Hainan Daily All-Media Reporter Sun Hui
In the first half of this year, the drilling progress of Well Fushenre 1, my country’s first over 5,000-meter deep geothermal scientific exploration well located in Haikou City, attracted widespread attention. In the end, the well was successfully drilled to 5,200 meters, setting a new record for the deepest geothermal scientific exploration well in my country and marking a new breakthrough in the field of hot dry rock exploration in my country.
Geothermal, "earth" means energy comes from underground, and "heat" means temperature and heat. It refers to the renewable energy contained in the earth's internal rock and soil bodies, fluids and magma bodies that can be developed and utilized by humans. With the development and progress of science and technology, this clean energy hidden deep in the ground is releasing huge development potential.
Hainan Island, located on the coast of the South China Sea, is rich in geothermal resources. Dry hot rock type geothermal energy is stored in the formation below 3,000 meters. What was drilled in the Fushenre 1 Well this time was hot dry rock resources.
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from the underground | Renewable energy
| 4.5 billion years ago, a fiery "newborn" in the universe - the earth was born. At that time, the earth was a sphere that emitted strong heat. The high-temperature magma in the core was boiling and rolling, and scalding magma erupted from time to time. The scorching heat flow spread all over the surface of the earth.
The first life was born in the high temperature and strong acid and alkali environment on the earth's surface. After 4.5 billion years, the earth has gradually cooled and the surface rocks have solidified. But in fact, deep in the earth's crust, hot magma is still flowing, continuously providing energy. This is the source of geothermal energy.
Geothermal energy is a renewable energy source with abundant reserves, wide distribution, stability and reliability. Humanity's use of geothermal energy began very early. For example, around 1500 BC, hot spring bath therapy appeared in Italy. According to incomplete statistics, about 80 countries around the world are currently developing and using geothermal energy. Among them, the Nordic region is the biggest beneficiary of this energy. In countries such as Iceland, almost every household can enjoy the convenience brought by geothermal heating and geothermal power generation.
In the context of many countries around the world pushing to achieve carbon peak and carbon neutrality goals, the energy structure is being adjusted at an accelerated pace. As one of the seven new energy sources, geothermal energy is bound to play a role in reducing the market share of traditional energy sources such as petrochemicals and reducing greenhouse gas emissions.
China has a vast territory and has considerable geothermal energy reserves, of which the western region is the most abundant, with geothermal energy reserves reaching 100 billion tons of standard coal. Some experts believe that if fully developed and utilized, geothermal energy may become the next pillar of energy in our country.
Fushenre 1 well construction site.
The uses of geothermal energy are beyond your imagination
You may ask, how useful is it to drill a well several thousand meters deep to find geothermal resources? In fact, human practice has already given the answer. Long Yuwei, a researcher at the Guangxi Academy of Social Sciences, introduced in his book "World Energy History" that the main ways for humans to use geothermal energy include heating through ground source heat pumps, direct heating, industrial utilization, greenhouse cultivation, bathing and recuperation, Sewage treatment, etc. Among them, ground source heat pump heating needs to convert geothermal heat into hot air through ground source heat pump equipment, and then transport it to the space that needs heating; direct heating means directly utilizing hot water or fluid from the ground. For example, in 1928, the Icelanders drilled a geothermal well on the outskirts of the capital Reykjavik. They laid a 3-kilometer-long geothermal water pipeline and introduced 87°C geothermal water into urban communities to heat residents.
The application of geothermal energy in industry and agriculture is nothing new. In the late 1970s, a food processing plant called "Gilroy" was established in Nevada, USA. The plant introduces geothermal water for onion dehydration processing to produce different types of dried onions.
The largest geothermal power station in my country, Tibet Yangbajing Geothermal Power Station, was completed and put into operation in 1977. At present, the geothermal power station has generated billions of kilowatt-hours of electricity. Not only that, there is also a geothermal greenhouse with an indoor area of nearly 10,000 square meters outside the power station, where tomatoes, cucumbers, green peppers, eggplants, leeks, green beans and other vegetables, as well as some fruits and flowers, are grown all year round.These green products are sold to Lhasa and other places.
In 1986, Tianjin Lizigu Farm built a geothermal system for breeding chickens, hatching, brooding, aquaculture and heating domestic water, which significantly reduced production costs. In the same year, the Fuzhou Energy Utilization Research Institute of Fujian Province built China's first large-scale special geothermal drying device - a geothermal drying tunnel mushroom drying device in Lianjiang County.
A model of the Earth's internal structure on display at the "Embracing Dual Carbon, Win-Win Future" geothermal science public welfare exhibition held in Beijing. Xinhua News Agency reported
The target is 250 million-year-old granite
Well Fushenre 1, located in Changliu Town, Xiuying District, Haikou City, is a proper "powerful" well. It uses a number of independent innovative technologies such as "dual-drive drilling + high-pressure injection" to drill a geothermal resource reservoir with a temperature of 150°C near 3,900 meters, and a geothermal resource reservoir with a temperature of 188.71°C at a depth of 5,123 meters.
In recent years, countries around the world have become more and more interested in the development and utilization of geothermal energy, but it is not easy to "dig treasure" deep in the earth. Because the richest geothermal resources are located about 20,000 meters deep underground, humans must not only develop advanced ultra-deep drilling technology, but also have a fully accurate understanding of the earth's internal structure.
My country has previously completed the drilling of more than 10,000 meters of deep oil and gas wells, but this time the drilling depth of Well Fushenre 1 exceeded 5,200 meters, which still attracted widespread attention. The reason is that there are currently only a handful of geothermal wells with a depth of more than 5,000 meters worldwide. In China, Well Fushenre 1 is the only geothermal scientific exploration well with a depth of more than 5,000 meters so far.
The working principle of a geothermal well is to use drilling equipment to drill a wellbore that can penetrate deep into the ground. Then, with the help of special pipelines and equipment, hydraulic fracturing and other technologies are used to transform the geothermal reservoirs inside the earth and remove high-temperature rocks. It becomes like a sponge, and then injects water into this layer of "artificial sponge", and then extracts hot water or steam from it and transports it to power stations or heat supply systems on the ground for human use. Guo Xusheng, academician of the Chinese Academy of Engineering and chief geologist of Sinopec, said in an interview with Xinhua News Agency that the drilling target of Well Fushenre 1 is granite 250 million years ago and is a deep dry hot rock geothermal well.
The "home base" of Qiongbei hot dry rocks
Hainan is located in the Pacific Rim high-temperature geothermal zone, one of the four major high-temperature geothermal zones in the world. It has strong modern volcanic activity and is a rich area of deep geothermal resources. This is where the Fushenre 1 well appeared. An important reason for Hainan. On Hainan Island, the Qiongbei Basin is a large geothermal field.
"According to preliminary detection and evaluation, the current hot dry rock resources in the Qiongbei area are equivalent to about 38.6 billion tons of standard coal. Calculated based on a resource utilization rate of 5% to 8%, the available amount is about 2 billion tons of standard coal, and the total power generation is estimated It can reach 6 trillion degrees to 7 trillion degrees," said Chen Shenghong, a former chief engineer of the Hainan Provincial Department of Natural Resources and Planning, accelerating the development and utilization of geothermal resources, adjusting and optimizing the energy structure of Hainan, and building a national ecological civilization pilot zone. and clean energy islands are of great significance.
Chen Shenghong believes that Hainan’s geothermal resources have broad development prospects, especially dry hot rock geothermal resources. If they can be fully utilized, they can be used for high-temperature power generation, heating and cooling, and the development of ecological agriculture, which is conducive to energy conservation, emission reduction, and further improvement. The ecological environment is also conducive to cultivating emerging industries and driving the development of related equipment manufacturing and engineering technology businesses.
At present, the development and utilization of geothermal resources in my country is mainly based on shallow and medium-deep hydrothermal geothermal resources. However, the development of deep geothermal resources buried below 3,000 meters, especially dry hot rock geothermal resources, is still in the exploratory stage. With technological advancement and the increasing demand for clean energy, the development and utilization of deep geothermal energy will become an important research direction in the future energy field.
In the process of realizing the "double carbon" goal, the large-scale and industrial development and utilization of geothermal energy resources is a new blue ocean. (Hainan Daily)
