Unions have been trying to halt refineries since early December, but the impact of their actions has been marginal so far as France's decentralised system of 200 fuel depots makes it hard to squeeze fuel supplies.

Here is how the strike is impacting the French oil sector:

TOTAL

Total said it was fully prepared for the Jan. 7-10 strike and there was no risk of shortages at its petrol stations.

Total said less than 5% of staff at its refineries were on strike. It said its five sites (Donges, Feyzin, Normandie, Grandpuits and La Mède) were in operation and were storing output as they await the end of union picketing at their gates.

With the exception of depots adjacent to its refineries, no other Total depots were blockaded and shipments were normal.

EXXON MOBIL

The CGT union on Tuesday called for strikes at Exxon refineries, which had seen little strike impact in recent weeks.

Exxon said a limited number of employees have joined the strike at its Fos (Marseille) refinery on Tuesday. As a consequence, product loading was disrupted, but the refinery continued to operate safely at a normal throughput.

At Exxon's Port Jerome (Gravenchon), a very limited number of workers had joined the protest and there was no impact on production that could impact supply, Exxon said.

FUEL DELIVERIES

France has a network of about 11,000 petrol stations, of which 3,500 are operated by Total. Total said only 26 of its stations had run out of fuel on Tuesday.

A spokesman for French petrol industry lobby UFIP said nationwide 150-160 petrol stations - about 1.5% - experienced shortages of some products. This was partly due to motorists stocking up on fuel. He said in coming days this number should remain stable.

CAPACITY

Total operates four crude oil refineries: 102,000 barrel-per-day Grandpuits (near Paris), 253,000 bpd Gonfreville Normandy, 117,000 bpd Feyzin and 220,000 bpd Donges. It also operates the La Mède bio-refinery.

Exxon operates the 240,000 bpd Port Jerome (Gravenchon) and 140,0000 bpd Fos-sur-Mer refineries; while PetroIneos operates 210,000 bpd Lavera (close to Marseille).

France has oil stocks equivalent to three months of consumption, with half held as crude, half as refined fuel.

(Compiled by Geert De Clercq; editing by David Evans)