Zapata Norness, Inc., Houston, Texas, announced that it has executed a purchase agreement with Loffland Brothers Co., Tulsa, Okla., to acquire the Loffland deep water LeTourneau jackup unit, Ocean Master I, for a price between $6- and $7-million.

This unit, presently working in the Gulf of Mexico, is capable of drilling in water depths to 300 feet.

The purchase becomes effective at the conclusion of the unit's current contract, anticipated to be about February 1, 1969.

Ocean Master I is almost identical to the Zapata mobile jackup units Chaparral, Heron and Endeavour, and is about three years old.