First Deepwater Campaign, Offshore Romania: Infrastructure, Design, and Execution to Deliver Drilling and Completion Fluids

Abstract

The Black Sea, offshore Romania, is one of the world's emerging deepwater basins. The objectives of the campaign presented in this paper include safe and compliant operations, data acquisition, reservoir characterization and de-risking of adjacent prospects over the course of a seven-well, deepwater exploratory campaign. The challenges inherent to deepwater are exacerbated in exploratory wells, with additional focus placed on the reduction of risks associated with ECD management, downhole losses, wellbore instability, gas hydrate formation and mitigation of shallow hazards. The scope of this project presented additional logistical challenges, as there were no dedicated facilities in this area to support large-scale deepwater projects. Deepwater projects in emerging areas present a variety of challenges including planning, constructing, and commissioning facilities with sufficient capacity to prepare and store the requisite volumes of drilling and completion fluids. Infrastructure preparation in this project included the design and construction of two liquid mud plants with the capacity to mix, condition and store large volumes of drilling and completion fluids for a multi-well campaign. Additionally, a bulk facility was built and commissioned for handling barite additives used in the project. Project management and monitoring techniques were used to ensure on-time completion of facilities following the critical paths of the project timeline. All planned operational objectives were safely achieved because of detailed planning, commitment, and capital investments in assets and the infrastructure to support operations. This approach enabled delivery of project objectives without incidents of fluids-related non-productive time (NPT). The logistical objectives were achieved on time, and in an environmentally compliant manner. All fluid volumes were safely prepared and delivered to the 5th generation semi-submersible for use in the target intervals. This included delivery of large volumes of high-density riserless kill fluid (RKF) that was stored for three months on a multi-purpose supply vessel (MPSV) without the occurrence of barite sag. All drilling and formation evaluation objectives were accomplished with a high-performance, non-aqueous fluid (NAF) specifically designed for use in this multi-well campaign. The delivery of well testing, plugging and abandonment objectives was facilitated by use of an integrated suite of wellbore cleanup (WBCU), completion fluids and filtration technologies.