The double-displacement process (DDP) is a method for immiscible tertiary gas displacement of a watered-out oil reservoir. In the Hawkins field of east Texas, the effectiveness of the immiscible nitrogen injection process is strongly driven by favorable gravity-drainage characteristics that lead to improved sweep and displacement efficiencies for the gas/oil system relative to the water/oil system. This paper documents the initial 6 years of the double-displacement project in the East Fault Block (EFB) of the Hawkins Field Unit, confirming the viability of the double-displacement recovery mechanism. It describes how early project performance indicated that oil gravity drainage was occurring slower than expected, the studies initiated to investigate the slower oil gravity drainage, and the successful outcome of those studies. In addition, the paper describes how the project has responded favorably to optimization efforts and gives a brief description of how results from the EFB have been applied to a proposed expansion to the West Fault Block (WFB).