After 24 deepwater wells and almost 300,000 ft drilled with Managed Pressure Drilling (MPD) in the Gulf of Mexico (GOM) for the Operator Company during the last four years using a specific MPD service- provider technology, our experiences ascertaining operating windows in real-time are described in this paper. Including the first-ever Dynamic Pore Pressure Test (DPPT), inducing a planned influx and circulating it through the riser and MPD system, along with several Dynamic Formation Integrity Test or Dynamic Leak Off Test (DFIT/DLOT) performed at the shoe and TD to safely deliver the well, balancing strategy, and casing running/cementing efficiently. The results of these dynamic tests enabled the operator to make decisions in real-time with the primary goal of keeping safety as the priority during the campaign.
The application of DPPT and DFIT/DLOT during the exploration well construction campaign in the deepwater GOM as part of the deliverables obtained from MPD to ascertain actual formation pressure limits in real-time has produced significant improvements in the safety standards for drilling specific hole sections with narrow pressure windows. Improvements were also seen in verifying accurate margins to trip with conventional well-balancing methods or using MPD for tripping out/in and running casing and cementing the sections using managed pressure procedures as an alternative to avoid a breach of the obtained margins. DPPT and DFIT/DLOT, in theory, and practice, are some of the essential benefits delivered by managed pressure technology. Both could radically influence verifying safety standards and margins during the well construction phase.
This technical paper describes the justifications for performing a planned or required DPPT and DFIT/DLOT in several deepwater exploration wells that encountered challenges while crossing narrow operating windows, jeopardizing the well objectives and safety requirements. Also, discussing the US GOM regulatory requirements for approval, procedures, training, execution process, and final results impacted positive results when ascertaining the real pressure margins downhole and being available to drill, trip, and cement successfully using MPD technology.