37 REFURBISHING OF OIL WELL DRILLING AND PRODUCTION EQUIPMENT; MODIFICATION, MODERNIZATION AND REPAIR OF BARGES AND VESSELS; REBUILDING AND OVERHAULING SUB-SEA PETROLEUM WELLHEAD EQUIPMENT; FABRICATION AND ASSEMBLY OF DRILLING RIGS, OIL FIELD EQUIPMENT, OFFSHORE HOUSING UNITS, AND SUB-SEA WELL COMPLETION SYSTEMS; MODIFICATION AND REPAIR OF ENGINES, PUMPS AND GENERATORS FOR PETROLEUM DRILLING AND MARINE OPERATION