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.

The objective of the paper is to present a case where a Managed Pressure Drilling (MPD) and an MPD Well Design process was used to design and drill a deepwater exploration well with an expected pressure ramp and narrow drilling margins while acquiring valuable subsurface data. The expected pressure ramp and narrow drilling margins combined with the uncertainty of subsurface data presented significant challenges to the well design team. Based on previous experience in the region, reaching well TD safely and efficiently using conventional drilling methods was predicted to be challenging. The MPD Well Design process enabled MPD techniques, including constant bottom hole pressure and dynamic influx management, to be integrated into well design process. MPD was also identified as a critical tool to collect dynamic pressure data and help reduce overpressure uncertainty. The drilling program, rig specific operations, and contingency procedures were developed accordingly. MPD was used to successfully drill through a pore pressure ramp and address a well control event in conjunction with conventional methods. MPD was also an enabler to optimize the location of the casing/liner shoes by identifying the pressure profile based on real-time pore pressure data. This feature was a key advantage to drilling deeper than planned and resulted in effectively saving one casing string. The proposed well design included five casing/liners, with potential for two contingencies. With the implementation of MPD, the actual well was drilled with four casings/liners to a deeper TD and met all evaluation objectives under budget. This paper presents a case for using MPD and the MPD Well Design process and its full capabilities to optimize all aspects of a well delivery process, including well design, safety, and subsurface data acquisition.

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.

This paper presents a case where Managed Pressure Drilling (MPD) was used to drill a challenging exploration well through a pore pressure ramp and to address a well control event in conjunction with conventional methods when an influx was encountered The MPD system was used to drill using primary and secondary indicators, such as background gas, cuttings shape, and changes in ROP to determine if onset of the pore pressure ramp was imminent. The MPD system provided a means to measure the flow in versus the flow out of the well and chokes to add surface back-pressure (SBP) to adjust the bottomhole pressure. The MPD operators monitored the trends as drilling continued and reacted if any indications of a pore pressure ramp were experienced. The pressure ramp was encountered, and the flow out exceeded the flow in. The driller applied more surface back pressure to control the influx and reduce the influx size. The well could not be controlled within the allowable back pressure limitations as outlined by the MPD Operations Matrix, so the well was shut in on the Subsea Blow-Out Preventer (SSBOP). The well was controlled with conventional well control methods, using the Driller's Method. The mud weight was increased to the extent that it was not enough to hydrostatically kill the well, but sufficient to allow operations to resume within a new MPD Operational Matrix adding back pressure to keep BHP overbalanced to the formation. This application of MPD reduced the impact of the influx event and allowed the rig to safely continue drilling and meet the well objectives without losing the hole section.

Surface Applied Back Pressure Managed Pressure Drilling (MPD) systems provide a potentially game changing technology for Deepwater Gulf of Mexico drilling applications by means of annular pressure manipulation for drilling through narrow margins, cementing across potential loss zones, assisting in running completions, and mitigating non-productive time. The technology however, is not without cost and the challenge remains to build the business case to utilize MPD in Deepwater applications. Recently several wells were successfully drilled using this technology to the planned target depth accessing reserves that would not have been possible otherwise. This type of scenario where using MPD to stay within a narrow margin has been the means to justify the upfront costs to get a rig outfitted with MPD and the operating costs of the system during use. Once a rig is outfitted with MPD, the economics for a project shift, however, justifying the business case purely based on NPT savings is still not typically viable. This paper will provide the operator's perspective of the cost-benefit analysis for MPD use and provide business case examples for the use in Deepwater Gulf of Mexico. The impact of lessons learned on an ongoing campaign and the savings viable for this and other implementation scenarios will also be discussed to develop a robust case for MPD adoption.