Oil & Gas Glossary 1.0

A blowout preventer placed on the seafloor for use by a floating offshore drilling rig.

Controls, usually located near the driller's position on the rig floor, that are manipulated to open and close the blowout preventers. See blowout preventer.

A blowout preventer that uses rams to seal off pressure on a hole that is with or without pipe. Also called a ram preventer.

Any valve installed in the drill stem to prevent a blowout through the stem. Mud can be pumped in but flow back up the stem is prevented. Also called an internal blowout preventer.

The assembly of pumps, valves, lines, accumulators, and other items necessary to open and close the blowout preventer equipment. Also called closing unit.

A device that stores hydraulic fluid under pressure in special containers and provides a method to open and close the blowout preventers quickly and reliably. Usually, compressed air and hydraulic pressure provide the opening and closing force in the unit. See blowout preventer.

A sealing component for a blowout preventer that closes the annular space between the pipe and the blowout preventer or wellhead.

1. a vertical arrangement of blowout prevention equipment. Also called preventer stack. See blowout preventer.

A device placed or hung in the casing below the blowout preventer stack to form a pressure tight seal. Pressure is then applied to the blowout preventer stack to test it for leaks

A training procedure to determine that rig crews are completely familiar with correct operating practices to be followed in the use of blowout prevention equipment. A "dry run" of blowout preventative action.

A pipe attached to the blowout preventer stack out of which kick fluids and mud can be pumped to the choke manifold when a blowout preventer is closed in on a kick.

A dart-shaped drill pipe inside blowout preventer installed on top of the drill stem when the well is kicking through the drill stem. It is stabbed in open then closed against pressure.

1. to force pipe or tools into a high-pressure well that has not been killed (i.e., to run pipe or tools into the well against pressure when the weight of pipe is not great enough to force the pipe through the BOPs). Snubbing usually requires an array of wireline bocks and wire rope that forces the pipe or tools into the well through a stripper head or blowout preventer until the weight of the string is sufficient to overcome the lifting effect of the well pressure on the pipe in the preventer. In workover operations, snubbing is usually accomplished by using hydraulic power to force the pipe through the stripping head or blowout preventer.

The closing and sealing components of a preventer, like the gate in a gate valve.

A blowout preventer that uses shear rams as closing elements.

See ram blowout preventer.

A blowout preventer that uses pipe rams as the closing elements. See pipe ram.

Abbreviation: blowout preventer.

See inside blowout preventer.

Abbreviation: blowout preventer equipment

In drilling, to assemble the blowout preventer stack on the wellhead at the surface.

A ram device used to close the annular space around the polished rod or sucker rod in a pumping well.

The assembly of pumps, valves, lines, accumulators, and other items necessary to open and close the blowout preventer equipment.

The assembly of well-control equipment including preventers, spools, valves, and nipples connected to the top of the wellhead.

One of several valves installed at the wellhead to prevent the escape of pressure either in the annular space between the casing and drill pipe or in open hole (i.e., hole with no drill pipe) during drilling completion operations. Blowout preventers on land rigs are located beneath the rig at the land's surface; on jackup or platform rigs, at the water's surface; and on floating offshore rigs, on the seafloor.

A device closed around the rods when the well may flow through the tubing while the rods are being pulled. It is a form of blowout preventer.

An integral part of a blowout preventer, which serves as the closing element on an open hole. Its ends do not fit around the drill pipe but seal against each other and shut off the space below completely. See ram

2. the pressure-sealing element of a stripper blowout preventer See stripper head.

The ratio between the pressure in the hole and the operating-piston pressure needed to close the rams of a blowout preventer.

An extension from the blowout preventer assembly used to direct control the flow of well fluids from the annulus to the choke.

1. a large valve located on the Christmas tree and used to control the flow of oil and gas from a well. Also called master gate. 2. the blind or blank rams of a blowout preventer (obsolete).

A fitting placed in the blowout preventer stack to provide space between preventers for facilitating stripping operations, to permit attachment of choke and kill lines, and for localizing possible erosion by fluid flow to the spool instead of to the more expensive pieces of equipment.

A short length of pipe (a nipple) installed on top of the blowout preventer. The top end of the nipple is flared, or belled, to guide drill tools into the hole and usually has side connections for the fill line and mud return line.

The component in a blowout preventer that cuts, or shears, through drill pipe and forms a seal against well pressure. Shear rams are used in floating offshore drilling operations to provide a quick method of moving the rig away from the hole when there is no time to trip the drill stem out of the hole.

To control a blowout by placing a very strong valve on the wellhead. See blowout.

A manually operated ram preventer especially adapted for closure around a wireline.

A manually operated ram preventer especially adapted for closure around a wireline.

A preventer having a unit of packing material whose closure depends on well pressure coming from below. It is used primarily to strip pipe through the hole or allow pipe to be moved with pressure on the annulus.

To take rams out of a blowout preventer and replace them with rams of a different size or type. When the size of a drill pipe is changed, the size of the pipe rams must be changed to ensure that they seal around the pipe when closed (unless variable-bore pipe rams are in use).

An uncontrolled flow of gas, oil, or other well fluids into the atmosphere or into an underground formation. A blowout, or gusher, can occur when formation pressure exceeds the pressure applied to it by the column of drilling fluid.

2. to dose the blowout preventers on a well to control a kick. The blowout preventers close off the annulus so that pressure from below cannot flow to the surface.

An oilwell that has come in with such great pressure that the oil jets out of the well like a geyser. In reality, a gusher is a blowout and is extremely wasteful of reservoir fluids and drive energy. In the early days of the oil industry, gushers were common and many times were the only indication that a large reservoir of oil and gas had been struck. See blowout.

The closing and sealing component on a blowout preventer. One of three types--blind, pipe, or shear--may be installed in several preventers mounted in a stack on top of the wellbore. Blind rams, when closed, form a seal on a hole that has no drill pipe in it; pipe rams, when closed, seal around the pipe; shear rams cut through drill pipe and then form a seal.

The assembly of blowout preventers installed on a well

A phenomenon that sometimes occurs when a well blows out. Rocks, sand, clay, and other debris clog the hole and stop the blowout.

The joint of drill pipe that is used in hang-off operations so that no tool joint is opposite a set of preventer rams.

A blowout prevention device consisting of a gland and packing arrangement bolted to the wellhead. It is often used to seal the annular space between tubing and casing.

An uncontrolled flow of gas, salt water, or other fluid out of the wellbore and into another formation that the wellbore has penetrated.

Preventers installed on top of the well or drill string as a precautionary measure while running wirelines. The preventer packing will close around the wireline.

A device made up in the drill stem and lowered into the well to allow the casing and blowout preventers to b pressure-tested. The sealing device is cup-shaped and is therefore called a cup.

An elastic material made of synthetic rubber or plastic; often the main component of the packing material in blowout preventers and downhole packers.

(slang) to cave in; to fail. After a violent blowout, the force of the fluids escaping from the wellbore sometimes blows a large hole in the ground. In this case, the well is said to have cratered. Equipment craters when it falls.

The ratio between the pressure required to open the preventer and the well pressure under the rams.

An electric or hydraulic pump on an accumulator that pumps hydraulic fluid under high pressure to the blowout preventers so that they may be closed or opened.

The first casing or conductor string (generally with a diameter of 30 to 36 inches) set when drilling a well from an offshore drilling rig. It prevents sloughing of the ocean-floor formations and is a structural support for the permanent guide base and the blowout preventers.

The act of ensuring that a pipe ram preventer will not close on a drill pipe tool joint when the drill stem is stationary. A pup joint is made up in the drill string to lengthen it sufficiently.

An arrangement of piping and special valves, called chokes. In drilling, mud is circulated through a choke manifold when the blowout preventers are closed. In well testing, a choke manifold attached to the wellhead allows flow and pressure control for test components downstream.

The valve on the choke and flow line that is nearest to the preventer assembly. Its purpose is to stop the flow through the choke and flow line.

A sealing device used to close off the annular space around the kelly in drilling with pressure at the surface, usually installed above the main blowout preventers. A rotating head makes it possible to drill ahead even when there is pressure in the annulus that the weight of the drilling fluid is not overcoming; the head prevents the well from blowing out. It is used mainly in the drilling of formations that have low permeability. The rate of penetration through such formations is usually rapid.

A large load-bearing structure, usually of bolted construction. In drilling, the standard derrick has four legs standing at the corners of the substructure and reaching to the crown block. The substructure is an assembly of heavy beams used to elevate the derrick and provide space to install blowout preventers, casingheads, and so forth. Because the standard derrick must be assembled piece by piece, it has largely been replaced by the mast, which can be lowered and raised without disassembly.