Glossary

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.

​

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

​

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

​

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

​

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.

​

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.