Risk Assessment of a Continuous Circulation System – Heart of Drilling (HoD ®) applied to drilling operations

In the current drilling environment, the industry is facing greater pressure-related challenges while developing mature and unconventional fields, both on land and offshore. Additionally, there is greater focus on improving the feasibility of tight pore-pressure/fracture-gradient wells, safety, and increasing efficiency. The challenges that are present while drilling these wells with these tight conditions, are solved by a technique called Managed Pressure Drilling (MPD), which is defined by the International Association of Drilling Contractors (IADC), as an adaptive process used to control the annular pressure profile throughout the wellbore. Among the MPD techniques, it is found one that maintains the pressure at the bottom of the well constant, and in order to face this challenge, Drillmec S.p.A. has developed a Continuous Circulation System (CCS) that accomplishes this goal, named Heart of Drilling (HoD®). It is important to notice that while the MPD techniques allows the drilling operation to be done in challenging environments it also adds more equipment to the drilling rig, turning the operations to be more complex and potentially riskier. This study describes the risk assessment performed for the system, starting from a risk identification, then an analysis and an evaluation The principal part of this study is focused on a qualitative examination of the continuous circulation device and its potential consequences, then, a quantitative analysis that provides the probability of failure of the equipment. The methodology followed provides a rational framework that allows to quantify the risk from tools utilised on the offshore field. The results of the analysis revealed that the possible failure scenarios that might arise from the utilisation of the CCS are directly connected with electrical failures of the tool while running, or the possibility of a malfunction on the software that controls the equipment, rather than mechanical problems.