The objective of this study is to examine the cause and probability of potential riser failures from operations through existing single and dual production risers with a surface BOP.

Task 1: A literature and industry survey to assess the operational frequency of use of surface BOPs for workover operations from floating production systems through existing single and dual TTR systems.

The comprehensive study will assess the equipment deployed and the conditions in which the equipment would generally be deployed, assuming that operations are being performed in the Gulf of Mexico.

Task 2: Based on Task 1, perform an industry survey of TTRs and potential component failure modes with emphasis on workover operations with a surface BOP. These failure modes will be based on MCS’s experience and consultation with operators and vendors and will include details of Failure Initiator, Failure Mechanism and Mitigation Measures. Task 2 will also include an analysis of the frequency of occurance of loss on integrity with a critical review of cause and effect which will feed into the failure modes assessment.

Task 3: Develop risk assessment methodology specifically adapted for TTRs in workover mode with surface BOP deployed, building on methodologies developed for other riser types,. Describe how to calculate the risk associated with each of the failure modes from Task 2.