Managed Pressure Drilling (MPD) is an existing technology that is emerging in Deepwater drilling operations. This paper provides a case study from the Operator’s view, of preparing and deploying an MPD Surface Back Pressure (SBP) system for use in a shallow horizontal well with narrow drilling margins in 8,000ft water depth in the Gulf of Mexico. This paper will describe the engineering, preparations and operational challenges of deploying a Below Tension Ring (BTR) MPD system. The paper will also include information on the hazard assessments, Mud Gas Separator (MGS) considerations, training plan, deployment plan and results, and engagement with the regulator. The paper will present a case for the requirement of MPD for use in the narrow margin shallow horizontal wells, including an analysis of the required mud weights and surface back pressure to drill through narrow margins. It will also include a summary of best practices and lessons learned.

Estimating hydraulic frictional loss in narrow annuli is challenging, especially for deepwater offshore wells with extremely narrow drilling margins. The challenge arises from annuli that are formed by big bore packers like Gravel Pack Packers, where the annular clearance isextremely small. In cases where open hole completions are run with MPD (Managed Pressure Drilling), the well typically would be displaced to heavier weight fluids before the packer is set and MPD is isolated. This paper illustrates the complications and limitations for estimating friction loss due to the narrow annuli when using drilling hydraulic programs. Accurate estimation of hydraulic friction loss is extremely essential when using MPD system to maintain BHP(bottomhole pressure) while drilling, tripping, cementing etc. While drilling, the hydraulic models would typically be calibrated to PWD (pressure while drilling) in the BHA (bottomhole assembly), but when running liners, casings or completion systems, the lack of PWD complicates hydraulics and friction loss estimations. This phenomenon is accentuated when displacing the well from lighter drilling fluids to heaviercompletion fluids,especially when the completion fluid reaches the narrow annuli and displays sudden increase in frictional loss value due to the hydraulic model limitations. This paper focuses on the limitations of estimating the frictional loss in narrow annulus created by the Gravel Pack Packers,when predicted using the drillinghydraulicmodels, and proposes a solution for mitigating such anomalies in calculations. To assess the sudden changes in the pressure loss estimations, the paper further utilizes CFD (Computational Fluid Dynamics) and the frictional loss estimations in these narrow annuli. As an outcome of the study, the paper proposes unique solutions to estimate the frictional pressure loss due to narrow annuli.

Managed pressure cementing (MPC) is an important technique for primary cementing operations in wells with narrow pressure margins between the pore and fracture gradients. This paper presents the design considerations, methodology and results of two deepwater MPC operations conducted to cement production casing strings within a target operating window of approximately three tenths of a pound. Slurry densities commonly lead to high equivalent circulating density (ECD) levels during cementing operations. This condition, combined with mud weights conventionally designed to be above pore pressure, typically results in downhole pressures which approach or exceed the fracture limit. Commonly, operators implement strategies to mitigate undesired results during the cementing phase, however, in most cases the root cause of the problem cannot be adequately addressed by taking a conventional approach. Modern transient hydraulic modeling software permit the calculation of adequate surface pressure levels to control the annular pressure profile during the different stages of a cementing operation. Based on a predetermined annular pressure target, different variables can be designed to produce surface and downhole pressures within existing limits of a particular operation. This capability combined with modern managed pressure drilling (MPD) systems enables accurate control of the annular pressure profile during cementing and allows obtaining near constant bottomhole pressures (BHP) throughout the cement placement operation while using statically underbalanced mud columns. This case study presents an overview of the engineering process used to plan and design the managed pressure cementing operations on two wells and the results obtained. The results of this study demonstrate the advantages of using modern MPD systems over the conventional approach when it comes to primary cementing within narrow downhole pressure windows often encountered during deepwater drilling operations.

As unconventional plays have grown, resources of experienced drilling personnel have become strained. Real time operations centers (RTOCs) are useful in reducing the strain on these resources by connecting technical expertise with field operations. Shell has recently developed a monitoring platform which has the flexibility to perform real time monitoring of drilling activities through a browser based platform. This paper focuses on the application of that technology in the Sichuan Basin, China to provide underbalanced drilling (UBD) and well control expertise to drilling operations, to monitor, coach, and mentor engineering and field personnel to reduce the recovery from well control events and to apply UBD techniques to this tight gas field. The UBD experts directly monitored and interacted with the engineering and field staff to effect changes in the operation. The RTOC's primary goal was to increase the safety of the operations by reducing kick volumes and kick recovery time with a secondary goal of training the onsite leadership in UBD techniques.Through this RTOC application, the rigs showed a decrease in average kick volume, kick recovery time, and a reduction in larger well control events that had caused losses in offset wells. Through the RTOC, UBD procedures were reviewed and disseminated to the rigs. For the final 2 wells of the RTOC deployment, the wells were drilled utilizing these procedures and applying back pressure to simulate the required mud weight (MW).This deployment of an RTOC shows that experts in a remote center can successfully optimize drilling operations. It also shows that an RTOC staffed with experts can train and coach field personnel to apply new drilling strategies remotely. The success of this operation gives operators an opportunity to leverage its unconventional experience and expertise without the need for redeployment of those staff.