The cumulative production of natural gas exceeds 1 billion cubic meters!
Not long ago, China’s first self operated 1500 meter ultra deep water atmospheric field “deep sea No. 1” handed over its proud report card since it was officially put into operation.
In Lingshui sea area of Hainan, the world’s first 100000 ton deep-water semi submersible production and storage platform – “deep sea No. 1” stands proudly on the blue ocean like a super large “Big Mac”.
It can extract natural gas 1500 meters deep underwater, connect it to the national natural gas pipeline network through submarine pipeline, and then transport the separated condensate to land through oil tanker.
From the 1500 meter deep sea to the stove of thousands of households, it takes only one day for natural gas to complete this “journey”. Behind this is the unremitting exploration of generations of Chinese offshore oil people towards “dark blue”.
From following to realizing three world-class innovations and 13 China’s first technologies, “deep sea 1” means a major breakthrough in China’s deep-water oil and gas development and deep-water offshore engineering equipment and technology.
find the “treasure” in the abandoned area
On June 25, 2021, the commissioning ceremony of “deep sea No. 1” ultra deep water atmospheric field of China National Offshore Oil Corporation (hereinafter referred to as CNOOC) was grandly held in Beijing and Nanhai gas field.
The “deep sea No. 1” atmospheric field is about 150km away from Sanya City, Hainan Province. The water depth of the sea area is 1220m to 1560m, and the East-West horizontal span of the gas field reaches 50km.
In 2006, CNOOC cooperated with well-known foreign oil companies to explore Qiongdongnan Basin, and drilled the first deep water well in the central Canyon of the block in 2010, realizing a breakthrough in deep-water exploration in the west of the South China Sea.
However, since then, due to the small scale of single-layer reserves in a single block of the deep water well, no development economy, and unclear understanding of the oil and gas accumulation conditions in the central Canyon, well-known foreign oil companies withdrew their exploration rights and interests in the block in 2012.
CNOOC people who dare to be the first did not give up. From a global perspective, since the new century, the pace of global offshore oil and gas exploration and development has been significantly accelerated. The total reserves of newly discovered offshore oil and gas exceed those on land, and the storage and production has continued to grow. It has become a strategic replacement area for global oil and gas resources.
From the Yinggehai oil seedling survey in 1956, China’s offshore oil industry has gone through more than 60 years of development. Entering deep water will become the next strategic goal of CNOOC.
On August 18, 2014, a huge orange flame erupted from the combustion arm of the drilling platform, instantly illuminating the South China Sea under the darkness. China’s first self-designed and built sixth generation deepwater semi submersible drilling platform – “offshore oil 981”, drilled a large gas field “deep sea No. 1” in Lingshui block 17-2 and tested and harvested high-yield oil and gas flow.
This is the first important discovery in the deep-water field since the “offshore oil 981” deep-water drilling platform was put into operation. At the same time, it proves the huge natural gas resource potential of Qiongdongnan Basin in the South China Sea. After that, CNOOC successively explored and discovered many deep-water gas fields in the sea area, and the energy treasure in the depths of the South China Sea gradually appeared in front of the world.
The discovery of these deep-sea atmospheric fields benefits from the persistence of Chinese offshore oil people in exploration technology theory and basic research.
“In the past, large foreign companies used the traditional Atlantic China Welding Consumables Inc(600558) passive edge theory, which is not applicable to us.” Xie Yuhong, chief scientist of CNOOC, said, “we inherited the traditional theory of oil and gas exploration technology, strengthened basic geological research, established a deep-water oil and gas accumulation model, improved the deep-water oil and gas exploration technology, and found a structural group with Lingshui 17-2 exploration potential in the central Canyon waterway of Qiongdongnan Basin.”
“thermos liner” is the first in the world
1500 meters is usually defined internationally as the boundary between deep water and ultra deep water. Although the ultra deep water area is rich in oil and gas resources, every step in the depth is “as difficult as heaven” – for every 1 meter increase in water depth, the pressure, temperature, inrush and other conditions will change dramatically. A set of equipment and facilities installed 1500 meters under the water are under the pressure equivalent to a person weighing 300 kg standing on the fingernail. Moreover, deep-water development has extremely high requirements for technology, equipment capacity and key design indicators. Only a few large oil companies in the world have the technical capacity of deep-water development.
Therefore, when the ultra deep water atmospheric field of “deep sea No. 1” was explored and discovered in 2014, the reaction of most people was foreign cooperation and joint exploitation.
But at that time, international oil prices were falling precipitously, and international oil companies withdrew one after another. Coupled with other objective reasons, “deep sea 1” energy station is on the road of independent innovation.
Difficult and heavy task, what should I do? CNOOC had mastered the development of oil and gas fields with a water depth of 300 meters at that time, but it had little practical experience in getting involved in deep-water gas fields from “shallow” to “deep”.
In the autumn of 2014, the design of development scheme was put on the agenda. Li dada, 35, is the deputy project manager and the person in charge of the floating body.
“We started research in October 2014 and proposed the option of building a semi submersible production platform with oil storage in May 2015.” Li Da said.
There was an uproar in the industry. Few people can think that CNOOC people who have never independently conducted deep-water design and “answered questions independently” for the first time will choose a path that even foreign deep-water counterparts have never thought of – learn from the principle of “thermos tank” and create a world precedent for column oil storage of semi submersible platform.
According to the conventional design of similar oil and gas fields in the world, the new condensate export pipeline is a technically feasible scheme. But this will increase the cost by about 800 million yuan.
Can a platform be designed to meet the production needs of the gas field and temporarily store a small amount of condensate? A new idea flashed through the design team.
They set up 5000 cubic meters of condensate tanks in the four floating columns of the platform, and equipped the oil tanks with customized “protective armor”, which can not only solve the problem of condensate storage, but also avoid the risk of oil collision and leakage.
This innovation, known as “U-shaped isolation and safe storage technology of condensate”, has set a world precedent for column oil storage of semi submersible platforms.
Then, “deep sea 1” gave birth to two other world firsts: large deformation semi floating precise closure technology of 50000 ton super large structure and pre inclined positive load lateral transfer technology of the world’s largest ton open structure. At the same time, it uses 13 Chinese first technologies, such as the design and installation technology of 1500 meter deep polyester cable mooring system and the design and detection technology of floating structure fatigue without docking maintenance for 30 years.
“diving” into the deep sea
The commissioning of “deep sea 1” is a major breakthrough in China’s deep-water oil and gas development and offshore engineering equipment technology, marking a historic leap in China’s offshore oil exploration and development capacity from 300 meters deep water to 1500 meters ultra deep water.
The Deepwater 1 gas field successfully produced 1 billion cubic meters, which proved the advanced and reliable system of China’s deep-water oil and gas exploration and development, production and operation and maintenance of the integrity of the technology system, and also marked the entry of China into the ranks of advanced oil and gas exploration and development countries.
After the “deep sea No. 1” energy station is put into operation, the natural gas produced will be connected to the national natural gas pipeline network through the submarine pipeline, and the stable gas supply to Guangdong, Hong Kong, Hainan and other places will be 3 billion cubic meters every year.
At present, with “deep sea No. 1” as an important hub, CNOOC is actively promoting the development of “deep sea No. 2” (Lingshui 25-1) and other gas fields, and promoting the construction of trillion atmospheric area in the South China Sea from blueprint to reality, so as to better meet the growing demand for clean energy in Guangdong Hong Kong Macao Bay area and Hainan free trade zone (Hong Kong).
China’s one belt, one road project, is not only a strong example of the Deepwater project, China’s shipbuilding, steel and electromechanical industries, but also a strong practitioner for building a “high-quality belt” and deepening international energy cooperation.
