For example, casing deformation isn’t a new issue, but it’s becoming more of a conversation in certain basins. As oil and gas companies are drilling in non-core areas, they’re having to deal with challenges they aren’t accustomed to or have never seen before. Casing deformation is no longer just an issue for academic papers. It’s becoming a reality for operators everywhere.
If you’re faced with new challenges (casing deformation or screen-out) or the unknown (U-shaped wells or 4-mile laterals), here are a few things you should be thinking about.
1. Type of frac plug
This shouldn’t come as a surprise, but the type of frac plug you’re using can help prepare you for screen outs. For example, if you’re worried about not being able to flow a ball back to surface, you can just pop the PurpleSeal™ StageSaver off the seat and reestablish injection rate. The StageSaver is adapted to the PurpleSeal™ composite frac plug, which is known for its high performance and fast drill-outs, even in low-pressure environments.
READ MORE: Meet the StageSaver: your screen-out insurance policy
2. Lateral length
It’s just a fact that horizontal wells are getting longer. The average wellbore used to be only 2–2.5 miles. Now you’re looking at 4-mile stretches. Long laterals like this have been common in the northeast for several years, but this is becoming a more popular way to lower well costs across the market.
Many companies haven’t done extended-reach laterals before. As they’re trying this method that’s new to their operations, they’re finding that certain plugs are limiting their ability to execute without disruptions. With longer laterals, you need a plug that pumps down and drills out better. It also needs to withstand the ride, especially when the deployment is several miles longer than it’s been in the past.
3. Lateral shape
Another emerging trend is a U-turn lateral. Let’s say you’re running a four-mile horseshoe-shaped well, with two miles out and two miles back. The first two miles is a straight shot with no issues. But once you make the turn on the horseshoe, the drill pipe has to overcome more friction, and the plugs in that second part of the lateral can be harder to drill out.
To complete that U-turn, you need a plug that doesn’t break loose when met with a bit and has consistently small cuttings to flow through both curves and back to surface. It’s a physics challenge. These plugs are being asked to go further and be put in corners of the well that are barely being explored. Your standard plug may not be up to the task.
4. Snubbing units
Speaking of drill-outs, we’ve noticed that the snubbing unit (also known as the hydraulic completion unit) is becoming a trend, too. You might think you can’t drill out more than two miles of composites—but you’d be wrong. In fact, the world record for the number of plugs drilled in a single trip is 262 (ahem… PurpleSeal) with a stand-alone snubbing unit, not a rig-assisted unit.
This particular drill out wasn't an anomaly, either. There were three other wells on the pad that totaled 260, 259, and 259 stages each, all drilled in a single trip.
CASE STUDY: Completion of long lateral well project in Marcellus Basin
5. Low-pressure areas
In previous wells, you might have been getting away with subpar isolation because the rock was so good it didn’t matter what was going on downhole. That’s not the case anymore. As you start getting into depleted rock, every stage and every cluster counts towards the EUR (and, more importantly, NPV) of a well. That means you need a plug that isolates so that your stages are treated as designed, but also drills out well in low-pressure environments.
Want more information about how PurpleSeal™ frac plugs perform downhole? Read our summary of the ConocoPhillips plug testing study, which compared six industry-leading plugs in a single-wellbore trial. You can also contact us for product specs and other information.
