Documentation of Risk and Cost-reducing Potential by Utilizing an Automatic Supervision and Decision Support System During Drilling a Challenging HPHT Well

Abstract

Abstract A very challenging HPHT well has been drilled while running an advanced decision support and ECD Management System including early diagnosis of upcoming problems and real time simulations using state-of-the art mathematical models. The System has been running in parallel with the operation, and used all available real time drilling data (surface and downhole) in combination with real time modelling to monitor and optimize the drilling process. This information was also used to visualize the wellbore in 3D in real time. Automatic forward-looking of ECD was also part of the active system. It was implemented in Total E&P Norge TASC (Total Activities Support and Collaboration) Center in Norway. The System was piloted by Total, and was therefore not integrated in Total's work and decision process. Among the challenges during planning and drilling of this well have been Very small window between pore and fracture pressure. RT ECD simulations were performed with an advanced hydraulic and thermal wellbore modelIncreased probability for instabilities in the tight window. This was mitigated in the System by RT stability modeling during drillingUncertainties in pore pressure predictions. This was mitigated in the System by updating predictions during drilling. Experiences from use of the System clearly show: -The forward-looking capability gave early warning of a near-future kick situation. And the diagnosis functionality gave first an early warning of an upcoming kick and then a firm diagnosis.-A loss situation was warned against and eventually diagnosed by the System.-Potentially at least 10 rig days, large amounts of drilling mud and a squeeze cement job could have been avoided by fully utilizing the System.-The drilling risks could have been reduced and safety increased through reducing the impact of the kick/loss situations and possibly even avoiding them.