Algerian state-owned energy company Sonatrach has signed an agreement with BP and Statoil to produce an additional 11 billion cubic meters (Bcm) of natural gas from its Tiguentourine gas field, Sonatrach’s CEO said Dec. 20.

The field produces 9 Bcm per year, but more investment is needed to maintain that output beyond 2035.

“Sonatrach, British Petroleum and Statoil have signed a deal to invest $500 million to recover an 11 [Bcm] additional reserve,” Sonatrach CEO Abdelmoumene Ould Kaddour told reporters during a signing ceremony at Sonatrach’s headquarter.

The field has produced 78 Bcm of gas involving an investment of $3.4 billion since opening in 2006, Sonatrach figures show.

Algeria’s annual gas production stands at 94 Bcm, according to official figures.