Balanced-Activity Oil Mud
Balanced-Activity Oil Mud :
(n.) Drilling Fluids. An oil-base mud in which the activity, or vapor pressure, of the brine phase is balanced with that of the formations drilled. Although long shale sections may not have a constant value for vapor pressure, aw, the oil mud will adjust osmotically to achieve an "average" aw value. Dynamic (autopilot) balance of mud salinity and drilled shales is maintained because as water moves into or out of the mud, it also moves out of or into the shale. As water transfer continues during drilling, the mud's water phase will be either diluted or concentrated in CaCl2 as needed to match the average aw value of the shale section andcuttings exposed to the mud. See: Activity Of Aqueous Solutions, Calcium Chloride, Chenevert Method, Diesel-Oil Mud, Humidity, Hygrometer, Inhibitive Mud, Methylglucoside Drilling Fluid, Oil-Mud Emulsifier, Osmosis, Silicate Mud
