T

Tack Weld
Noncontinuous weld used to hold members together prior to complete welding.

Tackle Hoist
Assembly of ropes and sheaves arranged for pulling.

Tadpole Plot
A plot of dipmeter log or drift results where the dip angle is plotted versus depth as the displacement of a dot.

Tail Chain
The short length of chain, with a hook attached, on the end of a winch line.

Tail Gate
The point in a gas processing plant at which the residue gas is metered prior to sale, return of gas to the lease, or return to the gas purchaser.

Tail Out Rod
To pull the bottom end of a sucker rod away from the wellbore origin when laying rods down.

Tail Pipe
Pipe run in a wellbore below a packer.

Tail Plug
The plug in the end of a gas lift valve which is the final seal on the dome.

Tail Swing
Clearance distance from center of rotation to maximum rear extension of revolving upperstructure. Also referred to as: Rear End Radius.

Take- In- Kind
The interest owner exercises his interest by taking his share of the product(s) for marketing or disposition rather than receiving his portion of the value. Also referred to as: In-kind.

Take- In- Kind Status
Identifies whether the take-in-kind option is active or inactive for the associated contract.

Take Or Pay
The quantity of gas that a gas purchaser agrees to take, or to pay for if not taken.

Taken Or Paid Amount
The invoice amount paid or credit taken.

Taken-in-kind Interest Owner Name
The name of the company or individual which identifies the interest owner associated with the taken-in-kind volume.

Taken-in-kind Operator Number
A number assigned by the regulatory agency to identify the operator associated with the taken in kind volume.

Taken-in-kind Volume
The volume of production taken in kind.

Tally
A record of the tubing or casing installed in a wellbore. It records the length of each joint, the number of joints, and the overall length of the string after making allowances for thread makeup.

Tandem Squares
Two or more square drill collars adjacent in a bottomhole assembly.

Tandem Stabilizers
Refers to the use of two or more stabilizers at one position in a bottomhole assembly.

Tangent
Tangent of the angle between the new equator and the reference meridian for an oblique Mercator projection.

Tangential Method
A borehole survey calculation method which uses only the inclination and direction angles measured at the lower end of the course length. The wellbore path is assumed to be tangent to these angles throughout the course.

Tangible Casing Cost
Cost of casing placed in the well, such as surface string, intermediate string, production string, and casing liners.

Tangible Casinghead Cost
Includes the cost of casinghead, control valves and spools, and flow pipes attached to the top of the casing.

Tangible Christmas Tree Cost
Costs of the assembly of valves mounted on the casinghead and/or spools through which a well is produced. The christmas tree also contains valves for testing the well and for shutting it in if necessary. Also included are the tubinghead, chokes, gauges, and PVC adapters.

Tangible Miscellaneous Materials And Equipment Cost Costs Of Miscellaneous Noncontrollable Equipment Not Identified Elsewhere.

Tangible Retrievable Packer Cost
Costs associated with the expanding plug used in a well to seal off certain sections of the tubing or casing when cementing, acidizing, or when a production formation is to be isolated. Packers are run in the tubing or the casing, and when in position can be expanded mechanically or hydraulically against the pipe wall or the wall of the wellbore.

Tangible Tubing Cost
Includes the cost of tubing, tubing nipples, tubing safety joints, tubing size screens, and blank tubing.

Tank
A cylindrical vessel for holding, measuring or transporting liquids.

Tank ( Air Receiver)
A vessel used to store air on an air compressor.

Tank Band
A circular piece of steel used to secure the staves of a bolted steel tank.

Tank Battery
A series of lease tanks and related equipment close together which are operated by means of common connections. Also referred to as: Battery.

Tank Bottoms
The accumulation of water and settlings in a tank.

Tank Car
A railroad car used to transport petroleum or petroleum products.

Tank Car Dome
The enclosed portion of the top of a railroad tank car where the valves and gauges are located.

Tank Dike
SEE: Fire Wall.

Tank Farm
An area embracing a collection of oil storage tanks.

Tank Gauge
A visual device for determining the height of liquid in a tank.

Tank Gauging
To determine the quantity of liquid in a tank or vessel by reading the height of liquid.

Tank Hatch
SEE: Hatch.

Tank Run
A transfer of crude oil from a stock tank on a production lease to a pipeline gathering system, for transportation to the buyer's facilities.

Tank Strapper
The person who measures a tank to see how much it will hold at various levels.

Tank Strapping
Measuring a tank to prepare a Tank Table showing volumes at various heights for that tank.

Tank Table
A table giving the barrels of fluid contained in a storage tank corresponding to the linear measurement on a gauge line.

Tanks Capacity
The number of barrels of oil that can be stored on a facility; i.e., the total capacity of all the oil storage tanks on the facility.

Tannic Acid
The active ingredient of quebracho and other quebracho substitutes; e.g., mangrove bark; chestnut extract; hemlock.

Tap
(1) To make a small connection to a vessel or to an existing pipeline;(2) A notched tool used to cut inside threads.

Taper
(1) Tubular Goods: The change in the pitch diameter of round thread and the change in the root diameter of the buttress thread.(2) Seismic: Reduce the amplitude by applying a gain that goes from full amplitude (gain = 1) to zero amplitude (gain = 0). The taper is applied to account for the Gibb's phenomena.

Target
(1) Projected three dimensional coordinates for each proposed drilling objective in a well. (2) A bull plug or blind flange at the end of a tee to prevent erosion at a point where change in flow direction occurs.

Target Plan
A set of targets for a drilling activity.

Target Point
The coordinates in space considered to be the preferred point within the target area for the wellbore intersection. The planned point, within the target area, for the wellbore to intersect.

Target Reservoir Depth
The proposed depth of the target reservoir.

Target Reservoir Name
The name of the reservoir designated as the target of the operations to be performed.

Tariff
The terms, conditions, and rate information applicable to various types of services. In the case of natural gas, the tariff is filed with and approved by the Federal Energy Regulatory Commission (FERC) or a state regulatory body.

Tattletale
A device on an instrument control panel to indicate the cause of a system shutdown or alarm signal.

Tax
An assessment by governmental agencies against profits; e.g., Federal; state; local taxes.

Tax Due Amount
Calculated tax liability.

Tax Exempt Amount
The monetary amount exempt from taxation.

Tax Exempt Code
An agency assigned identifier of the type of exemption claimed.

Tax Exempt Volume
The volume produced and exempt from taxes.

Tax Free Interest
(1) An interest in production which does not bear its portion of production taxes levied on production from the property. (2)The tax applicable to this interest is borne by other interest owners in the property. Differs from Exempt Interest.

Tax Liability Flag
An indicator of whether or not the party is liable for tax.

Tax Partnership Provision
The operating agreement will state whether the working interest owners elect to report all income and expenses under the partnership section of the internal revenue code.

Tax Rate
Tax rate for given product.

Tax Rate Classification Code
An indicator of the classification that may be used to indicate special tax rate.

Tax Reimbursement Amount
The payments by a gas purchaser to a seller for all or part of the production taxes paid by the seller on the gas sold under the applicable contract.

Taxable Volume
The volume on which taxes are based.

Taxing Agency Name
The identifier of a taxing agency; e.g., a school district name.

Taxpayer Name
The name of the company or individual which identifies the taxpayer.

Td
SEE: Well Total Measured Depth.

Technical Employee
An employee having special and specific engineering, geological, geophysical, land, accounting, or other professional and supervisory skills.

Tectonics
The branch of geology dealing with the broad architecture of the outer part of the Earth; i.e., the regional assembling of structural or deformational features, including their mutual relations, origin and historical evolution.

Tee
A pressure containing fitting with three openings. Two openings opposite one another to form the run portion of the tee, and one opening at 90 degrees to the line of the run. Tees may be threaded, flanged, or studded flange.

Tefra
An abbreviation for the Tax Equity and Fiscal Responsbility Act. This act allows the withholding of 20% from all proceeds going to an individual or company that does not have a valid social security or tax identification number registered with the paying agency so all proceeds can be reported properly to the IRS. This term is commonly used to refer to the monies that are withheld when there is no valid social security number registered with an agency.

Tefra Needed Flag
An indicator of whether a Tax Equity and Fiscal Responsibility Act (TEFRA) deduction is needed.

Telemetry
A system for the electronic transmission of data.

Telephone Extension Number
The telephone extension number, in addition to the area code and primary telephone number.

Telephone Number
The area code and telephone number.

Telescopic Joint
Riser joint designed to permit a change in length of the riser to accommodate platform movements. Also referred to as: Slip Joint.

Telescoping Boom
Consists of a base boom from which one or more boom sections are telescoped for additional length.

Tell-tale
An opening, with or without a valve, which can be used to detect or to check what is happening in a line or vessel; e.g., a hole drilled in a reinforcing pad to detect leakage behind the pad, a valved connection on a vessel to check liquid level, etc.

Temperature
An indication of the heat energy that a substance pocesses.

Temperature Bomb
An instrument lowered into the wellbore to record downhole temperature.

Temperature Controller
A device which uses temperature to regulate equipment operations.

Temperature Depth
The measured depth at which the temperature reading was recorded.

Temperature Gradient
Rate of change in temperature with distance in a specified direction.

Temperature Log
A well log of temperatures recorded within the borehole, utilizing a temperature sensitive element exposed to the fluid in the borehole.

Temperature Stability
The chemical characteristics of a material which determine its resistance to thermal decomposition.

Temperature Survey
An operation to determine temperatures at various depths. Usually run to locate water influx, improper cementing, create isotherm maps, or correct well log parameter surveys.

Template
SEE: Guide Base.

Temporarily Abandon
The act of isolating the completed interval or intervals within a wellbore from the surface by means of a cement retainer, cast iron bridge plug, cement plug, tubing and packer with tubing plug, or any combination thereof.

Ten Minute Gel
SEE: Gel Strength.

Tender
The barge anchored alongside an offshore drilling platform. Usually contains living quarters, storage space and the mud system.

Tendon
A system of components which form a link between the Tension Leg Platform (TLP) and the subsea foundation for the purpose of mooring the TLP.

Tendon Access Tube
A conduit within a platform column between the bottom of the column and the tendon top connector through which a tendon passes.

Tendon Connector
A device used to connect a tendon to the platform hull (top connector) or to the foundation template (bottom connector).

Tendon Coupling
A device which connects one tendon element to another or to a specialty component.

Tendon Element
Each of the similar or identical but discrete structural components which, when assembled with the flex elements, top and bottom connectors, and any other special components, comprise a complete tendon.

Tensile Strength
The ability of a material to resist a stress tending to stretch or pull it apart.

Tension
Actual tension in the pipe due to its own weight plus the product of the drilling fluid pressure and the cross sectional area on which the pressure acts.

Tension Bolt
Threaded bolt used with tension member.

Tension Leg Platform
The collective group of tendons associated with one column of the platform.

Tension Member
A number of devices which engage the edge of the screening surface and pull it taut over the support frame.

Tension Plate
Type of tension member that is located above the screening surface and closes the gap between the edge of the screening surface and the sideplate. Also referred to as: Board Plate.

Tensioner
A device, usually pneumatically or hydraulically powered, used to apply tension to tendons or risers.

Tensioner System
Tensioner units are used to maintain risers in tension as the platform moves in response to wind, waves, and current. Horizontal motions, heave, and setdown of the platform necessitate changes in length of the risers. Tensioners accomodate these movements, as well as relative angular motion between the platform and riser, while maintaining a nearly constant tension on the risers.

Tensioning
The stretching of the screening surface within the vibrating frame.

Terminal Angle
In a directional survey, the inclination and direction angles of the lower end of the survey.

Terminal Angle Method
SEE: Borehole Survey Calculation Method.

Termination Notice Advance Days Count
The number of days of prior written notice required to terminate a gas contract.

Terminator
A device used to physically end a SCSI device chain. It can be a set of resistors on a device or a physical terminator plug attached at the end of the SCSI cable.

Terminus
For horizontal wells, the terminus is the wellbore bottomhole in the reservoir.

Terminus Location
The closest point distance of the drainhole terminus or bottomhole from a specified lease, unit, or property line.

Tertiary Recovery
Recovery methods which increase ultimate production beyond that achievable with primary and secondary methods; e.g., alkaline flooding, cyclic steam injection, in situ combustion of reservoir oil, etc.

Tertiary Sort
The third value on which data is sorted.

Tertiary Waste Water Treatment
Waste water treatment, beyond the secondary or biological stage, that includes removal of nutrient such as phosphorous, nitrogen, and a high percentage of suspended solids. Tertiary treatment, also known as advanced waste treatment, produces a high quality effluent.

Test Agency
Any independent third party which owns or otherwise provides a test facility and administers a testing program recognized by the manufacturer and/or operator as being capable of meeting the test requirements.

Test Approval Flag
Indicates whether a well potential test should be used to establish the Maximum Production Rate (MPR).

Test Block
Special precision made blocks, used as standards to facilitate rapid calibration of an inspection instrument.

Test Date
The date that the identified test was run. The tests involved include: drillstem test, production, initial potential, reservoir limits, integrity, etc.

Test Duration
The time duration of a test. Examples of tests icluded drillstem test, production test, initial potential test, reservoir limits test, etc.

Test Gallons
SEE: Theoretical Gallons.

Test Gas Volume
The volume of gas produced during a test period.

Test Interval Base Depth
The deepest measured depth of the well test interval.

Test Interval Top Depth
The shallowest measured depth of the well test interval.

Test Midpoint Perforation Pressure
The calculated pressure at the midpoint of the perforations.

Test Oil Condensate Volume
The volume of oil produced during a test period.

Test Period
The test period of the data being reported.

Test Period Ending Date
The date that the test was completed or ended.

Test Period Starting Date
The date that the test began.

Test Pressure Base
The pressure base at which the gas is to be tested for analysis.

Test Product Code
Indicates the minerals produced during a well test.

Test Rack
An arrangement of gas lift receivers, gauges, valving, etc., so that nitrogen gas pressure may be applied to the bellows of a gas lift valve and simultaneously measured to determine the pressure required to open the gas lift valve.

Test Tank
A receiving vessel used for temporary measurement and storage of produced liquid during a well test.

Test Water Volume
The volume of water produced during a test period.

Testing Sieve
A cylindrical or tray like container with a screening surface bottom of standardized apertures.

Texas Abstract Name
The abstract name for the Texas metes and bounds survey providing the surface location.

Texas Abstract Number
The abstract number for the Texas metes and bounds survey providing the surface location.

Texas Block Number
A number assigned to a Texas General Land Office subdivision of a survey and an abstract number.

Texas Block Tract Bearing Survey System
Description of location based on a subdivision of a Texas survey name and an abstract number. Blocks are subdivided into a variable number of tracts. Distance and bearing are used for positioning.

Texas Block Tract Direction Survey System
Description of location based on a subdivision of a Texas survey name and an abstract number. Blocks are subdivided into a variable number of tracts. Footage calls are used for positioning.

Texas Labor Number
A number assigned to a Texas General Land Office subdivision of a league (Spanish land grant).

Texas League Labor Bearing Survey System
Description of location based on a subdivision of a Texas survey name and an abstract number. Leagues and labors are specified by numbers. Distance and bearing are used for positioning.

Texas League Labor Direction Survey System
Description of location based on a subdivision of a Texas survey name and an abstract number. Leagues and labors are specified by numbers. Footage calls are used for positioning.

Texas League Number
A number assigned to a Texas General Land Office subdivision of a survey (Spanish land grant).

Texas Rrc Lease
A legal document authorized by and approved by the Texas Railroad Commission (RRC). The lease conveys certain rights to a lessee to explore for and to recover specified minerals or materials. The lease covers both standard and commingled leases.

Texas Rrc Lease Number
Lease number assigned by the Texas Railroad Commission (RRC) for both standard and commingled leases.

Texas Section Number
The number corresponding to a section within a Texas township.

Texas Survey Name
The name assigned to a Texas General Land Office land subdivision.

Texas Survey Number
Legal number associated with a land survey name, used to clarify that name in Texas onshore. Not used for any other state or for Federal survey.

Texas Survey Primary Type
The type of primary land division used to describe the well location in Texas; e.g., block; league; township.

Texas Survey Secondary Type
Indicates the type of secondary land division in Texas and further divides the primary land division; e.g., labor; section.

Texas Township Number
The number identifying a township subdivision of a Texas survey.

Texas Township Section Bearing Survey
Description of location based on a subdivision of Texas survey name and abstract number. Townships are subdivided into a variable number of sections. Distance and bearing are used for positioning.

Texas Township Section Direction Survey
Description of location based on a subdivision of Texas survey name and abstract number. Townships are subdivided into a variable number of sections. Footage calls are used for positioning.

Texas Tract Number
A number assigned to a Texas General Land Office subdivision of a block.

Texture
Geometrical aspects of the component particles of the rock sample. Includes: size, shape, sorting and arrangement.

Theoretical Gallons
The content of liquefiable hydrocarbons in a volume of gas as determined from tests or analyses of the gas.

Theoretical Permeability Ratio
The theoretical permeability ratio (ki/ko) is the ratio of the ideal perforated permeability to the original effective permeability.

Theoretical Residue Gas Remaining
The volume of residue which theoretically remains after volume reductions attributable to the processing of a volume of gas in a plant, determined by applying a factor from a table or calculation to the volume of gas delivered to the plant.

Theoretical Residue Method
Indicates how to determine the calculation method for residue, after gas analysis has been performed and the liquid recovery has been calculated.

Thermal Alteration Index
An indicator of the geothermal maturity of a sample.

Thermal Anomaly
Unusual or abnormal temperature differences.

Thermal Conductivity
The measure of the ability of a material; e.g., tubular, rock or drilling fluid, to transmit heat.

Thermal Cracker
A vessel that uses a process in which relatively heavy hydrocarbons are broken up by heat into lighter products.

Thermal Cracking
A cracking process that uses a combination of heat and pressure to break apart the hydrocarbon molecules into smaller molecules.

Thermal Decomposition
The chemical breakdown of a compound or substance by temperature into simple substances or into its constituent elements. Starch thermally decomposes in drilling fluids as the temperature approaches 300 degrees F.

Thermal Expansion Coefficient
The change in length of a material as a function of its total length due to a change in temperature.

Thermal Gradient
SEE: Temperature Gradient; Geothermal Gradient.

Thermal Shield
A heat sink and insulator used to prolong the life of heat sensitive instruments used in borehole surveys.

Thermowell
Housing inserted in a pipeline or vessel to accommodate a thermometer.

Theta Angle
The angle that will correct grid north to true north.

Thick Thread
A thread that has the appearance of being cut off form. This appearance would have to be substantiated with the use of a thread comparator, lead gauge, and/or depth gauge.

Thickening Time
SEE: Cement Thickening Time.

Thief
A small cylindrical vessel designed to take a sample from any depth in a tank.

Thief Hatch
An opening provided with a hinged covering on the top of a tank for the pumper or gauger to use in taking a sample of the liquid content or gauging the tank.

Thief Sand
A rock unit responsible for excess fluid loss during drilling operations.

Thiefing
Obtaining fluids at different levels in a vessel to determine BS&W content.

Thinner
Any of various organic agents (tannins, lignites, lignosulfonates, etc.) and inorganic agents (pyrophosphates, tetraphosphates, etc.) that are added to a drilling fluid to reduce the viscosity and/or thixotropic properties.

Thread Angle
The included angle between the thread flanks. The flank angles of thread shall be defined as the angles between the flanks and a perpendicular to the thread axis. For 60 degree threads, the flank angles are half angles of the thread and therefore equal. For buttress threads, the leading flanks are 10 degrees and the following flanks are 3 degrees. For extreme line threads, the leading flanks are 6 degrees and the following flanks are 6 degrees.

Thread Axis
The axis of pitch cone of the thread, and the longitudinal central line through the threads. In basic thread design, all length measurements are related to the thread axis.

Thread Engagement Length
The length of contact between two mated parts measured axially.

Thread Flank
The surface of a thread that connects the crest with the root. Also referred to as: Thread Side.

Thread Form
The form of thread is the thread profile in an axial plane for a length of one pitch.

Thread Height
The distance between the root and crest of the thread measured normal to the thread axis.

Thread Profile Shoulder
SEE: Step.

Thread Protector
Plastic or steel protection device placed on the end of the pipe to protect threads and seals from damage.

Thread Run Out On Face
SEE: Featheredge.

Threaded Flange
A flange having a sealing face on one side and a female thread on the other for the purpose of joining flanged connections to threaded connections.

Threads Per Inch
The number of threads in one inch of thread length.

Three Dimensional Radius Of Curvature Method
SEE: Borehole Survey Calculation Method.

Three Phase Fluid-rock System
A fluid-rock system characterized by three mobile phases. One phase is characterized as being the wetting phase, a second phase is characterized as being the nonwetting phase, and the third phase is characterized as an intermediate wetting phase. The gas-oil-water system is an example of this fluid-rock system.

Three Phase Separator
Production vessel capable of separating gas, oil and water, and discharging in three separate streams.

Three Piece Sucker Rod
A rod whose body and pin or box ends are joined by threaded connections.

Thribble
A stand of three joints of pipe.

Throttle
(1) To reduce the rate of flow of a fluid stream by partially closing a valve.(2) Also to lower the rpm of an engine by reduction of the fuel flow.

Through Transmission
A test method using two transducers in which the ultrasonic vibrations are emitted by one and received by another on the opposite side of the part. The ratio of the magnitudes of vibrations transmitted and received is used as the criterion of soundness.

Throw
SEE: Stroke.

Thrust Fault
A reverse fault in which the fault plane is less than 45 degrees from the horizontal, such that the upper fault block is thrust over the lower.

Tide
The variance (+ /-) in mean water depth.

Tie Down
An anchor to prevent movement of equipment, usually the device to which a guy wire or brace is attached.

Tieback String
A tieback string is used to connect the top of another tubular string back to either the drill floor (for installation or retrieval purposes) or to a subsequently installed wellhead (from a mudline suspension system).

Tight Formation
(1) A formation of relatively low permeability.(2) A formation about which information is guarded by the operator.

Tight Hole
(1) A drilling well about which information is guarded by the operator; i.e., depth; stratigraphy encountered; drilling rate. (2) A section of borehole that is under gauged (of smaller than expected diameter).

Tilted Rig
SEE: Slant Rig.

Time Cycle Controller
A device that shuts down or starts an operation after a set time period.

Time Depth Function
The relationship between seismic two way travel time and depth.

Time Interval
The interval between two time stamps.

Time Stamp
An instantaneous point in time.

Tip Extension
SEE: Jib.

Titration
A method, or the process of using a standard solution, for the determination of the amount of some substance in another solution. The known solution is usually added in a definite quantity to the unknown until a reaction is complete.

To Date
The date through which the provisions of an entity ceased or were no longer in effect; e.g., a contract; the data attributes associated with an entity or event; the collecting of a well's cumulative production; the making of retroactive billing adjustments.

Tobin Coordinates
(1) The latitude and longitude coordinates of a lease or well as calculated by the Tobin company.(2) A number from a Tobin map.

Tolerance
(1) The relative capability of an organism to endure an unfavorable environmental factor.(2) The permissible deviation from the specified value.

Tongs
The large wrenches used for turning to make up or break out drill pipe, casing, tubing and other pipe; variously called casing tongs, rotary tongs, etc, according to the use for which they are designed. Power tongs are pneumatically or hydraulically operated tools that serve to spin the pipe up tight, and in some instances, to apply final makeup torque. Also commonly used in pipeline construction.

Tool
An implement or instrument that is used to do work or to make measurements.

Tool Azimuth Angle
The angle between north and the projection of a tool reference axis onto a horizontal plane, measured positive, clockwise.

Tool High Side Angle
The angle between the tool reference axis and a line perpendicular to the borehole axis and lying in the vertical plane.

Tool Joint
A heavy coupling element for drill pipe having coarse, tapered threads and seating shoulders designed to sustain the weight of the drillstem, withstand the strain of repeated makeup and breakout, and provide a leak proof seal. The male section (pin) is attached to one end of a length of drill pipe and the female section (box) is attached to the other end. Tool joints may be welded to the drill pipe, screwed onto the pipe, or a combination of screwed on and welded.

Tool Joint Inside Diameter
The inside diameter of drill pipe tool joint used in the bottomhole assembly.

Tool Joint Outside Diameter
The outside diameter of drill pipe tool joint used in the bottomhole assembly.

Tool Mark
Surface roughness on thread, chamfer, or counterbore surfaces caused by the machining action and condition of the cutting edge of single point, die, or chaser tools; also can occur in the form of a longitudinal ridge across thread crests due to an improperly shaped or adjusted chaser.

Tool Pusher
One who has charge of rig builders and a drilling crew. Sometimes superintends the work at two or more wells. Typically employed by the operator.

Top Connection
The uppermost fitting of a Christmas Tree through which the tubing of the wellbore may be entered with completion or workover tools.

Top Depth
The measured depth along a wellbore path of a well to the wellbore point that is the top (lesser value of measured depth) point of reference for the interval.

Top Latitude Of Area
The latitude bounding the top of an area. The northernmost latitude.

Top Lease
A lease granted by the landowner during the existence of a recorded lease which is to become effective if and when the existing lease expires or is terminated.

Top Of Pay
The measured depth to the top of a zone containing hydrocarbons penetrated by a borehole.

Topping
(1) A refinery technique employed to secure complete fractional distillation except a heavy residuum.(2) Sometimes used in a more narrow sense to mean the taking off of the lighter fractions of oil.(3) Refers to the practice of filling a tank to capacity.

Torn Thread
Thread surfaces which have portions that are chipped, rough, or ragged. Also referred to as: Thread tears.

Torque
A measure of the force times the distance. On a rotary rig this applies especially to the rotation of the drillstem in its action against the borehole.

Torque Converter
Auxiliary transmission connected to prime mover which multiples engine torque as load increases with corresponding decrease in speed.

Torsion Balance
An instrument for measuring force fields, in which the field being measured is opposed by a known force.

Total Adjustment Volume
Total increase or decrease in previous reported volumes.

Total Advance Rental
The total amount paid for an advance rental.

Total Assessments Amount
Total assessment dollars paid.

Total Authorized Cost
Costs associated with this authorization plus the sum of the costs associated with all previous authorizations.

Total Bonus Paid
(1) The total amount paid as agreed upon under a bonus agreement.(2) The bonus amount paid after a successful bid on an Outer Continental Shelf (OCS) tract in a Minerals Management Service ( MMS) lease sale.

Total Core Penetration
The distance from the original core face to the depth probed. It is obtained by subtracting from the total target penetration (TTP), the combined thickness of the steel and Hydromite. Commonly abbreviated as: TCP.

Total Deducted Volume
Total volume of product deducted before calculation of tax liability.

Total Deduction Amount
Total Of All Deductions Reported

Total Depth
SEE: Well Total Measured Depth.

Total Depth Area Code
Indicates the map area where the borehole bottom is located.

Total Depth Date
The date drilling on a well reached the final total depth.

Total Federal Area
The total surface area under the sovereignty and/or jurisdiction of the United States government.

Total Fluid Displaced Volume
The total amount of fluid that is pumped following the cement slurry in order to force the slurry to surface.

Total Gas Disposition Volume
The total volume of all gas dispositions.

Total Gas Production Volume
The total volume of gas produced during the period covered, expressed in barrels, gallons, MCF, etc., depending on the fluid.

Total Intangible Cost
Sum of all intangible costs.

Total Lease Production Volume
The total production reported for a lease.

Total Measured Depth
SEE: Well Total Measured Depth.

Total Oil/ Condensate Disposition Volume
The total volume of oil/condensate dispositions.

Total Oil/condensate Production Volume
The total volume of oil/condensate produced during the period covered, expressed in barrels, gallons, MCF, etc., depending on the fluid.

Total Organic Carbon
Total organic carbon percentage for a sample.

Total Payment Amount
The total amount paid or remitted.

Total Penalty Amount
The amount of penalties from an agency ordered assessment.

Total Production & Acquisition Volume
Total Gas Acquisitions for field operations as reported for LA State Regulatory production reporting.

Total Recovery Percentage
The percentage calculated by dividing the volume of the recovered condensate by initial sample volume.

Total Royalty Due Amount
The total amount of Royalties due.

Total Sale Transfer Volume
The total sale and/or transfer volume for the facility/ measurement point that has been allocated to each source listed.

Total Sales Volume
Total volume of oil and gas sold from lease during period covered.

Total Taken-in-kind Volume
Total volume of production taken-in-kind.

Total Tangible Cost
The sum of all tangible costs.

Total Target Penetration
The distance from the exterior steel face of the core target to the probe depth. The probe depth shall be determined by the maximum depth from the exterior steel face to the deepest point that can be probed with a 0.1 inch OD tube using 50 psi air pressure and a probe force not exceeding 10 pounds. Commonly abbreviated as TTP.

Total Tax And Fees Due Amount
Total calculated tax and fee liability.

Total Tax Due Amount
The total calculated tax liability.

Total Taxable Volume
Total volume on which taxes are based.

Total Transportation Cost Amount
The total amount for transportation charges.

Total True Vertical Depth
SEE: Well Total True Vertical Depth.

Total Water Disposition Volume
The total volume of oil/condensate injected during the period covered.

Total Water Production Volume
The total volume of water produced during the period covered.

Total Working Interest Nonconsensus Percentage
The total working interest portion that represents the working interest owners' share that elected to not participate in the project or operation.

Totalizer
A mechanical or electronic measurement device that records the total amount of fluid passing through a line.

Township
A public land surveying unit of 36 sections or 36 square miles. Numbered in rows north and south from a standard survey base line.

Township Direction
The township direction, north or south of a surveyed parallel line.

Township Name
Name of the township or farm.

Township Number
The number assigned to a full or partial township division north or south of the survey base line. In the United States, a Congressional township is generally a subdivision of a county consisting of 36 square miles.

Toxic Substance
A substance or material which can be detrimental to human health or the functional capacity of a person having exposure to it.

Toxicant
A substance that kills or injures an organism through its chemical or physical action, or by altering its environment; e.g., cyanides; phenols; pesticides; heavy metals.

Toxicity
The quality or degree of being poisonous or harmful to plant or animal life.

Trace Fossil
A sedimentary structure consisting of fossilized track, trail, burrow, tube, boring, tunnel or other disturbances of soft sediment resulting from the life activities of organisms where the body is not present. Also referred to as: Ichnofossil.

Traceability
The ability to determine the product history through markings and records.

Tracer
A dye or radioactive element introduced into a stream to facilitate study of its flow pattern.

Tracer Log
A well log used for the purpose of following, locating or monitoring the behavior of a traceable material; e.g., radioactive isotope; boron.

Tract Gross Rental
Total amount of all rentals payable for a given tract.

Tract Net Rental
The portion of the tract gross rental which is payable by the indicated company.

Tract Number
The identifier of a subdivision or section for civil boundaries. Tract level identifiers are Texas section (including section, labor, or tract), city block, and lot.

Tract Portion Percentage
The percentage that a tract contributes to a unit area, a communitized area or a participating area.

Transaction Code
An indicator of the type of transaction occurring between business partners.

Transducer
An instrumentation device for converting a signal from one form to another; e.g., a pressure transducer.

Transfer Mechanism
A procedure to account for the effects of differences in surface texture, curvature, etc., between calibration block and workpiece.

Transfer Order
A document whereby participants in a Division Order change the disposition of their share of the proceeds.

Transferred Volume
Volume of gas transferred to other fields and/or Operators.

Transformation
SEE: Coordinate Transformation.

Transformer
An electrical device that converts primary voltage to secondary voltage.

Transition Zone
The ice region existing between fast ice and the arctic pack, usually heavily deformed. It may vary in width from hundreds of feet to tens of miles depending on seasonal and annual changes. Fast ice may be found in this zone, adjacent to grounded features. Also referred to as: Shear; Stamukhi zone.

Transmission Angle
The incident angle of the transmitted ultrasonic beam. It is zero degrees when the ultrasonic beam is perpendicular to the test surface.

Transmission Construction Cost
Costs include construction costs and equipment, such as wiring, poles, transformers, light and power system from point of connection with the plant, and field or public-utility systems.

Transmission Horsepower Loss
The difference between output and input horsepower. It may conveniently be expressed as percentage of input horsepower.

Transmitter
A mechanism for converting sound waves into equivalent electric waves.

Transportation Agreement
An agreement between a shipper and transportation company which defines the terms and conditions of the transportation services and transportation transfer to be provided.

Transportation Cost Amount
The rate per unit of measure, rate for transportation charges per unit of measure.

Transportation Deduction Amount
The amount used to adjust the base residue rate for the transportation of gas in a gas system.

Transportation Type Code
An indicator of the mode of transportation utilized for a specified activity; e.g., pipeline, truck, barge.

Transporter
A legal entity which has the capability of providing the service of transporting a specified product. Transporter includes gathering companies, pipeline companies, and local distribution companies (LDCs).

Transporter Code
The indicator assigned by a regulatory agency to identify the oil transporter.

Transporter Name
The name of a company transporting a product.

Transporter Tank Number
An identifier of an oil, condensate, or applicable plant product storage tank or a meter. Numbers are unique by transporter. Tank numbers are assigned by the transporter and meter numbers are the manufacturer's serial number for the meter.

Transverse
Literally means across, usually signifying circumferential or substantially circumferential in direction.

Transverse Wave
SEE: S-Wave.

Trap
A reservoir rock and reservoir seal that has the potential to accumulate, through a hydrocarbon charge, hydrocarbon fluids. Traps include reservoir rock, within which reservoir fluids can potentially accumulate, and reservoir seal(s), which can act as barriers to further migration of hydrocarbon fluids, thus affecting a hydrocarbon charge of the reservoir rock within the trap. Traps are typically classified as structural, stratigraphic, hydrodynamic and combination trap.

Trap Pressure Measurement
The pressure held at the trap or separator.

Trapezoidal Method
Uses of the measured inclination and direction angles at both ends of the measured course in a fashion that recreates the borehole path. This is done by a sequence of trapezoidal integration segments using the measured angles as constraints on the integral over the measured course. Results obtained are essentially the same as the Acceleration, Balanced Tangential, and Vector Averaging Methods.

Travel Rate
The speed of material over the screening surface.

Traveling Block
The block containing sheaves and provided with clevis and hook which is connected with the load hoisted or lowered in a derrick.

Traveling Block Position
The block position given in distance above the rotary table at a point in time.

Traveling Cylinder View
A plat of the wellbore profile within the control cylinder.

Traveling Valve
A valve in the plunger of a sucker rod pump.

Traverse
An ordered collection of bin nodes through a 3D seismic data set used to construct a vertical section of panels displaying the earth's subsurface features. May be an inline, crossline or an arbitrary traverse.

Traverse Tables
Tables of numerical values used in calculating borehole survey results.

Treatable Water Depth
The distance from zero at the surface to the top of a water table where the water contains total dissolved solids of 10 ppm or less or could be treated to bring the total dissolved solids to 10 ppm or less.

Treated Interval
That space between two depths, usually the top perforated depth and bottom perforated depth, subjected to a chemical or physical process.

Treater
A vessel in which undesired components are removed from a fluid stream usually by the use of heat, chemicals, etc.

Treating
Separation of gas, oil, water and contaminants from emusified well streams by gravity and enhanced means of breaking emulsions such as heating, chemicals and/or coalescing sections.

Treatment
(1) A process performed to improve the productivity of reservoir rock.(2) A process to clean the borehole or equipment within it.

Treatment Additive Component Type
The kind of additive used during the treating operation.

Treatment Additive Name
The brand name or generic name of the treatment fluid additive.

Treatment Additive Volume
The volume of the treatment fluid additive used during the treating operation.

Treatment Date
The date that treating operations were performed on the indicated interval.

Treatment Deduction Value
Determines the value used to adjust the base residue rate for treatment of gas in a gas system.

Treatment Fluid Injection Pressure Measurement
The injection pressure of the treatment fluid after breakdown.

Treatment Fluid Injection Rate
The injection rate of the treatment fluid after breakdown.

Treatment Fluid Material
The kind of treating fluid used in the drilling operation of a well; e.g., oil; water; acid.

Treatment Interval Classification
The classification of the condition of the borehole for the interval treated; e.g., perforations; open hole.

Treatment Interval Measured Base Depth
The measured depth to the base of the interval that is treated.

Treatment Interval Measured Top Depth
The shallowest measured depth of the interval that is treated.

Treatment Material Type Code
An indicator of the type of material used to treat a borehole segment; e.g., sand, acid, water, foam).

Treatment Material Volume
The volume of the treatment fluid used in treating the reservoir rock.

Treatment Type Code
The kind of treatment operation performed; e.g., acidize, fracture.

Tribal Name
The officiall Bureau of Indian Affairs recognized name for a tribe.

Tribal Royalty Exempt Amount
The monetary amount exempt from taxation that relates to a tribal royalty exemption.

Trigger Bit
A drill bit with a removable center through which surveying instruments are run into the open borehole. Used prior to industry's general acceptance of nonmagnetic drill collars.

Trip
The operation in rotary drilling of pulling out, trip out, or running in, trip in, the drillstring, as required to replace a worn bit, extract a core, or recover fish.

Trip Gas
An accumulation of gas which enters the well bore while a trip is made. High pressure trip gas can cause serious problems.

Trip Rate
The estimated average rate of tripping pipe.

Tripping
(1) Torsional buckling of stiffener.(2) The pulling out or running in of the drillstring.

True North
The direction from any geographic location on the earth's surface to the north geographic pole.

True Vertical Depth
The vertical, straight line depth from the surface datum reference to the subsurface point of interest. Commonly abbreviated as: TVD.

True Vertical Depth Log
A log computed from well logs obtained from deviated wellbores, in which measured depths have been converted to true vertical depths.

True Vertical Total Depth
SEE: Well Total True Vertical Depth.

Trunk Line
SEE: Main Line.

Tts
Abbreviation for Time To Surface.

Tube Bundle
The assembly of tubes, baffles and tube sheets in a heat exchanger.

Tubing
(1) A small diameter removable pipe installed within a larger diameter casing and connected to a well completion; produced fluids are conducted to the surface through tubing.(2) The well activity of installing tubing.

Tubing Anchor
A device run into the wellbore of a pumper well as an integral part of the tubing which employs friction or slips between the anchor and the casing to prevent tubing movement with respect to the casing.

Tubing Average Pressure Measurement
Average pressure measureable within the tubing.

Tubing Catcher
A device with slips provided to engage the walls of the casing and catch tubing if dropped in a wellbore.

Tubing Collar
SEE: Collar.

Tubing Coupling
SEE: Collar.

Tubing Depth
The measured depth from the well elevation reference point to the bottom of the tubing string.

Tubing Grade
Grades given to the material properties of tubing that fall within the tolerances set by API specifications; e.g., H40; J55; K55; S80.

Tubing Hanger
A device included in the wellhead hook up and contained in the tubing head which, by use of a mandrel or slips, suspends and holds the tubing string.

Tubing Head
The top of the tubing string with control and flow valves attached.

Tubing Head Adapter
That equipment which adapts the uppermost flange of a tubing head to the lowermost valve of the Christmas Tree.

Tubing Head Spool
A piece of equipment attached to the uppermost casinghead or smallest casing string which serves to suspend the tubing and to seal the annular space between the tubing and casing.

Tubing Inside Diameter
The inside diameter of the tubing.

Tubing Job
SEE: Tubing.

Tubing Maximum Pressure
The maximum pressure measureable within the tubing.

Tubing Outside Diameter
The outside diameter of the tubing.

Tubing Pressure Measurement
The pressure measurable within the tubing.

Tubing Retrievable Gas Lift Valve
A gas lift valve mounted on a tubing retrievable mandrel.

Tubing Retrievable Mandrel
Commonly called conventional or standard mandrel. A tubing pup joint with a lug for mounting a conventional or tubing retrievable gas lift valve. The mandrel is an integral part of the tubing string.

Tubing Section
Identifies a contiguous tubing string segment with identical tubular and connection properties.

Tubing Set Date
The last date the tubing string was set in the wellbore. The tubing string may have been pulled and reinstalled more than once.

Tubing Temperature Measurement
The temperature inside the tubing.

Tubing Weight
The weight of the tubing measured in terms of unit length.

Tubingless Completion
A method of completing a well in which a small diameter casing is set through the pay zone with no tubing or inner production string employed to bring reservoir fluids to the surface.

Tubular
SEE: Tubular Assembly.

Tubular Assembly
Identifies an installation grouping of pipe installed in a well for production or injection.

Tubular Burst Rated Pressure Measurement
The manufacturer's minimum internal yield pressure rating for a given tubular product.

Tubular Burst Safety Factor Value
The burst safety factor for a given tubular.

Tubular Capacity
The volumetric capacity of the given tubular product.

Tubular Coating Type
The type of coating, existing on the tubular section.

Tubular Collapse Point
The stress required to collapse the given tubular product.

Tubular Collapse Rated Pressure Measurement
The manufacturer's minimum collapse pressure rating for a given tubular product.

Tubular Collapse Safety Factor
The collapse safety factor for a given tubular.

Tubular Compressive Strength
The compressive strength of the given tubular product.

Tubular Coupling Type
The type of coupling used to make up a wellbore tubular string; e.g., short round, long round, buttress.

Tubular Displacement
The fluid volume displacement of the given tubular product.

Tubular Goods
Refers to drillpipe, casing, tubing, line pipe, etc. A generic term for any pipe used in the oil fields.

Tubular Grade Code
An indicator of the grade given to the material properties of tubular that fall within the tolerances set by API specifications; e.g., H40, J55, K55.

Tubular Material Density
The mass per volume of the given tubular material. For cement this is its fluid density.

Tubular Outside Diameter
The outside diameter of the tubular.

Tubular Segment Measured Bottom Depth
The measured depth to the bottom of the tubular segment run into a wellbore.

Tubular Segment Measured Top Depth
The measured depth to the top of the tubular segment.

Tubular Segment Removed Length
The length of tubular segment emoved during specified operations (e.g., completion, plugging and abandonment, plug back)

Tubular Segment True Vertical Bottom Depth
The true vertical depth to the bottom of the tubular segment run into a wellbore.

Tubular Segment True Vertical Top Depth
The true vertical depth to the top of the tubular segment run into a wellbore.

Tubular Sub
Tubulars 2 feet to 12 feet in length (pup joint) used to set a production tubing string at the desired depth.

Tubular Tensile Rated Rated Strength Value
The manufacturer's minimum tensile strength rating for a given tubular product.

Tubular Tensile Strength Safety Factor
The tensile strength safety factor for a given tubular.

Tubular Test Pressure Measurement
The minimum acceptable integrity test pressure for a given tubular.

Tubular Type Code
An indicator of the type of tubular; e.g., casing; liner; drill pipe, line.

Tubular Weight
The weight of the tubular expressed as weight unit length.

Tugger Line
A wire rope line powered by a motor (pneumatic, hydraulic, or other) and used for the controlled lifting and lowering of light loads around a rig.

Turbidity
A measure of the resistance of water to the passage of light caused by suspended and colloidal matter.

Turbine
A rotating propeller-like motor driven by pressure reduction resulting in horsepower.

Turbodrill
A turbine driven rotary drill located at the base of a drillstring and utilizing the drilling fluid as a power source. Commonly used in Russia.

Turbolator
A core of baffles designed to induce turbulence in the return leg of firetubes which enhances heat transfer efficiency.

Turbulent Flow
Fluid flow in which the velocity at a given point changes constantly in magnitude and the direction of flow.

Turn
Change in bearing of the borehole axis. Usually spoken of as the right or left turn with orientation that of an observer who views the wellbore course from the surface reference.

Turns Per Inch
The number of thread turns in one inch of thread length.

Turntable
SEE: Revolving Upperstructure.

Tut
The abbreviation for Tutwiler, Tuteiler, or Tutwiller test. A test for determining the concentration of hydrogen sulfide and mercaptans in a gas.

Tvd
SEE: True Vertical Depth.

Twin Probe
SEE: Dual Search Unit.

Twist Angle
The azimuth change through which the drillstem must be turned to offset the twist caused by the reactive torque of the downhole motor.

Twist Off
To break the drillstem, usually by torsional stress, while it is in the wellbore.

Twisted-pair Wiring
Cable comprised of 2-4-6-8 wires with each pair twisted together at the rate of 6 turns per foot to provide electrical self-shielding.

Two Blocking
The condition when the lower load block or hook assembly comes in contact with the upper load block or boom point sheave assembly.

Two Crystal Method
In ultrasonic testing, the use of two transducers for sending and receiving. May be send, receive or through transmission method.

Two Phase Fluid-rock System
A fluid-rock system characterized by two mobile phases. One phase is characterized as being the wetting phase, the other is characterized as being the nonwetting phase. Other phases are immobile. Examples of these are oil-water and vapor-liquid systems.

Two Phase Separator
Production vessel capable of separating gas from liquid. May also include water knockouts which separate water from oil.

Type A Transportation Deduction Amount
The actual cost of transportation from the outlet of the initial dehydrator to the inlet of the main transmission line that can be deducted from taxable value.

Type B Transportation Deduction Amount
When no dehydration is performed, other than within a processing facility, this is the actual cost of transportation from the inlet to the transportation related compressor, custody transfer meter, or processing facility, whichever occurs first, to the inlet of the main processing plant or main transmission line. If there is no dehydration performed in the field and there is no transportation-related compressor or custody transfer meter, then there is no Type B transportation deduction allowed.

Type C Transportation Deduction Amount
The actual cost of transportation from the inlet of the main transmission line or outlet of the main processing plant to market, where transportation is included in the price.