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902 Well Site Preparation and Drilling Safety
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Preparing Drilling Fluid

Drilling fluid is an important component in the drilling process. There are several types of drilling fluids used depending on the drilling conditions encountered:

  • Water-based muds are used most frequently. The base may be either salt or fresh water.
  • Oil-based muds.
The Mud Pit
Fluid in a mud pit used for drilling process
  • Synthetic materials- The oil and gas extraction industry has developed many new oleaginous (oil-like) base materials from which to formulate high-performance drilling fluids.
  • Air and form fluids may be used in drilling wells. These fluids are less dense than drilling muds.

Drilling fluid is required in the wellbore to:

  • cool and lubricate the drill bit
  • remove the rock fragments, or drill cuttings, from the drilling area and transport them to the surface
  • counterbalance formation pressure to prevent formation fluids (i.e. oil, gas, and water) from entering the well prematurely (which can lead to a blowout)
  • prevent the open (uncased) wellbore from caving in

Knowledge Check Choose the best answer for the question.

4-4. Which type of drilling fluid is most frequently used in the drilling process?