The companies said in December they were discussing the 17 percent stake that RWE has in the Nabucco consortium.
The original Nabucco pipeline was reconfigured as Nabucco West, a 48-inch, 807-mile pipeline through Bulgaria, Romania, Hungary and Austria. It has an 813 billion cubic feet design capacity.
Nabucco spokesman Christian Dolezal said in an e-mail statement to United Press International that OMV took over all of RWE's interest in the project.
"RWE's decision to leave the project was due to internal considerations within RWE and has had no impact on the continued development of Nabucco," he said. "The exact financial details are confidential between RWE and OMV, so please understand that Nabucco cannot comment further."
That project is up against the Trans-Adriatic Pipeline to secure natural gas from Azerbaijan. A BP-led consortium operating there is expected to make a decision on its pipeline options by June.
Both projects are included in the Southern Corridor, a network of gas pipelines meant to break the Russian grip on the European natural gas sector.