Two Approaches to Rod Pump Simulation
Rod pump design is one of the most calculation-intensive tasks in artificial lift engineering. Getting the rod string, pump sizing, and operating parameters right requires solving the wave equation under realistic downhole conditions - and the tools engineers use for that work shape how they collaborate, iterate, and ultimately make decisions.
S-Rod and PetroBench both tackle this problem, but they come from different eras and different design philosophies. This page walks through the key differences so you can evaluate which approach fits your workflow.
S-Rod Background
S-Rod was originally developed by Norris Rods, which is now part of National Oilwell Varco (NOV). It is a Windows desktop application used primarily for rod pump design and analysis. S-Rod has a significant install base, particularly among operators in North America who work with Norris/NOV rod products. It is a separate tool from NOV's broader SCADA and automation portfolio - focused specifically on rod string simulation.
Product Architecture
S-Rod is a traditional desktop application that runs on Windows. Simulation files (.inp6e and .inp7, both XML-based formats) live on the user's local machine or shared network drives. Each engineer works with their own installation, and sharing results typically means sending files by email or through a shared folder.
PetroBench is cloud-based and runs entirely in the browser. There is nothing to install, no license server to manage, and no dependency on a specific operating system. Engineers access their work from any device with a browser, and all simulation data is stored centrally with automatic version history.
This is not just a convenience difference. Desktop vs. cloud fundamentally changes how teams work together, how IT manages deployments, and how quickly new engineers can get productive.
File Compatibility
If you have existing S-Rod simulation files, PetroBench imports them directly. Both .inp6e and .inp7 formats are supported. Upload your files and PetroBench parses the XML structure, maps the parameters, and creates a new simulation you can immediately run, compare, and share with your team.
This means you do not have to re-enter well data manually to start using PetroBench. Your existing work carries over.
Simulation Approach
Both S-Rod and PetroBench solve the wave equation for rod string behavior. This is the industry-standard mathematical foundation for predicting loads, stresses, and pump performance in a sucker rod system.
Where the two tools differ is in their fluid property correlations. S-Rod and PetroBench use different approaches to model multiphase fluid behavior downhole. When you import an S-Rod file into PetroBench, the system identifies where fluid correlation differences exist and flags those parameters for your review. This lets you make informed decisions about which assumptions to carry forward and which to adjust.
Neither approach is inherently wrong - different correlations have different strengths depending on the fluid system. The important thing is that you know what assumptions are driving your results.
Collaboration and Version Control
In S-Rod, collaboration typically means passing files between engineers. When multiple people work on the same well design, keeping track of which version is current - and what changed between versions - falls on the engineers themselves.
PetroBench handles this differently. Every simulation change is versioned automatically. Engineers can compare any two versions side by side to see exactly what parameters changed and how results shifted. Multiple team members can access the same well designs without file conflicts, and there is a clear audit trail of who changed what and when.
For teams working across multiple offices or with field engineers who need access to the latest designs, this eliminates a significant source of confusion and rework.
Integration and Automation
S-Rod operates as a standalone desktop application. Connecting it to other systems - SCADA platforms, production databases, or internal engineering tools - requires custom scripting or manual data transfer.
PetroBench provides a REST API that lets you programmatically create simulations, retrieve results, and integrate rod pump design into your broader engineering workflows. If your team is building automated optimization pipelines or connecting simulation results to field operations, the API makes that possible without manual intervention.
What S-Rod Does Well
S-Rod has been in the market for a long time, and it serves a real need. It is tightly integrated with NOV's rod product catalog, which makes it a natural choice for operators who are already buying Norris/NOV rod strings. Engineers who have used S-Rod for years have built up institutional knowledge and workflows around it, and that familiarity has genuine value.
If your operation is primarily North American, heavily standardized on NOV equipment, and your engineering team works independently rather than collaboratively on designs, S-Rod may continue to serve you well.
What PetroBench Does Differently
PetroBench was built from scratch as a modern engineering platform. Rather than digitizing a desktop workflow, it rethinks how rod pump simulation fits into a team-based, data-driven engineering process. The key differences:
- No installation required. Open a browser and start working. No IT tickets, no Windows dependency, no license servers.
- Built-in version control. Every change is tracked. Compare any two versions side by side to understand what shifted and why.
- Team collaboration. Multiple engineers work on the same well designs simultaneously. No file conflicts, no version confusion.
- REST API. Integrate simulation into automated workflows, connect to your production data systems, or build custom optimization pipelines.
- S-Rod file import. Bring your existing .inp6e and .inp7 files over without starting from scratch.
Migration Path
Moving from S-Rod to PetroBench does not require a hard cutover. Most teams start by importing a handful of existing S-Rod files to validate results against their known benchmarks. Once you are comfortable with the output, you can migrate your full library of simulation files at your own pace.
During the transition, PetroBench flags any fluid correlation differences so your team can review and adjust assumptions as needed. There are no surprises - you stay in control of the engineering decisions throughout the migration.
The bottom line: S-Rod is a proven tool with a loyal user base and deep ties to NOV's rod product line. PetroBench is built for teams that want cloud-based collaboration, version control, and API access as standard features rather than afterthoughts. If your workflow has outgrown desktop file sharing, it is worth evaluating what a modern platform can do for your team.
