Risk Analysis of Running a Deepwater Production Test From a Dynamically Positioned Vessel in the North-Atlantic

The present paper describes the key steps and issues involved in performing a quantitative risk analysis (QRA) for a dynamically positioned (DP) offshore vessel that is used to perform a short-term production test (PT) in North Atlantic deep waters. The basic approach is to focus on the “incremental” risk that would occur if the PT were run from a DP vessel as opposed to a fixed structure. The analysis is structured around two basic groups of risk: those specifically associated with DP vessel disconnection decisions and activities (all of which are seasonal) and those occurring during normal operation of the DP vessel. In the case of disconnection caused by hazards such as severe weather, ice, equipment or reference system malfunction, or human/operating error, a large variety of event sequences is assumed, each resulting in different consequences and risks. These are formulated for each analysis outcome in terms of loss of life, release of chemicals into the environment, damage and loss of assets and equipment, as well as overall failure cost. It is shown that the QRA provides a very useful basis for optimal decision making with respect to the feasibility, the planning, and the risk/benefit of deep-water production testing from a DP vessel.