The North Reggane project covers six gas fields in the Sahara desert and includes a pipeline for the export of gas, which is due to begin pumping in mid-2016, Repsol added in a statement.
Production is expected to stabilise at 8 million cubic metres a day for the first 12 years the project is in operation. That is equivalent to about 2.9 billion cubic metres a year and compares with Spanish demand of 36 bcm.
Algerian state concern Sonatrach has a share of 40 percent in the consortium, while Germany’s RWE Dea has 19.5 percent and Italy’s Edison the remaining 11.25 percent.
Repsol estimated reserves at 145 million barrels of petroleum equivalent in the Reggane basin as of 2009.
Algeria accounts for 38 percent of gas supplied to Spain, which imports more than 99 percent of its gas needs.