Offshore Installation of Extremely Shallow Water Platform in Zhaodong Oilfield

Typical offshore installation of fixed platform topside includes two types of fully-fledged methods: lifting installation and floatover installation with barge ballast.The topside weight of the drilling platform ODB in Zhaodong Oilfield is about 39 640 kN,but Lanjiang,the biggest derrick barge in China,has only the lifting capacity of 38 000 kN,accordingly lifting method is not suitable for ODB topside installation.Moreover,the platform is located in extremely shallow water area in Bohai Bay and the mean water depth is only 2.4 m at the platform site.The water depth is so shallow that floatover installation with ballast can’t be used.Therefore,floatover installation method with strand jack uplift is adopted,meanwhile the inserted leg type structure and favourable flood tide time are also utilized.Finally ODB topside is successfully installed.The installation course using floatover method with strand jack uplift is described,and the advantages and disadvantages as well.