"CT scan" 3,000 meters underwater? The ultra-deepwater exploration myth of China's "Hai Jing"!

Recently, my country's large-scale deep-water geophysical prospecting vessel "Hai Yang Shi You 720" equipped with my country's independently developed "Hai Jing" towed cable seismic exploration system completed 2,600 square kilometers of three-dimensional seismic data collection in the Pearl River Mouth Basin.

Source: Video screenshot

01 Do a CT scan of the seabed?

"Hai Jing" is the first set of marine towed cable seismic exploration equipment independently developed and manufactured by China. It is installed on a geophysical prospecting ship. When the ship is sailing, the equipment "plows" across the sea surface and uses seismic wave signals to achieve "CT scanning" of the seabed strata, so as to clearly see the oil and gas reservoirs on the seabed. This is the most direct, economical and efficient method in the world to detect the geological structure of the seabed.

Source: Video screenshot

"Hai Jing" is composed of multiple equipment systems such as source control, towed cable collection, integrated navigation, positioning and control, etc., which breaks through the 22-meter operating water depth limit of imported equipment; it has achieved full range coverage from small track spacing to conventional track spacing, and has 2 Hz ultra-low frequency signal collection capability, which greatly improves the resolution of seismic data.

With its ultra-low frequency and high-precision three-dimensional seismic acquisition capabilities, Haijing can accurately depict the "3D stereogram" of deep water layers and complex geological structures . On October 3 this year, the deepwater geophysical exploration ship "Haiyang Shiyou 720" carried the Haijing system to conduct ultra-deepwater seismic exploration operations and released China's first ultra-deepwater three-dimensional geological exploration map .

Source: Video screenshot

In accordance with the design requirements, the "Offshore Oil 720" deepwater geophysical prospecting vessel laid 10 cables of more than 8 kilometers in length in the "Hai Jing" system into the sea water one by one, forming a data collection network with an area equivalent to 1021 standard football fields . It carried out sea surface towing cable collection operations along the route, accurately demarcating the location of oil and gas reservoirs on the vast sea surface like "longitude and latitude lines", achieving significant improvement in the quality of mid-deep layer imaging, especially clearer and more continuous basement imaging.

Source: Video screenshot

02 How deep is ultra-deep water? Entering the ultra-deep water era!

Of the proven oil and gas reserves in China, about 40% of marine oil and gas resources are in deepwater areas. This operation is located in the 3,000-meter ultra-deepwater block of the Pearl River Mouth Basin. The average water depth in this area is about 2,000 meters, the maximum operating water depth reaches 3,500 meters, and the maximum buried depth of the exploration target layer is 5,600 meters . This breaks the record for the maximum water depth of China's marine 3D seismic exploration operations, marking a major breakthrough in China's independent marine exploration technology, which is of great significance to ensuring the independent and controllable development of China's marine oil and gas and improving China's deep-sea resource development capabilities.

Over the past decade, the "deepwater fleet" represented by "Marine Oil 201" and "Marine Oil 720" has successively overcome world-class technical difficulties such as conventional deepwater, ultra-deepwater, deepwater high temperature and high pressure, and formed a series of deepwater technology systems with independent intellectual property rights. It has all-round operational capabilities from deepwater to ultra-deepwater, from the South China Sea to the Polar Regions. my country has leapt into one of the few countries in the world that can independently carry out deepwater oil and gas exploration and development, and has become one of the world's advanced countries, achieving a major leap in the technical capabilities of deepwater oil and gas equipment.

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Before the 21st century, my country's deepwater oil and gas production was negligible. By 2012, the proportion of deepwater oil and gas production was only about 8%. However, with the gradual commissioning of my country's deepwater oil and gas fields, my country's water-seepage oil and gas production has reached tens of millions of tons, such as China's first deepwater gas field group and the first deepwater oil field group located in the Pearl River Mouth Basin, and the "Deep Sea No. 1" ultra-deepwater gas field located in the Qiongdongnan Basin.

Since 2012, CNOOC has explored and developed a total of 11 oil and gas fields in the deepwater areas of the northern South China Sea. In 2021, my country's first self-operated ultra-deepwater gas field "Deep Sea No. 1" was successfully put into production. The exploration, development and production capabilities of China's offshore oil industry have historically leapt from 300 meters to 1,500 meters in ultra-deep water, marking that my country's offshore oil exploration and development capabilities have fully entered the "ultra-deepwater era".

03 Summary

The application of marine towed 3D seismic exploration equipment technology in the field of energy exploration is extremely extensive. In the ultra-deepwater era, marine 3D seismic exploration technology is just in its prime. The threshold of this technology is relatively high and the research and development is very difficult. Before this, only three countries in the world were able to independently develop this equipment technology. Since its commissioning, "Hai Jing" has successfully completed 3D seismic exploration in 5 work areas totaling 6,552 square kilometers in Chinese waters.

The three-dimensional seismic exploration technology implemented by the "Haijing" system has solved the bottlenecks that restrict my country's oceans, especially deep-sea oil and gas exploration technology and equipment, and has comprehensively enhanced the core competitiveness of my country's offshore oil and gas exploration technology. It is of great significance to improving the overall integrated research and development capabilities of marine oil and gas equipment and ensuring national energy security.

Comprehensive sources: Science and Technology Daily, Hainan Association for Science and Technology, China News Network, Communist Youth League Central Committee, etc.