Abstract

This paper presents the relationship between barge hydrodynamic characteristics and water depth under shallow water conditions, six different depths of water were considered respectively, namely, 9.41m, 10.31m, 11.39m, 13.93m ,16.88m and infinite. In this paper, comparisons of hydrodynamic performance between different water depth and different wave angle are performed in frequency and time domain. Corresponding model tests are also carried out to verify the numerical results and it turns out that the test results agree quite well with numerical computation. On the basis of the spectrum analysis and time domain analysis of the motion response, the corresponding RAOs and mooring results are obtained. This comparative study not only ensures the integrity of the shallow undocking analysis, but also benefits safe float-over operations by calibrating the numerical modeling of the T-shaped barge in the float-over simulations of future topside installations.

Introduction

The JZ9-3 Oil Field is located in the northern of Bohai Liao dong Bay, the People's Republic of China,. JZ9-3 Oil Field infill development project is an upgrading project to existing installed facilities. Refer to Qin et al. (2018) for details. The CEPD platform, as a key part of the overall JZ9-3 Oil Field infill development, is a combined drilling and production platform with 24 well slots, and was successfully installed on Sep 16, 2014, The float-over barge is HYSY228, as following Fig. 1,the detail information in table 1.

The topside float-over undocking in Fig.2. Although the floating structures show advantages in this area, the shallow water depths introduce more technical challenges such as the strong non-linear in the propagating waves and the complex wave-structures interactions. Refer to Liu et al. (2006) for details. In particular, the significant wave height in the Gulf of Bohai can reach up to 6m in extreme storms with the period of 10.5s. The large wave height and the relatively shallow water depth enhance the non-linear and result in more challenges. The hydrodynamic sensitivity study was performed with variations of different barge drafts, different wave direction, etc. There are 6 kinds water depth, the water depth are 9.41m,10.31m, 11.39m, 13.93m, 16.88m and infinite, The water depth of 1000 meters is regarded as infinite water depth, the barge draft is 8.44m, and the ratio of water depth to draft is 1.12, 1.22, 1.35, 1.65, 2.0, ∞.

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