BEIJING - China's State Oceanic Administration (SOA) said Tuesday that US energy giant ConocoPhillips is responsible for an oil spill in the country's northern sea area.
The leak, which took place last month at the Penglai 19-3 oilfield in Bohai Bay, has polluted an area of 840 square kilometers, causing "a certain level" of damage to the nearby oceanic environment, said the administration.
The field is being mined by ConocoPhillips China (COPC), a subsidiary company under ConocoPhillips, under a joint development agreement with the China National Offshore Oil Corporation, the country's largest offshore oil producer.
Causes pending further probe
According to the SOA, oil seepage was first reported to the SOA North China Sea Branch by ConocoPhillips on June 4, with another incident reported on June 17. The leaking was brought under control by June 21.
The first leak from platform-B occurred at the seabed and resulted from increased pressure when workers injected water and drill cuttings into the earth. The latter incident from platform-C was due to a surge in the well, said the SOA, without giving details.
Guo Mingke, deputy chief of the SOA North China Sea Branch, said injecting water back to the reservoir and drill cuttings re-infection are common practices in the oilfield industry.
"It's the first time in the history of our country's oilfield operations that we've seen a seabed oil leak like what happened at the platform-B, and we don't have much experience of that," said Guo.
According to Guo, injecting water is to keep the normal pressure after the oil is pumped out, and re-infecting drill cuttings during operations to a certain depth underground is to prevent environmental pollution.
"Further research is needed to determine the causes of the leaks," Guo said.
The SOA has ordered ConocoPhillips China to locate where the leaks occurred and block the holes as soon as possible.
Long-term damage feared
As of Monday, a total of 70 cubic meters of water-oil hybrid in the area had been cleaned up, but "a small amount" of oil film can still be seen on the sea surface, according to the SOA.
"Our monitoring shows 840 square kilometers was polluted, but that doesn't mean that's all the affected area," said Cui Wenlin, environmental monitoring center with the SOA North China Sea Branch.
Bohai is a half-closed sea with comparatively low self-clean ability due to limited water exchange with the outside.
According to Cui, only part of the spill could be mopped up, and a large part will mix into the water or sink into the deep sea.
"Given Bohai's fragile environment, the impact of the oil spill might be very complicated," Cui said, adding that the SOA will keep close watch on its influence for a "very long time."
"With technical limits and weather influences, it usually takes a long time to monitor and draw a final conclusion on an oil spill incident," said Wang Bin, a senior official with the SOE oceanic environmental protection bureau, adding that a preliminary report is required usually one month after such an incident.
"The influence of an oil spill on the oceanic ecosystem is very long and slow. Right now, our monitoring workers are still collecting samples," Wang said.
Under China's law, operators will be fined up to 200,000 yuan ($30,770) if their offshore oil projects result in oceanic pollution.
However, Wang said maritime authorities will also claim environmental compensation from ConocoPhillips China according to relevant laws, and the figure will be "much more than" 200,000 yuan.