Introduction
Tutorials
Improving a discharge simulation
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.
For a list of new features and changes in recent versions of WellSim see here.
WellSim's basic flow simulation tools are:
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.
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.
Injection simulation Enter a pressure/flowrate measured at one point in an injection well, usually the wellhead. WellSim calculates the conditions along the wellbore.
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:
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.
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.
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.
Import and export data in many formats.
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.
Before a well is drilled, use measurements and estimates from geology and neighbouring wells to run trial simulations.
After a well is drilled use real well measurements to run improved simulations. Run what-if scenarios to estimate the effect of changes in the field or well.
As the field develops, rerun the simulations to allow for changes, such as changing reservoir pressure and enthalpy, or the the effect of scaling in the wellbore.
Links below are to tutorials that show how to enter data, run simulations, graph or export data.
If the well is vertical throughout:
Otherwise, if the well is deviated:
Enter the well deviation read how
Enter a casing configuration read how
Enter the geometry configuration for the deviated well read how.
If the well has secondary feedzones above the deepest feedzone, enter the secondary feedzones. If a well has one feedzone, this is handled in an output or injectivity simulation; do not enter any secondary feedzones.
Enter any formation temperatures read how.
Enter any measured discharge profiles read how.
Enter any measured output curves read how.
Enter any measured injection profiles read how.
Enter any measured injectivity curves read how.
Run a discharge simulation read how.
Do a lower bound analysis to check the measured discharge profile. If necessary, correct the measurements in the measured profile read how.
Review and improve the discharge simulation by comparing it to a measured profile (matching_analysis) read how.
Run an output simulation read how.
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.
You can set many preferences to control how WellSim works and looks, including units, language, formats for inputting and outputting data.
Use the suite of graphing tools to easily display and compare data.
Many options to import data from other WellSim or GeoData Manager databases on your computer, or import directly from files generated by field instruments.
Many options to export data and graphs to data files or to other WellSim or Geodata Manager databases on your computer.
Models liquid, two-phase, and dry steam flow. Calculates the depths of any transitions from one type of fluid to another and different flow regimes: bubble, mist, churn, annular, slug and so on.
Models dissolved solids content by an equivalent weight percent of NaCl (in total fluid) and models non-condensable gas content by an equivalent weight percent of CO2 (in total fluid) (WellSim models the ternary system H2O-NaCl-CO2).
Allows you to choose the flow correlation to use: WellSim's own correlation or the industry-standard Ansari Mechanistic Model, Aziz, Beggs and Brill, Duns and Ros, Hagedorn and Brown or Orkiszewski correlations.
Allows for any number of different casing, slotted liner, solid liner or open-hole sections. Each section can have a different diameter, roughness and angle. Standard casing and liner sizes are included as defaults.
Models deviated (non-vertical) wells with arbitrary angles down the wellbore. Reliable to a maximum deviation angle of 15° from the vertical.
Models any number of feedzones. At each feedzone you can specify one of a variety of feedzone relationships for calculating the feedzone's mass flowrate.
Models heat transfer with the surrounding rock formation and well casing.
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.
A database has a pre-defined structure, so you don't need to set it up.
All data is are stored in SI units, but WellSim can easily use other units to input, view, compare and output the data.
Every item of data in WellSim has a position in 3-dimensional space, relative to the wellhead, and a date and time; this allows different types of data to be compared.