Solids Removal by Mechanical Separation
Of all the problems that could conceivably occur during the drilling of a well, mud contamination from drilled solids is a certainty. The volume and type of solids present in drilling mud exert a considerable influence over mud treating costs, drilling rates, hydraulics, and the possibility of differential sticking, kicks, and lost returns.Solids control is one of the most important phases of mud control it is a constant issue, every day, on every well. If drilled solids can be removed mechanically, it is almost always less expensive than trying to combat them with chemicals and dilution.
The primary reason for using mechanical solids control equipment is to remove unwanted drilled solids particles fro the mud in order to prevent drilling problems and reduce mud and waste costs, thereby reducing overall drilling costs. The benefits of solids removal by mechanical separation can best be seen in terms of two outcomes:
A common method of trying to offset the build-up of drilled solids is the addition of more liquid.This is known as dilution and does not remove cuttings but reduces their concentration in a drilling mud, thereby reducing the percent of total solids in the mud.
However, it is important to note that dilution is expensive. Every barrel of dilution water (or oil) added requires and additional amount of chemicals, barite or other materials in order to maintain desired mud properties. The lower the drilled solids content to be maintained, the greater the dilution required. In the case of an oil-base mud, oil must be used for dilution which can become extremely expensive.
Effective solids removal by mechanical separation can maintain a minimum solids level in drilling mud and greatly reduce the need for dilution. Reducing the need to dilute the mud can drastically decrease the cost of having to purchase mud products such as weight material (barite) and chemicals.These materials are expensive mud costs can be 10% of the total cost of drilling a well.