Equivalent Circulating Density (ECD) Using Yield Point for MW greater than 13 ppg

Description:

Equivalent Circulating Density (ECD) accounts for the combined effect of mudweight and dynamic pressure losses while circulating drilling fluid.

Equation:

Yield Point (YP) Calculation: $$ \text{YP} = \text{Reading at 300} - (\text{Reading at 600}-\text{Reading at 300}) $$ $$ \text{PV} = \text{Reading at 600} - \text{Reading at 300} $$ Annular Velocity (AV) Calculation: $$\text{AV} = \frac{24.5 \times Q}{(D_h^2 - D_p^2)}$$ Equivalent Circulating Density (ECD) Calculation: $$\text{ECD} = \text{MW} + \frac{0.1}{D_{h} - D_{p}} \times \left[ \text{YP} + \frac{\text{PV} \times \text{AV}}{300 \times (D_{h} - {D_{p}})} \right] $$

Where:

\( \text{ECD} \) = Equivalent Circulating Density, ppg

\( \text{MW} \) = Mud weight, ppg

\( \text{YP} \) = Yield Point, cp

\( \text{Q} \) = Flow rate, gpm

\( D_h \) = Hole size, inch

\( D_p \) = Pipe OD, inch

Practical Consideration:

For mudweights above 13 ppg, the impact of flow rate is being taken into account the calculation of ECD.