As a novel type of mineral resource, gas hydrate has received a considerable amount of attention worldwide. This seismic detection method can detect abnormal phenomena such as the BSR, blank zones, velocity anomalies and polarity inversion of gas hydrate and become an important method of gas hydrate detection. The occurrence area of gas hydrate in the South China Sea is usually buried deep beneath the seabed. The current method cannot meet the needs of the shape and structure detection of gas hydrate deposits. With the support of the National Key R&D Program of China, some key technologies have led to developmental breakthroughs, such as ultra-high-energy plasma sources, small-group-interval high-resolution seismic streamers, and distributed three-dimensional seismic acquisition. The seismic profile obtained north of the South China Sea shows that the stratum penetration depth reaches nearly 1000 m at a depth of 1500 m, and the vertical resolution is better than 1.5 m. This system can serve the needs of high-resolution exploration of gas hydrate resources.

The marine controlled source electromagnetic (CSEM) method has been recognized as an effective exploration method of shallow hydrocarbons around the world. We developed our own underwater marine CSEM transmitter that consisted of many functional modules with various response times. We previously adopted a centralized software-control technology to design the transmitter circuit topological structure. That structure probably generated a control disorder or malfunction. These undesirable conditions could lead to repeated recovery and deployment of the transmitter, which not only consumed time but also affected data continuity and establishment of stable and continuous CSEM field. We developed an instrument design concept named 'control technology of hardware parallelism'. In this design, a noteworthy innovation of our new technology is to solve the above-mentioned problems at the physical and fundamental levels. We used several self-contained control-units to simultaneously accomplish the predetermined functions of the transmitter. The new solution relies on two technologies: multi-core embedded technology and multi-channel parallel optical-fiber data transmission technology. The first technology depends on many independent microcontrollers. Every microcontroller is only used to achieve a customized function. The second one relies on several multiple optical-fiber transmission channels realized by a complex programmable logic device and two optical-fiber conversion devices, which are used to establish a communication link between the shipboard monitoring and control-unit and underwater transmitter. We have conducted some marine experiments to verify the reliability and stability of the new method. In particular, the new technology used in the transmitter system could help us obtain more useful measured data in a limited time, improve real-time efficiency, and support the establishment of a stable CSEM field.