“The circumstances the country is going through have caused considerable losses to the oil and gas sectors,” said Abbas in a statement.
Abbas said the war had caused a $3.5 billion direct loss, in terms of stolen and wasted oil and gas, and damage or theft of infrastructure, pipelines and vehicles.
He added that indirect losses, or lost profits, accounted for $17.9 billion.
At the start of the revolt, Syria produced 385,000 barrels of oil a day. Production dropped to 17,000 barrels a day, while gas production has been halved.
In recent months, the jihadist Islamic State (IS) took control of all the main oil fields in resource-rich Deir Ezzor in eastern Syria. It is exporting oil through middlemen to Iraq and Turkey.
Meanwhile, since last Thursday, the Syrian regime army has been trying to expel IS from the gas field at Shaer, in Homs province, which the jihadists took over after killing 270 guards and employees, according to a monitoring group.
Despite the war, Abbas said the government was set to complete a gas project near the northern city of Tabaqa, which is under IS control.
The plant is scheduled to start operating in mid-August, and is expected to produce 1.22 million cubic metres a day to begin with, rising to 3.2 million by the end of the year.
Asked about the potential risks of opening a new plant near an IS-controlled area, the ministry said the site was “secure”.