What is WellSim ?

WellSim uses only a few measurements or estimates to model flowing, steady-state geothermal wells. The data from these models would be costly or impossible to measure directly.

What's new and changed

For a list of new features and changes in recent versions of WellSim see here.

WellSim's tools

WellSim's basic flow simulation tools are:

  1. Discharge simulation Enter data measured at one point in a discharging well, usually the wellhead. WellSim calculates the conditions along the wellbore, such as pressure, temperature, enthalpy, dryness. WellSim uses the thermodynamic properties of water and impurities and details of the well.

  2. Output simulation Enter one or two discharge simulations, or measurements at the well bottom. WellSim calculates the well's output curve (how wellhead mass flowrate varies with wellhead pressure) and details of the deepest feedzone.

  3. Injection simulation Enter a pressure/flowrate measured at one point in an injection well, usually the wellhead. WellSim calculates the conditions along the wellbore.

  4. Injectivity simulation Enter one or two injection simulations, or a few pressure/flowrate measurements at one point in an injection well, usually the wellhead. WellSim calculates the well's injectivity curve (how wellhead mass flowrate varies with injection pump pressure) and details of the deepest feedzone.

WellSim's advanced tools work with the basic flow simulation tools:

  1. Matching analysis Compare a discharge or injection simulation pressure/temperature profile with a measured profile. Improve the simulation (vary secondary feedzone characteristics or impurity (as NaCl or CO2 in total fluid)) until it matches the measured profile better.

  2. Lower bound analysis This analyses a well's measured discharge profile. At each depth down the well where flow is two-phase, it compares the measured pressure with the the saturation pressure of pure water at the measured temperature. The two pressures are not usually the same, because a typical well fluid has solids (usually NaCl) and gasses (usually CO2) dissolved in it. WellSim uses the pressure difference to calculate the minimum amount of NaCl or CO2 present.

    A lower bound analysis helps: find errors in the measured discharge profile; estimate impurity content (as NaCl or CO2 in total fluid) present; estimate the depths and characteristics of secondary feed zones.

  3. What-if scenarios Normally run WellSim using real measurements from wells that have been drilled. However, you can change some of the measurements to model the effects of future changes in the well or field. For example to find how the output curve changes with changes in reservoir pressure. Such models are called what-if scenarios.

  4. Import and export data in many formats.

  5. Graphing Quick Graph shows a simple graph of a few kinds of data. MultipleGraph shows a more complex graph of many kinds of data and has options to export or print the graph.

Overview of using WellSim and WellSim's tutorials

Use WellSim for all phases of a geothermal field

Links below are to tutorials that show how to enter data, run simulations, graph or export data.

1 - Before you start

2 - Create wells

If the well is vertical throughout:

Otherwise, if the well is deviated:

  1. Enter the well deviation read how

  2. Enter a casing configuration read how

  3. Enter the geometry configuration for the deviated well read how.

3 - Enter well details as they become available

4 - Run discharge and output simulations as required

  1. Run a discharge simulation read how.

  2. Do a lower bound analysis to check the measured discharge profile. If necessary, correct the measurements in the measured profile read how.

  3. Review and improve the discharge simulation by comparing it to a measured profile (matching_analysis) read how.

  4. Run an output simulation read how.

5 - Run injection and injectivity simulations as required

  1. Run an injection simulation read how.

  2. Run an injectivity simulation read how.

5 - And

These tutorials show you how to use WellSim itself:

WellSim follows the laws of physics: if you just make up data, then it will likely fail.

Key features

Key features of flow simulations

Data and the database

WellSim has several different kinds of data: well geometry, well details (such as secondary feedzones, formation temperatures), measured data (such as measured pressure/temperature profiles, measured injectivity curves) and simulation results (such as injection simulations, output curves). WellSim stores all data for each geothermal field in one Microsoft Access or Microsoft SQL Server database. These mature, well proven database managers ensure the database's integrity. Storing data in one database ensures all users have access to all data and simplifies security and backup.