Collision prevention control method for production riser system in deep sea. (15th December 2022) - Hu, Yongli
Abstract: In the deep-sea oil and gas exploitation process, the adjacent risers under the influence of environmental load and shielding effect will produce large amplitude vibration, which may lead to collision and damage to the riser structure. However, there is a lack of study on active collision-preventing control based on vessel flexible riser array system. This paper aims to better prevent the collision between vessel-risers and increase the motion spacing. Preliminarily, we model the vessel-risers system composed of top production vessel, riser array and environment load based on Hamilton's principle and the improved shielding effect model. In the next part, considering the control spillover problem, we design the collision-preventing boundary controllers directly for distributed parameter system (DPS) without discretization or simplification. And the uniform boundedness of the control system is strictly proved by the Lyapunov direct method. Eventually, we verify the effectiveness and feasibility of the collision-preventing controllers by simulating the system in different ocean currents. At the same time, the parameters of the collision-preventing controllers are independent of those of the riser array system, which ensures the robustness of the system. Highlights: Modeled vessel-riser array system composed of top production vessel, riser array and environment load based on Hamilton's principle and the shielding effect model. Under the influence of different current loads, the riser array system will produce different degrees of collisions at different positions. A set of boundary controllers with strong robustness are designed directly for infinite dimensional systems in order to avoid control spillover. Effectively prevent riser collision by controlling the top boundary spacing.