The contract requires the company to drill a series of onshore directional wells, with target depths in the 3000 m range.
Mexico's President Andres Manuel Lopez Obrador made the announcement at a press conference this week.
The Zama appraisal programme in Block 7 in Mexico's Sureste Basin is operated by Talos in a consortium with Sierra Oil & Gas and Premier Oil.
GulfSlope Energy will retain and deploy a supra salt evaluation team consisting of three geoscientists and a manager to identify, evaluate and recommend targets for lease acquisition, farm-in and drilling.
The company's interest has been sold to the existing partners in the Block 5 exploration licence, subsidiaries of Murphy Oil Corporation, Wintershall Dea and Petronas.
The engineering work is expected to begin immediately, and the contract will be reflected in McDermott's 2Q19 backlog.
Mitsui and MOL have participated in a long-term charter business operated by MODEC for the purpose of providing a FPSO for use in the Area 1 block.