Structural Integrity Assessment of FPSO Life Extension and Relocation

Since the first FPSO was built in the 1970s, FPSOs have been a very popular Floating Production Installation (FPI) concept, especially in deep-water application. The mobility of ship-type FPSOs makes them easy to transit, operate in a marginal field and relocate to other fields. Self-propelled FPSOs with a disconnectable turret can sail to safe harbor during a hurricane or other emergency. Oil transportation by shuttle tankers eliminates the need for oil transportation to shore by long-distance pipeline. Because of their flexible features and mature shipbuilding experience, FPSOs are good candidates for life extension at the same field and relocation to different fields at the end of its designed life. However, most FPSOs have been in operation for an extended life, some being converted from existing tankers. A rational and reliable procedure for the assessment of FPSO structures with designated scantling to validate structural integrity after FPSO life extension and relocation is called for, taking into account the expectation of safety and economic aspects. Special consideration is to be made between life extension at the same field or same operating area with updated environmental conditions, and relocation to a new field with different environmental conditions.