A compound of sulfur that contains the S-2 ion. It is used to denote compounds that revert to the highly toxic H2S gas when acidified with 2-molar citric acid solution, as opposed to inert sulfide, which is stable.

(a)  

The escaping tendency, or vapor pressure, of water molecules in an aqueous solution compared with that of pure water, typically abbreviated aw. Activity is expressed mathematically as the ratio of two vapor pressures: aw / p/po, where p is vapor pressure of the solution and po is vapor pressure of pure water.

(a)  

A group of organic chemicals with the general formula RCO-NH2 formed from reactions of ammonia (NH3) and a carboxylic acid, RCOO-H+.

(a)  

The mechanism by which partially hydrated cuttings stick to parts of the bottomhole assembly and accumulate as a compacted, layered deposit.

(a)  

Referring to a condition or a situation in which free oxygen exists in an environment.

(a)  

A group of organic chemicals that are analogs of ammonia (NH3), in which either one, two or three hydrogen atoms of ammonia are replaced by organic radicals.

(a)  

Pertaining to an aqueous solution, such as a water-base drilling fluid, which has more hydrogen ions (H+) than hydroxyl ions (OH-) and pH less than 7.

(a)  

Pertaining to systems, reactions or life processes of species, such as bacteria, in which atmospheric oxygen is not present or not required for survival

(a)  

What is the term for a viscosity of a fluid that measured at a given shear rate at a fixed temperature.

(a)  

The anhydrous mineral form of calcium sulfate, CaSO4.The presence of THIS in rock will influence the type of mud selected for drilling the rock because when CaSO4 dissolves in a water mud, Ca+2 and SO4-2 ions are formed.

(a)  

A chemical property of an aqueous system that implies that there are more hydrogen ions (H+) in the system, or a potential to produce more hydrogen ions, than there are hydroxyl ions (OH-), or potential to produce hydroxyl ions.

(a)  

A type of compound containing hydrogen and carbon atoms arranged in a symmetrical 6-carbon ring structure with single (C-C) and double (C/C) bonds alternating around the ring.

(a)  

A linear, nonionic polymer made of acrylamide monomers, CH2/CHCONH2 . High molecular-weight polyacrylamides are used as selective flocculants in clear-water drilling, low-solids muds and wastewater cleanup.

(a)  

A test to evaluate base oils that are used in oil mud. The test indicates if an oil is likely to damage elastomers (rubber compounds) that come in contact with the oil

(a)  

What is the term for a needle-like clay mineral composed of magnesium-aluminum silicate that can be used in saltwater mud to provide low-shear rate viscosity for lifting cuttings out of the annulus and for barite suspension.It has no capability to control the filtration properties of the mud.

(a)  

A term used to express the results of the methylene blue test, which determines the amount of clay-like materials in a water-base drilling fluid based on the amount of methylene blue dye absorbed by the sample

(a)  

A cone-and-plate rheometer designed to measure viscosity of non-Newtonian fluids at low shear rates and with more accuracy than is attainable with a 6-speed, direct-indicating viscometer

(a)  

An oil-base mud in which the activity, or vapor pressure, of the brine phase is balanced with that of the formations drilled.

(a)  

A coring fluid formulated with components that are not likely to alter the wettability in the pores of the rock sample and that has low dynamic filtration characteristics.

(a)  

A type of mud that contains the three components that form a chemical buffer, whether by design or by coincidence.

(a)  

A volume of 350 cm3. In mud laboratory experiments, 350 cm3 is the volume chosen to represent 42 US gallons (1 oilfield barrel) [6.6 m3], so that 1.0 gram mass represents 1.0 lbm. This is a convenient concept for mud technicians to use when mixing or pilot-testing mud samples.

(a)  

A two-parameter rheological model widely used in the drilling fluids industry to describe flow characteristics of many types of muds. Fluids obeying this model are called

(a)  

A log that uses the variations in amplitude of an acoustic signal traveling down the casing wall between a transmitter and receiver to determine the quality of cement bond on the exterior casing wall.

(a)  

A sample of mud from the deepest or current drilling depth of a well. The term refers particularly to a mud sample that has experienced stagnant conditions at the bottom of the hole, including the temperature, pressure and other conditions at that depth.

(a)  

Refers to the continuous phase in oil-base drilling fluids. Oil-base drilling fluids are water-in-oil emulsions in which water is the dispersed phase and oil is the dispersion, or continuous, phase

(a)  

To improve a mineral or ore for its designed use through chemical treatments or mechanical processes.

(a)  

List of products considered unsuitable by the Oslo and Paris Commission (OSPAR) for discharge, including mercury, cadmium and 'persistent oils and hydrocarbons of a petroleum origin

(a)  

An aqueous solution of sodium, calcium or zinc bromide salt or mixtures of these salts. These dense aqueous solutions are used for well completion and workover purposes.

(a)  

The act of passing the mud around a piece of equipment, such as passing mud returns around the shale shaker screens or going around a hydrocyclone device.

(a)