What is added to mud in a chloride test and why?
The chloride content in the drilling fluid can be maintained by adding salts such as potassium chloride (KCl) and sodium chloride (NaCl). If potassium chloride (KCl) is used, it is imperative to have sufficient potassium ions to react with the clay content from the formation.
What chemicals are used in drilling mud?
Most common chemicals added to OBM Muds:
- Barite.
- Bentonite.
- Diesel.
- Emulsifiers.
- Water.
What is mud salinity?
Water phase salinity is a factor showing the activity level of salt in oil based mud. In order to control the water phase salinity, salt is added into the drilling fluid. By increasing the chloride concentration (adding salt), the activity level in the mud will decrease.
What should the calcium level be before mixing drilling fluid additives?
The quality of the water is critical and will determine the effectiveness of any drilling fluid additives you will use. The water should 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).
What is the pH of drilling mud?
Typically, lignosulfonate drilling muds perform best at a pH range of 10.5 – 11.5, which is needed to activate or solubilize the lignosulfonates and lignites. At a pH above 8.5, formation clays hydrate and disperse due the presence of hydroxide ions.
Why is salt water used in oil drilling?
Hydraulic fracturing of shale gas well sites produces millions of gallons of this saltwater, also known as “produced water” or “oilfield brine.” The water brings oil and gas to the earth’s surface where impurities are chemically removed, resulting in a leftover liquid that must then be safely discarded.
Why bentonite is used in drilling?
The most common use of bentonite is in drilling fluids. The bentonite in the flush fluid lubricates and cools the cutting tools while protecting against corrosion. As the drilling fluid generates hydrostatic pressure in the borehole, it hinders fluid and gas penetration.
What should be added to lower the pH of mud?
If you find that the pH level is lower than 7, you will need to add soda ash to the water. Soda ash or another product such as pH 10, can be added at a rate of ¼ pound to ½ pound per 100 gallons.
Why drilling fluid is alkaline?
Alkalinity agents help provide fluid stability, improve polymer hydration and performance, and treat out contaminants like cement, carbon dioxide, hardness, and H2S encountered in mix waters or while drilling. sodium bicarbonate, a low-pH buffer.
How many types of pH are used in drilling mud?
There are two accepted methods of measuring pH: the colorimetric method using paper strips and the electronic method using a pH meter and electrode.
Why do you use a chloride drilling mud?
The water-based fluid may contain chlorides from the base fluid (e.g. Sodium or Potassium Chloride), or may pick up chlorides while drilling. Chloride Test Drilling Mud is useful for determining any unexplained changes in water-based mud salinity, because an increase or reduction in salinity will indicate salt or water contamination.
What kind of test is needed for drilling mud?
Filtrate Chemical Analysis Standard chemical analyses have been developed for determining the concentration of various ions present in the mud. Tests for the concentration of chloride, hydroxyl, and calcium ions are required to fill out the API drilling mud report.
How big of a sample do I need for a chloride test?
A larger water or filtrate sample volume should be used for checking fluids with low chlorides, as this will give a more accurate measurement (e.g. titrate with a 10 ml sample when checking the chlorides in mix water). Chlorides should be around 175,000 to 185,000 mg/L in salt saturated mud systems.
How is the temperature of oil based mud tested?
1. Fill the rheometer heating cup with oil-based mud that has been screened through a Marsh Funnel. 2. Check that the gap between the ES probe electrodes is clean and dry, and stir the mud with the ES probe until the mud sample temperature is uniform at 120°F (50°C)