Title: Aging of mechanical components on a modeled offshore oil & gas platform and the influence on the risk level – Incorporating renewals and surveillance

Life extension of offshore oil and gas platforms has become common as new technology has made available more oil and gas. It is often profitable to continue using an aging platform instead of deploying a new one. A common practice in quantitative risk analyses performed on aging platforms is to use constant failure rates for components and ignore a potential aging effect. This thesis intends to examine how failure rates of components change on aging platforms, how component maintenance can be incorporated in risk analyses and how the location specific fatal accident rate (LSFAR) is affected by aging. A simplified platform is defined and an analytical model on aging is developed. The model includes renewal and surveillance intervals and the failure rate increase due to aging. Together with a consequence analysis, the model yields LSFAR due to hydrocarbon releases. Calculations of LSFAR carried out with and without consideration of aging are compared. The results show that LSFAR increases at most 1 %. Thus, the practice of using constant failure rates on aging platforms cannot be rejected. Because the results are based on interpolated failure data, it is associated with uncertainties. To reduce these uncertainties, case specific data should be gathered