Jem leaders have so far declined to attend talks in Libya
A Darfur rebel group says its forces have attacked Sudan's Defra oilfield in the Kordofan region, taking a Canadian and an Iraqi oil worker hostage.
The facility targeted is the Chinese-led consortium, the Greater Nile Petroleum Operating Company.
The Justice and Equality Movement (Jem) say they want China to withdraw its support for the Sudanese government.
The kidnapping comes as the UN Security Council threatened sanctions for those undermining the peace process.
Talks to resolve the four-and-a-half year conflict in Darfur are due to start this weekend in Libya, but many rebel groups say they will boycott them.
During this time an estimated 200,000 people have died and two million have fled their homes.
The 2006 Darfur peace deal faltered because it was signed by the Sudanese government and only one rebel group.
Jem said the Chinese company had one week to leave Sudan.
"The oil revenue is not coming for the benefit of the people of Sudan, but to kill our people in Darfur," Jem field commander Abdel Aziz el-Nur Ashr told the BBC's Network Africa programme.
"All the people of Darfur believe that China is a partner for this genocidal government in Khartoum," he said.
In a statement on the rebel group's website on Wednesday, Jem said it was going to boycott the Libya talks - along with six other rebel factions.
But the UN Security Council has issued a statement urging all those invited to the talks to attend and warning of possible sanctions for any group seeking to undermine the peace process.
"That doesn't mean that simply non-appearance at the talks equates to impeding the peace process, but we do call on all those who are invited to the talks to take up those invitations," John Sawers, the UK's ambassador to the UN, said.
Jan Eliasson, the UN envoy mediating the talks along with the African Union, said the talks were a "moment of truth" and a "moment of hope" for Darfur.
He warned that it would be a "dangerous development" if this opportunity were missed but acknowledged there was little hope at this stage that some of the key rebel leaders would be in Sirte for the start of the talks.
Among the Darfuri rebels who have already said they will not attend are (Jem leader) Khalil Ibrahim, Ahmed Abdel Shafi, Ibrahim Ahmed Ibrahim, Jar al-Nabi Abdel Karim and Mohammed Aki Kelai as well as the Northern Command faction and another group of west Darfuri rebels.
Only the SLM/A faction of Khamis Abdallah Bakr has confirmed that it will attend the Sirte talks, while the SLM-Unity grouping has yet to announce a clear position.
"On Abdel Wahid (al-Nur) we have very little hope, if any, that he will turn up. I hope he sees the need to come later at the negotiations. There is a chair open for him," Mr Eliasson said.
The UN Security Council also heard from Secretary General Ban Ki-moon about problems with the deployment of peacekeepers to Darfur.
A hybrid 26-000-strong African Union-United Nations force is due to take over from the existing overstretched AU troops on 1 January 2008.
Khartoum has specific demands about the peacekeepers
But the Sudanese government has raised objections to the composition of the force which is still lacking helicopters and vital transport trucks.
Sudan's state minister for foreign affairs, Ali Karti, said technical components must be made up by China, Pakistan and Egypt and "any attempt to bypass these references would be considered an attempt to cause chaos".
Diplomats say as a result of the obstacles, the deployment may be as much as nine weeks behind schedule.
Meanwhile up to 4,000 European Union peacekeepers are on their way to Chad to protect Darfuri refugees and humanitarian workers.
The force commander, Gen Pat Nash, says he intends to protect innocent civilians.