Risk Assessment Of Offshore Pipeline Under Accidental Loads

In recent years, the ocean exploitation develops very fast, as an important meansof transporting ocean oil and gas, offshore pipeline is subjected to all kinds of risksdue to the complex ocean environment. One of the most important risks is beingimpacted by objects, in most cases, the load is hard to determine. Impact may result inthe damage of pipes and because it is very hard to check,maintain,and operate theoffshore pipelines. Once an accident happens, it is extremely difficult to repair.Therefore it is very necessary to carry the safe analysis under accidental loads. According to the evaluation thoughts put forward by "DNV- RP- F107", thepaper discusses three main accidental loads such as falling object when a liftis working,ship impacting riser and anchor impacting pipelines. Probability theory isused to deal with happening probabilities of hitting affairs; dent-energy relationshipand energy belt method are used to handle the impact energy. Relationship betweenimpacting energy and failure probabilities and relationship between impacting energyand breakage grade are set up to construct the relationship between failureprobabilities and breakage grade which is the base used to evaluate the risk ofimpacting affairs. Suggesting measures are given to decrease all kinds of the impactrisks. At last, the paper use C++ Builder and SQL Server computer language to writeapplied software of the compute procedure. The software is verified with an examplein DNV- RP- F107 and the computing result expresses that the software is dependable.The research is very valuable to the engineering practice.