McKenna joins as drilling and surface engineering lead, while Purewal bring his expertise to the role of petroleum and reservoir engineering lead.
Already on the technical team is Wilhelmus (Wim) Burgers who is the geologist and geophysical lead.
“Once more, we are adding seasoned professionals with major IOC backgrounds and experience working on some of the most prominent field development projects," Osamede Okhomina, ADM chief executive said in a statement.
“This is particularly important as the Aje partners focus on developing the gas reserves and tripling production at the asset. It also strengthens our position to accurately assess marginal fields in Nigeria and confidently progress investment opportunities across West Africa," he added.
McKenna brings to the role 38 years of operational and leadership experience with prior senior positions at ExxonMobil, Kosmos Energy, and Oracle Energy.
Purewal was previously head of reserves assurance for Europe and global reserves training in Shell, was chair of the Society of Petroleum Engineers committee, and presently chairs the Petroleum Working Group of the UN Economic Commission for Europe.
Burgers, meanwhile, has over 35 years in the industry with prior senior roles at ExxonMobil and ConocoPhillips.