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This example that I got from my junior member is very simple but it helps you a lot to understand about how to determine pressure loss during normal circulation.

Information given is listed below;

Circulate at 3 bottom up through open end tubing (Down tubing and up annulus) with 12.7 ppg mud.

Pump pressure = 1000 psi

Annulus friction loss = 50 psi

Inside tubing friction loss = 925 psi

Surface line friction loss = 25 psi

**Calculate the pressure in the well at 10,000’ (tubing tail). **

**What would ECD at 10,000’ TVD be?**

The concept of calculation that you should know : **total pressure at bottom = pumping pressure + hydrostatic pressure – pressure loss in the opposite way of fluid flowing.**

Then,

If I reference to** the drill string site**, I will get the equation like this.

Pressure at bottom hole= Hydrostatic Pressure at bottom hole + Pressure from pump- Pressure Loss in surface line – Pressure loss in tubing

Pressure in the well at 10,000’ = 0.052×12.7×10000 + 1000 – 25 – 925 = 6654 psi

If I reference to** the annulus site**, I will get the equation like this.

Pressure at bottom hole= Hydrostatic Pressure at bottom hole +Annular pressure loss

Note: Hydrostatic pressure and annular pressure loss force downward.

Pressure in the well at 10,000’ = 0.052×12.7×10000+ 50 = 6654 psi

Note: It doesn’t matter which site of u-tube you refer to the bottom hole pressure is still the same.

**ECD (Equivalent Circulating Density****) is calculated by this following equation:**

**ECD = Current mud weight in PPG + (annular pressure loss /(0.052xTVD))**

ECD = 12.7 + (50/(0.052 x 10000))

ECD = 12.8 ppg

**Ref book: ** **Formulas and Calculations for Drilling, Production and Workover, Second Edition**

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I ve been use this grup to be more informed about oil industry a my personal knowlege and has been helpful. I do not have experience in industry yet. thanks to all of you.

helpfull informations, it really helped me to catch this

Useful info.

can you please do dubble check of ECD formula I thing it is not correct.

E.C.D = BHP+ Annulus press./0.052*TVD

thanks

Mohanad,

The formula is correct. ECD = Current mud weight in PPG + (annular pressure loss /(0.052xTVD))

Cheers,

Shayne