With the South China Sea natural gas hydrate (commonly known as combustible ice) test full moon, combustible ice in the past "elusive" unconventional energy gradually opened the mystery. In the reporter recently boarded the "Blue Whale Ι" offshore drilling platform, Quest this "alternative natural gas" exploration and development frontier.
320 km away from the God of God in the sea of God, more than 100 meters high platform surrounded by the blue sea. Platform on the right side of the roar of water, combustible ice test lit orange flame is burning. This seemingly ordinary offshore oil and gas exploration platform is the world's first seventh-generation double derrick, semi-submersible drilling platform, which combustible ice mining process hidden in China's six major technical systems twenty key technologies of independent innovation.
Reporters from the China Geological Survey sea gas hydrate test platform and the Guangzhou Ocean Geological Survey was informed that since May 10, 2010 since the ignition test, to 14:52 on June 10, the platform has been continuous gas production for 31 days, The total gas production reached 210,000 cubic meters, the average Nissan 6800 cubic meters.
Combustible ice, as the name suggests, the appearance of ice, fire can burn. It is mainly distributed in deep sea sediments or permafrost in permafrost and is formed by natural gas and water under high pressure and low temperature conditions.
Combustible ice is cleaner than conventional gas and has great potential for resources. It is predicted that the amount of combustible ice is equivalent to twice as much as the world's proven total fossil fuel carbon. Countries are combustible ice as the future of alternative energy sources of oil and gas. Over the past few decades, Japan, the United States, Russia, Canada, Germany and other countries have invested heavily in research, however, the sea combustible ice and no successful mining precedent.
In 2013, Japan tried to exploit submarine combustible ice and extract methane, but because the sea sand into the production wells, the test was forced to interrupt only 6 days. Last month, Japan's second test, but after 12 days in succession, the trial and the same problem due to interruption, the total gas production is only 35,000 cubic meters.
The first time in China to achieve the stability of combustible ice mining, so many people began to believe that large-scale exploitation of combustible ice bright prospects. From the first survey voyage in 1999, to the first time in 2007 to obtain natural gas hydrate samples, and then in May 2017 to achieve a continuous production of gas for one month, China's combustible ice exploration and development in more than 20 years time to achieve From "blank" to "lead" across.
Concern for the environment of combustible ice mining, China Geological Survey Chief Engineer Yan Guangsheng pointed out that as early as the beginning of the design, these issues are considered. "We put a lot of monitoring points around the ore body, the whole process to monitor whether the seabed strata displacement, tilt, or geological changes, after a month of trial mining, and no signs of any landslides or moving," Yan said.
Some people believe that combustible ice mining will bring methane gas leaks despite the efficacious use of Inflatable Packers, leading to serious greenhouse effect. China Geological Survey Bureau of Guangzhou Ocean Geological Survey Ye Jianliang told reporters that combustible ice is formed under low temperature and high pressure conditions, within a certain temperature and pressure curve (for example: 500 meters of water depth, 5 degrees Celsius sea water temperature) , Methane gas spill, but also the second generation of hydrates, not a lot of ran to the air.
Natural gas hydrate in the natural conditions sometimes decomposed methane gas, forming the sea "cold spring". "We have a high level of monitoring in this area," said Lu Jingan, deputy director of the Office of the Ministry of Natural Gas Hydrate Test Site, because of this, Chinese explorers can find combustible ice. After close observation and monitoring, the mining, whether in the sea, seawater or wellhead is just above the air, have not found methane gas leak.
Platform site experts said that in fact, the Chinese sea combustible ice mining is very difficult. Japan, the United States, Canada and other countries aimed at natural gas hydrate test are sandy type, large pores, mining difficulty is the lowest of all types, but the type of resources accounted for only about 5% of the world's resources.
While China this time trial mining muddy silt type reservoir resources in the world accounted for more than 90%. However, this kind of reservoir has the characteristics of low porosity, low permeability and so on. At the same time, the shallow strata in the deep water area are easy to collapse and prone to leakage. The drilling risk is extremely high and the mining is the most difficult.
China's use of the sand control technology, reservoir transformation technology, drilling and finishing technology, exploration technology and so on in the forefront of the world's technology, are from independent innovation.
According to reports, the current test wells well gas production process is smooth, well bottom condition is good, access to the test data of 264 million units, for the next step laid a solid foundation.