This paper constructs a surrogate model for load inversion and response prediction of tubular joints based on sparse measurement data by integrating two-dimensional Chebyshev orthogonal polynomials and a radial basis function (RBF) neural network, to address the challenge of dynamic monitoring and structural response prediction for the service status of tubular joints in offshore jacket platforms and achieve accurate load identification and rapid response prediction. First, given the complexity of the surfaces at key tubular joints of the jacket platform, two-dimensional Chebyshev orthogonal polynomials are used to mathematically represent the distributed loads acting on these surfaces. Combined with truncated singular value decomposition (TSVD) and generalized cross-validation (GCV), high-precision and stable load identification is achieved from pre-set sparse measurement response data. Then, based on the inversion results, a high-quality training sample set consisting of 100 working conditions, covering spatial coordinates and load characteristic coefficients, is generated. Each sample uses spatial node coordinates and load coefficients as input features, with the corresponding equivalent stress as output. Finally, the RBF surrogate model is constructed and trained, with the coefficient of determination ( R²) used to evaluate model performance. The results show that the model achieves an R² of 0.913 78 on the validation set, enabling high-precision and high-generalization prediction of the stress field at key tubular joints of the jacket platform, providing effective technical support for real-time condition assessment and fatigue damage accumulation prediction of the jacket platform.

During the 14th Five-Year Plan period, driven by multiple positive factors including a restart of the market cycle and a recovery in external demand, the global offshore engineering equipment market steadily recovered. As international energy prices bottomed out and rebounded, the product structure shifted significantly: floating production equipment became the market focus, offshore wind power orders emerged as a new growth driver, and prices for offshore support vessels continue to rise under capacity constraints. Looking ahead to the 15th Five-Year Plan period, fossil energy is expected to regain prominence as the global energy landscape undergoes profound adjustments. Non-market factors, such as great-power competition and geopolitics, alongside supply-demand fundamentals, will continue to influence energy prices. Consequently, demand for offshore oil and gas equipment orders remains robust, while long-term potential in offshore wind power, other marine renewables, and innovative marine structures continues to hold promise. This paper reviews the recovery and evolution of the global offshore market during the 14th Five-Year Plan period, analyzes the underlying shifts in supply and demand dynamics, and discusses the sector’s development path for the 15th Five-Year Plan period in the context of the ongoing global energy transition, to provide insights for the industry’s high-quality development.

In 2024, the global offshore market witnessed a countertrend rebound with a double-digit surge in order values, indicating a renewed market recovery. Optimistic signals have emerged in the current offshore market. On the demand side, the expectation of international oil prices stabilized around $70 per barrel with minor fluctuations. The emerging nations continue to show great potential in offshore oil and gas exploration. Under the background of offshore oil accelerating towards the deep seas, orders for large-scale high-value oil and gas equipment such as floating production storage and offloading units (FPSOs) and floating liquefied natural gas systems (FLNGs) remain substantial. The rapid growth in demand for the offshore wind market and the imbalance in ship supply among various countries are still intensifying. On the supply side, the supply of the fleet will keep tight, and the production load of shipyards will remain full. Additionally, increasing stringent green and environmental protection requirements in maritime field are accelerating the demand for fleet renewal and the green transitions among offshore shipowners, in order to meet the new specification requirements.