Natural gas hydrate

Combustible ice

open 3 entries with the same name

Collection

zero Useful+1

zero

Natural Gas Hydrate/Gas Hydrate Combustible ice , natural gas and water The ice like crystal material formed under high pressure and low temperature is called "combustible ice" because it looks like ice and burns when it meets fire^[9] ）, "solid gas" and "gas ice".^[7] Natural gas hydrates are distributed in deep sea or land Permafrost In which only a small amount of carbon dioxide And water, which is far less polluted than coal, oil, etc., and has huge reserves, is internationally recognized as the alternative energy of oil, etc.^[8]

Combustible ice is not ice, but a natural existence Microstructure It is cage type compound. Combustible ice is its common name. Its appearance and structure look like ice, and it can burn in case of fire. Therefore, this natural gas hydrate is also called "solid gas" or "gas ice".

Natural gas hydrates generally occur in the sediments of more than 0~200 meters above the seabed surface layer with a water depth of no more than 2000 meters. Combustible ice is a solid. If pressure maintaining sampling is not carried out, its original low temperature and high pressure environment will change and volatilize rapidly.^[40]

Chinese name: Natural gas hydrate^[7]
Foreign name: Natural Gas Hydrate^[7]
Gas Hydrate^[7]
Purpose: High potential energy^[10]

Classification: Organic compound
Alias: Combustible ice^[7]
Generation environment: High pressure and low temperature^[10]
Discovery: First found in the laboratory in 1810^[18]
Discipline: geology^[9]

catalog

Causes

Announce

edit

Oceanogenesis

Molecular Model of Natural Gas Hydrate

There are two different types of marine stocks. The vast majority (>99%) are methane coated with structural type I Inclusion compound , and usually precipitate Can be found in the deep. In this structure carbon isotope Lighter (δ thirteen C ＜ -60‰）， Therefore, it is pointed out that microorganism By CO two Oxidation of Reduction And come. These inclusion complexes located in deep deposits are generally believed to be formed in situ from the methane environment generated by microorganisms, because these inclusion complexes and the surrounding dissolved methane thirteen C values are similar.^[11]

These deposits are located in the area with medium depth, about 300-500m thick sediments, called GasHydrate Stability Zone or GHSZ, where there is methane dissolved in pore water. Below this area, methane only exists in dissolved form, and the concentration gradually decreases with the distance from the sediment surface. And above that, methane is gaseous. At the Blake Ridge of the Atlantic continental ridge, GHSZ starts to extend to 450m at the depth of 190m, and reaches the gas phase equilibrium at this point. measurement result It is pointed out that the volume of methane in GHSZ accounts for 0-9%, while in the gaseous region it accounts for about 12%.^[11]

In the second rare structure found near the surface of sediment, some samples have a high proportion of hydrocarbon Long chain (<99% methane) is contained in the inclusion compound of structural type II. The carbon isotope of methane is relatively heavy (δ thirteen C is - 29 to - 57 ‰), it is inferred that Organic matter It is formed by thermal decomposition and upward migration of methane. This type of deposit occurs in the Gulf of Mexico and Caspian Sea.^[11]

Some deposits have characteristics between microbial and thermogenic types, so it is estimated that there will be two mixed types.^[11]

Methane of gas water compounds is mainly decomposed by bacteria of organic substances under anoxic environment. The organic matter in the top few centimeters of the sediment will be firstly Aerobic bacteria Decomposition to produce CO two And release from the sediment into the water mass. In the activity of aerobic bacteria in this area, sulfate Will be transformed into sulfide 。 If the sedimentation rate is very low (<1cm/1000 years) Organic carbon The composition is very low (<1%), and oxygen content When sufficient, aerobic bacteria will consume all organic matter in the sediment. However, the precipitation rate and organic carbon composition are very high pore water It is anoxic only a few centimeters deep, and methane will pass through Anaerobic bacteria Generate. The generation of such methane is a more complex process, requiring various types of bacterial activities Restore environment (Eh - 350 to - 450 mV), and the ambient pH should be between 6 and 8. In some sea areas (such as the Gulf of Mexico), at least part of the methane in the inclusion complex is generated by Organic matter It is produced by thermal decomposition, but most of it is from petroleum decomposition. The methane in the inclusion complex is usually bacterial isotope Characteristics, and very high δ thirteen C value (- 40 to - 100 ‰), about - 65 ‰ on average. At the bottom of the solid inclusion zone, a large amount of methane in the sediment may be released in the form of bubbles.^[11]

To determine whether there is inclusion compound in a given place, most of them can scan the interface between ocean floor sediment and inclusion compound stability zone by means of seismic reflection through observing the distribution of "Bottom Simulating Reflector" (BSR), Therefore, the density difference between general sediments and those containing inclusion compounds can be observed.^[12]

The reserves of methane inclusion compounds generated in the sea are little known. Since the 1960s to 1970s, Inclusion compound During the period when it is first discovered that it may exist in the ocean, its estimated reserves will be Order of magnitude The estimated speed of is decreasing. The once estimated reserves (up to 3 × 1018m ³) are built on the assumption that the inclusion complex is very densely distributed on the entire deep seabed. However, with the development of human understanding of inclusion compound chemistry and sedimentology With further understanding of knowledge, it is found that hydrate can only be formed in a narrow range (continental shelf) depth, and can only exist in the depth range of some places (GHSZ zone of 10-30% part), and usually in low concentration (0.9-1.5% of the volume) locations. The latest estimates force the use of direct sampling, pointing out that the global content is between 1 × 10 fifteen And 5 × 10 fifteen m three between. This estimated result corresponds to about 500 to 2500 billion ton units of carbon (Gt C), which is more than all estimated fossil fuel The quantity of 5000GtC is still small, but on the whole, it exceeds the estimated 230GtC of other natural gas sources. stay arctic circle In the permafrost zone, the reserve is estimated to be about 400Gt C, but the potential reserve in the Antarctic region has not been estimated. These are big numbers. Compared with the total carbon in the atmosphere, it is only about 700 Gt C.^[11-12]

These modern estimates are consistent with the 10000 to 11000 Gt C (2 × 10 sixteen m three ）The number is obviously less. The reduction of inclusion compound reserves has not lost it economic value However, the reduced overall content and the obviously low collection density in most of the producing areas do point out that only inclusion deposits in some areas can provide substantial economic value.^[12]

Continental generation

The methane inclusion compound in continental rocks will be limited to sandstone or silt with a depth of more than 800m Sandstone Sill Medium. The sampling results indicate that these inclusion compounds are characterized by thermal or Microbial decomposition The gas is mixed in such a way that the heavier hydrocarbons are selectively decomposed later. Such forms exist in Alaska and Siberia.^[12]

The reserves are hundreds of times larger than the total oil reserves on the earth. These combustible ice are stored on the seabed 450 meters deep around the world, and the surface looks like dry ice It can actually burn. In the 2700 square meters of underwater hydrates along the southeastern coast of the United States, there is enough combustible ice to supply the United States for more than 70 years. Its reserves are estimated to be 2.6 times of conventional reserves. If all of them are developed and utilized, they can be used for about 100 years. China University of Geosciences (Wuhan) and the Fifth Central South Petroleum Bureau geophysical prospecting The brigade is in The northern Tibet Plateau Large scale development in Qiangtang Basin Geophysical exploration The results show that: Tarim Basin Tibet is likely to become the second place in China in the 21st century oil resources Strategic succession zone.^[12]

Distribution range

Announce

edit

Natural gas hydrates are widely distributed in the slopes, activities and Passive continental margin The bulge of continental shelf And the ocean and some Inland lake Deep water environment. Under standard conditions, the decomposition of a unit volume of natural gas hydrate can produce up to 164 units of methane gas.^[13]

Natural gas hydrate

The main discovered natural gas hydrates at the bottom of Shanghai in the world range yes Atlantic Gulf of Mexico Caribbean , the eastern continental margin of South America, the western continental margin of Africa and the United States East Coast Black Sea Terrace, West the pacific ocean Maritime Bering Sea 、 Okhotsk Sea 、 Thousand Island Trench , Okinawa Trough Sea of Japan , Siguo Trough, South China Sea Trough Sulawesi Sea And the northern waters of New Zealand Central America Trough California Offshore and Peru Trough, etc, the indian ocean Of Oman gulf ， antarctic Of Rosshai and Weddell Sea , Arctic Barents Sea and Beaufort Sea , and intra continental Black Sea And Caspian Sea Etc.^[11]

About 27% of the earth's land is a potential area for the formation of natural gas hydrates, and about 90% of the world's ocean waters are also such potential areas. The discovered natural gas hydrates mainly exist in Arctic And the sea floor, land slope, land base and oceanic trench Medium. Due to the different standards adopted, different institutions have different Estimated value There is a big difference.^[12]

Distribution area of natural gas hydrate

According to the estimation of the Potential Gas Consortium (PGC, 1981), the natural gas hydrate resources in permafrost regions are 1.4 × 10 thirteen ～3.4×10 sixteen m three , including Marine gas hydrate Inside Total resources 7.6 × 10 eighteen m three 。 However, most people believe that the carbon stored in gas hydrate is at least 1 × 10 thirteen t， About is all currently verified fossil fuel (including coal, oil and natural gas). Due to the impermeability of natural gas hydrate, it can often be used as the capping layer of free gas in its lower layer. Therefore, this estimate may be larger when the amount of free gas in the lower layer of gas hydrate is added. If these predictions can be proved to be true, natural gas hydrate will become a rich and important energy source in the future.^[12]

Methane gas water inclusion complex is limited in the shallow lithosphere (i.e.<2000m deep). Found that in some necessary condition Only in the polar continent sedimentary rock , which surface temperature Below 0 ° C, or when the water depth exceeds 300m and the deep water temperature is about 2 ° C Marine sediment under. Continental Reserve Identified at Siberia And Alaska 800 m deep Sandstone and mudstone In bed. Marine type deposits seem to be distributed throughout Continental shelf And may appear under the sediment or on the surface where the sediment contacts with seawater. They may even cover larger amounts of gaseous methane.^[12]

The conventional oil and gas resources in the world are consumed enormously and will soon be exhausted. Scientists' evaluation results show that in the seabed area alone, combustible ice covers an area of 40 million square kilometers, accounting for 1/4 of the total area of the earth's oceans. In 2011, 116 combustible ice distribution areas have been found in the world Ore bed The thickness and scale are conventional gas field Incomparable. Scientists estimate that the reserves of combustible ice at the bottom of the sea are enough for humans to use for at least 1000 years.^[14]

Combustible ice in China is mainly distributed in the South China Sea, East China Sea Permafrost in Qinghai Tibet Plateau According to rough estimation, the resources of the zone and the northeast permafrost zone are about 64.97x10 twelve m three 、3.38x10 twelve m three 、12.5x10 twelve m three And 2.8x10 twelve m three 。 And has been in the Shenhu sea area in the north of the South China Sea Qinghai The physical samples of combustible ice were obtained from the Qilian Mountain permafrost zone in Hunan Province.^[15]

stay Honshu Island 30 miles away from the coastline, scientists found a trench with amazing reserves: the methane in the trench is crystalline, about 500m thick, with a total amount of 40 trillion m three 。 Although this reserve can not be compared with Saudi Arabia perhaps Russia Of oil resources But it is enough for Japan to use it for a while.^[16]

2018 (the 20th session) held in Tianjin on October 18, 2018 China International Mining Conference The China Mineral Resources Report 2018 was officially released. According to the report, it is preliminarily predicted that the natural gas hydrate resources in China's sea areas are about 80 billion tons of oil equivalent.^[4]

brief introduction

Announce

edit

Flammable ice distribution area^[1]

It is also called because it looks like ice and can burn in case of fire“ Combustible ice ”。 Its resource density is high, its global distribution is wide, and its Resource value Therefore, it has become a long-term research hotspot in the oil and gas industry. Since the 1960s, some countries represented by the United States, Japan, Germany, China, South Korea and India have formulated the exploration and development of natural gas hydrates Research plan 。 So far, people have Permafrost region Hydrate found Mineral occurrences More than 230 hot research areas of natural gas hydrate have emerged.^[17]

Historical evolution

Announce

edit

In 1810, natural gas hydrate was first found in the laboratory.^[18]

In 1934, American Hammer Schmidt was blocked Gas transmission pipeline It is the first time that humans have discovered "methane gas hydrate".^[1]

In 1946, Soviet Union The scholar Strinov believes that as long as there is appropriate temperature and pressure, natural gas hydrates will certainly form in nature. It can not only form, but also accumulate into "natural gas hydrate minerals". For example, "natural gas hydrate minerals" may be formed in extremely cold areas or underground with high enough pressure.^[1]

In 1968, the Soviet Union geologist It's chilly all the year round Siberia Maisuoyaha discovered "natural gas hydrate mineral".^[1]

In 1972, the Americans first cemented the Permafrost Natural gas hydrate samples collected from. Siberia and Alaska have permafrost all the year round, and the wind and snow are extremely cold, so it is natural to have extremely cold conditions to form "natural gas hydrate".^[1]

1968, USA“ Deep Earth Sampling Marine Research Institute Consortium (JOIDES) "Implementation Deep sea drilling program (DSDP), whose purpose is to drill a large number of shallow wells in the world ocean to collect sediments core And obtain data on the upper crust of the ocean floor. Tasked Challenger The Earth on the Drilling Vessel physical scientist A lot of seismic exploration , but found that seismic wave There is a strange phenomenon on the reflection profile: it is originally ordered layer by layer, and the velocity increases gradually towards the deep Wavetrain However, there are wave trains parallel to the seabed, shallow wave trains superposed on the deep low velocity layer with high velocity, and "blank" wave trains without reflection at a certain section of the seabed - these are called "seabed like" by geophysicists Reflector ”This strange phenomenon has aroused the suspicion of marine geologists; Whether the shallow high velocity layer is frozen by the low temperature ice at the bottom of the sea, and whether it is layered combustible ice.^[1]

In 1979, the US Challenger carried out Deep sea drilling program sixty-sixth, sixty-seventh voyage number , go Central America Trough The sea area with the strange phenomenon of "seabed like reflector" was found, and the result of drilling was to see the combustible ice that scientists had been looking forward to for a long time. This has convinced scientists that as long as there is a sea area with the strange phenomenon of "like submarine reflector", there may be combustible ice.^[1]

From 1981 to 1986, the 84th, 96th and 112th DSDP voyages Peru Trough, South Mexico Coastal zone 、 Guatemala Flammable ice has been found in coastal zone and other places.^[1]

During 1990-1993 the pacific ocean West Bank West Coast of the United States , Binhai, Japan South China Sea Trench Flammable ice was found in other places.^[1]

In 1992, Ocean drilling program ( ODP ）The 146th voyage in the United States Oregon Natural gas hydrate cores were obtained from the Cascadia Plateau on the western continental margin.^[11]

In 1995, the 164th ODP voyage carried out a series of operations at the Black Plateau in the eastern waters of the United States Deep-sea drilling A large number of hydrate cores have been obtained, which proves that natural gas hydrates have commercial value 。^[11]

In 1997, the expedition team of the Ocean Drilling Program used submarine stateside South Carolina The Blake Plateau on the sea completed the first direct measurement And bottom observation. In the same year, ODP Canada Deep sea drilling has been carried out in the slope area of Juan Devka mid ocean ridge on the west coast, and natural gas hydrate cores have been obtained. So far, DSDP led by the United States and its successor ODP have found large-scale natural gas hydrate accumulation in 10 deep-sea areas: Peru oceanic trench Continental slope, middle America Trench slope（ Costa Rica Guatemala, Mexico), Southeast America Atlantic Sea area, Pacific area in western America, two sea areas in Japan, Alaska offshore and Gulf of Mexico And other sea areas.^[11]

During 1996 and 1999, German and American scientists observed Grab bucket Sampling, off the coast of Oregon, Cascadia Plateau Of Seafloor sediment Take a white hydrate block sample with bubbles, which can be ignited and give off a flame.^[12]

In 1998, Japan cooperated with Canada Delta Hydrate drilling was carried out and 37m hydrate cores were obtained at 890-952m depth. The drilling depth is 1150m High latitude region Permafrost Belt study Gas hydrate The first well of.^[11]

In 1999, Japan Shizuoka Prefecture Yuqiaozaki offshore digs out natural gas hydrates that look like wet snowballs.^[11]

From 1999 to 2001, China Geological Survey scientific and technical personnel First time on South China Sea An earthquake indicating the existence of gas hydrates was found in the Xisha Trough Exception information (like Undersea earthquake Transmitted wave "BSR"). In 2002, the State Council approved the establishment of China's offshore natural gas hydrate Resource survey Special projects.^[19]

Since 2000, the research and exploration of combustible ice have entered fastigium , there are at least 30 countries and regions Participate. Among them, the plan of the United States is the most perfect -- the proposal of the President's Science and Technology Commission Research and development Flammable ice. In order to develop this new energy, the international community has established 19 countries The participating joint agency for marine geological sampling and research in deep strata has 50 scientific and technological personnel driving a ship equipped with advanced experimental facilities from the United States East Coast We set out to explore the combustible ice on the seabed. This special ship for combustible ice exploration was the only ship in the world that could take samples from rocks under the deep sea at that time. It was equipped with equipment that could be used for research Sedimentary layer Studies, ancient ethnology petrology 、 Geochemistry 、 geophysics Waiting Experimental equipment 。 This special ship is built by Texas Director of A · M University, provided by British, German, French, Japanese, Australian and American Science Foundation and European Joint Science Foundation economic aid 。^[20]

Since 2002, the China Geological Survey has made a great effort to Qinghai Tibet Plateau The geological geophysical Geochemical and remote sensing surveys found that China's permafrost regions have good natural gas hydrates Mineralization Conditions and prospecting prospects, including Qiangtang Basin Level I Prospective area ， Qilian Mountains Mohe Basin and Fenghuoshan Wuli area are Class II prospective areas.^[19]

In 1999, with the strong support of the National Development and Reform Commission and the Ministry of Finance, Ministry of Land and Resources The survey of natural gas hydrate resources was officially launched, including Pearl River Mouth Basin We carried out 40 voyages of comprehensive survey of natural gas hydrate, completed 45800 km of high-resolution multi-channel seismic survey, 36800 km of multi beam survey Stratigraphic section Measure 7100km Subsea geological sampling 1480 Station 、 Seabed heat flow measurement 222 stations, etc.^[21]

On April 14, 2005, China held the China Geological Museum Collect the first natural gas hydrate discovered in China carbonate rocks Specimen ceremony. Announces that China has discovered the world's largest scale for the first time Be treated as "Combustible ice" refers to the existence of important evidence of natural gas hydrate“ spring ”Carbonate rock range With an area of about 430 square kilometre 。^[20]

According to the relevant provisions of the Detailed Rules for the Implementation of the Mineral Resources Law of the People's Republic of China, and with the approval of the State Council, natural gas hydrate has become the 173rd mineral species in China, which was discovered by the China Geological Survey. The first discovery of natural gas hydrate in China's sea area was in June 2007, and its origin is the Shenhu sea area in the South China Sea. The geographical coordinates are 115 degrees 20.058 minutes east longitude and 19 degrees 55.711 minutes north latitude; The first discovery of natural gas hydrates in China's land area was in November 2008. The origin is Qilian Mountain in Qinghai Province. The geographical coordinates are 99 ° 10.260 east longitude and 38 ° 5.591 north latitude.^[41]

The natural gas hydrate sampling implemented in 2007 has successfully obtained physical samples for the first time, which proves that the northern South China Sea is rich in natural gas hydrate resources. As a result, China has become the fourth country to pass the national level after the United States, Japan and India R&D plan Countries where physical samples of natural gas hydrates have been collected.^[19]

In the early morning of May 1, 2007, China South China Sea The success of the first sampling in the northern part of the South China Sea confirms that the northern part of the South China Sea is rich in natural gas hydrate resources, which marks China's natural gas hydrate Research The level has entered the world's advanced ranks. China has successfully drilled the "combustible ice" of natural gas hydrate physical samples in the north of the South China Sea, making it the fourth country after the United States, Japan and India to collect physical samples of natural gas hydrate through national R&D programs.^[22]

In September 2009, the Chinese Geological Department announced that Qinghai Tibet Plateau A new environmental protection energy called combustible ice (also called natural gas hydrate) has been found, which is expected to be put into use in about ten years. Preliminary estimate, Prospective Resources At least 35 billion tons boe 。^[23]

In 2009, five of the eight drilled wells completed in the Scientific Drilling Project of Natural Gas Hydrate in Qilian Mountain Frozen Soil Area organized and implemented by the China Geological Survey obtained physical samples of natural gas hydrate. This is the first time that physical samples of natural gas hydrates have been drilled in permafrost regions in China, and also the first time in the world Low latitude Physical samples of natural gas hydrates were found in alpine permafrost regions.^[19]

In 2011, the State Council approved the establishment of a new national special project for natural gas hydrates. China Geological Survey Guangzhou Marine Geological Survey Through further exploration, favorable natural gas hydrates have been found in the eastern sea area of the Pearl River Mouth Basin Target area 。 From May to September 2013, 3 Leg 102 days in total Drilling sampling Work.^[19]

From June to September 2013, Chinese marine geological scientists and technicians first drilled high-purity natural gas hydrate (commonly known as "combustible ice") samples in the eastern waters of the Pearl River Mouth Basin along the coast of Guangdong, and obtained considerable Controlled reserves 。 The gas hydrate samples discovered this time are characterized by shallow burial, large thickness, multiple types and high purity. The controlled reserves are 100 billion cubic meters to 150 billion cubic meters, which is equivalent to super large Conventional natural gas Scale.^[24]

The picture shows the natural gas collected by Japan from the "combustible ice" on the seabed

Japan announced its success on March 12, 2013 from Aichi Methane has been extracted from the nearby deep-sea combustible ice, making it the first country in the world to master the technology of extracting seabed combustible ice. Japan hopes to develop mature technology and realize large-scale commercial production in 2018.^[25]

Oil and gas under the Ministry of Economy and Industry of Japan Metallic minerals Resource institutions implementation. The agency used the deep earth exploration ship "Earth", from Aichi County Ottoman Peninsula About 1000 meters of the sea bottom nearby is dug into 330 meters. After reaching the combustible ice layer, the pressure of the combustible ice is reduced by pumping out the water in the combustible ice, so that water and methane are separated, and then methane is extracted. The agency will continue to conduct excavation tests in the sea area for about two weeks to further improve the technology.^[25]

Exploration of Natural Gas Hydrate Resources in Qilian Mountains and Adjacent Areas, August 2013 Project team Once again on Qinghai Province Tianjun County Muli Town DK-9 Scientific drilling Test well The physical samples of natural gas hydrates were successfully drilled, with a single layer thickness of more than 20 meters.^[19]

In 2014, the eighth session hosted by the China Geological Survey and the Chinese Academy of Sciences International Gas Hydrate Conference At the opening ceremony in Beijing on the 29th, reporters learned from the conference that China plans to implement the drilling project of natural gas hydrates in China's sea areas in 2015, which will strongly promote the exploration and development of "combustible ice" in China and trigger China's energy development The "revolution" of utilization.^[26]

On the morning of June 25, 2016, the Guangzhou Marine Geological Survey reported that, following the discovery of a large area of combustible ice in the South China Sea, China found an unprecedented active cold spring in the western sea area of the northern continental slope of the South China Sea for the first time“ Hippocampus Cold Spring ”The distribution area is about 618 square kilometers. Its discovery is a major breakthrough in the exploration of natural gas hydrate cases in China.^[27]

In January 2017, after more than 10 years of technical research, Jilin University The scientific research team has developed Key technologies for cold drilling and thermal recovery of continental gas hydrate , filling the gap in this field in China and reaching the international advanced level in general.^[28]

Compared with internationally used“ Passive The drilling principle of "pressure maintaining and thermal insulation sampling" is different. The new technology first proposed the principle of "active cooling and freezing sampling" and invented Drilling mud Enhanced refrigeration method, hydrate hole bottom Quick freezing Sampling method And high temperature pulse Thermal excitation Mining technology, mainly Technical indicators It is superior to similar foreign technologies.^[28]

In May 2017, China's first offshore gas hydrate (combustible ice) Trial production success. On May 18, the Central Committee of the Communist Party of China and the State Council extended warm congratulations to all the research and testing units and personnel participating in this task.^[2-3]

The first trial mining of combustible ice in China

In 2017, China was in the north of the South China Sea Divine Fox The trial production of combustible ice in the sea area was successful. This trial production Operation area be located Zhuhai City The Shenhu sea area 320 kilometers southeast.

On March 28, 2017, the first test production well was drilled.

At 14:52 p.m. on May 10, 2017, the ignition was successful, and natural gas was extracted from the natural gas hydrate minerals 203-277 meters below the seabed with a water depth of 1266 meters.

By 10:00 a.m. on May 18, 2017, gas production has been continuous for nearly 8 days, with an average of Nissan More than 16000 cubic meters, exceeding the target of "10000 cubic meters per day, lasting for one week". Jiang Daming, the minister of the Ministry of Land and Resources, announced the success of the first pilot production of natural gas hydrates in China's sea areas at the scene, which was sent by the CPC Central Committee and the State Council a congratulatory message 。 China has become the first country in the world to successfully pilot exploit natural gas hydrates in sea areas.^[29]^[39]

By May 26, 2017, the test production well had produced gas for 16 consecutive days, with an average daily output of more than 10000 cubic meters.

From May 27, 2017, according to construction plan Overall arrangement of temperature and pressure changes Reservoir , bottom hole pit shaft 、 Gas flow And other scientific testing and research work.

At 14:52 on June 10, 2017, the total gas production reached 210000 cubic meters, with an average daily output of 7000 cubic meters test data 2.64 million groups. The gas production process is stable and the bottom hole is in good condition, laying a solid foundation for the next work.^[30]

Physical and chemical properties

Announce

edit

The combustion of natural gas hydrate hardly produces any residue, Pollution ratio Coal, oil and natural gas are much smaller. One cubic meter of combustible ice can be converted into 164 cubic meters of natural gas and 0.8 cubic meters of water. A large amount of methane gas can be released when the solid "natural gas hydrate" is heated and depressurized during mining.^[31]

Solid natural gas hydrates are often distributed in Seafloor sediment Or cold Permafrost Medium. Submarine gas hydrates rely on the pressure of huge thick water layers to maintain their solid state, and their distribution can be from the seabed to within 1000 meters below the seabed, and then to the depths due to ground temperature It is difficult to exist because its solid state is destroyed.^[32]

from physical property It can be seen that the density of natural gas hydrate is close to and slightly lower than the density of ice, shear coefficient, electrolytic constant and Thermal conductivity Are lower than ice. Acoustic wave of natural gas hydrate propagation velocity It is obviously higher than that of gas bearing sediment and saturated water sediment, Neutron porosity Below saturated water sediment, these differences are Geophysical prospecting method Identify nature gas The theoretical basis of hydrate. In addition, the natural gas hydrate capillary pore pressure Higher.^[32]

There are three ways to form combustible ice Basic conditions : Temperature, pressure and raw materials.^[33]

First of all, combustible ice is generated at 0-10 ℃, and will decompose when it exceeds 20 ℃. The sea bottom temperature is generally maintained at 2-4 ℃;^[33]

Secondly, at 0 ℃, only 30 pieces of combustible ice are needed pressure It can be generated. With the depth of the ocean, 30 atmospheres is easy to guarantee, and the higher the pressure, the less easy the hydrate will be to decompose.^[33]

Finally, the submarine organic compound Precipitation, in which rich carbon passes through Biotransformation , which can generate sufficient air source. The seabed stratum is porous medium Under the conditions of temperature, pressure and gas source, combustible ice crystal Will be generated between the voids of the medium.^[33]

Composition

Announce

edit

Natural gas hydrate

natural gas hydrate It is a white solid material with strong combustion power, mainly composed of water Molecules and Hydrocarbons Gas molecules (mainly methane ）Composition, which is determined under certain conditions (appropriate temperature, pressure gas saturation , water salinity, pH value, etc.) volatility White solid crystalline substance formed during the interaction between liquid and water. Once the temperature rises or the pressure decreases, methane will escape and the solid hydrate will tend to collapse.^[32]

Under high pressure, the structure of methane gas water inclusion complex is still stable at 18 ℃. The general composition of methane gas water compound is 1 mole However, this ratio depends on how many methane molecules are "embedded" in various coating structures of the crystal lattice. The observed density is about 0.9g/cm3. One liter of methane gas water inclusion complex solid contains an average of 168 liters of methane gas.^[11]

Methane forms a structural type hydration Matter, per unit Unit cell There are two Dodecahedron (20 endpoints therefore have 20 water molecules) and six tetrahedrons (24 water molecules) water tap Structure. The hydration value 20 can be obtained from MASNMR. Methane gas water inclusion complex spectrum at 275 Kelvin And 31 Megapascal Skadder records show that each cage shape reflects the peak value, and there are individual peaks for gaseous methane.^[11]

Mining method

Announce

edit

Traditional mining

(1) Thermal stimulation mining method is to directly heat the natural gas hydrate layer to make the temperature of the natural gas hydrate layer exceed its Equilibrium temperature So as to promote the decomposition of natural gas hydrate into water and natural gas. This method has experienced direct injection into the gas hydrate layer Thermal fluid Heating, fire drive heating, downhole Electromagnetic heating as well as microwave heating And so on. The thermal excitation mining method can realize cyclic heat injection, and Action mode Faster. The continuous improvement of heating mode has promoted the development of thermal excitation mining method. However, this method has not yet solved the problem of low heat utilization efficiency, and can only Local heating Therefore, this method needs to be further improved.^[34]

Natural gas hydrate

(2) Decompression mining method Decompression mining method is a mining method that reduces the pressure to promote the decomposition of natural gas hydrate. There are two main ways to reduce pressure: ① drilling with low-density mud to achieve the purpose of reducing pressure; ② When there is a gas hydrate layer Free gas Or other fluids, reduce the pressure of the gas hydrate layer by pumping out the free gas or other fluids below the gas hydrate layer. Decompression mining method does not need continuous excitation and has low cost. It is suitable for large area mining, especially for floating downward Gas reservoir The exploitation of natural gas hydrate is the most promising technology among the traditional methods of natural gas hydrate exploitation. However, it has special requirements for the nature of natural gas hydrate production. Only when the natural gas hydrate production is located in Warm pressure When the balance boundary is near, the decompression mining method has economic feasibility 。^[34]

Natural gas hydrate

(3) Chemical reagent injection mining method Chemical reagent injection mining method injects some chemical reagents, such as brine methanol 、 ethanol 、 glycol 、 Glycerol Such as destroying the production of natural gas hydrate phase equilibrium Conditions to promote the decomposition of natural gas hydrate. Although this method can reduce the initial energy input, its defects are obvious. The chemical reagent required is expensive, and its effect on the natural gas hydrate layer is slow environmental problems Therefore, there is relatively little research on this method.^[34]

New mining

Natural gas hydrate

(1) CO two Replacement mining method. This method was first proposed by Japanese researchers, and the method is still based on Gas Hydrate Stability Zone Pressure conditions. Under certain temperature conditions, the natural gas hydrate needs Pressure ratio CO two Hydrate is higher. Therefore, within a specific pressure range, natural gas hydrate will decompose, and CO two Hydrate is easy to form and keep stable. If CO is injected into the gas hydrate production at this time two Gas, CO two Gas may generate CO with water decomposed from natural gas hydrate two Hydrate. The heat released by this action can make the natural gas hydrate decomposition reaction To continue.^[34]

Carbon dioxide replacement method

(2) Solid mining method. The solid mining method was initially used to directly collect solid gas hydrates from the seabed and drag them to shallow water areas controllability Disassemble. This method has evolved into Mixed mining Method or ore slurry mining method. The specific steps of this method are to first promote the decomposition of natural gas hydrate into gas and liquid in situ Mixed phase , collect mixed mud mixed with gas, liquid and solid hydrates, and then import the mixed mud into the sea Workboat or Production platform Conduct treatment to promote the complete decomposition of natural gas hydrate to obtain natural gas.^[34]

Mining example

Announce

edit

Exploitation of Natural Gas Hydrate in Mesoyaha Gas Field

Natural gas hydrate

Mesoyaha gas field Discovered in the late 1960s, it is the first and only gas field that has conducted commercial exploitation of natural gas hydrate production so far. The gas field is located in the front Soviet Union Western Siberia Northwest, perennial gas field area layer of frozen earth With a thickness of more than 500 m, it has favorable conditions for the occurrence of natural gas hydrates. Mesoyaha gas field is a conventional gas field, and the natural gas in the gas field passes through Caprock Migration occurs in favorable environment condition The gas hydrate layer is formed above the gas field. The natural gas hydrate production of the gas field is firstly unintentionally exploited through decompression. Through the exploitation of natural gas hydrates Conventional natural gas The pressure of the gas hydrate layer is reduced, and the gas hydrate is decomposed. Later, in order to promote the further decomposition of natural gas hydrates and maintain gas production, natural gas hydrate minerals were injected methanol and calcium chloride etc. Chemical inhibitor 。^[34]

Mackenzie Delta Regional gas hydrate test acquisition

McKenzie Delta is located in the northwest of Canada, in the cold environment of the Arctic, and has favorable conditions for the generation and preservation of natural gas hydrates. The study of gas hydrates in this area has a long history. As early as 1971~1972, when drilling the conventional exploration well MallikL-38 in this area Permafrost Evidence of the existence of natural gas hydrate was found in the lower 800~1100 m well section; Well Mallik 2L-38 was drilled specially for gas hydrate exploration in 1998. Natural gas hydrates were found and produced in the 897-952m section of the well core 。 In 2002, a pilot production study of natural gas hydrate was carried out in the McKenzie Delta. This item is created by Geological Survey of Canada , Nippon Petroleum Corporate league Germany Earth science Research Institute USGS 、 US Department of Energy India Gas Supply Company Indian Petroleum The joint investment with 9 institutions in 5 countries, including the natural gas company, is the first ever natural gas hydrate production test in the region, and the first international cooperative pilot production research on natural gas hydrates on such a large scale in the world.^[34]

Natural gas hydrate exploitation test in the northern slope area of Alaska

The Prudhoe Bay Kupalek River area in northern Alaska, the United States, is located in the northern slope of Alaska. In 1972, ARKO and Exxon Oil Company drilled conventional wells in the Prudhoe Bay oil field Oil and gas wells Natural gas hydrate cores were recovered in the 664~667m interval. Later, a lot of gas hydrate research was carried out in the northern slope area of Alaska. On this basis, a remarkable research project on gas hydrate pilot production was carried out in this area in 2003. The project is jointly sponsored by Anadarko Oil Company, Noble Company, Maurer Technology Company and the US Department of Energy Development plan It is jointly initiated by the Division, with the goal of drilling natural gas hydrate research and production test wells -—— Hot ice Well 1. This is the first exploration well drilled specifically for the research and pilot production of natural gas hydrates in the northern slope area of Alaska.^[34]

Gas hydrate exploitation environmental problems

Natural gas hydrate

The exploitation of natural gas hydrates will change the temperature and pressure conditions on which natural gas hydrates exist and cause the decomposition of natural gas hydrates. If the temperature and pressure conditions cannot be effectively controlled during the exploitation of natural gas hydrate production, a series of environmental problems may occur, such as greenhouse effect The intensification of Marine ecology And submarine collapse events.^[34]

(1) Methane as strong greenhouse gases , it does Atmospheric radiation balance Its contribution is second only to that of carbon dioxide. On the one hand, the amount of methane contained in global natural gas hydrates is about Atmosphere 3000 times the amount of methane in; On the other hand, the amount of methane generated by the decomposition of natural gas hydrate entering the atmosphere will accelerate significantly even if it is only 0.5% of the total atmospheric methane global warming The process of. Therefore, if the methane gas cannot be well controlled in the process of natural gas hydrate exploitation, it will inevitably intensify Global greenhouse effect 。 In addition to the greenhouse effect, marine environment The exploitation of natural gas hydrates in China will bring more problems. ① Methane entering seawater will affect marine ecology. When methane enters the sea water microorganism oxidation , affecting seawater chemical property 。 If a large amount of methane gas is discharged into seawater, its oxidation will consume a large amount of oxygen in seawater, making the ocean form Anoxic environment , so as to Marine microorganism Of Growth and development Bring harm. ② If the amount of methane entering the sea water is too large, it may also cause sea water vaporization and tsunami, or even sea water turbulence and negative air pressure Entrainment , seriously endangering sea operations and even sea aviation operations.^[34]

(2) In the process of exploitation, the decomposition of natural gas hydrate will also produce a large amount of water, release the pore space of rock stratum, make the consolidation of the stratum in the natural gas hydrate storage area worse, and cause geological disasters. Marine gas hydrate The decomposition of may lead to submarine collapse. It is found that the degradation of continental slope stability due to the decomposition of submarine gas hydrate is an important reason for submarine collapse events. If a large amount of natural gas hydrate is decomposed during drilling, it may also cause drilling deformation and increase Offshore drilling platform Risk.^[34]

(3) How to treat the water produced by the decomposition of natural gas hydrate in the process of natural gas hydrate exploitation is also a problem that should be paid attention to.^[34]

China's first trial production of combustible ice in sea area

On July 9, 2017, the Ministry of Land and Resources China Geological Survey The South China Sea Gas Hydrate Pilot Production Project organized and implemented has fully achieved the expected goals, and the first well's pilot production gas production and Field test The research work was successfully completed and formally implemented Shut in Job. Since May 10 Gas testing Since the ignition, the pilot production has been carried out for 60 consecutive days, and the cumulative gas production has exceeded 300000 cubic meters, achieving the longest continuous gas production time, the largest total gas production, and stable gas flow environmental safety And many other major breakthrough achievements, creating a world record 。^[35]

This trial mining Operation area be located Zhuhai Shenhu sea area 320 kilometers southeast of the city. On March 28, the first trial production well was drilled. At 14:52 p.m. on May 10, the ignition was successful, and natural gas was extracted from the natural gas hydrate minerals 203-277m below the seabed with a water depth of 1266m. As of 14:52 on July 9, China's natural gas hydrate trial production has been continuously tested and ignited for two months, with the cumulative gas production exceeding 300000 cubic meters, on average Nissan More than 5000 cubic meters, the maximum output is 35000 cubic meters/day, and the methane content is up to 99.5%. Access to science experimental data 6.47 million groups, the follow-up scientific research A large number of accurate and reliable data have been accumulated.^[35]

The success of this trial production is the first time in China and the first time in the world to successfully realize the safe and controllable exploitation of argillaceous silty natural gas hydrate, which accounts for more than 90% of the world's resources and is the most difficult to develop. After nearly 20 years of unremitting efforts, China has made independent innovation in the theory, technology, engineering and equipment of natural gas hydrate exploration and development, and achieved a historic breakthrough.^[35]

The second round of trial production of combustible ice in China sea area

On February 17, 2020, the second round of pilot production was successfully ignited, and the scheduled target task will be completed until March 18. The total gas production of this round of trial production in one month is 861400 m3, and the average daily gas production is 28700 m3, 2.8 times the total gas production of the first round of 60 days. Trial production has conquered the deep-sea shallow Soft stratum Horizontal well The core key technologies of drilling and production have greatly improved the gas production scale, laying a solid technical foundation for productive pilot production and commercial exploitation. China has also become the first country in the world to use horizontal well drilling and production technology to test the production of marine gas hydrates.^[5]

On March 26, 2020, the reporter learned from the report video conference held by the Ministry of Natural Resources that the second round of trial production of natural gas hydrates in China's sea areas had been successful and overfulfilled.^[6]

Main hazards

Announce

edit

The development of "combustible ice" is complex and dangerous. If the temperature and pressure conditions cannot be effectively controlled during the exploitation of natural gas hydrates, a series of environmental problems may occur, such as greenhouse effect The intensification of Marine ecology And submarine collapse events.^[36]

Because natural gas hydrates are formed under low temperature and high pressure, once they leave the ground or ocean floor, they will be rapidly gasified. The natural gas hydrate trapped on the ocean floor for a long time is like a Pandora's box that has been opened, releasing a large amount of methane gas. Its intensity may lead to seabed Collapse or other disasters are very dangerous. Therefore, American Geological Survey This warning was issued: "The development of combustible ice must be carried out with caution to avoid problems after brewing."^[36]

While natural gas hydrate brings new energy prospects to mankind, it also poses severe challenges to the human living environment. The greenhouse effect of methane in natural gas hydrate is CO two And the total amount of methane in the global undersea natural gas hydrate is about Earth's atmosphere The total amount of methane in the sea floor is 3000 times of that in the sea floor. If the methane in the natural gas hydrate escapes into the atmosphere accidentally, it will have unimaginable consequences. Moreover, the hydrate consolidated in the seabed sediment will change the physical property , greatly reducing the engineering mechanics Characteristics, soften the sea bottom, and large-scale Submarine landslide , destruction Submarine engineering Facilities such as submarine power transmission or Communication cable And offshore oil drilling platforms.^[36]

As we all know, there are some sea areas with high incidence of air and sea disasters in the world, which are known as "Devil Sea Area", such as Bermuda Triangle area. Despite the objections, in the 1980s, the United States Canada , front Soviet Union According to the results of the joint investigation by scientists, the killer of the disasters in these waters is the submarine natural gas hydrate. Natural gas hydrates that exist in the seabed in solid form will decompose and gasify once the temperature rises or the pressure decreases, and overflow into the air from the sea surface. A large number of bubbles must make Sea water density If the buoyancy decreases, the passing ships will suddenly sink into the sea bottom due to insufficient buoyancy. The aircraft passing through this sea area were also burned because of the burning tail gas that ignited the natural gas emerging from the ocean.^[36]

Natural combustible ice is solid, not like Petroleum exploitation It flows out automatically. If it is moved out from the seabed one by one, methane will evaporate during the transportation from the seabed to the sea surface, and it will also cause great harm to the atmosphere.^[36]

the way to distinguish

Announce

edit

Natural gas hydrates can be sampled from sediment Drilling sampling And deep diving survey, etc Reflector (BSR), speed and amplitude of the earthquake wave Abnormal structure Geochemistry Abnormal, many wave velocity Bathymetry and submarine TV camera indirect all-recognition 。 Here are some indirect signs.^[37]

Seismic marker

The main seismic indicators for the existence of marine gas hydrates include the pseudo submarine reflector (BSR) amplitude Deformation (blank reflection), velocity inversion, velocity amplitude anomaly structure (VAMP). Large scale methane hydrate accumulation can be achieved through high resistivity (>100 Ω/m), low acoustic velocity bulk density Equal sign Number for direct interpretation.^[37]

BSR is a reflection interface on the seismic profile that is parallel or basically parallel to the seabed and can cut through all layers or faults, Gas Hydrate Stability Zone It's still common trap There is a large amount of free methane gas, resulting in Seismic reflection BSR is generated on the profile. It has been confirmed that BSR represents the base of the gas hydrate stability zone. Above it is a solid hydrate interval with high acoustic velocity, and below it is Free gas Or only pore water filled sediment , the sound wave speed is low, so seismic profile Formed strongly on Negative impedance Reflective interface. Therefore, BSR is due to the low permeability hydrate layer and the large amount of free gas and Saturated water Between sediments acoustic impedance (or sound wave propagation speed). Because the bottom interface of the hydrate layer is mainly affected by the Geothermal gradient It is usually located at a certain depth below the seafloor, so the BSR is basically parallel to the seafloor, which is called "pseudo seafloor reflector". BSR is used to identify the existence of natural gas hydrates and prepare hydrates Distribution map In addition, it is also used to judge the top and bottom boundaries and occurrence of the gas hydrate layer, and calculate the depth, thickness and volume of the hydrate layer.^[37]

However, not all hydrates have BSR. It is difficult to identify BSR even if there are gas hydrates in the flat seabed. BSR often occurs in the slope or sea area with undulating terrain. In addition, not all BSRs correspond to natural gas hydrates. In rare cases, other factors may also lead to BSR. It should also be noted that although most hydrate layers are located above BSR, not all hydrate layers are located above BSR, which has been Deep-sea drilling prove. Therefore, BSR cannot Be treated as The only sign of natural gas hydrate should be combined with other methods Comprehensive judgment 。 Analysis and study of earthquake Velocity structure Become the forefront of the discipline. Hydrate layer is High speed layer , the lower gas saturated or water saturated layer is Low velocity layer 。 On the velocity curve, the velocity at the BSR interface will suddenly decrease, showing an obvious velocity anomaly structure. In addition, the analysis of amplitude structure can also identify gas hydrates. In contrast, the hydrate layer is a rigid layer, and its lower saturated gas or saturated water layer is a plastic layer. On the amplitude curve, the amplitude at the BSR interface will suddenly decrease, showing an obvious amplitude anomaly structure. These methods are particularly important for the sea area with flat seabed.^[37]

Geochemical marker

The methane concentration in shallow sediments and bottom seawater is abnormally high, and the pore water Cl in shallow sediments - Content (or Mineralization degree ）And δ 180 are abnormally high, and heavy oxygen rich Siderite Can be used as natural gas hydrate Geochemical marker 。^[37]

Submarine landform signs

In the marine environment, hydrocarbon gas seepage in the hydrate enrichment area can form on the seafloor Special environment And special micro topographic features 。 The geomorphic signs of natural gas hydrate mainly include leakage transom Methane Air seeding 、 Mud volcano , pitted terrain, carbonate crust, chemical synthesis Biota Etc. In Germany Kiel University Geomar Institute, through seabed observation Oregon west continental margin Cascadia hydrate Plateau I found a lot Discontinuous distribution , 5cm in size two The left and right hydrate vent windows, where methane seeps out one by one, Gassing The speed is 5 liters per minute. There are microorganisms, clams and carbonate shells around the seepage flow.^[37]

economic impact

Announce

edit

The global reserves of natural gas hydrates are twice of the existing reserves of natural gas and oil, with broad development prospects. The United States, Japan and other countries have found and exploited natural gas hydrates in their respective waters. It is estimated that China South China Sea Natural gas hydrate Resources 70 billion tons boe About half of China's onshore oil and natural gas resources.^[11]

In an era when mankind is increasingly trapped in energy, the successful trial production of combustible ice is naturally attracting the attention of all. This is the first time for China to successfully test mining in the world, achieving six Technical system Twenty items key technology Independent innovation. However, this is only a critical step in the long march. There is still a long way to go to realize industrialization and commercial exploitation in the future.^[3]

On June 9, 2017, Economic Daily · China Economic Network The reporter took a helicopter from Zhuhai Take off, fly over the vast South China Sea for an hour and a half, and land steadily on a giant standing on the sea -“ Blue Whale One ” drilling platform 。^[3]

This is a big building with 37 floors high. It is the world's largest self built building in China Operating water depth , the deepest drilling depth Semi submersible drilling platform 。 Recently, it is attracting the attention of the whole world. China has successfully realized the trial exploitation of combustible ice here.^[3]

Combustible ice, in short, refers to the ice that can be burned, and its scientific name is "natural gas" water Compound "is composed of methane Dominant Organic molecule It is wrapped by water molecules calorific value It is about 1/6 of petroleum, and only generates carbon dioxide And water, which is said to be available for human use for thousands of years.^[3]

Therefore, on May 18, 2017, China announced that Trial production After the success of combustible ice, becoming the first country in the world to obtain continuous and stable air flow in the trial production of combustible ice in sea areas, praise and doubt came. Some people say that it is not so easy to mine combustible ice, and whether the environmental protection is up to standard is a question mark. Others believe that the successful mining will soon be industrialized, capital market The shares with a little edge on the market soared.^[3]

The reporter came here to find out: can we mine combustible ice safely and environmentally? Can we lead the world technically? There is still a long way to go for industrialization.^[3]

Looking into the sea from the "Blue Whale 1" drilling platform, the blue sea is sparkling, and sometimes huge fish jump out.^[3]

Combustible ice is known as "the energy of the future". 164m3 of solid combustible ice can be released after decomposition of 1m3 Standard status % of gaseous natural gas is only equivalent to 1/6 cubic meter of liquid or solid natural gas, so the calorific value is only equivalent to about 1/6 of oil.^[3]

However, the difficulty of combustible ice mining is also recognized by the industry. Combustible ice is stored at low temperature and high pressure. If the temperature rises, hydrate Methane in may overflow; Or if the ice melts and the pressure rises, it may cause Submarine landslide And other geological disasters.^[3]

China Geological Survey Yan Guangsheng, the chief engineer, said that for these two difficulties, they had been fully considered and repeatedly demonstrated before the trial production, and deployed several Monitoring points Real time monitoring, surrounding gas and Submarine topography Nothing has changed.^[3]

It is understood that before the trial production, the China Geological Survey carried out more than 10 voyage number Environment Baseline survey , obtained marine geology marine organism 、 Seawater chemistry etc. Background Data, as well as mechanical parameters of seabed strata. In the process of trial production Environmental management system , Process Safety risk management And other standards, adopted strict Environmental protection measures 。^[3]

Lu Jing'an, deputy director of the pilot production site headquarters office, said that during the pilot production process Quaternity The monitoring system has implemented real-time monitoring of methane, carbon dioxide, etc. and seabed subsidence. Compared with the background data, there is no abnormal change in methane, and the seabed topography unchanged There is no environmental pollution and no geological disaster. At the same time, China's first 4500m operational underwater robot“ Hippocampus number ”When diving into the seabed, no changes in the seabed topography and methane leakage were found.^[3]

The "Blue Whale 1" drilling platform is 117 meters long and nearly 100 meters wide. The deck is very open. Xie Wenwei, deputy director of the pilot production site headquarters office, told reporters that this drilling platform is equipped with two Derrick The downhole environment monitor can monitor the data in real time and will be taken out together after the completion of trial production.^[3]

Lu Jing'an said that after the completion of the pilot production, all-round three-dimensional environmental monitoring will continue to be carried out to provide a scientific basis for the development of environmental protection plans for the exploitation of natural gas hydrates.^[3]

Outside the "Blue Whale 1" drilling platform, a torch was burning brightly. For safety's sake, huge Water curtain Separate the torch from the platform. This torch burns the natural gas extracted from the seabed more than 200 meters below the water depth of 1266 meters.^[3]

Chief Engineer of Guangzhou Ocean Bureau Yang Shengxiong Said that this was the first time that argillaceous powder was realized in the world Sand mold Ignitable Safe and controllable exploitation. This type of combustible ice accounts for more than 90% of the world's resources and is the most difficult to develop.^[3]

It is reported that in this trial production, China has achieved independent innovation in 20 key technologies of six major technology systems. First, Sand control technology 3 items. Including "formation fluid extraction", non diagenetic ultra-fine Reservoir Sand control And natural gas hydrate secondary generation prevention technology. Second, Reservoir reconstruction 3 technologies. Including rapid and fine reservoir evaluation and productivity dynamic evaluation And other technologies. Third, there are three drilling and completion technologies. Including narrow density window balanced drilling, wellhead stability enhancement and downhole testing system integration Technology. Fourth, four exploration technologies. Including 4500m ROV Detection, pressure retaining sampling, marine high-resolution seismic detection and marine controllable source electromagnetic detection technology.^[3]

Many big countries compete in the field of combustible ice. Among them, the United States announced on May 12 that Gulf of Mexico Carry out research on combustible ice mining. In 2013, Japan was in the South China Sea Trough Offshore trial production was carried out, but due to Sanding And other technical problems. In April 2017, Japan conducted the second trial production in the same sea area, and on May 15, gas production was again suspended due to sand production.^[3]

Relevant experts said that combustible ice is the strategic commanding height of global energy development in the future. China took the lead in the world in the successful trial production, and achieved the goal of leading rather than following in this field.^[3]

Flammable ice is mainly distributed in two types of regions in the world: the first is the seabed with a water depth of 300 meters to 3000 meters; Second, on land Permafrost region , especially in the arctic frozen soil area. It is predicted that the global natural gas hydrate resources are equivalent to 21 trillion tons of oil equivalent.^[3]

Office director of pilot production site headquarters Qiu Haijun It said that China's offshore natural gas hydrate resources are about 80 billion tons of oil equivalent. Through the general survey of key areas, 11 advantages have been identified Prospective area , 19 Metallogenic area Band. Through drilling verification, two hundred billion cubic meters of mineral deposits have been delineated.^[3]

Relevant experts said that China's first successful trial mining in the world is only a critical step in the long march. There is still a long way to go to realize industrialization and commercial mining in the future.^[3]

Qiu Haijun said that in the future, he will strive for Divine Fox Maximize the trial production results in the sea area. At the same time, continue to increase natural gas hydrate Resource survey Strength and focus Target area And provide 2 to 4 large-scale resource bases to lay a resource foundation for promoting industrialization. In addition, pilot production of different types of natural gas hydrates will be carried out to strengthen environmental protection Put it in a prominent position.^[3]

He said that based on China's combustible ice Research and Technical reserve It is estimated that China is expected to realize commercial exploitation of combustible ice around 2030.^[3]

"Combustible ice", which experts call "natural gas hydrate" or "methane hydrate", is a solid substance produced by mixing water and natural gas under high pressure and low temperature conditions, and its appearance is similar to ice or Solid alcohol , ignition can burn. "Combustible ice" is rich in reserves and widely distributed. Scientists predict that it is the best for conventional oil and natural gas alternative energy sources 。^[38]

China's seabed and land area are rich in Shale gas And combustible ice resources can fully meet China's energy demand and improve Energy self-sufficiency rate , Guarantee Energy security Supply, so as to achieve sustainable and healthy economic and social development.^[38]

China is one of the countries with the largest reserves of "combustible ice" resources. In 2004, the "Sun" research ship of the Sino German joint scientific research team found the world's largest carbonate Crust, area up to 430 square kilometre 。 It fully confirmed that a large amount of methane was released from the methane hydrate on the sea floor. Experts predict that the Xisha Trough in the South China Sea, the southwestern continental slope of Taiwan Nansha Trough 、 Okinawa Trough There may be a large amount of methane hydrate resources on the seabed, which can meet China's demand for hundreds of years in the future. In the summer of 2009 Qilian Mountains In the south, a cluster of flames burns, which is exciting news: China has become the first country in the world Low latitude Countries where "combustible ice" is found in permafrost regions. According to experts' estimation, the resource reserve of "combustible ice" in China is 80.344 billion tons of oil equivalent, which is close to China's conventional oil resources Conventional natural gas Double the amount of resources. according to Ministry of Land and Resources Experts estimate that China's land area is "combustible ice" Prospective Resources At least 35 billion tons of oil equivalent can be used by China for nearly 90 years.^[38]

Novice on the road

Growth task Getting Started with Editing Edit Rule Edit by myself

I have questions

Content query Online Service Official post bar Feedback

Complaints and suggestions

Report bad information Failed to appeal through entries Complaint of infringement information Blocking query and unblocking

Jinggong Network Anbei No. 1100000200001