Mud chemicals is very popular word in oil drilling chemical industry and basically used in drilling process where it is used as an additive in conjunction with bentonite and other chemicals. Mud chemicals are often known as drilling chemicals or drilling mud. These chemicals are also known as fluid chemicals or drilling fluid. The product is generally used in the process of drilling deep boreholes into the earth. These holes are drill for the extraction of gas and oil in the drilling process.
Mud chemicals play a vital role in drilling process as it provides a hydrostatic pressure into the boreholes to prevent the uncontrolled increment of lubricants and reservoirs fluid. It helps in the drilling by fracturing the rock from the jets in the bit. To control its rheological and chemical properties, the additives that are added into it must be carefully chosen. It is usually a shear thinning fluid of variable viscosity which is lower when it is under more shears, and it becomes more viscous when it returns to the surface under less shear stress.
One of the commonly used additives is Bentonite which helps in controlling and maintaining the viscosity and preventing fluid invasion by forming a mud cake on the borehole wall. It acts as a holder for the materials being drilled and protects the stability by controlling pressure and friction. Mud chemicals must be chemically compatible with the formation being drilled and that’s why it can be used as water based, oil based and gas based. The ranging of the mud from other materials must be true or balanced such as bentonite clays to synthetic drilling fluid.
Throughout the process, these chemicals are re- circulated and the process of re- circulation is designed with the aim to cut down the waste by using mud as much as possible. Different type of screens are needed to trap the material depending up on the material used and if some materials itself coated with mud, than they need to be washed first after filtration process.
The most considerable property of mud chemicals is the mud weight. If it exceeds the formation fracture pressure, than may be formation fracture and large amount of mud may be loose to it and if it is lower than the formation pressure than it will cause pressurized fluid to flow into the wellbore.
There are some environmental issues associated with the use of mud chemicals. Typically the contaminated mud is dumped into the open pits which pollute the natural environment. In addition there are some aggressive chemicals which are used to clean materials in case when filtration process is not sufficient. These chemicals have tendency to pollute the natural surroundings and can create various environmental problems.