The role of a "wiper plug" in single stage cementing of a casing string; 1:40 minutes
Consultants, supervisors, company men and rig hands in drilling operations all get exhausted from being up in the middle of the night, two, sometimes three nights in a row, and start having brain farts. It happens. It's the oilfield.
Having a wiper plug not be loaded in a cementing head, or not get dropped from the head before displacement starts, or a wiper plug that gets stuck and does not release, is a potential disaster. I've had it happen three or four times in the four hundred wells I've drilled in the past 50 years and when it happens all you can do is feel wormed out if you were responsible. If you expect folks to do their job, with your personal money plopped down on the well, then you start looking for asses to eat out. Trust me man, I'm old school, don't have an HR department to bow down to, and I can eat asses out like nobody you EVER worked for. Worm is NOT a four letter word around my chicken shit outfit.
Here's a trick I learned in S. Texas a long time ago that they don't teach in petroleum engineering school, I assure you. If you asked Halliburton hands to do this they'd look at you like you were nuts; on the other hand, the last half dozen wells I've drilled, including one last week, I've used BJ Services out of San Antonio and noticed they always use this little trick, asked or not. I like BJ; they're good, happy to be on location working and they help me learn better Spanish on the intercom headsets while the job is going on. Listen and you shall learn.
Before pre-loading the wiper plug in the cementing head, take some thin copper wire and build a cradle, or a loop on the top of the plug, like you see above. Take another long strand of the same copper wire, tie it to the loop and thread it thru the cementing head when loading the plug and leave a long tail on it that everyone can see, like this:
When you finishing pumping your tail slurry, the lines are all washed and the cementing hand opens valves in the head and pulls the pin to release the wiper plug. When it falls ahead of the displacement fluid... watch, or hold on to the little copper wire, and whoosh, its gone, getting pumped down hole with the plug. Then you know the plug's dropped and you can forget about THAT potential problem and start worrying about the next one that's getting ready to happen.
Like this one:
Actually the only problem here was that I had forgotten what dark clouds look like; I mean, it's been two full months since we had any rain. I guess I got a little... confused. In the end this was really not a problem at all, it was great! It had been 112 degrees while we were running casing, with 70% humidity; this little storm dropped the temperature 20 degrees. It didn't ever rain, but what the hell. I almost had to go get a hoodie out of my work bag to put on, it got so cold.