In 1900, while drilling an oil well in Spindletop, Texas, workers ran a herd of cattle through a pit filled with water. The mud that resulted was pumped into the borehole. While drilling fluids still are called mud, engineers no longer rely only on water and clay. Instead, they carefully design compounds and mixtures to meet specific needs under various drilling conditions.
Long ago, people generally were drilling for water, not for oil. In fact, they were annoyed when they found oil by accident because it contaminated the water. It wasn't until the industrial revolution of the 19th century that drilling for oil became widespread as industrialization greatly increased the need for petroleum products.
The earliest records of well drilling date back to the third century B.C. in China. The Chinese were relatively advanced in the art of cable tool drilling and are credited with the first intentional use of fluids in the process of drilling. In this case, the fluid was water. The Chinese realized that the water made penetration easier and aided in the removal of cuttings.
In 1833, a French engineer named Flauville was watching a cable tool drilling operation when the drilling apparatus struck water. He realized that the gushing water was very effective in lifting the cuttings out of the well. The principle of using moving fluid to remove cuttings from the well bore was established. He conceived an assembly in which water would be pumped down the inside of a drilling rod and carry cuttings with it as it returned to the surface in the space between the drilling rod and the wall of the well bore - a standard procedure today.
As wells have gotten deeper, drilling fluids have taken on increased importance, serving a number of purposes and solving a variety of challenges that vary greatly from project to project.
This article is provided through the courtesy of the Schlumberger Excellence in Educational Development (SEED) program, a nonprofit enterprise committed to the educational needs of young people around the world (www.slb.com/seed).
