Santos Basin, Brazil: Successful Drilling Campaign 2008-2010

Abstract

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper OTC 22336, ’Case History: Performance of a Drilling Campaign in the Santos Basin, Brazil, 2008-2010: A Success Story,’ by Humberto Carrizo, Giovanny Ortuno, and Tarcilio Dutra Neto, Repsol Sinopec Brasil S.A., prepared for the 2011 Offshore Technology Conference Brazil, Rio de Janeiro, 4-6 October. The paper has not been peer reviewed. The evolution in well design and continuous-improvement actions are reported for the execution of five shallow-water and deepwater wells drilled by Repsol using a third-generation semisubmersible rig during 2008–2010. As part of the continuous-improvement approach, the quality-assessment/quality-control (QA/QC) procedures were tightened throughout the campaign. The proper use of after-action reviews at the completion of each well phase was paramount for the lessons learned from each well and their application to subsequent wells. Introduction The exploration-drilling campaign during 2008–2010 in the Santos basin used a moored semisubmersible drilling rig and was the first campaign in Brazilian waters by Repsol Sinopec Brasil. The blocks where these operations were performed are approximately 180 naut miles from the shore base. These wells were post-salt prospects in shallow and deep waters. The map in Fig. 1 shows the well locations for Wells A, B, C, D, and E. In the lower right of the figure is the order in which they were drilled, together with the respective water depth. The complete paper details well design and well operations from spud to total depth (TD). Actions considered key for performance achievements are framed by a continuous-improvement process, with tangible actions to reduce total time on well, and can be summarized as in Fig. 2. The total time on well can be reduced within the two stages of the well-construction process. During well planning: Make well-design improvements and/or plan application of a new technology. During project execution: Make well-operation improvements to remove invisible lost time (ILT) and reduce non-productive time (NPT). Well Planning Well-design activities carried out by the multidisciplinary project team are governed by the company’s well-construction process (WCP). The WCP is a gated four-phase process: visualization, conceptualization, definition, and execution. At the end of each phase, a gate-event meeting occurs in which a multidisciplinary technical team, based at headquarters, appraises information from the phase and then, depending on the results, decides whether to continue to the next phase. The WCP receives well data from the geological and geophysical team, and these data are essential input for well-design activities until the well design is fixed at the second gate and the basis of design is delivered. Design activities end with the drill-well-on-paper document. At the third gate, the drilling program is signed as the main deliverable before starting well operations.