Cleanup to FPSO or Through a Rig in Deep Water—Pro and Cons

Abstract After the drilling and completion of every well, a crucial step involves its preparation for transfer to production. During this operation, we aim to extract the fluids and debris present within the well and potentially in the subsea line system and to reclaim some of the infiltrated substances and fine particles that have encroached upon the vicinity of the wellbore, thereby restoring the well to its peak productivity. This cleanup procedure is orchestrated through a smart selection and strategic placement of fluids within the wellbore, meticulous control of underbalance, potential perforating processes, and a systematic sequencing of choke valve adjustments during the gradual opening of the well to induce flow to the surface. The separation and processing of fluids typically occur close to the wellhead, where they are either prepared for sale or disposed of through various methods. A major question remains of whether to process the fluids at the surface on an FPSO or on a drilling or completion rig. FPSO cleanup presents advantages such as reduced total cost of ownership, easier fluid disposal facilities, recovery of liquid hydrocarbons, and verification of the full system operational readiness from sand face to the surface production system. However, it usually does not lend itself to a precise control of wellbore cleanup parameters and can create significant stresses on the surface production system. We establish a methodology to evaluate the benefits and drawbacks of each solution based on a fit-for-purpose cleanup transient simulator and an optimization routine that enables the determination of nonintuitive sequence of control parameters that in both cases can result in significant gains. The comparison of predicted outcome versus realization in deepwater confirms that nonintuitive considerations must be evaluated to achieve a proper balance of all factors, ranging from met-ocean to rig availability and FPSO tolerance and to slugs and large amount of solids. The concept starts from the reservoir drilling phase and some previously ignored factors can be overwhelmingly important. The paper outlines how a thorough assessment of field development architecture, operational scheduling, and the overall environmental emissions can result in a mutually beneficial solution for the cleanup process. Significantly and counterintuitively, we demonstrate the feasibility of reducing flared hydrocarbon quantities through intricate sequencing of cleanup activities. These seemingly unconventional operational sequences become achievable through the integration of remotely controlled and automated choke sequences along with real-time monitoring of well conditions.