Marsh Funnel viscosity, in the context of drilling fluids, refers to the time it takes for a specific volume of the fluid to flow through a standardized Marsh funnel. It’s not a true measure of viscosity in the scientific sense, but rather a quick and simple way to get a qualitative indication of the fluid’s consistency.
In drilling activities, the pressurized mud balance serves as a critical instrument for precisely gauging the mud weight of drilling fluid. Unlike a conventional mud balance, this tool functions under pressure to eliminate the impact of gas bubbles present in the fluid, making it the preferred method for obtaining highly accurate readings of drilling fluid density (mud weight), particularly crucial for wellbore stability and safety.
Here’s a breakdown of its operation:
Design: The pressurized mud balance shares a resemblance with a traditional balance, featuring a fixed-volume mud cup on one end and a counterweight on the other. The distinguishing factor is a pressure chamber that houses the mud cup. This chamber can be pressurized to compress any gas bubbles within the fluid sample.
A pressurized mud balance
Operating Principle: Continue reading
The Electrical Stability (ES) of drilling fluids holds significant importance in gauging the strength of emulsions. This property is indicative of the fluid’s emulsion stability and its ability to wet oil. Essentially, ES measures the fluid’s resistance to conducting electricity, with higher values denoting a more robust emulsion that resists separation between oil and water components. This stability is paramount for achieving optimal drilling performance and safeguarding the wellbore.
In oil and gas industry, a specialized drilling fluid known as high-vis sweep is often used and its primary purpose is to optimize hole cleaning and remove cuttings from the wellbore. What distinguishes this fluid is its heightened viscosity, a quality achieved by incorporating polymers or other additives into the base drilling fluid. This augmented viscosity empowers the sweep fluid to transport cuttings up the annulus out of the well.
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. The salt added into the system will be dissolved by water in the mud; therefore, the chloride content will increase.
By increasing the chloride concentration (adding salt), the activity level in the mud will decrease. Salt is added in order to create an activity level which is equal to or less than formation water. Therefore, the water phase in the mud will not move into formation and cause a clay swelling issue. Practically, calcium chloride (CaCl2) or sodium chloride (NaCl) is the chemical to be used.
