VIBRATION AND SHOCK LOADS ASSESSMENT OF THE RECIPROCATING COMPRESSOR ON AN OFFSHORE PLATFORM

The Reciprocating Compressor is becoming one of the common classes of mechanical equipment and plays an important role in offshore oil field re-vitalisation. A wide variety of vibration and failure problems may occur in reciprocating compressors, associated supporting frames and offshore support structure. Excessive vibration problems usually occur when a mechanical natural frequency of the support structural system or compressor manifold system is excited by a pulsation or mechanical excitation source. Since reciprocating compressors generate high pulsation levels at numerous harmonics, which in turn produce shaking forces, vibration and failure problems in these systems are common. These can lead to failures of the compressor, bearings system and or offshore supporting structure/platform. In addition, special problems can occur due to the torsional natural frequencies and the high harmonic torques, due to the compressor loading. Shock absorbers can be designed to control and mitigate the vibration from the compressor applied to the supporting structure. In order to design an appropriate number and location for shock absorbers, it is important to determine the vibration characteristics of the reciprocating compressor on the offshore platform and assess the interactions between it and the supporting structure. This paper gives an overview of the challenges and also discusses various aspects of vibration and shock load assessment of the reciprocating compressor on an offshore platform. Application of the proposed methodology were presented for an offshore structural unit.