How One Missing Port Plug Almost Cost Me the Whole Job

Posted on by Crissa Fel Tawadan

I’ve been in the field long enough to know that sometimes, the most dangerous mistakes in wireline operations aren’t the big mechanical failures—they’re the small ones that slip through because someone didn’t double-check. And I’ve seen firsthand how that one unchecked detail can turn a routine wireline well logging operation into a downhole nightmare.

We were in the middle of a pump down perforating job on a tight pad—standard cased hole logging setup. The crew was sharp, the wireline truck prepped, all our wireline tools rebuilt and verified. At least, that’s what I thought.

A Port Plug, a Switch Test, and a Lesson in Attention

After assembling the gunstring, we ran a switch test at surface—green across the board. Equalized, hit 200 ft, performed another test… and boom—short circuit. Pulled the string. Found it flooded.

The root cause? A missing port plug. It had been removed for troubleshooting a faulty switch, and in the confusion of shift change, it was never reinstalled. That one missing component cost us two hours of lost time, a gunstring teardown, and a frustrating post-job report.

This is why, in every one of my wireline courses and with every crew I train, I hammer home the basics:

  • Double-check port plugs after any troubleshooting or gun rebuild

  • Physically inspect the full wireline unit before any run

  • Never assume—it’s not paranoia, it’s process

In cased hole wireline operations, those port plugs are your gatekeepers to maintaining well integrity and keeping your perforating gun functional under pressure.

Grounding Springs and Intermittent Switch Failures

Another job, same lesson. We were prepping a wireline perforating system when we started noticing intermittent failures during switch tests. The string would test fine on surface but fail 1000 ft in.

The culprit? Inconsistent grounding. We implemented grounding springs in every sub moving forward. Now, every wireline perforating gun includes:

  • A dedicated ground spring

  • Twisted ground wires from the detonator, loading tube, and spring

  • Megging and retests after every 5 runs

It’s a best practice that’s now non-negotiable. These grounding systems have become a core part of complete wireline solutions we apply across the board.

Measuring Head Mayhem and Depth Mismatches

And then there’s the infamous measuring head chaos. I was once on a job where the cable tension was calibrated perfectly—or so we thought. Turns out, the measuring head bearings were loose, causing subtle inconsistencies in depth tracking. The result? We set a plug 10 ft off target.

Before every job now, my checklist includes:

  • Check for 2.023 ft/rev on the measuring wheel

  • Verify tension calibration on both Warrior and the winch panel

  • Inspect all bearings—if there’s any lateral movement, replace them

  • Confirm all systems (backup, Warrior, and winch panel) are synchronized

In wireline well logging, especially when preparing for well perforation or production logging services, accuracy isn’t optional—it’s critical.

Why Crossed Armors Still Haunt Me

Let’s not forget the time a crossed armor strand nearly ruined a run. It snagged below the grease head during retrieval, tore insulation, and sent our logging cable into the scrap bin. These days, I don’t rehead a wire line without:

  • Verifying armor strand count and pattern

  • Feeling the line for high spots before and during the run

  • Watching for abnormal tension changes during both RIH and POOH

It’s a small investment in time that prevents a huge investment in fishing wire line or explaining delays to a client.

Bringing It All Together

Wireline tech has come a long way. But no wireline control system, no perforating gun oil and gas setup, and no wireline truck full of the latest wireline equipment can replace a process-oriented crew that knows the “why” behind every step.

That’s why I created my library of wireline courses. These aren’t just theory—they’re built on actual misruns, near-misses, and successes like these. If you’re in the wireline business, running wireline and perforating operations, or trying to lead your wireline company through the fast-changing wireline services oil and gas sector, this training is essential.

Stay safe. Stay sharp. Stay prepared. That’s what makes a real wireline provider.