Operations related to construction and/or installation of engineering structures (here referred to as engineering operations) involve risk to the structures themselves. Although the probability of occurrence may be low, the economic consequences in case of failure will in most cases be unacceptable and the safety of the operations may have to be improved. In the offshore industry this is particularly exemplified through the construction and installation of large offshore support structures. Risk analysis has become an important tool in quantifying the operational risk to offshore installations and industrial plants. This tool can furthermore be utilized to quantify the risk levels for all types of identified operations. The total risk calculated can thereafter be analysed to evaluate the safety of the operations and to identify measures to improve safety if necessary. Of particular importance are human factors related risk, risk caused by possible loss of buoyancy and risk related to the impact of one structure onto another. Statoil has used risk analysis as a tool to verify new engineering operations. An example of how this tool has been used to verify the safety of installing concrete gravity structures over predrilled wells will be given. The measures identified to obtain acceptable safety of the operations are given particular attention.
As a major North Sea operator, Statoil has invested in several large offshore hydrocarbon production platforms and the design of new structures IS being evaluated. Plans are being made to Install wellhead platforms and to transfer the full wellstream or first stage separated products to the main platforms for final processing. In the early as well as in the later stages of offshore development projects, Statoil IS using risk analysis to verify and improve engineering operations for both the construction and installation phases.