China and Kazakhstan have encouraged a rapid expansion of trade and partnership in the area of economic development, particularly for the use of Kazakhstan`s oil, natural gas, minerals and other important energy resources.   Due to the rapid growth in domestic energy demand, China has attempted to play a leading role in the culture and development of the energy industry in Kazakhstan.  Along with the development of four small oil fields, China National Petroleum Corporation in 2005 purchased Petrokazakhstan, the largest independent oil company in the Soviet Union, for US$4.18 billion and still has US$700 million for an oil pipeline that will bring oil to the Chinese border. Petrokazakhstan was the largest foreign purchase ever made by a Chinese company.  Until 2016, Chinese companies (for example. B China National Petroleum Corporation, Sinopec and others) have invested more than $20 billion in Kazakhstan`s oil sector.  The southernmost part of the border (i.e. about the southern half of the modern border between China and Tajikistan) remained unsealed, in part because of the continuing rivalry between Britain and Russia for supremacy in Central Asia, known as the Great Game; They finally agreed that Afghanistan would remain an independent buffer state among themselves, with the Wakhan Corridor established in Afghanistan in 1895.  China was not a party to this agreement, and the southernmost part of the Sino-Russian border remained undefined.  The origins of the China-Kazakhstan border date back to the mid-19th century, when the Russian Empire was able to establish its control over Lake Zaysan. The establishment of the border between the Russian Empire and the Qing Empire, which is not too different from the present Sino-Kazakh border, was provided for by the Beijing Agreement of 1860;  The actual boundary of the convention was drawn by the Chuchak Protocol (1864), which left Lake Zaysan on the Russian side.
  The military presence of the Qing Empire in the Irtysh Basin collapsed during the Dungan Revolt (1862-1877). After the fall of the rebellion and the recapture of Xinjiang by Zuo Zongtang, the border between the Russian and Qing empires in the Irtysch Basin was slightly adapted by the Treaty of St. Petersburg (1881) in favor of Russia.