Patent ID: 7735378

Claim:
A method for determining flow rate and density of a return drilling fluid flowing through a tubular conduit, the method comprising the steps of: a) measuring, within a section of the tubular conduit, the fluid level “a,” corresponding to the distance from the fluid surface to the top of the tubular conduit, to determine a dynamic volume for the fluid flowing through said section, wherein said section of tubular conduit is defined by a diameter “D” and a length “L,” and wherein said dynamic volume “V dynamic ” is arrived at via the following eguation: V dynamic = ∫ 0 D ⁢ π ⁡ ( ( D - a ) 2 / 4 ) ⁢ L ⁢ ⁢ ⅆ a ; b) correlating the dynamic volume so determined with a flow rate via calibration methods; c) measuring, at any instant, the weight of fluid flowing through said section of the tubular conduit; and d) combining the measured fluid weight “W sum ” with the determined dynamic volume to determine the density “ρ” of the fluid flowing through the tubular conduit via the following relationship: ρ= W sum /V dynamic .