INTRODUCTION TO DRILLING FLUIDS OVERVIEW

Drilling fluid or drilling mud as many people call it is a vitality in a rotary drilling process. The term “drilling fluid” includes air, gas, water and mud. “Mud” refers to the liquid that contains solids and water or oil. The mud is made up with clay and other additives that give it desirable properties.

MUD TYPES

Water Based Mud

Often, water is the base of drilling mud. Water makes up the liquid part or phase of a water-based mud. Crew members put clay and special additives into the water to make a mud with the properties needed to do its job well. For example, clays give it thickness or viscosity. The water in the mud may be fresh water, sea water or concentrated brine (salt water). The one used depends on its availability and whether it gives the mud the needed properties to drill the hole efficiently.

Oil Mud

At times, down hole drilling conditions require the crew to add oil to the mud, or in some cases, crew members use oil instead of water as the base of the mud. This is called oil-based mud. Oil based mud has many advantages. It can stabilize the formation and reduce downhole drilling problems. However, it is harder for the crew to work with because it can create slippery conditions and environmental precautions must be used. From an environmental standpoint, mud with oil is more difficult to handle because the oil clings to the drill cuttings. The oil must be cleaned off the cuttings before they’re disposed of.