The Bohai Bay oil spill has resulted in calls for changes in the relationship between China and the foreign oil companies that enable the search for resources, as Zhou Yan reports in Beijing.

Amid the criticism heaped on ConocoPhillips Co - the United States-based energy conglomerate whose operations spilled more than 700 barrels of oil into the waters of China's Bohai Bay in June - the nation's industrial experts are clamoring for a review of the policies for oil and gas exploration with foreign oil companies in China.

Some oil analysts have said that the spill was not "disastrous" either in terms of the amount of oil leaked or its environmental impact and is not comparable with BP PLC's massive oil spill in the Gulf of Mexico. However, the accident stirred up widespread public anger against ConocoPhillips China because of what some Chinese observers claimed to be the company's "inefficient cleanup" operation and its perceived indifference.

Eventually the country's top maritime watchdog prepared a lawsuit against a foreign oil company for the first time in relation to an oil spill.

Apart from the public outcry, however, some experienced industry experts have raised a question mark over the applicability of policies implemented in the 1980s regulating the participation of foreign companies in domestic oil exploration and production and have called for amendments to them.

Despite the strategic importance of oil resources to the country prior to its economic advance in the 1980s, China endeavored to attract foreign oil giants to participate in domestic oil exploration to help exploit the country's large untapped natural resources and develop its fledgling oil industry with cutting-edge foreign technologies, said Sun Zhengchun, the former chief geologist of China National Petroleum Corp, the country's biggest energy company in terms of production.

As such, in the early 1980s the central government introduced two regulations, one concerned with the exploration of onshore petroleum resources and the other focused on offshore exploration to encourage foreign companies to participate in oil and gas exploration in China.

The regulations, which were amended slightly in 2001 and 2011, stipulate that foreign oil companies involved in offshore oil discoveries must enter into production sharing contracts (PSC) with China National Offshore Oil Corp (CNOOC), which is the only entity authorized by the government to carry out domestic offshore oil exploration activities.

A standard PSC requires the foreign parties to bear all the costs of exploration, but when a field is discovered and goes commercial, CNOOC, on behalf of the central government, will have the option of taking a participating interest of up to 51 percent, with the foreign party taking the remainder.

As the country's earliest and most explored offshore area for oil resources, northeast China's Bohai Bay is the area most open to overseas cooperation and therefore has the greatest number of PSCs. ConocoPhillips, along with other oil giants, including BP and Husky Energy Inc of the US, has actively participated in China's marine oil and gas exploration ventures.

The joint exploration between China and foreign partners has resulted in a leap in the country's offshore oil exploration, with the production of oil and natural gas reaching more than 50 million metric tons of oil equivalent (a unit based on the approximate amount of energy released by burning one barrel of oil) in 2010. That compared with total oil production of about 630,000 metric tons between 1967 and 1979, according to Li Xiangfang, a professor from the China University of Petroleum in Beijing.