The Benchamas development in the Gulf of Thailand is an oil play in a predominantly gas/condensate region. The project is being developed as a waterflood with horizontal and monobore producers and injectors. The waterflood was designed to maintain the gas cap to maximize recovery. Because simulations performed during the design stage of the waterflood project indicated that some horizontal injector wells would be required to achieve the required injection rates, three horizontal injectors were planned. The full-length paper details the unique design challenges presented to the asset team, discusses the efforts undertaken to address these challenges, and presents the drilling, completion, cleanup, and injection results.