Mud recycling systems in general are fairly simple units to operate but there are some items that need to be watched and maintained in order to to keep your system running smoothly. The following are some suggestions and tips in order to get the most out of you mud recycling system:
1. Mud recycling systems in general do not require a degree in chemistry to run and operate but it is a must that the operator has some training and understanding of how the unit works and operates in order to get the most out of the system. Most manufacturers are more than happy to send a technician out with a new unit to do the initial startup and training in the proper operation of that particular unit. If follow-up training is required for whatever reason, most manufacturers have people available to send to do the followup training.
2. At minimum, there are a few tools that you should have on every mud recycling system that you have in your fleet. A Marsh funnel is a must; without this, there is no way to accurately know what the viscosity is of your drilling fluid. The next must-have item is a sand content kit, which measures the amount of sand in your drilling fluid. Without this piece of equipment, there is no way to accurately know how well your mud system is performing. Finally, a mud scale should be a part of your mud kit. The mud scale is exactly what it sounds like: It is a scale designed to measure the weight of a given amount of drilling fluid. This can tell you how many ultra fines are in your drilling fluid. The ultra fines are the particles too small to be measured by the sand content kit. All of these tools mentioned are fairly inexpensive and easy to use with minimal training. Without them, there is no way of knowing how well your system is working or how good your drilling fluid is.
3. Screen selection is a big question most manufacturers get asked about and it is probably the hardest question to answer. As manufacturers, we can recommend screens that are most common and will probably do the job. But without being
on the job to see the conditions, it is hard to know the best screen mesh for the job. Screens are expensive and, for the most part, fragile so most contractors don’t want to have a bunch of them laying around the jobsite to get ruined. However, if the soil conditions change and you need a different mesh to get the solids out and you didn’t bring any other mesh screens, then you might have to drill with dirty mud for a few days until you can get the correct mesh. And by then, you may have done hundreds or even thousands of dollars of damage to your mud pump or your mud motor. The screens are the first line of defense in your mud system and it is important to keep them in good shape and change them as needed.
4. Hydrocyclones are pretty simple in design and don’t require a lot of maintenance. One thing to check every so often is the cone manifold pressure. The cones operate at approximately 32 psi and if that pressure falls off considerably, then the cones will not perform at optimum performance. This will result in drilling mud that is not as clean as it should be. If the pressure falls off, it is usually because part of the cone is washing out from the abrasives being pumped through it. If you separate the cone and look inside, you will see a swirling effect. This swirling effect is a definite sign that the cone needs replaced. The inside of a new cone will have a smooth tapered wall. The other most common reason for low cone manifold pressure is a worn out impeller in the cone feed centrifugal pump. If the impeller is worn out, it will not be able to move enough fluid to build the required pressure and will have to be replaced or repaired. There are other items that could contribute to low cone manifold pressure, but these are the two most common causes.
5. Centrifugal pumps are simple pumps to maintain but some things should be done to ensure you are getting the most out of them. Centrifugal pumps that use square rope packing will have a grease zerk on them, usually at the top of the packing gland. This grease zerk should have two to three shots of grease for every couple of hours of operation. You should also check the packing every few hours for excessive leakage. Centrifugal pumps that use this square rope packing should never have the packing tightened so tight that the packing quits dripping at all. If you tighten the packing this tight, it will burn the shaft and then you will be forced to replace the shaft, as you will not be able to keep packing in the packing gland. Centrifugals that use mechanical seals do not leak fluid and generally require less maintenance — but they do cost more to initially purchase. The centrifugal will either have bearings that are in an oil bath or there will be a grease zerk at the top of each bearing housing that you will have to grease every few hours when you are checking the packing. Oil bath types only need to have the oil level checked once a day. Pay attention to the condition of the oil while you are checking it to ensure it doesn’t have water or drilling mud in it.
6. Shakers, depending on the manufacturer and the screen type, can differ quite a bit. The main thing with any shaker is to make sure the screens in the shaker do not have holes of any size in them and that they are not blinded off. A screen with a hole the size of a nickel can allow a lot of sand and gravel to enter the mud system, causing huge headaches down the road. Imagine you have a hole the size of a nickel and a few rocks the same size get into the system. Now imagine they get picked up by the desilter cone feed pump. These rocks, the size of nickels, are now stuck in the end of your desilter cone and the only way to get them out is to take the cone apart and remove it by hand. This operation takes a minimum of five to 10 minutes. As soon as you reassemble the cone and turn the system back on, be assured that you will have another one picked up and stuck in the end of the cone. If you do this all day or night it starts to eat up a lot of time and can get costly, as you will have to shut the rig down because you can’t keep up. Regarding the blinded off screens, this happens when the diameter of the sand is just big enough to get stuck in the open area of the screen mesh. This plugs the mesh and if enough of this happens you can end up with 50 to 75 percent of your screen unusable. You may need to go to the next finer mesh screen and see if this helps. However, many times you can take the screen off and turn the screen around, using your pressure washer you can blast the stuck sand particles out of the screen and reuse the screen.
Hopefully these are some good tips that will help contractors get better results and longer life out of your mud recycling systems.