We were deep into a long week of back-to-back cased hole logging jobs. The kind of week where the wireline truck barely gets a break, and the crew runs on muscle memory and good habits. The last well on the list was a high-temp perforation well—deep zone, heavy casing, hot formation. We’d loaded up with the usual downhole tools, logging cable coiled tight, and a set of shaped charges rated to perform under stress.

But there was one thing that made me pause—HMX.

Now, if you’ve ever worked in the wireline oilfield long enough, HMX isn’t just another line on your inventory sheet. It’s a serious explosive used in high-temperature primacord, shaped charges, and tubular cutters. It also happens to be one of the most heat-sensitive materials we use in wireline perforating. And in this case, we were headed straight for that threshold.

We double-checked everything—formation temperature, toolstring length, casing specs, pressure control equipment readiness. We had all the right wireline tools, followed the procedures from every good wireline course, and documented the explosives classification for this particular run. Still, I couldn’t shake the thought of what 300°F does to HMX.

See, explosives don’t act the same when they’ve been stressed. When HMX crosses its phase transition temperature—about 300°F—it becomes more sensitive to mechanical shock. That means if it doesn’t detonate downhole, and you bring it back up to the surface still live, you’ve got a potential hazard in your hands. Literally.

That’s exactly what happened.

We made the run. Everything looked normal. But we didn’t get a fire signal. The gunstring came back intact, unfired. And that meant those charges—now exposed to bottom hole temperature—were potentially unstable.

That’s where real wireline service companies earn their name. We followed explosives handling protocols down to the letter:

• The wireline unit was isolated.

• The gunstring was placed in a designated safe zone.

• No one touched a detonator.

• We waited 24 hours before disarming the system, just like we were trained.

In this business, wireline and perforating isn’t just about getting data or cutting pipe—it’s about controlling energy. It’s understanding the chemistry behind PETN, RDX, HMX, and knowing how each reacts under different conditions. And when it comes to formation evaluation, production logging, or perforation services, your success depends on more than just the depth of the perf gun.

It depends on how well you know what you’re loading.

Explosives in the oil field aren’t just tools—they’re forces. Every time we handle a detonator or shaped charge, we’re trusting that our training, equipment, and judgment will carry the day. That’s why wireline services oil and gas operations place such heavy emphasis on explosives classification, safe transportation, and regulatory compliance.

You learn early that temperature ratings, detonation velocities, and flash points aren’t just numbers on a sheet—they’re the rules of survival in the wireline business.

So whether you’re running a high-temp zone with PETN, a casing job with RDX, or a backoff shot with black powder, take the time to know your materials. Ask the questions. Review the labels. And if you’re ever unsure, walk away before something walks back on you.

In this world of cased hole wireline, wireline control systems, and downhole explosives, hesitation doesn’t make you weak—it makes you wise.