In the battle for the future of the rebel cause, the oilfields may begin to play an increasingly strategic role. All are in the three provinces closest to Iraq - Hasakeh, Deir al-Zour, and Raqqa - while the Iraqi border regions are the homeland of the Islamic State of Iraq, as al-Qaeda's branch in the country calls itself.
It was fighters from the Islamic State of Iraq, both Iraqi and Syrian, who are thought to have founded Jabhat as the protests against the rule of President Assad turned into civil war.
Because of sanctions, Jabhat's oil is largely shipped to thousands of home-built mini-refineries that have sprung up across the north of the country. The crude is distilled in hand-welded vats dug into the ground and heated with burning oil residue.
It is not clear how much money is being channelled back to the group. But all those buying the raw product were aware that Jabhat was profiting.
"Jabhat do not ask for taxes or charges for this trade," said one of them, Omar Mahmoud, from Raqqa province. "But we are buying the oil from them so they do not need to."
Syria's oil output, never as great as that of some of its Arab neighbours, fell to about 130,000 barrels a day after the outbreak of the revolution against the Assad regime.
Jabhat is now putting that to good use. The home refineries are turning out poor-quality but usable petrol and kerosene for domestic stoves.
Their product might not meet the quality, and certainly the health and safety standards, demanded by Shell or ExxonMobil, but it provides a living to thousands of blackened figures willing to risk the business' inherent dangers.
In parts of northeast Syria, the stills are set up at roadsides, the produce sold like fruit from lay-bys to drivers as they pass.
The centre of the industry is the desert outside the small town of Mansoura, a few miles west of Raqqa city and on the other side of the Euphrates River.
Here, the entire horizon is a blighted scene of billowing clouds out of which dark figures occasionally emerge on foot or roaring motorcycles. Near the road sit oil tankers carrying the raw product.
"I make £3000 Syrian [$30] a day," said Adel Hantoush, 19, his legs dripping with crude, a filthy headscarf wrapped around his face. A building site casual labourer in better times, he helps support his father, mother and nine brothers and sisters.
Black smoke blew past his head as colleagues poured fuel into the burning pit under their tank. "The last thing I think about is my health," he said. "If I don't do this, my family will die."
It is a Mad Max scene, indicative of the chaos the war has unleashed in Syria, creating a landscape ideal for the methods of dominance al-Qaeda learned in postwar Iraq.
General Selim Idriss, the head of the Military Council opposition, has appealed for Western help to seize the fields from Jabhat, but the forces required - he put it at 30,000 men - make that a pipe dream. Even pro-Western rebel militias in the area admit that the level of support received from the council is at present minimal.
Jabhat has used its greater proficiency at fighting, honed by jihad in Iraq and elsewhere, to take a leading role at the battlefront.
"They are more disciplined," Abu Hamza, a fighter with a rival Islamist rebel brigade in Aleppo, admitted.
In Raqqa, Jabhat also controls flour production, earning money from selling to bakeries, some of which it owns as well.
Defiant Assad rejects US Russian peace move
Bashar al-Assad dismissed an international push to forge a peace agreement in Syria, also declaring he was determined to stand for re-election next year.
He dismissed the prospect of any breakthrough in the conference being planned by the United States and Russia next month, insisting the West was not committed to peace on equal terms.
"We do not believe that many Western countries really want a solution in Syria," Assad told Argentinian newspaper Clarin, blaming those countries for supporting "terrorists". "We must be realistic," he said. "There cannot be a unilateral solution in Syria; two parties are needed at least."
The rebels were fromhundreds of different groups, he said, "and who can unify thousands of people?"
