A GLOSSARY OF PIPELINE TERMS

 

 

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

 

 

A  Return

 

API Gravity - An industry method of referring to the relative density of oils and products. There is a direct correlation between API and specific gravity.

 

ACT - Automatic Custody Transfer A system for automatically measuring and sampling oil or products at points of receipt or delivery (other than at leases).

 

Analog Display - A gauge or readout that displays information as a percent of a full scale.

 

Annunciator Panel- A panel with "flags" to indicate the cause of trouble at a pump station. One section is usually devoted to unit protective shut down devices such as low suction pressure, high bearing temperature, etc. Another section will indicate station troubles such as high sump, low air supply or high discharge pressure. The relay flags must be manually reset if tripped.

 

Appurtenances -  The nozzles, man-ways, ladders, mixers, etc. which are added to a storage tank.

 

Arm - Used in reference to selecting a control point preparatory to making a change. Controls for the valve, pump or meter are first armed, and then, upon an execute signal, the status change can be made. As a security measure, no change can be made until the device is armed.

 

Auto-Refrigeration - The unassisted reduction in temperature generated by expanding a fluid from a pressure to a lower pressure.

 

Auto-Ignition -Temperature at which ignition will occur without presence of spark or other ignition source.

 

B  Return

 

BHP - Brake Horse Power, the input horsepower to the pump shaft from the driver.

 

B.S.& W. -  Basic Sediment and Water. Impurities contained in crude oil and products. Generally, pipeline tariffs limit the content of B.S.&W. to 1% of the volume of oil.

 

Back Pressure Valve - A control valve used to maintain a minimum pressure at a meter installation, station or terminal. Such valves are used on LPG and other high vapor lines to assure that sufficient pressure is maintained on the product to keep it in the liquid state.

 

Ball Valve - Similar to plug valve except that it uses a ball-shaped piece of steel with a hole to allow fluid to pass when aligned with pipeline. It will block line when the hole is rotated 90° or perpendicular to pipeline.

 

Batching - Pumping shipments (tenders or batches) of a product or crude through the line without mixing with other tenders.

 

Barrel-Mile - A unit of measurement of pipeline shipment of oil, which signifies the movement of one barrel a distance of mile.

 

C  Return

 

 

Check Valve - A valve designed to allow flow in one direction only. It usually has a clapper, which closes, against a seat when there is no flow.  Flow in the right direction lifts the clapper from the seat; flow in the reverse direction forces the clapper against the seat.

 

Combinator - A device that accumulates a number of separate readings and combines them into one composite total.

 

Common Carrier - Any transportation system available for hire by the public for transporting cargo. Almost all interstate pipelines are common carriers.

 

Computer - A data processor that can perform substantive computation, including numerous arithmetic or logic operations, without intervention by an operator during the run.

 

COMPRESSIBILITY - The ability to change volume with a change in pressure or temperature.

 

Control Valve - A control valve is provided at trunkline stations to assure that the discharge pressure does not exceed a value, which can be set into the "discharge pressure controller". Should the pressure reach the set point, the controller will cause the valve to throttle as necessary to maintain the discharge pressure at the discharge pressure control setting.  Several controllers can be used with one control valve. At intermediate stations where the pumps are filled by the incoming stream pressure (i.e., no booster pumps) a "suction pressure controller" is provided. The control valve will then throttle to maintain the suction pressure at a preset minimum. Other controllers which have been used are "flow controllers" (to restrict flow to a preset minimum) and load or "demand controller" which control flow to maintain the total power supplied by the station to a preset maximum.

 

Custody Change - A transfer of custody of a crude oil or product batch from one common carrier to another.

 

Cycles - A scheduling term denoting a complete delivery of products from, for instance; gasoline to kerosene to fuel oil to jet fuel and then back to gasoline. The cycle might recur every 3-1/2, 7, or 10 days, depending on tankage, throughputs, batch sizes, etc.

 

D  Return

 

DOT - Department of Transportation. This is a federal agency authorized to regulate certain aspects of the pipeline industry. The DOT issues rules, which have the weight of law through the Code of Federal Regulations. In general, liquid pipelines are covered by CFR 195; gas pipelines by CFR 192. Both require certain minimum standards, record-keeping and reporting. Shell construction, operating and maintenance standards are written to cover DOT and all other pertinent governmental regulations. For instance, contingency or emergency plans spell out reporting procedures required by law.

 

Data Processing - The execution of a systematic sequence of operations performed upon data. This usually denotes a series of calculations by a computer rather than the performing of supervisory chores such as scanning, etc.

 

Dead Wood - Structural members on the interior of tanks. Their volume is deducted when computing the capacity of a tank.

 

Dearm - To de-energize a control point that has been selected.

 

Demand - Demand, as an electrical energy term, denotes the instantaneous power requirement of a motor or electric pump station. Demand in kilowatts (KW) is usually measured by a kilowatt-hour meter (over a period of 15 or 30 minutes), which is scaled to read out in KW. Power in electrical terms (KW) is equal to 0.746 times horsepower (HP).  Therefore, if the input to a motor used to drive a pump is equivalent to a load of 1,000 horsepower, and the unit is operated for the full 15 or 30 minute span measured by a KW meter, the demand created by this unit will be 746 KW.

 

Delivery Man - An employee representing the shipper or pipeline company when custody of a batch of product takes place.

 

Density - The mass of a substance per unit volume.

 

Developed Pressure - Developed pressure is the resulting head (expressed in psi) which a pump will produce at a given flow rate. In a centrifugal pump, the head developed at a given flow is virtually constant. The developed pressure will vary according to the specific gravity of the liquid in the pump. Assuming that a pump develops 1,000 feet of head, the pressure with water (specific gravity of 1.0) will be 433 psi; with a 0.85 specific gravity oil 365 psi.

 

DEW POINT - The temperature at which a sample of air has a relative humidity of 100%.

 

Digital Display - A gauge or other readout that displays information in numerals.

 

Discharge Pressure - Discharge pressure is the pressure measured on the outlet side of a pump or station. At a pump station, the discharge pressure is the pressure downstream of the control valve. Station case pressure is measured upstream of this valve.

 

Displacement - Line fill between stations stated in barrels.

 

Downstream - The pipeline direction towards which the stream moves, i.e., to the terminal of the system.

 

DOE - Department of Energy. Established October 1, 1977, to coordinate and administer federal energy-.policy and programs.

 

Dye Plug - A colored dye injected at the interface of two batches to identify the interface.

 

E  Return

 

EPA - Environmental Protection Agency. Coordinates a governmental action on behalf of the environment. EPA endeavors to abate and control pollution.

 

Emergency stop - An emergency stop pushbutton (crash or panic button) is usually provided at trunkline stations to completely shutdown and isolate the station from the rest of the system. In some cases, the emergency stop trips the main breaker, cutting off all electric power at the station. This usually requires that an electrical technician be called out to reset the breaker before the station can be restarted. In any event, an emergency stop normally will shut down all operating units and, at some stations, close the station suction and discharge valves. Fittings - The ells, tees, flanges, etc. used along with valves and line pipe to make up a pipeline manifold. Valves and fittings are pressure rated to indicate the type of service in which they may be used.

 

F  Return

 

FERC - Federal Energy Regulatory Commission. A commission in the Department of Energy, which handles functions of former Federal Energy Administration, Energy Research and Development Administration, the Federal Power Commission, and some functions of Interstate Commerce Commission (setting oil pipeline rates).

 

Flag - A warning or indicating marker. Annunciators have several premarked flags to indicate the source of trouble. The word flag is also used to denote the warning tag (usually red) used to tag a switch or valve (during maintenance work), which must not be operated until the man who placed the tag removes it.

 

Floating Roof - A tank roof, which floats on the surface of the oil contained in a tank rather than being supported on structural members. It rises and falls with the level of the liquid in the tank. Its purpose is to reduce the amount of vapor space and hence the loss of vapors from the tank.

 

Float Tank - A tank whose main gate valve is open to the main line at a station. Oil from the main line may enter the tank and leave it as pumping rates in the line vary.

 

Format - The arrangement of data. Usually the way data is listed on a sheet of paper from a computer printout or on the display screen of a CRT.

 

G  Return

 

Gate Valve - A device used to block the flow of fluids in pipelines using a sliding plate of steel.

 

Gathering Line - A pipeline, usually of small diameter, used to gather crude oil from the oil field to a point on a main pipeline.

 

Gauging - Determining the volumetric content of a tank by measuring the liquid level.

 

Gravitometer - A device used to continuously measure the API or specific gravity of a flowing stream.

 

Grind Out Machine - A centrifuge used to determine the amount of B.S.&W. in a crude sample.

 

H  Return

 

Hardware - Physical equipment of a computer as opposed to the computer program. This Contrasts with "software" which defines the use of the equipment.

 

"Hot" Product -  A product batch, which has been contaminated as, in off specification. Usually this is an indication of excess vapor pressure or flash point.

 

Hydraulic Head - Pressure exerted by, or imparted to a column of fluid. It is usually expressed in feet or inches of water or other liquid. It may be converted to units of pressure.

 

Hydrocarbon - An organic compound containing only carbon and hydrogen.

 

I  Return

 

I.C.C. - Interstate Commerce Commission. A Federal agency, which has jurisdiction over pipelines engaged in interstate commerce. Authority to set oil pipeline rates has been transferred to FERC in DOE.

 

Input Data - Information put into the I/O (Input/Output) device used with a supervisory computer to call for data or initiate a specific sub-routine or event.

 

Integrity - State or quality of being complete, undivided or unbroken. In a pipeline, leak-free.

 

Interface - When products or crudes are handled as separate batches or tenders in a pipeline, the interface is that portion of the stream where two grades of material join. A mixture of the two grades is usually present in lengths varying from a few feet to several thousand feet in the line, depending on the size of pipe, flow rate and characteristics of the two materials. Tank switches on crude lines are normally made at the center of the interface. On product lines, care must be exercised to keep gasolines out of oils and switches (or cuts) are always made to keep the oils clean - i.e., switch so that only oil goes to an oil tank and all of the interfacial mixture is cut to the gasoline (or to slop).

 

Interfacial Mixture - The blend of two products at the interface of batches in the line. The interfacial mixture must be kept to a minimum to maintain product purity.

 

J  Return

 

Joint Movement - The shipment of a tender of oil through the facilities of two or more pipeline companies.

 

Joint Tariff - A rate sheet issued jointly by two or more companies setting forth charges for moving oil over the facilities of each.

 

K  Return

 

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L  Return

 

LACT - "Lease Automatic Custody Transfer".  An automated unit for measuring, sampling and transferring oil from a lease into a pipeline.

 

LPG - Liquefied Petroleum Gas, such as butane, propane, etc.

 

Leaching - The adding of fresh water to a salt formation to enlarge a cavity size or create brine.

 

Line Fill - Line fill is the term used to describe the volume of product in a line or a particular section of line. The line fill, divided by the pumping rate, indicates the time required for a new barrel moved to the line to clear the line. Capline has a line fill of 5,023,561 barrels. At a rate of 555,000 B/D, it takes 9 days to move a barrel from St. James to Patoka.

 

Line Wash - Displacement of a product in a segment of line with another type of product to avoid contamination.

 

Log Sheet - Daily report sheet on which operating data is entered. Log sheets are permanent records and should never be destroyed.

 

Logic - The science of correct reasoning. As applied to a computer, the successive steps which make up a program.

 

M  Return

 

MACRO - A set of computer instructions to perform a specific operating function. The term macro means large (versus micro which means small) and usually a macro is prepared to handle several sequential tasks.

This may include switching valves, starting or stopping pumps, etc.

 

Magnetic Drum or Disk - A cylinder or circular plate with a magnetic surface on which data can be stored by selectively magnetizing a portion of the surface.

 

Manifold - An arrangement of piping and valves to provide interconnecting lengths between a number of pumps, tanks, and lines at a pump station or tank farm.

 

Mainline - A trunk pipeline.

 

Memory - In computer language, pertaining to a device into which data can be entered, in which they can be held, and from which they can be retrieved at a later date.  Usually a disc, etc., which can be readily magnetized and demagnetized.

 

Meter Report - A form, designed to be completed at 7:00 a.m. on the first of each month, indicating the electric meter readings at a station. Both the power company's meters and Shell meters are noted.  This is important in the allocation of charges when two or more companies are involved in utilization of power at a location.

 

Microwave - Ultra-short wave radio communications system. The signal waves in this system are focused to travel on a line-of-sight between sending and receiving equipment.

 

Mile Pole - A location on the pipeline rights of way. This is a holdover from the days when a company owned telegraph or telephone line was installed along the line for communications. The poles were numbered, beginning at the originating station. The pole one mile out became MP1 and the next pole MP1+1, etc. Airpatrol markers were later placed on top of the poles and carried the same number as the pole.  Locations are now marked in miles and tenths of miles rather than miles and "poles".

 

Mnemonic Symbol - A symbol or abbreviation to convey a meaning, chosen because it is easy to remember. For instance, LO for lockout, VLV for valve, etc.

 

Module - In computer language, a program unit that is discrete and identifiable with respect to compiling. A packaged functional hardware unit designed for use with other components.

 

Molecular Weight - Summation of the atomic weights of individual atoms, e.g., ethylene = C2H4 = 2 x 12 = 24 4 x 1 Molecular Weight.

 

Motor Efficiency - A measure of the useful power provided by a motor in relation to the amount of electrical energy supplied to the motor. Mainline motors range from 90-97 percent efficient.

 

N  Return

 

NPSH - Net positive suction head is the total available head (adjusted for the vapor pressure of liquid being pumped) available to a pump. A centrifugal pump has a specific required NPSH. If the suction head provided to a pump is less than the required NPSH, the pump will cavitate and the pump may be seriously damaged.

 

O  Return

 

OSHA -  Occupational Safety and Health Administration. Develops and promulgates occupational safety and health standards, develops and issues regulations, and conducts investigations to determine status of compliance with safety and health standards and regulations.

 

Orifice Plate - A plate of steel with a machined hole in the center that is placed between two flanges in a pipeline to create a known resistance to flow. The difference in pressure on either side of the plate is used for flow measurement and indication.

 

Output Data - Information from the supervisory computer that may include operating data and the status of various pieces of equipment.

 

P  Return

 

PPM - WT. VOL. - Parts per million, Weight - 1 pound per 1 MM pounds; Volume - 1 gallon per 1 MM gallons.

 

Parameter - A parameter is a unit of measure, which may be assigned arbitrary values or limits. Parameters, or assigned limits to a given variable such as flow-rate, help to define a problem by restricting the maximum and/or minimum value, which might be expected. For instance, a pipeline to be designed to handle 20,000 to 100,000 B/D eliminates consideration of a lot of pipe sizes, since no size less the 12" diameter or over 18" diameter would be practical.

 

Pig - A scraper used to internally clean the pipeline. Also sometimes called a Go-Devil.

 

Plug Valve - A device used to block the flow of fluids in pipelines using a round wedge-shaped plug of steel. The plug has a hole that allows fluid to flow when aligned with pipeline. When plug is rotated 90°, the flow is blocked.

 

Positive Displacement Pump - A pump whose propulsive effort is effected by the reciprocating motion of plungers or pistons operating in a cylinder, or a pump that moves fluids with gears, vanes or lobes.

 

Pour Point - A characteristic of crude or lube oil, which indicates the temperature at which the product goes from the solid to fluid state.

 

Pre-Select - A panel with devices, which allow an operator to set up a tank or valve switch to occur at some future time. The preselected scheme may execute on a barrel count. Several valves may be switched in a specific sequence to divert the flow from one tank to another upon execution.

 

Pressure Enthalpy - Depicts thermodynamic relationships between CHART pressure, temperature, specific volume, entropy and enthalpy.

 

Products Cycle - The sequence or order in which a number of different products are batched through a pipeline.

 

Products Line - A pipeline used for the shipment of refined products.

 

Program - A series of computer actions arranged in order to achieve a certain result. A program in the overall solution or event, it may include several "routines" or "sub-routines" which handle a particular part of the total problem.

 

Prover - A device used to prove meters and determine their accuracy.

Meter factors are developed from proving each grade of crude or product measured by the meter.

 

Pump Efficiency - A measure of the useful work performed by the pump in relation to the horsepower provided by the driver. Mainline pumps range from 70-90 percent efficient.

 

Q  Return

 

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R  Return

 

ROC - Rate of change. While it is most common to rely on specific values for status indications, the rate at which such values change 'are better indicators at times. For instance, where a discharge pressure might normally vary from 500 to 700 psi, any specific value (say 625 psi) within these limits might appear normal to a Controller. However, if the discharge pressure should rise from 500 to 625 psi in a relatively short period of time, this might indicate a blocked line. Conversely, when the Controller starts a unit he should expect a rather quick rate of change in discharge pressure. If this increase in discharge pressure does not occur, it may indicate trouble. While we do not ordinarily think of it, flow is the rate of change of barrels pumped. On small diameter lines, integrity checks are made by measuring barrels received vs. barrels delivered, usually over a period of one, four or eight hours. An instantaneous check can be made when flow rates are checked at various points along a system.  To go one step further, the ROC of flow can be watched and compared. Should the flow rate abruptly change, a line block or break might be indicated.

 

REID VAPOR PRESSURE - Vapor pressure at 100°F.

 

Relief Valve - A valve, which can be preset to open automatically when a continuously monitored pressure exceeds a given amount. Most relief valves are pressure or spring loaded, although some relief valves are held closed by a pin or nail which will shear off and allow the valve to open if the pressure exerts enough force to shear the pin.

 

Right of Way - A strip of land usually from 30 to 80 feet wide on which permission has been granted by landowners for construction and operation of a pipeline.

 

S  Return

 

SCADA   Supervisory Control and Data Acquisition.

 

Scan - To examine sequentially, part by part. The repetitive checking of pre-selected, remote points in a specific order by the supervisory equipment.

 

Scraper Trap - Special piping used to launch or receive a scraper or sphere.

 

Segment - A portion of a pipeline, usually between two stations.

 

Set Point - A variable limit, which can be manually set, which then becomes a control point. For instance, the discharge pressure controller may normally be set to control at 600 psi. This set point may be reduced to 200 psi when welding is scheduled on the line downstream of the station.

 

Shipper - Owner of crude or product moved by common carriers. The customer.

 

Slip Stream - A portion of the main stream being moved in a pipeline, which is directed, to a customer tank, sampler or gravitometer.

 

Slop - On product lines where the interfacial mixture cannot be handled in either of the batches being handled, the mixture is termed "slop" and is moved into a suitable tank (slop tank) to be disposed of as convenient. Short line fills are sometimes run to slop to prevent degrading a different product scheduled for movement through the line.

 

Specific Gravities - The ratio of the density of crude oil or product to the density of pure water.

 

SPECIFIC VOLUME - Number of cubic feet of product required to make 1 pound; Inverse of density.

 

Software - A set of computer programs, procedures, and possibly associated documentation concerned with the operation of a data processing system. The software contains the instructions and logic through which the "hardware" - i.e., the physical equipment, is able to perform its desired function.

 

Standby Power Supply - Normally, a battery or an engine-driven generator, which is immediately available in case of power failure. In some cases, the engine is started automatically within seconds after primary power supply is interrupted.

 

Stock - The amount of crude oil or product in storage at a given time.

 

Strapping - Physical measurement of a tank and calculations to determine the capacity of the tank. This is done to provide tables to convert feet, inches, and fractions of liquid level into barrels.

 

Strip - To make a side delivery or slip stream delivery. For instance, if a 5,000-barrel delivery of gasoline is scheduled at a location, it may be "stripped" off of a passing 50,000-barrel batch during the time the gasoline passes that location. The delivery is started after the gasoline interface passes the take-off lateral and stopped before the end of the gasoline batch.

 

Stratify - The division of two or more products or crude grades into layers when stored in a tank: Stratification occurs because of the difference in gravity, the heavier fluid settles to the bottom and the lighter fluid rises to the top.

 

Suction Pressure - Suction pressure is the incoming pressure at a station or the inlet pressure to a pump. Suction pressure is usually controlled to some minimum (say 50 psi) to assure that the first pump will be filled.

 

Supervisory Controls - Those pieces of equipment that allow remote monitoring and control of pipeline facilities. This includes the devices at the remote station, which read and transmits local status as well as the equipment at the control center.

 

System Integrity - The test of a system's security. In pipelines, it is usually a comparison of barrels in and out of the system.

 

T  Return

 

Tariff - A rate sheet of charges made by pipelines companies for moving oil.

 

Tank Bottoms - The accumulation of heavy elements in the bottom of a tank. In a products tank, this could be rust or scale, water and other dense liquids. In a crude tank, this could be a waxy or asphaltic build-up, foreign matter, etc.

 

Tank Farm - Several storage tanks connected to a pipeline and a pump station so that oil can be received into and withdrawn from tankage as scheduled.

 

Tank Table - A tabular listing of the volume contained in a particular tank when the liquid level is at various specific heights, usually stated in feet, inches and eighth-inches. The volume is dependent upon tank diameter and the "deadwood" in the tank. Deadwood is the structural members, hoses, etc., within the tank, which fill the space, which, would otherwise be available to the liquid in the tank.

 

Tender - A shipment of oil or products presented to a pipeline company for movement.

 

Terminal - A point to which oil is transported through pipelines. It usually includes a tank farm and may include tanker loading and unloading facilities.

 

THERMAL EXPANSION - Increase in volume or pressure in a closed container caused by an increase in temperature.

 

THERMODYNAMICS - Science that deals with heat and work, and those properties of substances that bears a relation to heat and work.

 

Thief - A device used to sample a tank for suspended and settled B.S.&W.

 

Throttling - To throttle is to control flow by partially closing a valve. Throttling is detected by noting the difference in the station case and discharge pressures. While any valve, which can block the mainline, can be used to throttle, it is usually a station control valve in the control position that throttles the flow on a pipeline. It is usually pressure (rather than flow) that the control valve is designed to monitor and control. See "Control Valve". The pressure drop across a control valve (like any other restriction in a pipeline) represents a loss of energy or power available to move the oil in the line. Some throttling, particularly in a line handling batched crude or products, cannot be avoided. Excess throttling is a waste of energy. For example, if one or more control valves on a system throttle 200 psi, the energy loss is equal to that required to operate a pump capable of producing 200 psi at the system flow rate.

 

U  Return

 

Ullage - The space at the top of a tank, compartment or other liquid container, which is not filled with the liquid. This is a vapor space for volatile liquids. This is the space initially gauged in the "outage" method.

 

Upstream - The pipeline direction from which the stream moves, i.e., towards the beginning of the system or initial station.

 

V  Return

 

Velocity - Time rate or linear motion in a given direction. Usually expressed in feet per second for pipelines. Normal range of flow is

5 to 6 feet per second (3 to 4 miles per hour): 10 feet per second is considered the upper range for pipelines.

 

Viscosity - The quality of a fluid that resists internal flow.

 

Viscosity Index - The degree of change in resistance of a fluid to flow with a change in temperature.

 

W  Return

 

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X  Return

 

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Y  Return

 

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Z  Return

 

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