THE EFFECT OF USING DIFFERENT WEIGHTS OF CAUSTIC SODA ON THE WATER-BASE MUD DRILLING FLUID

The main function of the drilling fluid is to keep the rotary drilling system working through the
circulation of the fluid continuously down through the drill pipe, out through the bit nozzles
and to the surface. The drilling fluid which is called the drilling mud can have several chemical
and physical properties depending on the drilling process that is why we have different types
of drilling fluids based on their compositions. This study concentrates on just one type of these
drilling fluids which is water-base mud. The water-based mud drilling fluid systems are
considered the most widely used system in the drilling operations due to its low cost comparing
to the other types of the drilling fluid systems. The water base-mud is usually a mixture of
water, clay and a few other chemicals such as the caustic soda which is the main concern of
this study.
The caustic soda is the common name of the sodium hydroxide (NaOH). It is used in most of
the water-based mud systems in order to control the PH value and the salinity of the drilling
fluid system. During this study the main focus is on the effect of using different weights of
caustic soda on water-based mud systems. As the drilling mud can be the first line of defense
if any blow out occurs because it has a great effect on the pressure control that prevent any
possibilities of loss of well control caused by formation pressure. So the rheology of the drilling
mud is very important to identify the drilling mud ability to control the formation pressure.
This study is conducted by using the mud balance test and the viscometer equipment on each
mud sample to test the rheology. From the findings, the increase of using the weight of caustic
soda in the Water-Base Mud drilling fluid leads to increase in the mud density, apparent
viscosity, yield point values and the Gel strength values.