Calculate Annular Pressure Loss

From the previous post, Equivalent Circulating Density (ECD) in ppg, you may want to know how to determine annular pressure loss in order to calculate Equivalent Circulating Density (ECD) in ppg.

So use the following formula to calculate annular pressure loss. This formula will give you idea about how much annular pressure loss you will encouter.

P= [(1.4327 x 10^-7) x MW x Lx V²] ÷ (Dh – Dp)

P = annular pressure losses, psi

MW = mud weight in ppg

L = length of annular in ft

V = annular velocity in ft/mm

Dh = hole or casing ID in inch

Dp = drill pipe or drill collar OD in inch

Example:

Mud weight = 13.0 ppg

Length = 8000 ft

Circulation rate = 320 gpm

Hole size = 6.5 in.

Drill pipe OD = 4.0 in.

Determine annular velocity, ft/mm: v = (24.5 x 320) ÷ (8.5² – 5.0²)

v = 299 ft/min

Determine annular pressure losses, psi: P = [(1.4327 x 10^-7) x 13.0 x 8000 x 299²] ÷ (8.5 – 5.0)

P = 531.65 psi

Please find the Excel sheet to calculate annular pressure loss

PS, if you want to get the more accurate, you may need to contact your drilling fluid company to do it for you because they have the actual database and more complex formula that may help you get the good number.