Drilling for oil and gas clearly involves at least one liquid…the oil being extracted. In order to facilitate this process, however, some other liquids are utilized on the driller and producer’s end, aptly named drilling fluids, and completion fluids. These fluids have a wide range of functions, making them of the utmost importance in many modern drilling operations.
Purposes of drilling fluids
Some of the most important functions of these fluids include cooling the bit, maintaining pressure on the outside rock and hydrocarbon formations, and carrying and suspending cuttings. As the bit cuts, friction causes it to heat up in much the same way heat would be experienced from rubbing a hand across a carpet quickly, except to a much larger degree. The fluids act as a cooling agent, helping to prevent the equipment from overheating. Also, as the bit cuts into the earth, the surrounding pressure from formations is offset by the viscous drilling “mud.” Another byproduct of drilling is all of the crushed up material that results from the drill going through the earth. Drilling fluids suspend and carry this material away from the process, making it easier to access the bit should problems occur, and just plain keeping the process a little more uncluttered.
Types of drilling fluids
There are three general types of drilling fluids, water, oil, and synthetic based, each with their own specializations. Water-based fluid is certainly not just water, however, water does act as the base. Oil based fluids provide more lubrication and can withstand higher heats, but have increased concerns in terms of cost and disposal. Synthetic based fluids are similar to oil-based fluids in many regards but are often used offshore due to fewer problems with fumes out of concern for workers in enclosed workspaces.