Flow pattern identification and inline multiphase flow measurements are essential matters regarding design and production control of oil and gas rigs. multiphase flow measuring equipment are expensive, often fragile and applied in tight measuring ranges. therefore, the development of low cost measuring systems with wider measuring ranges and capable of withstanding the challenging production conditions is essential to oil and gas industry. accurate and continuous oil-gas-water flow measurements are critical for maximizing process control and avoiding production stoppages for metering purposes. the present work aims at characterizing flow patterns and measuring liquid mass flow rate in liquid-gas flows using ultrasonic sensors and a venturi tube. ultrasonic waves is applied in transmission and reception mode, and in pulse echo approaches. measurement techniques were tested on an experimental bench where water, oil and air multiphase flows are possible. the experimental rig is instrumented with various sensors such as coriolis and electromagnetic flow meters, thermocouples and pressure transducers. liquid and gas instantaneous flow images are possible due to electrical capacitance tomography (ect) technique. data acquisition were performed using labview software. experiments in static columns were executed with piezoelectric sensors and a tdc1000-7200 board from texas instruments. the latter allows transit time measurement of ultrasonic waves in the fluid column, determining the interface position and concentration. the interface position of water and crude oil columns were determined with relative errors less than 10%. higher errors for determining the crude oil interface occurred owing to uncertainties regarding the sound speed in the applied crude oil. bubbly, slug and stratified flow patterns were tested at the multiphase setup. flow pattern identification was possible through the application of the fast fourier transform (fft) on concentration signals obtained by ect and on differential pressure signals along the venturi tube. liquid flow rate measurements were performed in air-water flows with the aid of a venturi tube and an ultrasonic meter. errors of liquid flow rate below 20% were observed with the venturi meter for void fractions less than 0.35. errors below 35% were noted with ultrasonic sensors. liquid flow rate assessments by means of ultrasonic meters were only possible for void fractions less than 0.18 in horizontal direction, and less than 0.32 in vertical direction.