Adverse conditions are often encountered during managed pressure drilling (MPD). These conditions can include wellbore instability, kicks, and losses that create challenging scenarios for cementing operations, such as a narrow operational window (below 0.1 lbm/gal) between the pore and fracture pressure, which can compromise the necessary barrier and require unconventional solutions in deep water. We will review a successful managed pressure cementing (MPC) operation and presents findings and lessons learned. MPD allows the operator to control wellbore pressure as the hole is being drilled. By performing dynamic formation integrity test (DFIT) and flow testing, wellbore conditions are revealed, providing precise data, such as the necessary equivalent mud weight (EMW) to help prevent losses and surface back pressure (SBP) to overcome kicks. In the case discussed, information was generated during the drilling stage to provide parameters and input to proceed with cementing operation modeling, which was analyzed using state-of-the-art software to identify the crucial steps necessary for a successful operation. MPC modeling should be performed using the most reliable data to help select the best approach and tool to achieve expected cementing results. This allows densities to be defined as well as slurry and spacer volumes, displacement rates, and the recommended minimum SBP necessary for safe execution, thus helping minimize losses and avoid kicks. For the case discussed, casing was run on drillpipe using an inner string. Once landed, the cementing models were calibrated before beginning the operation using obtained DFITdata. The cementing operation was executed in accordance with the defined schedule, including surface rates, events, stages expected, and SBP. Using this method, displacement was completed, lifting pressure was observed, and then SBP was controlled in such a manner that wellbore control was maintained. Losses occurred; however, according to the final pressure recorded compared to the model, the expected top of cement (TOC) was achieved. After waiting on cement (WOC) and drill out, the leakoff test (LOT) confirmed good cement in place. Key aspects, such as communication between personnel involved during execution and the SBP control as per the design, were important to the success of this operation.

This content is only available via PDF.
You can access this article if you purchase or spend a download.