My last column gave detailed instructions for removing a string of stuck tools that cannot be pulled out with the drill line. The first of order of business with this fishing job involves cutting the drill line at the rope socket. I wrote about that in detail last time. With that done, we can proceed to grab the stuck tools with a fishing string and remove them.
Once you free the drilling line from the stuck tools, you attach it to a new socket. Some drillers prefer a solid socket for fishing, but experience tells me that a swivel socket works fine. Besides, once you retrieve the tools from the hole, you can attach the new socket to the formerly stuck tools and continue drilling.
Drill Tool Fishing Setup
The fishing tool of choice that we will use is a combination socket. This will catch the fishing neck of a wireline socket and the pin of any tool lost in the hole (for whatever reason). A combination socket to run in a 4-inch hole will catch a 2⅝-inch API pin or a 2½-round round. This is bigger than normal 4-inch tools will feature. A combination socket for a 5-inch hole will catch a 3-inch API pin, or 2.75-inch round or normal 5-inch tools. A combination socket for a 6-inch hole will catch a 3¼-inch API pin or a 3¼-inch round. I emphasize the importance of selecting the proper combination socket to do the fishing job. As I have written before, selecting the wrong fishing tool or using the wrong procedure complicates any fishing job many times over.
I recommend you measure all the tools used, especially the diameters of the fishing neck of the rope socket and collar, as well as both the pin and box parts of the joint. Record these measurements and keep them in a safe place for reference, but not hidden away where no one can find them.
When setting up a fishing string, remember: The weight of the fishing string plus the drilling string cannot exceed the lifting capacity of the rig’s bull reel. It’s important. Fishing work like this also gives us a friendly reminder not to make the drill string the maximum weight the drill rig can handle.
Getting to the Drill Tool Fishing
After proper setup, we are finally ready to go downhole, get a hold of the stuck tools, lost bit or what-have-you, and remove them. Again, know what the particular combination socket you use can catch and select the correct slips for it. Most of the time, the fishing neck of a rope socket will be a standard size — for example, 2-inches for a string of 4-inch tools, and either 2.75- or 3.25-inches for a string of 6-inch tools, depending on the joint size. Our fishing string consists of a rope socket, a fishing stem, fishing jars and a combination socket.
First, determine whether the socket can go over the fish and that no obstructions exist. To do this, wedge a soft wood stick across the mouth of the socket with the slips removed. Lower this into the hole as far as it can go. Mark the drill line to show the exact depth the tools went down, and then remove the fishing string. If the wood block has been knocked out, the socket can engage the stuck tools. If not, the descending socket probably hit an obstruction. The driller then has to use bailers, flushing pipes or any number of other means to clear the stuck tools. An obstruction above stuck tools greatly complicates a tool-fishing job.
Presuming the fishing string went all the way to the stuck tools, we now assemble the combination socket. Clean and oil the inside of the socket, the slips themselves any other parts, and then assemble. Lower the assembled socket down to the stuck tools, observing the line marked during the previous step, which lets the driller know the fishing string has reached the tools. Then, start the spudder beam and make some light blows downward. Stop the beam and apply a bit of tension to the fishing line. At this point, the tools may (thought probably won’t) come free. It often takes repeated attempts. If not, restart the spudding action and let out just enough line to allow light jarring by the fishing jars. Remain patient. Often, just some light jarring can loosen the stuck tools and you can pull both strings pulled from the hole.
If light jarring does not loosen the stuck tools, then harder jarring is necessary. I recommend short, rapid strokes as opposed to long, hard strokes. In most cases, this can loosen the stuck tools. However, if after a long time jarring, you still cannot free the tools, you need to break the hitch on them. Accomplish this by jarring both up and down. In doing so, there is a good chance the slips may be lost or the combination socket damaged. Then, remove fishing string from the hole. In my opinion, the next option becomes abandonment. No one likes to leave tools in the hole, but resist the temptation to keep trying and trying and trying, only to ultimately fail and spend more money than the stuck tools and the drilled hole are worth.
If the fishing job succeeds, remove the combination socket from the fish by knocking out the wood block inside it. This block applies pressure to a spring, which keeps the slips tight. With it removed, you can the combination socket. If you properly sized the rope socket in the fishing string, you can attach it attached to the formerly stuck tools and continue drilling — hopefully with drilling jars in place to avoid getting stuck again.
The best advice about drill tool fishing is to avoid it at all costs. But it is part of the drilling business, no matter how good the driller, so it’s best to stay ready. Next time, I write about a way to attach the drilling line to the tools that makes it impossible to fish for them, as well as other fishing tools.
In my monthly weather report, we had a cool and rather nasty spring here in southern Michigan. Then, with only a few nice spring-like days, the weather turned very hot with no rain falling and none expected. My infamous lawn is still green, but how long it will stay that way is anybody’s guess.
Until next time, continue to work hard, avoid those fishing jobs and, if possible, and remember to enjoy life too.
For more John Schmitt columns, visit www.thedriller.com/schmitt.
The Full Interview
We interviewed Jeff Blinn for our Drilling In-Site series. Our talk covered training, mud school, mentoring and other topics from his 40-plus years in the industry. See the full conversation at www.thedriller.com/insite, or listen to the podcast version at www.thedriller.com/insite-podcast.
Working on an interesting project or have industry wisdom to share? Email email@example.com to be considered for a guest spot on Drilling In-Site.