Underbalanced and Managed Pressure Drilling


This 2-day course  is intended to provide  an introduction and overview of the current underbalanced and managed pressure drilling technology. It serves as an introduction to the current technology. The course is intended to explain how and why underbalanced or managed pressure drilling is carried out. It also highlights the differences between underbalanced and managed pressure drilling and it includes the variations of managed pressure drilling technologies such as dual gradient drilling and continues circulation methods. It provides an overview and a basic understanding of the equipment used in both managed pressure drilling and underbalanced drilling operations. The course also highlights the relevant issues that need to be addressed in well planning and well design for both underbalanced  and managed pressure drilling. The well integrity and well control aspects for these drilling techniques are also addressed.

Objective of this course is to gain a basic understanding of the underbalanced drilling and managed pressure drilling technologies. Understand when to use underbalanced drilling and when to use managed pressure drilling and what the various limitations and advantages are of these drilling  techniques. Understand  the  equipment requirements for underbalanced drilling and managed pressure drilling and gain an understanding of how what is different in the well design process.

At the end of the course attendees will be able to understand the differences between underbalanced drilling and managed pressure drilling and will be able to understand the equipment and engineering requirements for these drilling techniques.

Day 1: Underbalanced Drilling

  • What is underbalanced drilling?
  • Why drill underbalanced?
  • History of underbalanced drilling
  • Limitations and advantages of UBD
  • UBD classifications
  • Candidate selection
  • Well planning
  • Fluids and gasses used
  • Flow modeling
  • MWD systems and their limitations
  • Isolation valves
  • Nitrogen equipment
  • Compressors
  • BOP’s and rotating control diverters
  • Separators
  • Flare stacks
  • Underbalanced drilling equipment
  • Case histories

Day 2: Managed Pressure Drilling

  • What is managed pressure drilling?
  • Why use managed pressure drilling?
  • Variations of managed pressure drilling
  • Dual gradient variations
  • Continues circulation
  • Well control in MPD
  • MPD choke manifolds
  • Rotating control devices
  • Planning MPD projects
  • Case histories

Course Length

2 Days

Who Should Attend

Drilling engineers, reservoir engineers, drilling managers, service company engineers, and mud loggers as well as any G & G staff that are either involved in underbalanced  or managed pressure drilling activities or are planning to use UBD or MPD. Participants should have an understanding of the basic drilling technology and the terminology used in drilling and well operations.


Engineers  are responsible  for enhancing  their professional  competence  throughout  their careers. Licensed, chartered, and or/ certified engineers are sometimes required by government  entities to provide proof of continued professional development and training. Training credits are defined as Continuing Education Units (CEUs) or Professional Development Hours (PDH).

Attendees of SPE training courses earn 0.8 CEUs for each day of training. We provide each attendee a certificate upon completion of the training course.


Steve Nas

Steve Nas holds an MSc in drilling engineering from The Robert Gordon University in Aberdeen. He has over 35 years of oilfield experience of which 32 years as a drilling engineer including 15 years as a wellsite engineer.

Nas was born and raised in Nijmegen in the Netherlands and started his career in 1977 as a Mud logger. He became a wellsite drilling engineer in 1980. In 1988, he joined Shell in the Southern North Sea initially as a wellsite engineer and then as operations engineer. In 1995, he joined Smedvig and became involved in underbalanced drilling operations drilling numerous UBD wells in the North Sea, Indonesia, Thailand, and Colombia as well as in other parts of the world. In 2004, he joined Weatherford in Asia Pacific and was involved in numerous managed pressure drilling operations including the first deepwater MPD operations from a drillship. Nas joined the SPT group in 2011 where he headed their well engineering group further, specialising in well control and hydraulic flow modelling technology. In 2012, SPT was acquired by Schlumberger and he is now Adviser for Drilling Software at Schlumberger. He is a recognised expert in advanced drilling technology and has authored and presented numerous papers on underbalanced drilling, coiled tubing drilling, and managed pressure drilling. Nas also authored the UBD Chapter of the SPE Petroleum Engineering Handbook (Volume 2 Chapter 12) as well as the chapter on “Underbalanced Drilling Operations” of the SPE Advanced Drilling and Well Technology book.