There’s a moment in every wireline engineer’s journey when something simple turns into something critical—and fast. I’ve seen it more than once in cased hole logging operations, where one loose connection or overlooked detail in the wireline toolstring can turn a well perforation run into a long day of fishing wire line or replacing blown components. But one job in particular taught me that even the smallest hardware update can save a toolstring—and a crew—from disaster.
We were prepping for a pump down perforating run. The operation involved standard cased hole wireline with multiple downhole tools in sequence. At the bottom, we usually ran a double female arming sub and a PSA crossover with a selective switch setup. But this time, we made a small change—one that would reduce connection points and improve reliability. We replaced the old setup with a female PSA sub and a modified quick change. Fewer threads. Fewer electrical components. Less risk.
Sounds minor, right? But what I didn’t realize then was just how much this would help downhole.
Mid-run, just before reaching target depth, our logging cable tension spiked briefly. No alarms, but I knew something wasn’t right. Pulled the string back, checked every wireline connection—and that’s when I realized: if we’d still been using the old PSA insert with that additional sub, we might’ve had another short to mass. That old design had failed before due to electrical tape residue creating a path to short. It cost us a misrun and hours of troubleshooting. This new setup eliminated that entire failure mode.
More Than Just Connections
On the same project, we also had to inspect the 2-inch fishing necks on the over-the-line weight bars. I’d seen reports of lips on those fishing necks hanging in the bottom of the lubricator, which could lead to surface pullouts. Sure enough, one of ours had a pronounced edge—easy to miss but dangerous under pressure. We swapped it for a modified, rounded version and added a visual inspection step to our perforation checklist.
This kind of proactive maintenance is what separates a safe, efficient wireline run from a costly recovery job. It’s why I teach this in all my wireline courses—if you’re not checking the simple stuff, the complex stuff won’t work either.
Watch the Depth—It Can Bite Back
And speaking of pullouts, I’ll never forget a miscommunication during a well perforation job where a positive bump-up depth wasn’t reported to management. The engineer on shift didn’t get the update and referenced the wrong well sheet during pullout. Within half a second, the logging cable tension spiked, and we nearly lost the toolstring to the grease head. The lesson? Always flag abnormal conditions and notify your team. Depth mismatches can lead to toolstring loss, wireline truck downtime, and massive operational delays.
Lock Rings and Loose Ends
One final kicker—our weight bars. Some came with internal lock rings to secure the guts in place, others didn’t. After a few intermittent failures during switch tests, we found the root cause: those lock rings had backed off. In a few runs, they’d loosened just enough for the internal components to shift. Now, every weight bar gets broken down and rebuilt before a job, and if it’s a lock ring type, we use the proper tool to torque it correctly.
This is what wireline services oil and gas comes down to—rigorous attention to the things others overlook. Whether it’s a wireline gun setup for perforating, managing your wireline control systems, or simply making sure your wireline truck leaves the yard with fully tested equipment, every step matters.
I’ve built wireline courses based on these exact situations—not theory, but field-proven solutions and standard operating procedures that help you avoid costly mistakes. If you’re navigating the wireline services market, working with cased hole solutions, or exploring what is wireline in oil and gas, these lessons are your starting point.
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👉 Wireline Training and Courses
Because wireline isn’t just about running tools—it’s about knowing how and why they fail, and how to stop it before it happens.