It appears we are having issues again, but I will try to post this anyway.
I started wondering what the relations were between Iran and China so I did some digging.
China–Iran relations
Diplomatic links between China and Iran have been maintained into the 20th and 21st centuries with the formation of both the People's Republic of China and the Islamic Republic of Iran, in 1949 and 1979 respectively. The economic, cultural, and political ties are discussed below.
In fact after the JCPOA was signed in July 2015, China and Iran agreed to expand trade relations to $600 billion in ten years from January 2016, on the occasion when Xi Jinping paid Hassan Rouhani a state visit.[13] This constitutes an increase of over 1,000%.[14] The agreement was concordant with One Belt, One Road framework. A total of 17 agreements were signed, including one which relates to the Iran nuclear programme. The Chinese will help connect Tehran with Mashhad via their TGV technology.[15]
One of the main pillars of the relationship is oil and gas. China switched to petroleum primarily to move its energy supply from coal. There was a rapid increase in oil importation from 1974 into the 1990s.[16] In 2011, approximately 10% of China's oil imports were from Iran.[17] Approximately 80% of China's total imports from Iran are oil and the rest is mineral and chemical products. Because of this reliance on Iranian oil and gas, China is now investing in the modernization of Iran's oil and gas sector to secure access to the resource.[18] The China National Petroleum Corporation (CNPC) was granted an $85 million contract to drill 19 wells in the natural gas fields in Southern Iran and signed another similar $13 million contract.[16] Then again in 2004, an agreement was reached where China would import 270 million tons of natural gas over 30 years from South Par fields which is the richest natural gas fields in the world for $70 billion. Another Chinese company, Sinopec Group, gets half-share in Yardarvaran oil fields worth about 100 billion for the purpose of exploration.[19] Later in 2007, CNPC signed a $3.6 billion deal to develop offshore gas fields in Iran and then signed another $2 billion contract to develop the northern Iranian oil field near Ahvaz.[18] Not only is China helping to develop the oil and gas sector, but China supports Iran's ambitions to bring Caspian Sea oil and gas to Southern Iranian ports through pipelines so the resources can be exported to Europe and Asia.[16] Iran relies upon its oil sales to China to ensure its fiscal well-being.[18] China also sells gasoline to Iran despite international pressures that have halted Iran's ability to get gasoline from other suppliers.[20]
China considers Iran a permanent partner for its exports and a source of its growing energy demand. In March 2004, Zhuhai Zhenrong Corporation, a Chinese state-run company, signed a 25-year contract to import 110 million metric tons of Liquefied Natural Gas (LNG) from Iran. This was followed by another contract between Sinopec and Iran LNG, signed in October of the same year. The deal, worth $100 billion, adds an extra 250 million tons of LNG to China's energy supply, to be extracted from Iran's Yadavaran field over a 25-year period. In January 2009, Iran and China signed a $1.76bn contract for the initial development of the North Azadegan oil field in western Iran. In March the two countries struck a three-year $3.39 billion deal to produce liquefied natural gas in Iran's mammoth South Pars natural gas field. Because of its limited refining capacity, Iran imports one-third of its refined products such as petrol from China.[21][22]
In 2011, the group Green Experts of Iran reported that Beijing and Tehran had signed an extensive deal that would give China exclusive rights to several Iranian oil and natural gas fields through 2024. Under the terms of the deal, Iran will give Chinese oil companies exclusive rights to three large regions of Iranian land as well as the rights to build all necessary infrastructure for these regions, all of which sit atop of large oil and natural gas fields. In return, China promises to treat any foreign attack against these regions as attacks against its own sovereign territory, and will defend them as such. China will have no need for prior permission from the Iranian government to maintain and increase its military presence in Iran, and will control the movement of Iranians in and out of these territories.[23] The Green Experts of Iran speculate that this agreement was the concrete basis for Major General Zhang Zhaozhong's statement that "China will not hesitate to protect Iran even with a third World War." [24]
China has been Iran's crude oil sink since the JCPOA was signed.[14][25] In 2017, 64% of an export total $16.9 billion with China was labelled "crude oil".[26]
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https://en.wikipedia.org/wiki/China–Iran_relations
There is more but I will let you read that on the link.