Quantified Risk Analysis of DP Operations - Principles and Challenges

Abstract

Abstract Risk of position loss is intrinsic to all DP vessels. A position loss may happen on DP1 vessels, as well as on DP2 and DP3 vessels. The consequence is vessel and operation specific, and can be catastrophic to personnel, environment and asset. Quantification of the risk originated from DP vessel position loss is viewed necessary for the offshore oil and gas industry and is a good way to focus the attention in DP risk management. The paper presents a five-step methodology to perform quantified risk analysis of DP operations. That is, 1) Assess frequency of position loss, 2) Establish vessel speed and distance profile involved in position loss, 3) Estimate probability of successful intervention in case of position loss, 4) Calculate frequency of accident and estimate accident consequences, and 5) Conclude the risk picture and investigate risk reduction measures. Key principles are described with case studies to illustrate the methodology. One of the main challenges for a quantified risk analysis of DP operations is related to the frequency of positon loss. The DP incident reporting scheme in the industry at present however does not provide position loss frequency. The authors recommend an alternative DP incident data reporting scheme which combines both incidents and corresponding DP operational time. By having transparency on reporting and deriving less uncertain position loss frequency figures, such reporting scheme will contribute to the DP safety management and in the long run bring benefits to all stakeholders involved in offshore DP marine operations.