An Overview of Air/Gas/Foam Drilling in Brazil

Air, gas, and foam drilling has been used in specific areas in Brazil as an alternative to the traditional drilling process. This work focuses on the benefits and operational improvements obtained with those two-phase flow drilling operations. The comparison between the performance of conventional and two-phase flow drilling has been showing that this technique, when appropriately used, presents some advantages: (1) minimum or no damge to sensitive pay zones, (2) immediate and continuous evaluaion of cuttings for hydrocarbon shows, (3) avoidance of lost irculation, and (4) higher penetration rates in hard formations. This work shows recent on-shore two-phase flow drilling field ases in Brazil using both, jointed pipe and coiled tubing techniques. The results obtained in those wells are analyzed and also the surface equipment design, the appropriate technique for connections, as well as the comparison between field data and predictions from simulators are discussed. Future plans for two-phase flow drilling operations in Brazil are also commented. Additionally, potential areas and concrete actions for improving operational feasibility of this technology are identified. The target is a safer and more economical air, gas, or foam drilling operation.