Wellbore Stability Challenges in the Deep Water, Gulf of Mexico: Case History Examples from the Pompano Field

Abstract

Abstract Several wellbore stability challenges are faced when drilling in deep water. Overburden sediments are typically weak and overpressured; pore-frac windows are therefore narrow; salt bodies may have to be penetrated; rubble zones may exist adjacent to the salt bodies; reservoir formations may be depleted, with consequent risks of lost circulation and differential sticking. Extended reach wells, required to access satellite reserves, require close monitoring of ECDs when drilling. The pore-frac drilling window may be further complicated by changes in water depth existing over the length of the well path being drilled. All these challenges have arisen in the various wells drilled at BP's Pompano field in the deepwater Gulf of Mexico. This paper describes the wellbore stability challenges faced. Citing well case history examples, the paper describes the experiences gained in tackling these challenges through the pre-well analyses and post-well observations. The paper concludes by providing guidelines and recommendations for data collection, pre-planning activities, drilling practices and real-time ECD / wellbore stability management that should be implemented to eliminate non-productive time when drilling in these challenging environments.