Because before the discovery of Daqing Oilfield, foreign experts, after their investigation, said that there were no large oil fields in China, so they asserted that China was a poor oil country. But soon, China's own experts discovered several big oil fields such as Daqing and Shengli through investigation. So China's theory of being poor in oil fell apart. Daqing Oilfield planned to be built in the second five-year plan was discovered on the basis of the original petroleum geology theory of China geologists. Premier Zhou fully affirmed Li Siguang's oil exploration thought and theory in his government work report.