Reference
Glossary
Petroleum engineering terms and definitions used in PetroBench
Glossary of petroleum engineering terms used throughout PetroBench. Terms are organized alphabetically for easy reference. Click any term from the platform's help tooltips to jump directly to its definition.
A
Abandonment Pressure
Minimum economic reservoir pressure at which a well is no longer profitable to produce.
Additional Pump Load
Additional tension to be added to the anchor to account for the forces caused by a pump on tap.
Anchor Depth
Distance from the surface to the tubing anchor along the wellbore path, measured in feet.
Anchor Tension
The minimum tension required at the tubing anchor to prevent tubing movement during pumping operations.
Azimuth
Compass direction of the wellbore measured clockwise from north (0-360 degrees). Used with measured depth and inclination to calculate the 3D wellbore trajectory.
API Gravity
Oil density measure developed by the American Petroleum Institute. Higher API = lighter oil. Classification: Heavy (less than 22°), Medium (22-31°), Light (greater than 31°).
API Number
American Petroleum Institute unique well identification number assigned by regulatory agencies. Format varies by state/country.
API Pump Type
API classification of pump type based on configuration. Letters indicate: R=Rod, T=Tubing, W=Wall-anchored, A=Traveling barrel, B=Stationary barrel, H=Heavy wall, C=Cup-type, M=Metal plunger, P=Soft-packed. Example: RWBC = Rod pump, Wall-anchored, stationary Barrel, Cup-type.
Axial Loading
Tensile/compressive axial loads on rod string by depth. Shows load distribution and identifies critical stress zones.
B
Ballooning Effect
Increase in tensile force due to differential pressure between tubing and annular pressure causing tubing expansion.
Beam Weight
Weight of the walking beam in pounds. Used for HGC unit calculations and structural load analysis.
Belt Length
Calculated length of drive belt connecting motor sheave to gearbox input sheave.
Bottomhole Temperature
Temperature at the bottom of the well, typically measured at total depth or pump setting depth.
Bubble Point Pressure
Pressure at which dissolved gas begins to evolve from oil, forming free gas bubbles.
Buckling Tendency
Shows critical buckling load percentage vs depth. Values greater than 100% indicate compression and buckling risk.
Buoyant Rod Weight
Weight of rod string submerged in fluid (air weight reduced by buoyancy). Used to calculate net downhole loads.
C
Calculate Fluid Load
Option to automatically calculate fluid load from fluid level measurement.
Calculate Guides
Automatically calculates the number of rod guides needed to prevent buckling and contact with tubing.
Calculated SPM
Calculated strokes per minute based on simulation parameters and actual unit performance.
Casing ID
Internal diameter of the production casing in inches.
Casing Pressure
Pressure in the casing annulus at surface. Often vented in rod pump wells to maximize drawdown.
Casing Type
Type of casing string (Surface, Intermediate, Production) based on its function in the well.
Center Distance
Distance between motor sheave center and gearbox input sheave center.
Centralizers
Number of centralizer devices installed to keep casing centered in the wellbore for proper cement placement.
CO2 Content
Percentage of carbon dioxide in the gas stream. Affects fluid properties and corrosion rates.
Component OD
Outside diameter of a component (rod, tubing, etc.) inside the casing.
Counterbalance Effect
Effective counterbalance force in pounds. Represents the load relief provided by the counterbalance system.
Coupler OD
Outside diameter of the tubing coupling in inches. Must clear casing restrictions.
Coupler Type
Type of coupling used to connect tubing joints (Regular, Slim-hole, or specific manufacturer type).
Crank Hole
Position of crank arm connection on counterweight. Changes stroke length. Lower numbers = shorter stroke.
Cumulative Oil
Total oil produced from well since startup. Used to calculate remaining reserves and decline curves.
Cumulative Probability
Statistical probability for reservoir analysis and production forecasting.
Cylinder ID
Internal diameter of the hydraulic pump cylinder in inches.
D
Damping Factor Down
Damping coefficient for downstroke. Removes energy from the rod string system.
Damping Factor Up
Damping coefficient for upstroke. Removes energy from the rod string system.
Directional Survey
Wellbore directional survey data used to calculate true vertical depth and dogleg severity along the wellbore path.
Dogleg Severity
Wellbore curvature severity measured in degrees per 100 feet. High dogleg severity causes increased rod wear and fatigue.
Down Stroke Time
Time duration for downward stroke in seconds (hydraulic units).
Drift
Minimum internal diameter guaranteed for passage of tools, accounting for manufacturing tolerances.
Dynamometer
Load vs position diagram showing polished rod load, permissible load, and pump load throughout the pumping cycle.
E
East-West
East-West displacement from the wellhead in feet, calculated from measured depth, inclination, and azimuth using the minimum curvature method.
Elastic Modulus
Young's Modulus - measure of material stiffness in psi. Higher values indicate stiffer material.
Elevation
Well site elevation above sea level affecting air density and engine performance.
EUR Oil
Estimated Ultimate Recovery - total oil expected to be produced from the well over its lifetime.
F
Fillage
Percentage of pump barrel filled with fluid during upstroke. Normal: 70-95%. Low values indicate gas interference or worn pump.
Fluid Above Pump
Height of annular fluid column above the pump in feet.
Fluid Gradient
Change in pressure per unit depth, typically in psi/ft. Pressure increases predictably with depth in normally pressured zones.
Fluid Level
Depth to fluid surface in the annulus, measured from surface. Used to calculate pump intake pressure.
Fluid Load
Total weight of fluid column above pump in pounds. Calculated from fluid specific gravity and pump depth.
Fluid Production
Total liquid (oil + water) production rate in barrels per day.
Fluid Shot Data
Acoustic fluid level survey data. Use Most Recent, 30, or 90 day average to determine fluid above pump.
Fluid Specific Gravity
Combined specific gravity of produced fluids (oil + water blend).
Foam Column Top
Depth where foam/gas accumulation begins above pump.
Friction Coefficient
Dynamic friction coefficient between rod guides and tubing wall. Typical range: 0.2-0.4.
Full Pump
Indicates if the pump is operating at 100% fillage during the upstroke.
G
Gas Free Height
Height of liquid column if all gas were removed from foam.
Gas Specific Gravity
Ratio of gas density to air density at standard conditions. Used for gas calculations.
Gear Reducer Ratio
Gear reduction ratio of the pumping unit gearbox. Reduces motor RPM to pumping speed.
Gearbox Loading
Analysis of gearbox torque loading percentage. Evaluates if unit is appropriately loaded.
Gearbox Torque
Net torque on gearbox throughout 360° rotation. Dashed line shows gearbox rating.
GOR
Gas-Oil Ratio in standard cubic feet per barrel (scf/bbl). Higher GOR reduces pump efficiency.
Gross Pump Stroke
Actual plunger travel distance in inches, accounting for rod/tubing stretch and geometry.
Ground Elevation
Ground level elevation above sea level in feet at the well site.
Guide Type
Material type of rod guide: N70 (nylon), PPS (polyphenylene sulfide), PPA (polyphthalamide). Selection depends on temperature and well conditions.
Guide Weight
Weight of rod guides included in total rod string weight calculations.
Guides Per Rod
Number of rod guides installed per rod joint. Typically 1-2 guides per joint depending on well deviation.
H
H2S Content
Percentage of hydrogen sulfide in the gas stream. Affects material selection and safety requirements.
Hole Diameter
Diameter of each perforation tunnel in inches.
Hydraulic Pump
Displacement volume of the hydraulic pump per revolution.
Hydraulic Timing
Time parameters for hydraulic units including turn-around time, acceleration, and deceleration settings.
I
Inclination
Wellbore angle from vertical in degrees. 0 degrees is vertical, 90 degrees is horizontal. Used with measured depth and azimuth to define the wellbore trajectory.
Inner Diameter
Inside diameter of tubing in inches. Determines flow area and rod clearance.
Intake Pressure
Pressure at the pump intake. Critical for determining pump submergence and efficiency.
K
KB Elevation
Kelly Bushing elevation above sea level in feet. Reference point for all depth measurements.
L
Largest Dogleg Above
Maximum dogleg severity value encountered in the wellbore section above the pump.
Latitude
Geographic latitude coordinate of the well location in decimal degrees. Range: -90 to 90.
Length
Length of rod or tubing section in feet.
Length Difference
Difference between PSN depth and total rod length. Should be 0.00 for proper rod string design.
Liquid Rate
Total liquid production rate including oil and water in barrels per day.
Longitude
Geographic longitude coordinate of the well location in decimal degrees. Range: -180 to 180.
M
Measured Depth
Distance along the actual wellbore path from the Kelly Bushing to a given point, measured in feet. Unlike true vertical depth, measured depth follows the borehole trajectory including any deviations.
Manufacturer
Manufacturer of rods, tubing, or pumping unit equipment.
Manufacturer Line
Product line designation from equipment manufacturer (e.g., Lufkin C-Series).
Max CB Moment
Maximum counterbalance moment in inch-pounds needed to balance pumping loads.
Max Dogleg Above PSN
Maximum DLS tolerance for rod string cycling through the wellbore.
Max Dogleg Severity
Maximum dogleg severity tolerance for pump setting location.
Max Inclination
Maximum inclination tolerance for pump setting depth.
Max Load
Maximum load rating for the pumping unit.
Max PSN Depth
Maximum allowable pump setting depth based on well geometry constraints.
Min Pump Length
Minimum barrel length required to accommodate gross pump stroke and clearances.
Model
Specific model designation of pumping unit (e.g., C-160D-173-74).
Motor Type
Type of prime mover driving the pumping unit (Electric Motor, Gas Engine, VFD Electric).
MPRL
Minimum Polished Rod Load - minimum load at surface during downstroke. Negative values indicate counterbalance issues.
MPRL/PPRL
Ratio of minimum to peak polished rod loads. Ideal range: 0.25-0.50 for proper counterbalance.
N
Neutral Point
Additional tension required at anchor to counter thermal, piston, and ballooning effects.
North-South
North-South displacement from the wellhead in feet, calculated from measured depth, inclination, and azimuth using the minimum curvature method.
Nitrogen Content
Percentage of nitrogen in the gas stream.
O
Oil API Gravity
Density of oil measured in degrees API. Lighter oils have higher API gravity values.
Oil Production
Oil production rate in barrels per day.
Oil Production Rate
Daily oil production in barrels (BOPD). Key metric for well performance.
Outer Diameter
Outside diameter of tubing or casing in inches.
Overpull
Distance the tubing is pulled past desired tension point to set the tubing hanger.
Overpull Hookload
Pulling force required at surface to achieve proper overpull.
P
Parameter One
Primary simulation parameter selection (e.g., Stroke Rate, Desired Production).
Parameter Two
Secondary simulation parameter for result estimation method.
Peak Gearbox Torque
Maximum torque applied to gearbox during pumping cycle in inch-pounds.
Peak Load
Maximum upstroke load measured at the polished rod.
Permissible HP
Maximum safe horsepower for the pumping unit based on API ratings and structural limitations.
Piston Effect
Decrease in tensile force caused by falling sucker rods and pump plunger.
Plunger Diameter
Diameter of the pump plunger in inches.
Plunger Length
Length of the pump plunger in inches.
Polished Rod Diameter
Diameter of the polished rod at surface. Must match stuffing box size.
Polished Rod HP
Horsepower delivered at the polished rod. Represents actual power for lifting fluids.
PPRL
Peak Polished Rod Load - maximum upward load at surface during upstroke in pounds.
PRHP/PLHP
Ratio of Polished Rod HP to Permissible HP. Should be less than 1.0 for safe operation.
Prime Mover
Engine or motor driving the hydraulic pump or pumping unit.
Prime Mover RPM
Motor or engine speed in revolutions per minute. Reduced to pumping speed through gearbox.
Producing Level
Depth to fluid level when well is producing.
Producing Temp
Temperature of produced fluid at wellhead during production operations.
Production Data
Historical production volumes for oil, water, and gas with calculated metrics.
PSN Depth
Pump Seating Nipple depth - measured depth from Kelly Bushing to pump intake in feet.
PSN Dogleg
Dogleg Severity in degrees per 100ft at the Pump Seating Nipple location.
PSN Inclination
Wellbore inclination angle at the Pump Seating Nipple location.
PSN TVD
True Vertical Depth at the Pump Seating Nipple.
Pump Condition
Operating condition when pump is not full. Options: Gas Interference or Fluid Pound.
Pump Diameter
Internal diameter of the pump plunger in inches. Common sizes: 1.25", 1.5", 1.75", 2.0", 2.25", 2.5".
Pump Fill
Pump fillage percentage. Default 85% when gas interference is expected.
Pump Friction
Friction coefficient between plunger and barrel.
Pump Separator TVD
Vertical depth from surface to pump or separator installation point.
Pump Slippage
Volume of fluid lost due to pump inefficiency from plunger-barrel clearance.
Pump Space
Clearance between plunger and pump seating assembly at bottom of stroke.
Pumping Unit Type
Type of surface pumping unit (Conventional, Air Balanced, Mark II, etc.).
Q
Quantity
Number of identical tubing joints or rod joints in a section.
R
Rec Plunger Length
Recommended plunger length for optimal pump performance and seal life.
Required HP
Minimum horsepower required at motor to lift design production rate.
Reservoir Pressure
Formation pressure driving fluids into wellbore. Used for IPR calculations.
Reservoir Temp
Temperature of the in situ reservoir fluid.
Rod Buckling
Analysis of compression forces on rod string. High buckling stress causes rod/tubing wear.
Rod Class
API rod class designation (e.g., C, K, D, KD). Defines material grade and strength properties.
Rod Diameter
Nominal diameter of rod in inches. Common sizes: 5/8", 3/4", 7/8", 1".
Rod Grade
API rod grade classification. Manufacturers have internal grades aligned with API use classes.
Rod Guided
Whether rod section uses rod guides to prevent rod-tubing contact.
Rod Loading
Percentage of rod ultimate strength being used. Safe range: less than 70% for continuous operation.
Rod Manufacturer
Manufacturer of sucker rods.
Rod Stress Calc
Stress calculation method for rod loading (e.g., T/4, T/2.8 for steel; Fiberflex API for fiberglass).
Rod Taper
Position of rod section in string (1 = top section). Each taper represents different diameter.
Rod Tensile Strength
Ultimate tensile strength in ksi. API grades: D=60ksi, K=85ksi, C=90ksi, KD=115ksi.
Rod Top Max Stress
Maximum tensile stress at top of rod section during upstroke in psi.
Rod Top Min Stress
Minimum tensile stress at top of rod section during downstroke. Negative indicates compression.
Rod Type
Type of sucker rod (Steel, Fiberglass, Coated, Sinker Bar).
Rotation
Direction of pumping unit rotation as viewed from wellhead (Clockwise or Counterclockwise).
Run Time
Total operating time for simulation. Cannot exceed 24 hours.
S
Service Factor
Safety factor applied to steel rod string design. Typical values: 0.50-0.75.
Set Depth
Depth where casing shoe is set, measured from Kelly Bushing.
Set Tension
Tension applied to casing string when cemented.
Sheave Diameter
Belt pulley diameter in inches. Determines speed reduction ratio.
Shots Per Foot
Perforation density, typically 4-16 shots per foot.
Side Loading
Lateral forces on rod string by depth indicating rod-to-tubing contact.
Slippage
Volume of fluid lost due to pump inefficiency.
Specific Gravity
Ratio of fluid density to water density.
SPM
Strokes Per Minute. Typical range: 3-12 SPM for beam pumps.
Static Level
Depth to fluid level when well is shut in.
Static Temp
Stabilized temperature at wellhead when well is static.
Step Length
Calculation interval length in feet. Smaller values increase precision but slow computation.
Stress Load
Percentage of rod ultimate strength being used. Safe: less than 70%, Caution: 70-80%, Risk: greater than 80%.
Stroke Length
Length of pumping unit stroke in inches. Typical range: 30-168 inches.
Stroke Rate
Strokes per minute (SPM) of the pumping unit. Typical range: 3-12 SPM.
Structure Load
Percentage of unit structural rating being utilized. Greater than 100% indicates overloading.
Stuffing Box Friction
Friction from the stuffing box on the polished rod.
Stretch Loss
Production loss due to tubing stretch in barrels per day.
System Efficiency
Overall system efficiency combining mechanical, volumetric, and electrical losses. Typical: 40-55%.
T
Taper
Position of rod section in string. Tapered strings use larger rods at top, smaller at bottom.
Target Depth
Optimal pump depth for the well.
Target Fluid Level
Estimated operating fluid level from surface in tubing.
Target Intake Pressure
Target pressure at pump intake in psi.
Target Level
Desired fluid level for optimization.
Target Pressure
Target casing pressure for optimization.
Target Production
Desired daily production rate in barrels.
Target Stroke Rate
Reasonable maximum stroke speed for selected pumping unit.
Tensile Strength
Ultimate tensile strength of rod material in ksi.
Thermal Effect
Drop in tensile force from tubing expansion from static to production temperature.
Thickness
Total thickness of perforated interval (bottom - top depth).
Thread Type
Thread connection type at tubing joint (e.g., EUE, NUE, Premium).
Top Depth
Measured depth from Kelly Bushing to top of section in feet.
Top Max Stress
Maximum tensile stress at top of rod section during upstroke.
Top Min Stress
Minimum stress at top of rod section during downstroke.
Total Hookload
Total tension required when setting anchor to achieve desired anchor tension on production.
Total Length
Sum of all rod section lengths. Should match PSN depth.
Tubing Anchored
Whether tubing is mechanically anchored to prevent movement during pumping.
Tubing Description
Descriptive name or identifier for tubing string section.
Tubing Grade
Steel grade designation (e.g., J55, N80, P110). Higher grades have greater tensile strength.
Tubing ID
Inside diameter of tubing in inches.
Tubing OD
Outside diameter of tubing body in inches.
Tubing Pressure
Pressure inside tubing string at surface, also called flowing wellhead pressure or flowline pressure.
Tubing Stretch
Elastic elongation of tubing string under tensile load during upstroke.
Tubing Weight
Weight per foot of tubing string in pounds.
Turn Around Time
Time delay at stroke reversal points for hydraulic units.
TVD
True Vertical Depth - actual vertical distance from surface reference point.
U
Unit Model
Specific model designation of the pumping unit.
Unit Structural
Pumping unit structural load rating. Values greater than 100% indicate overloading.
Unit Type
Type of surface pumping unit (Conventional, Air Balanced, Mark II, etc.).
Up Stroke Time
Time duration for upward stroke in seconds.
Use Fluid Level
Option to use fluid level for calculations.
V
Vertical Friction Down
Friction coefficient for vertical rod-tubing contact during downstroke in directional wells.
Vertical Friction Up
Friction coefficient for vertical rod-tubing contact during upstroke in directional wells.
Viscosity
Fluid viscosity affecting pump efficiency and slippage.
Volumetric Efficiency
Percentage of theoretical pump displacement actually produced. Default 85% for gas interference.
W
Water Cut
Percentage of water in total liquid production. Critical at greater than 95%.
Water Gravity
Specific gravity of produced water. Fresh: 1.0, Brine: 1.02-1.08.
Water Production Rate
Daily water production in barrels (BWPD).
Water Specific Gravity
Ratio of water density to fresh water density.
Weight
Weight per foot of tubing or rod in pounds.
Weight in Water
Expected hook load exerted by tubing string hanging in water.
Well Depth
Total measured depth of well from Kelly Bushing to bottom.
Well Name
Unique identifier for the well. Typically includes lease name and well number.
Wellbore
3D visualization of wellbore trajectory showing MD, TVD, and lateral displacement.
Additional Terms
Actions
Available operations for a record including edit, duplicate, delete, and view details.
Air Balanced
Type of pumping unit that uses compressed air cylinders for counterbalance instead of conventional counterweights. Minimum cylinder volume ensures adequate counterbalance force.
Bottom Depth
Measured depth from Kelly Bushing to the bottom of a section in feet.
Bottom Min Stress
Minimum stress at bottom of rod section in psi. Negative values indicate compression and potential buckling risk.
Calculators
Engineering calculation tools within PetroBench for analyzing well performance and equipment sizing.
Casing
Steel pipe installed in the wellbore to prevent collapse and isolate formations.
CF Elevation
Cellar Floor elevation above sea level in feet.
Comparison
Side-by-side analysis of multiple simulation results to evaluate different rod string designs.
Country
Country where the well is located.
County
County or parish where the well is located.
Created
Date when a record was created in the system.
Created By
User who created a record in the system.
Equivalent Gas Free Liquid
Height of liquid column if all gas were removed from foam above the pump.
EUR
Estimated Ultimate Recovery - total oil expected to be produced from the well over its lifetime.
Flow Velocity
Speed of fluid flow in tubing or annulus. Used to assess flow regimes and erosion risk.
Foam Column
Gas-liquid mixture above the pump that affects fluid level measurements and pump performance.
Hydraulic Lift
Hydraulic pumping unit calculations including power requirements and cycle time analysis.
Installed
Indicates if a simulation is currently installed on the well as the active rod string design.
IPR
Inflow Performance Relationship - describes the relationship between bottomhole pressure and production rate.
KB-CF Distance
Distance from Kelly Bushing to Cellar Floor.
KB-Ground Distance
Distance from Kelly Bushing to ground level, typically 10-15 feet.
Last Modified
Date and time when a record was last updated.
Lease Name
Name of the lease or property where the well is located.
Maximum Rated Load
Maximum load rating for a pumping unit in pounds.
Name
Identifier for a simulation, comparison, or other record.
Neutral Point Tension
Additional tension required at anchor to counter thermal, piston, and ballooning effects.
Operator
Company or entity responsible for operating the well.
Organization
Company or organizational unit within PetroBench. Can be structured as HQ → Division → Region.
Owner
User who created and owns a simulation or record.
Perforation Bottom
Bottom measured depth of perforated interval.
Perforation Thickness
Total thickness of perforated interval (bottom - top depth).
Perforation Top
Top measured depth of perforated interval.
Perforations
Holes made through casing and cement into the formation to allow fluid flow.
Permissions
Access controls that define what actions users can perform in PetroBench.
Plunger Barrel Clearance
Clearance between pump plunger and barrel walls affecting slippage.
Producing Fluid Level
Depth to fluid level when well is actively producing.
Producing Wellhead Temperature
Temperature of produced fluid at wellhead during production operations.
Pump Intake Pressure
Pressure at the pump intake (PIP). Calculated from fluid level and fluid gradient. Critical for pump submergence.
Pumping Unit
Surface equipment that provides reciprocating motion to the rod string for lifting fluids.
Reservoir Temperature
Temperature of the in situ reservoir fluid.
Rod Pump Production
Theoretical and actual production rates from rod pump systems based on displacement and efficiency.
Rod String
Complete assembly of sucker rods from surface to pump, including tapered sections.
Simulation
Rod string design calculation that models equipment performance and predicts stresses.
State
State or province where the well is located.
Static Fluid Level
Depth to fluid level when well is shut in and not producing.
Static Wellhead Temperature
Stabilized temperature at wellhead when well is static/shut in.
Tubing
Production tubing string through which fluids are produced to surface.
Tubing Weight in Water
Expected hook load exerted by tubing string when submerged in water.
Well
Oil or gas producing wellbore with associated equipment and production data.
Well Performance
Historical performance data including fluid levels and production rates.