|Ronald B. Peterson reports that the first step as discussed in a Water Well Journal column earlier this year (WWJ, May 2016) is proper planning. Included in the planning phase is obtaining an appropriate drilling fluid program, as property owners, hydrogeologists, or engineers often require a drilling-fluid program.|
Your chosen drilling fluid vendor can either provide a drilling fluid program for you or facilitate getting one prepared for you. Make sure you provide them with as much data as you can so the program is appropriate for your project.
We need to locate and verify a quality water source. The quality of the water is critical and will determine the effectiveness of any drilling fluid additives you will use.
The water needs to be low in salt (less than 500 ppm chlorides), low in hardness (calcium less than 100 ppm; average hardness is around 200 ppm), and low in chlorine (minimal detectable odor). The pH and the hardness can be adjusted using soda ash (about one-half to two pounds per 100 gallons).
Excessive chlorine is harder to deal with and may require a different water source or adjusting the drilling fluid additives to obtain the desired drilling fluid properties. Water quality properties for drilling fluid applications are measured using pH strips, calcium strips, or various titration methods to obtain more specific properties like alkalinities or the ratio between calcium and magnesium hardness as well as more specific chloride content.
Viscosity depends on the drilling discipline. There are two ways to clean a borehole, velocity and viscosity. Velocity is speed or rate of flow. Viscosity is the thickness of the fluid (defined as resistance to flow).
When drilling with air, the fluid (air) is made thicker by adding a foaming agent. A water-based fluid is made thicker by using bentonite or a polymer. When adjusting viscosity, always use the most cost-effective product available that is designed for use in a drilling fluid.
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