, which would further increase the attractiveness of the development of these fields in Santos basin. This paper presents the technological evolution employed in drill bits, from the beginning of the exploratory campaign in Santos basin until newer developments, newer PDC bits designs, and geometric cutters currently used in pre-salt carbonate drilling. In addition, the contractual improvements and results are also presented, showing consistent evolution of ROP and perforated extension over the years, with the development and use of new drill bits in Petrobras.
