Safe exploitation of the marine natural gas hydrate (NGH) resource is essential to meet the demand of the future energy requirement. To enable real-time monitoring of methane leakage during the production test of NGH, an ocean stereoscopic monitoring system based on underwater single-point mooring structure is developed, which supports in situ monitoring of marine environment at the sea-air interface, the euphotic zone, and th...

The thermophysical properties of working fluids serve as a fundamental basis for the design and analysis of subsea hydraulic systems. Precise characterization of hydraulic oil properties—including bulk modulus, thermal conductivity, and viscosity—is critical for optimizing system efficiency and energy conservation in deep-sea applications. However, no existing model accurately describes the variation patterns of these paramete...

Marine water resources (including seawater and pore-water) provide important information for understanding the marine environment, studying marine organisms, and developing marine resources. Obtaining high-quality marine water samples is significant to marine scientific research and monitoring of marine resources. Since the 20th century, marine water resources sampling technology has become the key research direction of marine...

Offshore oil and gas resources play a crucial role in supplementing the energy needs of human society. The crisscrossing subsea pipeline network, which serves as vital infrastructure for the storage and transportation of offshore oil and gas, requires regular inspection and maintenance to ensure safe operation and prevent ecological pollution. In-line inspection (ILI) techniques have been widely used in the detection and inspe...

Methane leakage at the interface between sediment and overlying seawater is an important basis for gas hydrate exploration. Therefore, a transfer device with working pressure of 30MPa and corresponding scheme are proposed to separate and transfer the sediment and overlying water inside the sampler under the condition of pressure-retaining. Based on the pressure relief valve with adjustable threshold pressure, the device transf...

Clay sediments are the main component of seabed sediment. Interactions between the nano-sized, disk-shaped and charged clay particles are complicated, as they control the sediment’s rheology. In this study, we studied the rheological behavior of the clay sediment modeled by laponite and bentonite suspensions experimentally using a rotational rheometer. The yield stress decreased when water content increased. Meanwhile, the yie...

Reliable sampling technology for deep-sea sediments is a prerequisite for studying the sedimentary environment in the geological history, the mechanical characteristics of sediments and sediment biology. In this study, we develop a new sampling device in order to achieve a convenient and economic pressure sampling for hadal sediments. The overall structure, as well as the key component such as the pressure-holding part, and th...