Analysis and Research on Mobile Drilling Rig for Deep Seabed Shallow Strata

Abstract

Drilling rigs for deep seabed shallow strata are commonly used to explore ocean cobalt-rich crust resources and other fields. This paper mainly presents the structure and mechanism of a mobile drilling rig for use in acquiring seafloor cores that are up to 1.5 m in length. The software Simcenter Amesim is used to establish the mobile drilling rig's hydraulic propulsion system model, which is the basis and a core part of the rig. Moreover, closed-loop and PID (proportion-integral-differential) control methods are separately used to control the hydraulic propulsion system for simulation analysis. Comparison of the simulation results shows that the PID control method is more convincing in verifying the design rationality of the hydraulic propulsion system. In the simulation of the PID-controlled hydraulic propulsion system, the co-simulation technology of Simcenter Amesim and MATLAB/Simulink not only establishes the hydraulic and control models but also determines the relevant simulation parameters, thereby helping improve system simulation efficiency. In its verification deployment in the South China Sea, the mobile drilling rig has been operated many times at different depths, and some cores have been successfully obtained. It was also used during the 55th Voyage of China Oceanic Scientific Expedition, which was supported by the China Ocean Mineral Resources R&D Association. Several sites were explored, and a large number of cobalt-rich crust cores were obtained. Theory and sea trials are explained to support further research on the survey of abyssal resources.

Analysis and research on the constant-rate penetration mechanism of the seabed cone penetration test system

“…Open systems with valve-controlled hydraulic systems utilize proportional valves or servo valves to control the joystick. This approach features energy efficiency, low heat generation, and precise control (Ferrari et al, 2013;Ren et al, 2021). To ensure a good dynamic response performance, this paper uses a hybrid hydraulic system comprising both pump and valve controls.…”

Recent Advances in Methods of Gas Recovery from Hydrate-Bearing Sediments: A Review

“…Some scholars have proposed an NGH development mode by circulating well groups, which is essentially a combination of the production and drilling in different blocks of HBS to increase productivity while reducing drilling and production costs . Moreover, benefiting from the simple structure and smaller space volume, no requirement of the dynamic positioning system, and working dependently with a sea state compared to conventional offshore drilling platform, developing a seafloor drilling rig may be one of the solutions to save drilling costs …”

“…394 Moreover, benefiting from the simple structure and smaller space volume, no requirement of the dynamic positioning system, and working dependently with a sea state compared to conventional offshore drilling platform, developing a seafloor drilling rig may be one of the solutions to save drilling costs. 395 The above key challenges are rooted in the existing research gaps on the strong multiphysics coupling relationship of thermal−hydraulic−mechanical−chemical (THMC) aspects in HBS during gas recovery (shown in Figure 24). However, the multifield relationship is in the weak coupling stage, which simplifies the nonlinearity degree of HBS and makes the NGH development idealized.…”