Global Standards

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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

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Compression Ratio

Ratio of absolute discharge and absolute suction pressures. Source: IADC UBO / MPD Glossary, December 2011. Global Standards

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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

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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

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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

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Coefficient of Thermal Expansion

Incremental increase in the volume of a unit of fluid for a rise in temperature. Source: IADC UBO / MPD Glossary, December 2011. Global Standards

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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

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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

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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

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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

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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

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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

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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

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Centripetal Force

Pulls or pushes an object towards the center of a circular path. Source: IADC UBO / MPD Glossary, December 2011. Global Standards

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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

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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

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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

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Capacity

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

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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

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Centrifugal/Gear Pump

Pump used to draw the crude oil at a constant pressure and flow rate. Source: IADC UBO / MPD Glossary, December 2011. Global Standards