Investigation On Field Measurement Method Of Jacket Platform Float-over Installation In South China Sea

With the consumption of natural resources since the industrialrevolution, the oil, gas and freshwater resources onland are dring up. Butthere are rich resources reserve in the deep water. Therefore, thedevelopment of the ocean engineering is boud to the deep water.Since the development of deep-water resources need to face the harshocean environment, the larger and stronger offshore structures are needed.However, one of the challenges for these large structures is theirinstallation process. Float-over method is one of prospective methods tosolve the problem for these large strutures, which usees the largebuoyancy force brought by tidal changes to transfer the weight ofoffshore strcuture from the float barge to the prepared supportingstructures.This paper is based on the float-over installation of Liwan3-1toconduct researches about field measurement method for float-overinstallation. According to these field measurement data, analysis for theprediction methods of float-over installation are conducted.The main content of this paper is summarized here: using GPS/INSto monitor6DOFs of barge motions; using X-band wave radar to obtaindata of current and wave; using pressure-type tide gauges and mechanicalanemometer to monitor tide and wind; using fiber optic strain gauges tomonitor loads of fenders of barge; communicating and displaying allmeasuring data on integrated platform; The quality of field measurementresults is assessed; Post-processed field data is applied for numericalanalysis in order to evaluate the reliability of numerical simulatingfloatover and installation process.Several results are obtained in this paper. A precise measuring skemeto obtain barge motions and environment data is provided in this paper.Meanwhile, an applicable method to approximately estimate loads offenders of the barge is proposed. Furthermore, this paper also provides amethod for the integration of data communication and exhibition. Accordingly, reliable data are derived from filed measurement whichcould be used to compare with those derives from numerical simulationand model test. By comparing results from field measurement andthoeritical calculation, conclusions could be made that prediction usingtime domain analysis for the barge motions within wave frequency isreliable.