China has completed its first deep-water stratigraphic structure map through using indigenous technology, which has been used to explore seabed geology up to 3500 meters deep for over a month.

The six-meter-long map shows the stratigraphic of the seabed with lines in various colors, suggesting geological structures including river course and geological depressions. The map would aid experts in oil and gas exploration. 

The map reflects China's increasing capability in homegrown deep-water surveying and mapping technology.

The exploration equipment for this mapping, the "Haijing" system, is a marine seismic exploration and data acquisition equipment using submarine cables. It is developed and manufactured by China and composed of a variety of systems, including submarine cable-powered acquisition, integrated navigation, as well as positioning and control.

During the exploration, a large deep-water geophysial exploration vessel Haiyang Shiyou 720, which is owned by the China National Offshore Oil Corporation (CNOOC), deployed 10 submarine cables of the "Haijing" system to carry out the data collection work covering an area of 2,500 square kilometers along the designated route.

"Compared with foreign-made equipment, the seismic data collected by 'Haijing' has a higher degree of identification, which can accurately depict the complex geological structure of the 10,000-meter-level stratum through waters 3,000 meters deep," said Ruan Fuming, chief engineer of "Haijing" equipment research and development at the CNOOC.

The seismic waves transmit the acoustic energy through water which is then captured by a hydrophone. The hydrophone transforms it into electric signals which return to the exploration system.

"China has successfully mastered the technology to develop hydrophone on its own," said Ruan. The homegrown hydrophone has ultra high sensitivity which can detect faint signals reflecting from roughly 10,000 meters under water.

Some components have been installed on the cables to measure and adjust the distance between each other in operation to avoid entanglement or collision, as well as keep the cables in balance under the sea.

"Our technology to control the cables can be more accurate than an air pistol shooter hitting a dynamic bullseye 10 meters away with just one shot," Ruan said.