Shale shakers are devices that remove drill cuttings from the drilling fluid that is used for boring holes into the earth. Controlling the solids in drilling fluid is an important component of the cost of drilling, so research into improved shaker design is ongoing.
Shale shaker design
Shale shakers typically consist of large, flat sheets of wire mesh screens or sieves of various mesh sizes that shake or vibrate the drill cuttings, commonly shale, across and off of the screens as the drilling fluid (mud) flows through them and back into the drilling fluid system. This separates the solid drill cuttings from the fluid so that it can be recirculated back down the wellbore. In oilfield industry, linear motion shale shakers are widely used.
Shaker Screen Panels
Screen panels play a major role by removing particles larger than the mesh size. Screen selection is critical since shaking is the primary stage in the removal of solids. Improper screen selection can lead to de-blinding[clarification needed], loss of drilling fluids, premature pump part failures, overloading of other solids removal equipment within the mud systems, decreased service life , reduced flow rate capacity, and serious problems in the wellbore.
Causes of screen failure
The top 10 causes of premature screen failure are:
- Personnel improperly trained on handling, storage, maintenance and installation of deck rubbers and screens
- Careless storage of screen panels prior to use
- Screens damaged before use from improper handling during installation
- Deck rubbers improperly installed
- Deck rubbers dirty, worn or missing
- Dried cuttings or drilling fluid left on screen during shutdown of shaker
- Personnel walking on screens or using the shaker as a work table
- Tools being dropped on screens
- Extremely high mud weights or heavy solids loading
- Defective or improperly manufactured screens
- Use of high pressure wash guns to clean plugged screens
Screen Panel Designation
An explanation and FAQs for the API RP 13C screen designation tests and data can be found at the link below.
The American Petroleum Institute (API) Screen Designation is the customary identification for screen panels. This includes:
- API Number: the sieve equivalent as per API RP 13C
- Conductance: the ease with which a liquid can flow through the screen, with larger values representing higher volume handling
- Microns: a unit of length equal to one-thousandth of a millimeter
- Non-blanked area: an evaluation of the surface area available for liquid transmission through the screen