A piece of pipe that has been twisted off inside a female connection; or a short section of material, such as belting or pipe, used to lengthen existing equipment.

Drill stem test

A single well that produces from two separate formation at the same time.

Production from each zone is segregated by running two tubing strings with packers inside the single string of production casing, or by running one tubing string with a packer through one zone while the other is produced through the annulus.

In a miniaturized dual completion, two separate 4 1/2-inch or smaller casing strings are run and cemented in the same wellbore.

A generic term, originally a trademark name, used to describe a stage tool, used in selective zone primary cementing.

A blanking valve placed in a gas lift mandrel to block off annular communication to the tubing.

Trade name for a downhole motor driven by drilling fluid that imparts rotary motion to a drilling bit connected to the tool, thus eliminating the need to turn the entire drill stem to make hole.

Used in straight and directional drilling.

The conventional method of formation testing.

The basic drill stem test tool consists of a packer or packers, valve or ports that may be opened and closed from the surface, and two or more pressure-recording devices.

The tool is lowered on the drill string to the zone to be tested.

The packer or packers are set to isolate the zone from the drilling fluid column.

The valves or ports are then opened to allow for formation flow while the recorders chart static pressures.

A sampling chamber traps dean formation fluids at the end of the test.

Analysis of the pressure charts is an important part of formation testing.

An exploratory or development well found to be incapable of producing either oil or gas in sufficient quantities to justify completion as an oil or gas well.

A special valve installed below the kelly.

Usually, the valve is open so that drilling fluid can flow out of the kelly and down the drill stem.

It can, however, be manually closed with a special wrench when necessary.

In one case, the valve is closed and broken out, still attached to the kelly to prevent drilling mud in the kelly from draining onto the rig floor.

In another case, when kick pressure inside the drill stem exists, the drill stem safety valve is close to prevent the pressure from escaping up the drill stem.

The amount of pressure exerted inside the drill pipe as a result of circulating pressure, entry of formation pressure into the well, or both.

A check valve in the drill string that will allow fluid to be pumped into the well but will prevent flow from entering the string.

See kelly bushing

1.

Circulating fluid, one function of which is to force cuttings out of the wellbore and to the surface.

Other functions are to cool the bit and to counteract downhole formation pressure.

While a mixture of barite, clay, water, and chemical additives is the most common drilling fluid, wells can also be drilled by using air, gas, water, or oil-base mud as the drilling fluid.

2. any of a number of liquid and gaseous fluids and mixtures of fluids and solids (as solid suspensions, mixtures and emulsions of liquids, gases and solids) used in operations to drill boreholes into the earth.

Synonymous with “drilling mud” in general usage, although some prefer to reserve the term “drilling fluid” for more sophisticated and well-defined “muds.” classifications of drilling fluids has been attempted in many ways, often producing more confusion than insight.

One classification scheme, given here, is based only on the mud composition by singling out the component that clearly defines the function and performance of the fluid: (1) water-base, (2) non-water-base and (3) gaseous (pneumatic).

Each category has a variety of subcategories that overlap each other considerably.

synonyms: drilling mud, mud.

See keyway.

1.

The operation during the drilling procedure when the cement is drilled out of the casing and the wellbore after the casing has been cemented.

2.

To remove the settlings and cavings that are plugged inside a hollow fish (such as drill pipe) during a fishing operation.