The Misfired Plug That Changed How We Build Our Firing Heads Forever

Posted on by Crissa Fel Tawadan

You don’t forget the sound a plug doesn’t make.

If you’ve worked in wireline and perforating long enough, you know what I mean. You prep the wireline tools, verify the shot sheet, check your wireline control systems, and go through all the motions—only to realize the plug didn’t set. The power charge never lit. And now, you’ve got a dead run, a confused client, and a plug still hanging off your firing head.

That’s what happened on this job. And it’s the reason we now mandate a secondary igniter in every standard power charge firing setup. This wasn’t a complex well. This wasn’t exotic wireline technology. This was a straightforward job that reminded us why the smallest missing component can lead to the biggest mistakes.

A Standard Setup, A Standard Tool, and a Not-So-Standard Outcome

We were running a routine pump down perforating job in a gas well. The goal: set a plug and shoot the guns. Horizontal wireline conditions, typical downhole temperature, nothing too challenging.

The setting tool was a Baker #10 with a standard power charge. No secondary igniter installed. The engineer had used this same configuration before on other tools—mainly with Baker #20s—and it worked fine in those scenarios. But this one didn’t.

We got a “short” notification from the wireline truck—one of those subtle little alerts that doesn’t scream, just whispers. No other signs. The client gave the green light to proceed. We fired the perforating guns and ran the string back up.

At surface, everything looked intact—except the plug was still there.

The perforating gun had functioned, but the plug hadn’t set. The firing head was pulled and inspected. The primary igniter had fired—but it wasn’t enough. The power charge remained unburned. We had a misrun.

Why the Igniter Failed—and What It Taught Us

The issue wasn’t the power charge itself or the firing head design. It was the assumption that the primary igniter alone would generate sufficient energy to ignite the charge under those downhole conditions.

In this case, the power charge lacked a built-in ignition booster, and no secondary igniter had been added to compensate. That gap in the ignition chain was all it took.

This failure prompted a full review of our ignition procedures and led to a sweeping change across our cased hole wireline operations.

The Fix: Secondary Igniters Are Now Mandatory

To prevent future incidents like this one, we implemented a new standard:

Any standard power charge used in any firing head MUST be paired with a secondary igniter—unless the charge already contains an integrated ignition booster.

Here’s what this procedure looks like today:

New Firing Head Assembly SOP for Plug Setting

1. Identify Power Charge Type

  • Confirm whether the power charge contains an integrated ignition enhancer or booster.

  • If not, a secondary igniter is required—no exceptions.

2. Select the Correct Secondary Igniter

  • Match the igniter model to the firing head and pressure rating.

  • Confirm electrical compatibility with your wireline control systems and logging cable voltage.

3. Install Both Primary and Secondary Igniters

  • Primary igniter is seated first and connected as standard.

  • Secondary is added into the firing head body—aligned to ensure proper energy transfer upon initiation.

4. Double Verify Electrical Continuity

  • Use resistance and voltage tests to confirm both igniters are correctly seated.

  • Perform a full switch test before running in hole.

5. Include Ignition Details on the Run Sheet

  • List primary and secondary igniter types and lot numbers.

  • Provide configuration specifics to client rep for transparency.

Why It Matters in Wireline Services Oil and Gas

In today’s high-output, high-scrutiny wireline services market, clients expect 100% tool performance. A misfired plug isn’t just a headache—it’s lost time, delayed frac stages, and a dent in your reputation as a wireline provider.

This failure taught us that you can’t rely on history. Just because something worked last time doesn’t mean it’s right for the next job. The wireline oilfield evolves—and so must we.

Built Into Every Wireline Course and Toolbox Meeting

This incident became a cornerstone example in all our wireline courses. New and veteran techs learn:

  • The difference between standard and boosted power charges

  • How to identify when a secondary igniter is required

  • How downhole conditions affect ignition reliability

  • Why relying on “what worked last time” is a dangerous habit

Every firing head assembly is now subject to a dual-signoff process before rig-up. If the secondary is missing, the string doesn’t go downhole—period.

Supporting Better Performance Across All Services

This procedure applies to more than just plug setting. We now use it as part of our firing SOP for:

  • Perforation services

  • Production logging tools that require explosive-actuated sequencing

  • Fishing wire line operations where back-off or severing tools may be used

  • Specialized downhole tools like mechanical punchers, backpressure relief systems, and emergency cutters

Even pipe recovery tools are now verified for secondary ignition when power charges are involved.

Final Thoughts – Ignition Is Not Optional

If you’re running a wireline service company, managing wireline trucks, or planning to expand into new cased hole logging territories, this is the kind of procedural rigor that will set you apart.

In wireline logging, there’s no prize for getting lucky. The only wins that matter are repeatable, verified, and documented. That’s what complete wireline solutions are built on.