The current study deals with two major sides of measurements technique in petroleum industry, which one is condensate and another is natural gas flow rate. Condensate is a low density, high API gravity colorless or light yellow liquid hydrocarbons which is generally found with natural gas. A strong world economy is expected to underpin solid increases in oil demand. Strong economies will, in turn, use more oil and we expect demand to grow at an average annual rate of 1.2 mb/d. By 2023, oil demand will reach 104.7 mb/d, up 6.9 mb/d from 2018. Bangladesh Oil Gas and Minerals Corporation short named Petrobangla operates oil and gas exploration, development, transmission, distribution and conversion together with development and marketing of minerals in Bangladesh. The present scenario of Bangladesh Oil Gas and Minerals Corporation is reported that the last year (during 2018- 2019) condensate and natural gas production are respectively 11650 BBL and 3170 MMSCF. In the petroleum industry is very common to find oil or natural gas condensate storage tanks, in various geometrical shapes which would be partially or fully filed with fluid. The liquid volume calculation of these tank and their calibration processes would be the best challenges for any petroleum engineers at the beginning of the industry. Similarly the natural gas flow measurement by various measuring devices like orifice, turbine or flow computer meter and their selection criteria for petroleum field would be the another challenges for any petroleum engineers. This project aims to perform a comparative study on measuring principle, provide the best mathematical equation, measuring devices, calibration study of the liquid storage tanks and the best meter selection criteria for gas flow measurement.