Sonatrach, the state-owned energy company of Algeria, has signed an agreement with BP and Statoil to produce an additional 388 Bcf of natural gas from its Tiguentourine field, the Algerian company said. The field produces 318 Bcf per year, but more investment is needed to maintain that output beyond 2035. The field has produced 2,755 Bcf since opening in 2006, with approximately $3.4 billion having been invested in the project.