37 OIL AND GAS WELL SERVICES, SPECIFICALLY SURFACE LISTENING SERVICES TO HEAR SOUNDS FROM UNDERGROUND DURING THE CONSTRUCTION, REPAIR AND MAINTENANCE OF OIL AND GAS WELLS
42 OIL AND GAS WELL SERVICES, SPECIFICALLY SURFACE LISTENING SERVICES TO HEAR SOUNDS FROM UNDERGROUND DURING ACTIVITIES IN OIL AND GAS WELLS OTHER THAN THE CONSTRUCTION, REPAIR AND MAINTENANCE OF THE OIL AND GAS WELLS