A method of preparing a well for production in which no production casing or liner is set opposite the producing formation. reservoir fluids flow unrestricted into the open wellbore. an open-hole completion has limited use in rather special situations. also called a barefoot completion.

Drilling in which the size of the hole is smaller than the conventional hole diameter for a given depth. this decrease in hole size enables the operator to run smaller casing, thereby lessening the cost of completion. see miniaturized completion.

Generally, the first string of casing in a well. it may be lowered into a hole drilled into the formations near the surface and cemented in place; or it may be driven into the ground by a special pile drive (in such cases, it is sometimes called drive pipe); or it may be jetted into [...]

All members in the assembly used for rotary drilling from the swivel to the bit, including the kelly, drill pipe and tool joints, drill collars, stabilizers, and various specialty items. compare drill string.

Clamps that grip a stand of casing, tubing, drill pipe, or sucker rods so that the stand can be raised or lowered into the hole.

A casing in which the outside diameter of the joint is the same as the outside diameter of the casing itself.

A downhole tool with rough, sharp, extremely hard cutting surfaces for removing metal by grinding or cutting. mills are run on drill pipe or tubing to grind up debris in the hole, remove stuck portions of drill stem or sections of casing for sidetracking, and ream out tight spots in the casing. they are also [...]

The depth in the hole at which the drill stem, tubing, or casing is stuck.

1. a device secured around the casing at the regular intervals to center it in the hole. casing that is centralized allows a more uniform cement sheath to form around the pipe.
2. one of several centralizer designs intended to keep the casing better centered in the borehole to get better cement jobs.

Pressure of the annular fluid on the casing at the surface when a well is shut in.

Drill pipe, drill collars, casing, or tubing that has inadvertently become immovable in the hole. sticking may occur when drilling is in progress, when casing is being run in the hole, or when the drill pipe is being hoisted.

A standardized measure of casing-strength properties. since most oilfield casing is of approximately the same chemistry (typically steel), and differs only in the heat treatment applied, the grading system provides for standardized strengths of casing to be manufactured and used in wellbores. the first part of the nomenclature, a letter, refers to the tensile strength. [...]

(bha) the lower portion of the drillstring, consisting of (from the bottom up in a vertical well) the bit, bit sub, a mud motor (in certain cases), stabilizers, drill collars, heavy-weight drillpipe, jarring devices (“jars”) and crossovers for various threadforms. the bottomhole assembly must provide force for the bit to break the rock (weight on [...]

To use a whipstock, turbodrill, or other mud motor to drill around broken drill pipe or casing that has become lodged permanently in the hole.

Pressure of the annular fluid on the casing at the surface when a well is shut in