1. the viscosity of a fluid measured at a given shear rate at a fixed temperature. in order for a viscosity measurement to be meaningful, the shear rate must be stated or defined.
2. the viscosity of a fluid measured at the shear rate specified by api. in the bingham plastic rheology model, apparent viscosity [...]

1. barium sulfate; a mineral frequently used to increase the weight or density of drilling mud. its relative density is 4.2 (or 4.2 times denser than water). see barium sulfate, mud.
2. weighting material with a specific gravity of 4.37 used to increase the apparent density of a liquid drilling fluid system. barite [baso4] is the [...]

Density of one rock relative to another. the contrast can be positive or negative. gravity anomalies within sedimentary sections can be analyzed as structural or lithologic anomalies.

An adaptive drilling process used to precisely control the annular pressure profile throughout the wellbore (iadc definition).

1. the ratio of the weight of a given volume of a substance at a given temperature to the weight of an equal volume of a standard substance at the same temperature. for example, if 1 cubic inch of water at 39 degrees f weighs 1 unit and 1 cubic inch of another solid or [...]

Weight per unit volume of drilling fluid usually expressed in pounds per gallon or pounds per cubic foot. see hydrostatic pressure.

The force exerted by a body of fluid at rest. it increases directly with the density and the depth of the fluid and is expressed in pounds per square inch or kilopascals. the hydrostatic pressure of fresh water is 0.433 pounds per square inch per foot of depth (9.792 kilopascals per meter). in drilling, the [...]

The specific gravity or density of oil expressed in terms of a scale devised by the american petroleum institute. the lighter the oil, the greater the gravity; other factors being equal, the higher the api gravity, the better price the oil will bring.

The increase in bottomhole pressure expressed as an increase in pressure that occurs only when mud is being circulated. because of friction in the annulus as the mud is pumped, bottomhole pressure is slightly, but significantly, higher than when the mud is not being pumped. ecd is calculated by dividing the annular pressure loss by [...]

The mass or weight of a substance per unit volume. for instance, the density of a drilling mud may be 10 pounds per gallon (ppg), 74.8 pounds per cubic foot (lb/ft), or 1,198.2 kilograms per cubic meter (kg/m3). specific gravity, relative density, and api gravity are other units of density.

Heavy crude oil or extra heavy crude oil is any type of crude oil which does not flow easily. it is referred to as “heavy” because its density or specific gravity is higher than that of light crude oil.
heavy crude oil has been defined as any liquid petroleum with an api gravity less than [...]

A displacement. in the reservoir a sweep is displacement of a hydrocarbon fluid from a reservoir rock by a flooding fluid. in the wellbore, a sweep is a viscous pill circulated around to help clear the wellbore of cuttings or debris.

A drilling mud that contains entrained formation gas, giving the mud a characteristically fluffy texture. then entrained gas in not released before the fluid returns to the well, the weight or density of the fluid column is reduced. because a large amount of gas in mud lowers its density, gas-cut mud must be treated to [...]

Ppg; a measure of the density of a fluid (such as a drilling mud).

A downhole device that isolates wellbore pressure and fluids in the event of an emergency or catastrophic failure of surface equipment. the control systems associated with safety valves are generally set in a fail-safe mode, such that any interruption or malfunction of the system will result in the safety valve closing to render the well safe. downhole [...]