Proper shaker screens selection

Shaker screens selection

Shaker screens are one of the most important, (and overlooked) pieces of equipment on the drilling rig. The Shale Shakers are your first line of defense against drilled solids & your primary solids control equipment. They are a key factor in determining the success of your drilling mud and centrifuge.

Shaker screens selection is critical in the operation of a drilling rig, as the shale shakers are the primary stage of drilling mud solids control system. Shaker screens can remove the solids that are larger than the screen mesh openings. The drilling mud with small solids would flow through the screen meshes, and down to the mud tank for a further purification. while the large solids or the cuttings would stay on the screen, and be vibrated and flow to the discharge end of the shaker basket.So it is really important to have the right shaker screen selected for your formation cuttings, bit type, and mud properties. On surface holes drilled solids are usually larger solids which can be removed easily with a coarse mesh shaker screen. A mesh of 50, 84 or 110 is usually adequate. However, intermediate and main hole cuttings are typically finer – therefore requiring a finer mesh. A minimum mesh of 110 is kindly recommended all the way up to 320’s & beyond for very fine sand.

Shaker screens selection

Pay attention to followings when select screen

When selecting a screen, end users should pay special attention to the screen design and the size of the opening. Most manufacturers focus on the frame structure and shaker fastening applications. However, focusing on a multilayered, wire cloth formula and wire diameter is critical. One manufacturer’s bottom layer of screens is comprised of thicker, market-grade wire. This yields a stronger base, which allows the other layers to maximize performance during the most severe conditions.

Screen selection

We must choose a proper shaker screen according to the solids diameter, mud gravity, viscosity & density etc. As improper screen selection can lead to loss of expensive drilling fluids, premature pump failures, overloading of other solids removal equipment such as a decanting centrifuge, decreased equipment life, reduced rate of penetration and serious problems in the well bore.

Proper maintenance on shaker screen

Maintaining your shaker screens is as important as the screen selection itself. In normal drilling it is important to ensure that the fluid comes about 25%-50% of the way across the screen furthest from the flow line. Try to have the Shaker deck as level as possible. This will allow for more consistent wear across the screens and typically means that the right size mesh has been selected. Jacking or raising the Shaker deck up, increases the amount of time that the solids will be on the shaker screens closer to the flowline. This will decrease the shaker screen life. Be careful when cleaning shaker screens, not to puncture the mesh as this will diminish the effectiveness of the screen. A shaker screen with the top layer of mesh gone is also less effective and should be replaced.

When a shaker screen has a hole in it there is no protection against drilled solids. Why leave things to chance. This will have a dramatic effective on your drilling fluid. Replacing a shaker screen is a lot cheaper then replacing a mud system, or rebuilding mud pumps & directional tools; not to mention the increased costs on the completions side of the well. It is also important to ensure that the shaker deck rubbers, shaker bypass and other shaker components are in good working order at all times. If you open the bypass while drilling, all the shale goes below the shakers and into the mud tanks – providing zero efficiency.

Please try above tips for increased success on your current or future drilling project