density of fluid?

**yasiobasio123** · 09-10-2011, 01:29 AM

Hi all,
I have Production Logging (PLT) data.
Pressure is in Bar.
I want to find the pressure derivatives and the density of the fluid in g/cc.
Please do let me know how can i find the pressure derivatives and density (g/cc).
Please remember pressure in Bar.

Look forward to hearing.

Many thanks!

**vinomarky** · 09-10-2011, 01:48 AM

Assuming your fluid cuts and rates are consistent over the time of logging, then the only difference from working out the densities from RFT data would be the flowing aspect (friction)

If pressure at some depth downole is P1 at D1, and similarly at some point uphole P2 and D2, then

Static Fluid Pressure gradient = (P2 - P1 - Friction) / (D2 - D1)

Where Friction is a function of tubular ID, flowrate, length and (for gas especially) pressure & Temp. Depending on the geometry, rate and fluid types you may want to neglect this or not.

You would probably have to look at your data noise to decide over what distances to average the data. If you choose too large a distance, then the density of the fluid (again, especially gas) may be significantly changing within the distance. Too small a distance and you'll come up with fluctuating densities

**yasiobasio123** · 09-11-2011, 08:19 PM

thanks for the reply.
I have loaded data in LAS format and that is a big interval about 340 m.
If I just divide the Pressure with Depth (P/D), will I get the Gradient at individual depth?
Besides, this, how to estimate the density, once gradient is determined?
Look forward to hearing.
Thanks.

**vinomarky** · 09-12-2011, 01:38 AM

It's accuracy over that range depends on how much gourd his density is liable to change over that range o pressures. If liquid probably not much, I gas at shallower depths then there could be a large error. Converting pressure gradient to density Is simple math. Just look at the units. Lbs per square inch divide by ft is actually weight per volume, you just need to change the inches square to ft square so that you end with lbs per ft cubes. If you can't work that out for metric units, then I think you wasted your time at uni