Safety in cable-deployed well services for oil and gas is more than just a priority—it’s a necessity.One overlooked step can turn a routine job into a high-risk operation, especially when working with wireline perforating, pressure control equipment, or logging cables.
Stray voltage is one of those hidden dangers that doesn’t always announce itself. A simple check can mean the difference between a smooth wireline operation and an unexpected incident. That reality hit hard during a cased hole wireline job when a routine well perforation almost turned into a dangerous situation.
The Risk of Stray Voltage in Wireline Logging
Stray voltage is an unseen hazard that can cause serious issues in wireline and perforating operations. If not properly checked and eliminated, it can:
- Cause unexpected electrical discharges when working with perforating guns
- Damage wireline control systems and logging cable connections
- Put personnel at risk of electrocution when handling wireline tools
- Affect well integrity and delay wireline service providers from completing the job
Cased hole logging, pipe recovery, and production logging services rely on stable electrical environments to function properly. That’s why performing stray voltage checks is a step that should never be skipped.
How to Perform a Stray Voltage Check in Wireline Operations
Before beginning wireline logging, perforation well operations, or cased hole solutions, it’s critical to ensure there is no stray voltage present.
Equipment Needed:
- Digital Multimeter to detect AC/DC voltage
- File and Emory Cloth to ensure clean contact points
- Ground Clamps to test for proper resistance and grounding
Method for Stray Voltage Checks:
- Verify that ground clamps are properly connected and functional
- Ensure the resistance between the cable and the ground clamp is below 1 ohm
- Check for stray voltage between the wireline cable and the wellhead
- Check for stray voltage between the wireline cable and the rig/crane
- Check for stray voltage between the wellhead and the rig/crane
- Always check for both AC and DC voltage readings
- Ensure that all voltage readings are below 0.25 volts before proceeding
- If voltage is above 0.25 volts, identify and eliminate the source before grounding
- If necessary, perform additional stray voltage checks for multi-well pads
Applying Stray Voltage Best Practices in Wireline and Perforating Services
A stray voltage check was all it took to prevent a potentially dangerous electrical hazard during a recent wireline oilfield job. The initial voltage reading showed a small but significant 0.21 volts DC between the wireline cable and the wellhead.
Instead of rushing into the operation, the team:
- Rechecked grounding clamps and ensured they were attached to bare metal
- Used emory cloth to clean contact points for accurate readings
- Verified voltage elimination after attaching grounding cables
The final voltage reading dropped to zero, allowing the job to proceed safely.
Lessons Learned in Wireline Well Logging and Cased Hole Wireline
A strict stray voltage testing procedure has resulted in:
- Zero electrical-related misfires in perforation services
- Improved wireline equipment reliability and logging cable safety
- Compliance with wireline service market regulations for safety
For any wireline service provider, these safety steps are critical. Perforating systems, pressure control equipment, and cased hole wireline jobs all require consistent and thorough stray voltage testing.
Ignoring this step isn’t an option. In the wireline business, the smallest mistake can have the biggest consequences.
Check your ground. Check for voltage. And never assume safety—verify it.