The company submitted a request to carry out the 1.8 year project across 21,000km2 in Mexico's offshore economic zone in May.
Dowell will have commercial rights over the data for 12 years when it completes the work, but not exclusivity over the authorized area.
Year to date, CNH has also granted survey and exploration authorizations to CGG, TGS and Stratascan.
In total, the watchdog has authorized 66 projects for 21 companies, 20 projects of which are underway and four set to begin, while 20 have been completed, 13 have expired and nine have been withdrawn.
The London-based junior operator also said that the JV has selected the Ensco 8503 rig to undertake the Zama appraisal program, with the first well scheduled to spud next quarter, pending CNH approval.