Equivalent Circulating Density
The Equivalent Circulating Density (ECD) is defined as the increase in bottom hole pressure due to friction and it is normally expressed in pounds per gallon. Equivalent Circulating Density (when forward circulating) is defined as the apparent fluid density which results from adding annular friction to the actual fluid density in the well.
Where; ECD = equivalent circulating density (ppg), FPann =annular friction pressure (psi), TVD = true vertical depth (ft), FD = fluid density (ppg)
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