In wireline perforating, safety isn’t just a priority—it’s a necessity. I’ve seen how a single oversight in explosive handling can lead to near-misses or even catastrophic failures. One particular job sticks in my mind, where a gun was retrieved with an undetonated charge. That day, I realized the Explosive Safety Checklist isn’t just paperwork—it’s what keeps everyone alive.

The Importance of Explosive Safety in Wireline Services

Working with perforating guns, detonators, and high-energy explosives demands strict adherence to procedures. Whether performing cased hole logging, well perforation, or production logging services, failing to follow safety protocols can result in:

• Misfires leading to dangerous retrieval operations
• Stray voltage ignitions
• Downhole pipe recovery due to lost tools
• Injuries from unintentional detonations

By following the Explosive Safety Checklist, wireline engineers minimize these risks and ensure smooth operations.

Pre-Job Safety Checks

Before any wireline perforating job begins, a structured pre-job safety check must be conducted. Key steps include:

• Conduct a Safety Meeting
  • Review the Explosive Safety Checklist with the crew.
  • Identify potential hazards like stray voltage, electrical welding, and adverse weather conditions.
• Grounding and Stray Voltage Checks
  • Verify that grounding clamps are securely installed and continuity is below 0.5 Ohm.
  • Confirm stray voltage is under 250 mV.
• Establish a Safe Work Zone
  • Set up a designated area for arming and disarming perforating guns.
  • Ensure radio silence is maintained to prevent unintended electrical signals from triggering detonators.
• Disable Electrical Interference
  • Lock out rig electrical top drives.
  • Disable cathodic protection to prevent static discharges.

Arming the Explosive Device

Once pre-job checks are complete, the arming process must follow strict electrical before ballistic (EBBA) procedures.

• Turn Off Perforating Power Supply Panel
  • All unnecessary electrical panels must be shut down.
• Remove the Safety Key
  • The safety key remains with personnel outside the wireline unit until the perforating gun reaches 250 feet below ground level.
• Verify Safe Working Conditions
  • Ensure all non-essential personnel are cleared from the gun arming area.
  • Check that voltage is zero on the wireline before making electrical connections.
• Attach and Secure Detonators
  • Only approved detonating cord crimpers and cutters are used.
  • The HOT wire is grounded to the gun body before connecting detonators.
• Confirm the Explosive Device is Safe to Deploy
  • The Engineer signs off on the arming process.
  • The tool is carefully lifted using safe lifting practices and lowered into the well.

Retrieving Explosive Devices from the Well

Even when a perforating gun has fired, it must be treated as if it hasn’t until confirmed otherwise. If the device is coming out of the hole:

• Hold at 250 Feet and Conduct a Safety Meeting
  • Stop retrieval at 250’ and review safety procedures.
  • Maintain radio silence.
• Check for Detonation
  • Visually inspect the perforating gun for proper detonation.
  • Be aware of potential trapped pressure in the gun body.
• Disarm the Device
  • Follow ballistic before electrical rules to remove the detonator safely.
  • Only then can the safety key be returned inside the wireline unit.

Final Thoughts

In wireline and perforating, there are no shortcuts when handling explosives. Whether working on cased hole wireline, pump down perforating, or formation evaluation, strict adherence to explosive safety procedures ensures that every crew member returns home safely.

That day, when we retrieved an undetonated gun, was a wake-up call. Now, every time I arm a perforating gun, I treat it as if my life depends on it—because it does.