Creating a Simulation
Set up a RodSim simulation in PetroBench. What each input tab does, the order to fill them in, and what to enter to get a clean run.
A simulation in PetroBench is one rod pump design tied to one well, at one set of operating conditions. You build it by filling in five input tabs, then click Static or Dynamic to run it.
This page walks you through the whole setup, in the order you should do it.
Step 1: Create the Simulation Entry
- Open your well from the Wells list
- Click the RodSim tab
- Click New Simulation
- Confirm the auto-generated name (or edit it) and click Create
PetroBench will name it Design #XXX.YY [Well Name] [Date]. The number bumps each time you make a new design; the decimal bumps when you duplicate one.
If the well already has an "installed" simulation, the new one starts as a copy of it. Otherwise you start from sensible defaults.
Step 2: The Five Input Tabs
Across the top of the simulation page you will see five tabs with green check marks:
Simulation Preferences → Tubing → Well Data → Rods → IPR
Fill them in left to right. Each green check turns on once that tab has the minimum data the simulator needs.
Simulation Preferences
This tab tells PetroBench what you are trying to design for. Open it first.
The two most important fields are at the top:
| Field | What it does |
|---|---|
| Parameter One | The primary thing you are designing for. Pick from Stroke Rate, Production, Fluid Level, or Pump Intake Pressure |
| Parameter Two | A second target, usually a constraint. Common pairing: Stroke Rate as One, Pump Intake Pressure as Two |
| Target Stroke Rate (SPM) | The pumping speed you want, if Parameter One is Stroke Rate |
| Target Pump Intake Pressure (psi) | The PIP you want to maintain, if Parameter Two is PIP |
| Full Pump? | On = assume the pump fills 100% each stroke. Off = use Pump Fill % below |
| Step Length (ft) | Calculation step size. 50 ft is the default and works for most wells |
| Directional Survey | Which survey to use for geometry. Defaults to your primary |
| Damping Factor (UP/DWN) | Fluid damping coefficients. 0.10 is the default for most cases |
Click the Fluid Shot Data buttons (Most Recent, 30d Avg, 90d Avg) to auto-fill target fluid level and PIP from the well's fluid shot measurements.
Tubing
This tab describes the pipe carrying fluid up the wellbore and where the pump sits.
The fields that drive the simulation:
| Field | What to enter |
|---|---|
| PSN Depth Selection (ftKB) | Measured depth where the pump sits. This is the single most important number on this tab |
| Maximum Allowable Inclination @ PSN | Maximum well angle at the pump. Default 30° |
| Maximum Allowable Dogleg Severity @ PSN | Maximum curvature at the pump. Default 6°/100ft |
| Tubing Anchored? | Yes if the tubing is anchored. Set the Anchored Depth below |
| Target Fluid Level (ft/SURFACE) | Auto-fills from your fluid shot data |
The Tubing table below holds the actual pipe joints. Pick OD, Grade, Weight, and Top/Bottom Depth. ID and drift auto-populate from the API tables.
Well Data
This tab is the fluid and equipment context for the run.
Three groups of fields:
Fluid composition
| Field | Description |
|---|---|
| Water Cut (%) | Percentage of water in the produced fluid |
| Oil Density (API) | API gravity of the oil |
| Water/Gas Specific Gravity | Density relative to water (1.05) and air (0.82) |
| Fluid Specific Gravity | Average produced-fluid SG |
Pump specs
| Field | Description |
|---|---|
| API Pump Type | Insert, Tubing, etc. |
| Pump Diameter (in) | Plunger diameter |
| Pump Vol Eff (%) | Volumetric efficiency. 0.85 is typical |
| Stuffing Box Friction (lbs) | Surface friction at the wellhead |
| Casing/Tubing Pressure (psi) | Surface pressures |
Pumping unit
| Field | Description |
|---|---|
| Pumping Unit Type | Branded picks from the catalog. Custom uses your own |
| Manufacturer Line / Model | The unit catalog model |
| Rotation | CW or CCW |
| Crank Hole Number (in SL) | Stroke-length crank hole |
If your unit is not in the catalog, create it under Equipment > Pumping Units and come back. The same applies for rods: missing rod specs can be added under Equipment > Rods > Custom Rods.
Rods
Build the rod string from surface down to the pump.
Top-of-page fields:
| Field | Description |
|---|---|
| Polished Rod Diameter (in) | 1.00", 1.25", 1.50", 1.75", or 2.00" |
| Steel Rod Service Factor | Goodman service factor (default 0.69) |
| Calculate Guides Per Rod? | On = PetroBench computes guides for deviated sections |
| Include Buoyant Guide Weight? | On = include guide weight in fluid load |
The rod table is your taper string, top to bottom:
| Column | What it means |
|---|---|
| Row Type | Branded (catalog) or Custom |
| Rod Type | Sucker Rod, Sinker Bar, Continuous, Fiberglass |
| Supplier / Grade / Diameter | Material spec |
| Stress Cat | Goodman stress category |
| Guided / Guide Type / Guides per Rod | Guides for side-load wells |
| Length (ft) | Length of this taper |
Total rod length must be within ±50 ft of PSN depth. If it is off, fix the bottom taper length.
The Dogleg Severity sidebar on the left shows where the wellbore curves. Use it to decide which tapers need guides.
IPR
The IPR (Inflow Performance Relationship) tab is optional. Use it when you want PetroBench to predict production from reservoir behavior instead of just matching a target rate.
| Field | Description |
|---|---|
| Static BHP (SBHP) | Reservoir pressure at mid-perf when shut in |
| Bubble Point Pressure | Pressure where gas comes out of solution |
| Mid-Perforation Depth | Middle of the perforated interval |
| Test Pressure / Oil / Water / Gas | Stabilized production test point |
Then go back to Simulation Preferences and turn on Use IPR Data.
If you enter two or more test points at different rates, PetroBench auto-calculates the deliverability coefficient (C) and exponent (n). Otherwise enter them manually (n is typically 0.5 to 1.0, with 0.8 for most oil wells).
Skip IPR for a first run. Add it later if you want better deliverability predictions.
Step 3: Run It
When all five tabs show green checks, two run buttons light up in the top-right.
| Button | What it does |
|---|---|
| Static | Steady-state run. Returns dyno cards, stress, loads, gearbox torque. 10 to 30 seconds |
| Dynamic | Time-domain run with full transient response. Slower, much more detail |
Click Static for your first run.
You will see a progress modal stepping through:
- Processing Input Variables
- Solving Wellbore Profile (deviated only)
- Generating Wave Equation Calculations
- Establishing Steady State System Dynamics
- Simulating and Collecting Data at Steady State
When it finishes, the page scrolls down to results automatically.
Step 4: Read the Results
Results appear below the inputs in this order.
Design Evaluation
Four cards summarising whether the design works.
| Card | Reading it |
|---|---|
| Rod Loading | Are any tapers overloaded above 95%? |
| Rod Buckling | Is the sinker bar long enough? |
| Gearbox Loading | Is the gearbox over its rating? |
| Unit Structural Loading | Is the surface unit overloaded? |
Each card explains the issue and gives a recommendation.
Graphs
Three rows of charts.
Wellbore + dogleg + buckling
Dynamometer + side load + axial load
The dyno card is the headline chart. Polished rod load (blue) should sit between the permissible limits (red).
Gearbox torque runs across the bottom, showing torque over the crank cycle.
Calculated Results
Numbers tables grouped into Calculated Results, Tubing & Pump, and Pumping Unit Analysis.
Key numbers most users look at first:
- Fluid / Oil Production (bbl/day): what the design produces
- PPRL / MPRL (lbs): peak and minimum polished rod load
- Required HP: motor horsepower needed
- GB Loading (%): gearbox loading vs rating
- Unit Structure Load (%): structural loading vs rating
Rod String Table
Per-taper detail at the bottom: stress, length, top max, top min, bottom min for each rod section.
Red numbers are over the service factor and need attention.