Surface Area Analyzer used in oil & gas typically employ the principle of gas adsorption/desorption. The most common technology used is the Brunauer-Emmett-Teller (BET) method to measure the specific surface area. This method involves measuring the amount of gas adsorbed onto the material's surface at different pressures and temperatures. Other advanced technologies include micropore analysis using the t-plot method, which is used to determine the micropore surface area and volume, as well as mesopore and macropore analysis using various techniques like BJH (Barrett, Joyner, Halenda) or the DFT (Density Functional Theory) method. N₂, Ar or CO₂ gas is commonly used as the adsorbate. The analyzer controls pressure and temperature precisely and uses specialized software for data analysis.