Introduction

Tutorials

Reference

Tutorial: Discharge simulations

A discharge simulation is the calculated conditions (such as pressure, enthalpy, fluid type) down a well discharging at a given steady-state mass flowrate read more.

This tutorial shows you how to run a discharge simulation for a well:

Entering the data for the simulation

This tutorial assumes you measured this data at the wellhead during the discharge test:

Data Value
Mass flowrate 100 t/hr
Fluid type Liquid
Wellhead pressure 65 barg
Wellhead enthalpy 1,500 kJ/kg
Wellhead CO2 4,000 ppm in total fluid
Wellhead NaCl 0 ppm in total fluid
  1. In the sample database, open a new discharge simulation for .

  2. Enter this data:

Common headers

Field Enter
Description TD 100 t/hr

Simulation properties

Data Enter Note
Geometry Index 1: Actual geometry From the drop-down list, select a geometry configuration for MY WELL that you have entered earlier.
Feedzone Index None MY WELL does not have any secondary feedzones above the deepest, so it does not require a secondary feedzones dataset for this tutorial. If your well has secondary feedzones, then from the drop-down list, select the secondary feedzones for the the well you have entered earlier.
Formation Index None This tutorial does not require measured formation temperatures, so select None here. Usually the effect of specifying formation temperatures is slight. If you have a formation temperature profile for the well, select it from the drop-down list.
Test direction TopDown Select from the drop-down list read more
Flow correlation WellSim Select a flow correlation from the drop-down list; the default, WellSim , is usually best read more

Fluid parameters

You must enter two of Pressure, Temperature, Enthalpy or Fluid dryness. When WellSim runs the discharge simulation, it calculates the other two fluid parameters.

Usually specify pressure and enthalpy.

For this tutorial, enter:

Field Enter Note
Mass flowrate 100 [t/hr]
Fluid type Liquid Select from drop-down list
Pressure 65 [barg] Tick the box under Pressure
Temperature (empty) No tick in box under Temperature
Enthalpy 1500 [kJ/kg] Tick the box under Enthalpy
Fluid Dryness (empty) No tick in box under Fluid dryness

Fluid impurities

Field Enter Note
Equation of state Complex Select from the drop-down list. The options are Simple and Complex. Complex is usually best, especially with significant concentrations of gas and or salts read more.
CO2 4000 [ppm] (in total fluid)
NaCl 0 [ppm] (in total fluid)

Calculation depths

Measure all depths relative to the same point at the wellhead read more.

Field Enter Note
Start depth 0 [m] Should always be zero.
Depth type Measured
Finish depth 2500 [m]
Depth type Measured
Depth increment 25 [m]

Now

The window should now look like this:

Running the discharge simulation

  1. Click to preprocess the data. If WellSim finds errors, correct the numbers and click again.

    During preprocessing, WellSim:

    • checks you have entered enough data

    • checks that the numbers you entered are consistent

    • estimates any fluid parameters that you did not enter (Pressure, Temperature, Enthalpy or Fluid dryness)

    • adjusts the fluid type and any numbers where WellSim considers them to be inconsistent with the fluid composition

    • displays any errors it finds

  2. Click .

    If you get the error Solution did not converge see here.

Interpreting a discharge simulation

WellSim displays the calculated data down the well:

Note

Click (top of window) to display the results as a graph:

If your graph does not look like this, change it.

Note

Change the graph to display Pressure gradient to see what causes the increase of pressure with depth at this mass flowrate:

This shows the friction and acceleration losses are small and the main cause of the pressure increase is gravitation, ie the weight of fluid in the wellbore:

The simulation log

As WellSim runs a discharge simulation, it writes a log file for the simulation, which can be useful if the simulation has a problem. To see the file after you have run a simulation, click the Simulation Log tab.

NOTE

Finally

Data inconsistency warnings

Each discharge simulation uses a geometry configuration and might use a secondary feedzone feedzone configuration and a formation temperature configuration. If you change any of those configurations you will probably need to rerun the simulation to reflect the changes - the discharge simulation is said to be inconsistent.

To warn you about this, when you go to the discharge simulations window, WellSim checks if any of the discharge simulations use the configurations that have changed. If any have:

WellSim gives these warnings for other kinds of data that become inconsistent, for example:

Next

Before you use a discharge simulation, try to improve it by changing it to better match a measured discharge profile at the same mass flowrate see here.