Keep your mud recycler working hard over the long haul with these tips
A mud-recycling system is fairly simple.
“It looks like a lot is going on, but it’s just fluid being transferred from one cycle to another and back to the drill. It’s just a circle, with a few loops in between,” says Seth Matthesen, senior product manager for Ditch Witch.
But that simple system can be a big benefit to the bottom line of a drilling contractor. Less outside water has to be hauled in and waste doesn’t have to be disposed of as frequently, saving a lot of time and expense. The machine can only provide those benefits when it’s operating effectively, though, so good maintenance practices are a must.
SCREENS TOP THE LIST
To separate the liquids from solids, the screens are doing the greatest amount of work, so they are the component that experiences the most wear, Matthesen says. They’re made to withstand a tough job site environment, but they still vary in cost and quality. The key, says Matthesen, is to match the screen to the soil conditions.
“If you’re working with a very abrasive material, you may want to use a more expensive, higher-quality screen. That way you’re not having to stop work on the job site and change out screens as often,” he says. “And there might be other times where you’re not in as abrasive of a soil and you can get by with a less-expensive screen. It’s all about job management.”
Because how a screen wears is so dependent on job site conditions, Matthesen says there is no hard timetable on when screens should be replaced. Operators just need to monitor them regularly. Before a job, make sure there are no holes in the screens. Even a small hole will let in solids that could damage other machine components. Matthesen says quick-dry silicone is commonly used to cover a worn area on a screen to extend its life, or at least allow work to continue until a replacement screen can be installed. Outside of an obvious hole, Matthesen says there are other signs that can indicate it’s time to consider replacement.
“The screens we use at Ditch Witch are in a mesh pattern. If those mesh pieces start to get misshapen that can cause the screen to allow more material through than it’s supposed to,” he says.
To limit premature wear, Matthesen says operators should watch the angle they set the screens at. A higher angle will keep material on the screen longer and produce drier cuttings, but that increased time on the screen will also cause more wear.
“Watch the way the material is coming off the end of the screen,” he says. “You want the material to stay on there long enough to take as much moisture out of it as possible. If the material is in a dry condition — or at least not really wet — coming off the screen, then you probably have the correct angle.”
That ideal angle will vary depending on the material. For example, in clay it’s more difficult to remove the moisture and a higher screen angle may be necessary.
“In some material you may just keep the screens perfectly level,” Matthesen says.
It also helps to keep the mud thin, or flowable as Matthesen says, by pumping enough volume downhole. Another technique for keeping that “flowable” consistency is to dig a deeper area on one side of the pit to provide a place for larger rock cuttings to settle.
“That way you’re not taking those huge rock cuttings off the bottom,” Matthesen says. “If you get into a situation with a lot of large rock cuttings on the screen, their bouncing up and down can potentially cause damage.”
A good way to troubleshoot a mud recycler is to monitor the system pressure. Matthesen says Ditch Witch’s MR90 mud recycler operates at just under 30 psi. Depending on the size of the system, most mud recyclers will run in the 20 to 30 psi range. Any out of the ordinary pressure reading could be a sign of a problem.
“That really is the key to the utilization of the system,” Matthesen says. “It could be from the pump getting old. There may be a gasket that is wearing. It may be a hydrocyclone. Hydrocyclones wear from the inside out, so it’s not something you can visually see without taking it apart or checking that pressure.”
If a hydrocyclone is the culprit, oftentimes it is nothing more than a plugged nozzle, Matthesen says.
“The material should spray out the bottom of a hydrocyclone. If it’s just flowing out like on a bathtub faucet, then there’s something wrong,” he says. “Typically the nozzle gets plugged up. Then you’re reducing your system capability. If you’re running five hydrocyclones, you’ve just cut it off by 20 percent.”
Another troubleshooting method is to regularly monitor the mud weight and sand content of the material while working out in the field. Keeping those at the right level can also prevent excessive wear on the machine components.
“You need to dispose of the material if it gets too high,” Matthesen says. “The heavier the weight, the higher the sand content, the more quickly things wear out not only for the recycling system but also for the drill.”
On Ditch Witch’s MR90 it is recommended that users dispose of material once it exceeds 9.5 pounds per gallon for mud weight and 1 percent for sand content. Those tests should be done every half-hour to an hour.
“If one day it took you 24 hours to get to the threshold and then three days later it only takes you 12 hours, there’s probably something going on with the system you need to recognize,” he says.
In cold-weather conditions, Matthesen says it’s important to properly drain the system after off-loading, and to use antifreeze as an additional measure to prevent any problems.
“You have to off-load and drain the pumps and the hoses, which is why there is a low-point drain,” he says. “I still recommend putting some antifreeze in the pump itself just so there is some liquid in it. It’s hard to get every bit of fluid out of a pump a lot of times. Otherwise the low-point drain will get everything else out.”
Yet another easy way to keep a mud recycler in good working order, says Matthesen, is to keep the pit pump hose that connects to the system clearly distinguishable from the transfer hose that transports clean fluid. If a mix-up occurs, the system’s pump could be damaged.
“It sounds pretty simple, but I’ve seen it happen. That dirty hose gets used on the clean side and causes damage to the pump,” he says. “I would recommend using two different types of hoses, two different colors of hoses, one collapsible and one solid. Something so you don’t mix up the hoses out in the field.”