Drilling with Aerated Fluid from a Floating Unit. Part 1: Planning, Equipment, Tests, and Rig Modifications

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractUnderbalanced Drilling (UBD) can be compared today with the horizontal drilling technology 15 years ago. Most probably, the majority of the wells will be drilled underbalanced in the near future. While onshore and offshore operations from fixed platforms have been conducted, UBD from floating units is still a challenge. With the majority of its hydrocarbon reserves located in deepwater, Petrobras decided to start a project to develop technology to drill wells with light-weight drilling fluid from a floating platform. This technology is seen today as the first step to reach UBD from a floating vessel, including deepwater locations. The present paper describes the steps taken so far to develop all the new equipment required and the HazOp meetings to discuss and approve the technical details and procedures. The paper also discusses the difficulties encountered during the negotiations with a rig contractor, to allow and fully understand the operation on board of one of its platforms. The paper finally discusses the best options from the lessons learned so far to have rigs ready to use this technology in the near future.