Challenges and Solutions for Asset Integrity Activities on Normally Unattended Offshore Facilities

Abstract

Abstract The future of the oil and gas industry includes zero manning onboard complex facilities such as Floating Production, Storage and Offloading (FPSO) units. Driven by safety concerns, the use of Normally Unattended Facilities (NUF) aims primarily at reducing human exposure to hazards related to offshore operations. The application of NUFs implies that Asset Integrity Management activities including inspection and maintenance would be carried out remotely and/or with limited human intervention. This paper identifies the challenges faced in managing remote integrity management activities of complex NUFs. Aiming at maintaining safe and continuous operations of complex NUF facilities, operators need to mitigate the likely challenges that would affect the remote integrity activities. This paper approaches these activities in a NUF in parts, depending on the characteristics of the asset and the criticality of each element. Quantitative risk assessment method that incorporates the role of age is used to evaluate potential disruption and define mitigation techniques. The role of age is described in four stages: early life, operational life, late life, and end life. Risk Priority Number (RPN) are obtained to judge the effectiveness of the defined mitigation techniques at the four stages of the life cycle. Class Society standards are also an important tool for this evaluation. As a consequence, recommended methodologies are identified to address the NUF integrity management processes. Despite NUFs being designed and operated considering limited occurrence of manned activities based on a pre-determined duration, unforeseen events can distort the daily operations of complex facilities such as FPSOs. In addition, as the NUFs age, the required human intervention is expected to increase due to the natural degradation of the asset. The result of this investigation shows that at the different stages of the life of a NUF, the survey, inspection, and maintenance challenges will present different demands, therefore requiring an adjustment on the methodology and technology applied on the integrity management activities. Several factors contribute to this, including changes in operation profile, failure modes and degradation mechanism. As a result, the intervention program may need to be altered to accommodate such changes, enabling effective remote surveys, inspection, and maintenance.