A lawyer representing 30 Shandong province fishermen feels confident about his chances of succeeding in a lawsuit he recently filed against companies he believes are responsible for the ongoing oil leak in Bohai Bay.

Jia Fangyi, a lawyer at the Beijing-based Great Wall Law Firm, is asking for the parties that are found responsible for the leak to pay 30 million yuan ($4.7 million) in compensation for the economic damage they caused.

His clients calculate that amount will be enough to make up for the loss of their early investments - estimated to be worth 7 million yuan - and their average yearly profits of about 13 million yuan to 14 million yuan.

Jia said the 30 fishermen only constitute a small number of the people who have been harmed by the disaster and that more than 700 are awaiting compensation.

The oil spill originated in Penglai 19-3, the country's largest offshore oilfield, which was developed by the China National Offshore Oil Corp (CNOOC) and is now operated by the US-based ConocoPhillips. Jia said the law places the onus on those companies to disprove certain claims that his lawsuit makes against them.

"The victims of the oil spill cannot prove there is a link between the damage and the leak without cooperation from ConocoPhillips and its partner CNOOC," Jia said.

Jia sent the lawsuit by express mail to the Qingdao Maritime Court on Friday and it is expected to arrive on Monday. Phone calls to the court were not immediately returned.

Regulations give the court a week to decide if it will accept the suit.

Qu Baozheng, one of the 30 fishermen who filed the lawsuit, said the spill has caused nearly all the scallops he has raised to die.

More than 200 lawyers from about 20 Chinese law firms are now helping fishermen affected by the spill to conduct investigations or file lawsuits. But because a direct connection between their losses and the disaster has yet to be established, no court has so far accepted the suits.

Jia said he is confident about his lawsuit's chances. He explained that in tort claims concerning environmental pollution, the defendants - ConocoPhillips and CNOOC in this instance - are responsible for proving that they have not caused the deaths of aquatic creatures.

"If the court still rejects the suit, it is not that we haven't taken the correct legal procedures, but something beyond the law is blocking us," Jia said.

He said the case will show if the courts represent giant energy companies or the common people.

But Wang Yamin, an associate professor from Shandong University's marine college, said he is not optimistic about the case's prospects.

Even though Jia can try to place the onus of disapproving the lawsuit's claims on the defendants, he "still has to prove the harm to the fishermen was caused by oil pollution", Wang said.

He said the suit bears many similarities to one that was filed earlier by fishermen in Laoting, Hebei province, and was eventually rejected by the court.

On Nov 11, the State Oceanic Administration released an investigation report on the Penglai 19-3 oil leak. The report blamed the disaster on ConocoPhillips' illegal operating procedures.

Learning of that incensed Jia.

"It is like a car accident that many people die in," he said. "But instead of saving (the other victims) at once, the authorities are spending months to investigate what's wrong with the car."

The oil leak has polluted 6,200 square kilometers of water in Bohai, an area roughly nine times the size of Singapore, according to the investigation report.

In August, the State Oceanic Administration said in a statement that a lawsuit will be filed against the companies found responsible for the series of leaks that began appearing in the bay starting in June. But no further legal actions have been taken.

In mid-September, ConocoPhillips China and CNOOC announced a plan to establish two funds for the damages caused by the spill, but no details about the funds have been released so far.