As a key datum in the petrochemical industry, Water content ratio plays an important role in dehydration, storage selling and petroleum refining. According to the oil well production site, this thesis is based on the oil-water mixture’s density to calculate the water-rate in petroleum, carried on the error analysis to this measuring method, and assessed the scope which this metering equipment is suitable. The wellhead drop back pressure device is effective in monitoring oil wells, to achieve the single well production of display, and when the ...