To overcome the long-standing technical bottlenecks of conventional metering in oil- and gas-drilling operations—namely cumbersome installation, the need for hot-work tapping, costly maintenance, and poor accuracy under intense vibration and electrical noise—this invention delivers a non-contact, array-ultrasonic wireless flowmeter. The instrument adopts an innovative, non-intrusive clamp-on architecture that permits true hot-tap deployment without production shutdown. A multi-path ultrasonic se