Control System

Control System

Definition(s)

Control System

System where a comparison between a measured control variable a set point prompts an action to achieve the set point. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Control Panel – Remote or Secondary

Control Panel – Remote or Secondary

Definition(s)

Control Panel – Remote or Secondary

A system of controls usually convenient to the driller, used to actuate controls at the Master or Primary panel. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Control Panel, – Master or Primary

Control Panel, – Master or Primary

Definition(s)

Control Panel, - Master or Primary

A manifold system of valves which is usually situated at the power source, which may be operated manually or by remote control, to direct pressurized fluids to well closing . Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Constant Choke Pressure Method

Constant Choke Pressure Method

Definition(s)

Constant Choke Pressure Method

The adjustment of choke size to maintain constant casing pressure. Used in well killing operations where the influx is composed of water, does not work with gas due to expansion of the gas as it rises up the wellbore. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Constant Bottom Hole Pressure (CBHP)

Constant Bottom Hole Pressure (CBHP)

Definition(s)

Constant Bottom Hole Pressure (CBHP)

Methodology within MPD, Proactive Category; whereby bottomhole pressure is kept constant during connections to compensate the loss of AFP when mud pumps are off. Typical methods include:
  1. By keeping     continuous     circulation     during
  2. By trapping annular pressure prior to shutting down mud
  3. By diverting mud pump flow across the wellhead
Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Connection Gas

Connection Gas

Definition(s)

Connection Gas

The small amount of gas that enters a well after stopping the mud pumps for a connection. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Continuity Equation

Continuity Equation

Definition(s)

Continuity Equation

Equation to balance mass in a closed system. Prevents mathematical destruction or creation of mass in the system.. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Compressibility

Compressibility

Definition(s)

Compressibility

Change in volume and density of a fluid with respect to changes in pressure and temperature. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Comm.-out

Comm.-out

Definition(s)

Comm.-out

Communication outage; loss of communications from one or more stations requiring operation of those stations without analytical data. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Column Separation

Column Separation

Definition(s)

Column Separation

Condition that occurs in areas of low pressure, where a large number of bubbles coalesce and form a vapor cavity. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Closed Returns System

Closed Returns System

Definition(s)

Closed Returns System

Flow path from the drill string non-return valves (floats) to the rotating control device and flow choke that can hold pressure. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Clearance

Clearance

Definition(s)

Clearance

Percentage of the swept volume of gas through a reciprocating compressor that remains within the cylinder (see also: sweep).. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Choked Flow

Choked Flow

Definition(s)

Choked Flow

  1. operating condition that occurs when pressure at the vena contracta drops below the liquid vapor pressure and the liquid starts to vaporize and form bubbles.
  2. operating condition that occurs when the fluid velocity reaches its sonic velocity in the equipment and no additional flow can be handled.
Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Choke/Kill Manifold

Choke/Kill Manifold

Definition(s)

Choke/Kill Manifold

An assembly of valves, chokes, gauges, and lines used to control the rate of flow and pressure from the well when the BOPs are closed. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global Standards
Choke/Kill Line

Choke/Kill Line

Definition(s)

Choke/Kill Line

A high-pressure line that allows fluids to be pumped into or removed from the well with the BOPs closed. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global Standards
Choke/Kill Line Valve

Choke/Kill Line Valve

Definition(s)

Choke/Kill Line Valve

The valve(s) connected to and a part of the BOP stack that controls the flow to the choke and kill manifold. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global Standards
Certified

Certified

Definition(s)

Certified

Components manufactured and maintained under a quality control program to ensure conformance with design specifications.. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Cavitation Index

Cavitation Index

Definition(s)

Cavitation Index

Ratio of pressure drop across the valve divided by the difference between the inlet pressure and the vapor pressure of the liquid. Valve selection to ensure operation above the cavitation point is the primary use. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Cavitation

Cavitation

Definition(s)

Cavitation

Formation of pockets of vapour in a liquid that suddenly collapse, causing very high localized pressures which can lead to serious erosion of boundary surfaces. Source: ISO 14692-1:2017, Petroleum and natural gas industries — Glass-reinforced plastics (GRP) piping — Part 1: Vocabulary, symbols, applications and materials, Second Edition, August 2017. Global Standards

Cavitation

Is when the fluid pressure in the line or vessel drops below the vapor pressure of the liquid being transported resulting in the rapid formation and collapse of vapor bubbles in a flowing liquid. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Carbon Doxide/Monoxide

Carbon Doxide/Monoxide

Definition(s)

Carbon  Doxide/Monoxide

Naturally occurring substances resulting from combustion of hydrocarbons. Are also found as components in hydrocarbon reservoirs. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Capacity

Capacity

Definition(s)

Capacity

Volume of fluid per unit time that the pump or compressor can move. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Can-type Vertical Pumps

Can-type Vertical Pumps

Definition(s)

Can-type Vertical Pumps

Pump where liquid enters through the inlet valve and flows to the can bottom increasing the pump suction head. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Bypass Valve

Bypass Valve

Definition(s)

Bypass Valve

ON/OFF valve that allows fluid to bypass a station when open, and forces fluid to enter a station when closed; operates together with the station inlet valve. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Butterfly Valve

Butterfly Valve

Definition(s)

Butterfly Valve

relatively flat, rotating disc mounted on a bearing that allows it to rotate its axis. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Bull Heading

Bull Heading

Definition(s)

Bull Heading

The practice of pumping into a closed – in well without returns, or forcing fluid down a well under pressure Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Bubble Flow

Bubble Flow

Definition(s)

Bubble Flow

A multiphase fluid-flow regime. The gas phase exists as bubbles distributed through the liquid phase. Where the bubbles coalesce and form a less uniform distribution of the gas phase, slippage will occur between the phases. Source: IADC UBO / MPD Glossary, December 2011. Global Standards
BTU

BTU

Definition(s)

BTU

British Thermal Unit; the amount of heat required to raise the temperature of one pound of water one degree Fahrenheit. Equivalent to 252 calories or 778.2 foot- pounds. Source: IADC UBO / MPD Glossary, December 2011. Global Standards