D
D
The symbol (d) refers to the nominal internal diameter of a conduit.
D & P Platform
A drilling and production platform.
Daily Condensate Volume
The volume of gas well condensate produced in a 24 hour period.
Daily Drilling Progress Length
The footage drilled since the last daily report.
Daily Gas Production Average Volume
The average daily gas production volume the well and or reservoir produced.
Daily Gas Volume
The quantity of gas which the property/well/reservoir produced or injected in a 24 hour period.
Daily Oil Volume
The volume of oil produced from a property,well, or reservoir during a 24 hour period.
Daily Production Volume
The quantity of a product produced during a 24 hour period.
Daily Water Production Volume
The quantity of water produced from a property/well/reservoir during a 24-hour period.
Damage Cost
Costs associated with property refurbishment as a result of this project.
Dampener
A device used to reduce surge; i.e., a chamber used to reduce liquid surge from a pump.
Damping
A slowing down or opposition to oscillation due to dissipation of the oscillation energy. For underdamped systems (most geophones) the quotient of the logarithm of the ratio of two successive oscillations is the damping factor.
Damping Transducer
A device that limits the duration of vibration in the search unit by either electrical or mechanical means.
Damping, Ultrasonic
Decrease or decay of ultrasonic wave amplitude with resspect to time.
Darcy's Law
The rate of flow of a homogeneous fluid through a porous medium is proportional to the pressure or hydraulic gradient and to the cross sectional area normal to the direction of flow and inversely proportional to the viscosity of the fluid.
Darcys Law
The rate of flow of a homogeneous fluid through a porous medium is proportional to the pressure or hydraulic gradient and to the cross sectional area normal to the direction of flow and inversely proportional to the viscosity of the fluid.
Data Accepted Code
An indicator of whether data has been received, processed and accepted by the agency.
Data Source
A company, company suborganization, vendor, individual, state or government agency designated as the source of information.
Dataset
A general term for any set of data.
Date Of First Delivery
SEE: First Delivery Date.
Date Of Manufacture
The date of manufacturer's final acceptance of finished equipment.
Datetime
Any of year, month, day, hours, minutes, seconds to an appropriate accuracy.
Datum
(1) General: A Reference value used as a basis for calculating or measuring.(2) Seismic Processing: An arbitrary reference surface or location. Reduction to this surface minimizes local topographic and near surface effects.
Datum Horizon
A horizon used as a reference for elevations. For most topographic work, the datum plane is mean sea level. In structural mapping, the bed or horizon to which all elevations are finally reduced to called datum horizon, key bed, or marker. For bottomhole pressure mapping, the datum is usually selected at the approximate mid-elevation of the reservoir referred to sea level.
Datum Statics
SEE: Seismic Datum Shift.
Days For Billing To Be Paid Count
Provisions in the operating agreement state that all joint interest billings are due to be paid within a given number of days from the date that the billing is received by the nonoperator.
Days Late Count
The total number of days the interest and or penalty is calculated.
Days On Injection Count
The number of days the particular injectant was injected into the wellbore during the month.
Days On Production Count
The number of producing days the well/reservoir produced or injected for the month. A producing day is the amount of uptime, to the nearest hour, in a day. Producing days are used in the allocation process.
Days Operated Count
The total number of days a well produced or injected during the month. An operating day is a day in which a minimum of 10 minutes of operation occurred. Operational days are reported to state and Federal regulatory agencies.
Days Shut-in Count
The number of days during the year that a well was curtailed due to mechanical failure or disruption.
Dc Field
This is either a residual magnetic field or an active magnetic field produced through the use of direct current (DC).
Dead Oil
Crude oil containing essentially no dissolved gas when it is produced.
Dead Well
A well which has ceased to produce, either temporarily or permanently.
Dead Zone ( Ultrasonic)
SEE: Ultrasonic Dead Zone.
Deadline
The end of the drilling line which is not reeled onto the hoisting drum of the rotary rig. This end of the drilling line is anchored (usually to the derrick substructure) and does not move as the traveling block is hoisted, hence the term deadline.
Deadman
A timber, concrete block, metal block or pipe buried in the earth to which a line may be attached, thus serving as an anchor.
Decanting Centrifuge
A continuously conveying centrifuge which removes solids drained of their free liquid.
Decimal Interest Number
A fraction of the total ownership applicable to one owner. Ownership relates to an entity that has been identified; e.g., property; lease. 100% would be shown as 1.0000000 and 50% would appear as 0.50000000.
Deck
The upper sections of a platform above the waterline on which equipment is placed.
Deck Area (cantilever)
That portion of the main deck, cellar deck or sub cellar deck area outside the boundary line of perimeter deck columns.
Deck Area (central)
That portion of the main deck, cellar deck or sub cellar deck within the boundary line of perimeter deck columns.
Deck Area (rig)
That area of the deck necessary for support of drilling or workover operations.
Deck Beam
Secondary structural elements spanning between intermediate girders and/or main girders.
Deck Plate
Flat plate or grating spanning between deck beams.
Deck Screen
A vibrating screen component consisting of a support frame, screening surface, and accessories. Used to classify materials.
Declination
SEE: Magnetic Declination.
Decline
The decrease in yield of oil or gas from a well, well completion; lease, reservoir or field. The first yield is called the flush production. For a while, the decline may be rapid, becoming more steady until settled production is reached. Decline curves in which yield is plotted against time show graphically the change in rate of production.
Decline Curve
Plotted points of production volume vs. time on either Cartesian coordinates or on semi-log graph used to estimate future recoverable reserves, to study reservoirs, and to study the rate of production decline for wells.
Decontaminant
Material added to cements or cement slurries for the specific purpose of counteracting the effects of contamination.
Dedendum
The distance between the pitch line and root of thread.
Deducted Volume
The volume of product deducted before calculation of tax liability.
Deep Plate Girder
Deep plate girder with the web stiffened in both the longitudinal and transverse directions.
Deep Propagation Log
A well log that provides the resistivity and dielectric constant of the formation by measuring the attenuation and velocity of an electromagnetic wave traveling in the formation.
Deepest Tool When Pipe Stuck Depth
The measured depth to the deepest tool when the pipe became stuck.
Deethanizer
Equipment used to remove ethane and lighter components from a hydrocarbon stream.
Defect
An imperfection whose size, shape, orientation, location or properties make it detrimental to the useful service of the pipe or exceed the accept/reject level of the applicable specification.
Defect Reflection
The oscilloscope presentation of the energy returned by a rejectable flaw in the material.
Deferred Bonus Amount
A mineral owner's bonus, the payment of which is made in installments spread over a number of years, as distinguished from the usual mode of payment, which is in a lump sum on execution and delivery of the lease.
Deferred Bonus Flag
An indication of whether or not a bonus is still due to a mineral owner.
Deferred Production Agreement
An agreement between working interest owners of a lease under which an owner's share of the gas reserves under the lease is considered to remain in the reservoir while other owners' share of the gas is being produced.
Deferred Production Payment
A production payment which does not commence until after the operator has realized a specific sum from production on the lease or after a primary production payment.
Deferred Tax
A result of time differences between recognition of tax liability and actual payment. Occurs when taxable income differs from financial book income, often because of different depreciation and amortization methods employed for tax and financial books.
Deficiency Gas Volume
The difference between the quantity of gas a purchaser is obligated by a gas sales contract to either take or to pay for if not taken, and the quantity of gas actually taken.
Deficiency Payment
The amount paid by the purchaser for the quantity of Deficiency Gas as required by a gas sales contract.
Deflected Hole
SEE: Deflected Wellbore.
Deflected Wellbore
A wellbore that has been intentionally deviated.
Deflocculation
Breakup of floes of gel structures by use of a thinner.
Defoamer
Any substance used to reduce or eliminate foam by reducing the surface tension. Also referred to as: Defoaming Agent.
Deformed Ice
The antithesis of smooth ice.
Degasser
Equipment used to remove undesired gas from a liquid, especially from drilling fluid.
Degrees Api
An arbitrary scale for expressing the gravity of hydrocarbon liquids. Degrees API = (141.5/specific gravity) - 131.5.
Dehydration
Removal of water and water vapor by any means from a gas, liquid, or solid; i.e., loss of water by filtration of cement slurries during or after displacement.
Dehydration Deduction Value
The value used to adjust the base residue rate for dehydration in a gas system.
Dehydration Unit Cost
Includes costs for all equipment such as meters, heaters, exchangers, and vessels used primarily for the dehydration and treating of LPG stored underground.
Dehydrator
A piece of production equipment utilizing glycol in a process to remove water vapor from natural gas.
Dehydrator Count
The number (count) of dehydrators on a facility.
Delay Rental Amount
A sum of money payable to the lessor by the lessee for the privilege of deferring the commencment of drilling operations or the commencement of production during the primary term of the lease.
Delayed Sweep
A means of delaying the start of horizontal sweep, thereby eliminating the presentation of early response data.
Deleted Bit
SEE: Crippled Bit.
Deliquescence
The liquefaction of a solid substance due to the solution of the solid by adsorption of moisture from the air; e.g., calcium chloride.
Deliverability Capacity
The maximum amount of gas a producer can deliver to the purchaser at a specified delivery point.
Deliverability Test Period
A specified period of time, agreed to by the producer and purchaser, to flow the well completions covered under the gas sales contract at their maximum rate in order to establish the producer's true delivery capacity.
Delivered Production Volume
The volume of production reported as being delivered or transferred: (1) If allocated by meter measurements, this is the actual meter readings. (2) If allocated by well tests, this is the production calculated from the well test data.
Delivery In Kind
SEE: Take In Kind.
Delta Effect
Acoustic energy reradiated by a discontinuity.
Demagnetization
The process of removing part or all of the existing residual magnetism from pipe.
Demulsifier
A chemical used to break down crude oil/water emulsions so the water may be removed from the oil.
Densitometer
An electronic device used to determine the density of a liquid hydrocarbon stream for measurement calculations.
Density
(1) Mass per unit volume of a substance.(2) The number of bytes per unit area on a recording media.
Density Gradient
The variation in density as a function of depth.
Density Log
A well log which records formation density.
Dent
A local change in surface contour caused by mechanical impact, but not accompanied by loss of metal.
Department Name
The name of the company department or agency program.
Department Of Energy
A Department of the U.S. Federal Government, commonly abbreviated DOE.
Department Of Transportation
A Department of the U.S. Federal Government, commonly abbreviated DOT.
Departure
Horizontal displacement of one station from another in an east or west direction.
Dephlegmator
The rectifying section of an oil stripping still. The term is usually applied where that section is a vessel separate from the stripping section.
Depletion
(1) In financial terms, it is the provision for noncash deduction from current income which provides for the recovery of a portion of the capitalized costs of an oil or gas property due to exhaustion of resources.(2) In nonfinancial terms, depletion is the act of emptying, reducing, or exhausting, as in depletion of natural resources.
Depletion Drive
SEE: Reservoir Drive Mechanism; Solution Gas Drive; Reservoir Energy.
Depolarize
To increase rate of corrosion reaction by removing a polarizing corrosion product.
Depositional Environment
A geographically restricted complex within which a sediment accumulates, described in geomorphic terms and characterized by physical, chemical and biological conditions, influences or forces; e.g., lake; swamp; floodplain; near shore marine.
Depository Bank Number
A unique number assigned to identify a depository bank, savings and loan institution or credit union which accepts deposits into a payee's account.
Depth
The distance below a specified reference datum, commonly the surface of the earth or the mean sea level. A positive value denotes a point deeper than the reference point. When given without specifying a reference value, it is assumed that it is referenced to the earth's surface or sea surface as appropriate.
Depth Basis Code
Code identifying the basis for depth measurement.
Depth Control Log
A well log run in cased holes for the purpose of providing correlation with open-hole logs in order to establish depth control for certain well completion operations. Usually the depth control log is made with a radioactivity logging tool in conjunction with a casing collar locator.
Depth Of Invasion
The distance from the borehole wall radial to the centerline of the borehole to which mud filtrate has invaded porous and permeable rock.
Depth Shift
Amount of change to the depth scale of a core record or well log necessary to align that scale to another depth scale used as a depth reference.
Derating (engine)
The horsepower reduction of an internal combustion engine because of altitude.
Deregulated
Statutory or federal administrative removal of government regulations in regard to pricing. Deregulation of Natural Gas Liquids (NGLs) occurred in 1980 and 1981. Deregulation of certain Natural Gas Policy Act (NGPA), 1978, as amended, vintages occurred January 1, 1985.
Dermal Toxicity
The ability of a chemical to poison an animal or human by skin absorption.
Derrick
A semipermanent structure of square or rectangular cross section having members that are latticed or trussed on all four sides. This unit must be assembled in the vertical or operation position, as it includes no erection mechanism. It may or may not be guyed.
Derrick Lift Capacity
The maximum weight which a structure or mechanism is certified to support or lift.
Derrick Mast
The steel tower component of a drilling or well servicing rig which supports the crown block, traveling block, and hoisting lines. Derricks and masts may be stationary structures normally requiring dismantling and disassembly when moved from location to location, or may be portable with the capability of being laid down and raised to and from ground level fully assembled.
Derricking
The operation of changing boom angle in a vertical plane.
Derrickman
An individual whose work station is in the derrick while tubular goods are being hoisted from or lowered into the wellbore.
Desalinization
Salt removal from sea or brackish water.
Desalting
This is a form of emulsion treating which may be identical to conventional treaters with the addition of supplemental injection and mixing of low salinity water into the feed emulsion to dilute the brine phase and thereby lower the salt content of the treated crude. Desalting is used both in oil producing areas and refineries. It may consist of one or more stages to achieve maximum desalting efficiency.
Desand
To remove sand particles from the drilling fluid.
Desander
A centrifugal device for removing sand from drilling fluid to prevent abrasion of the pumps.
Design Life
Maximum anticipated operational years of service for the platform; i.e., the period of time from commencement of construction until removal of the structure.
Design Load
That force or combination of forces which a structure is designed to withstand without exceeding the allowable stress in any member.
Design Pressure Measurement
The performance rating of a given system or system component, usually expressed in pounds per square inch (psi) or pounds per square inch gauge (psig). Not the maximum vented pressure that the system can sustain.
Design Verification
The process of proving design by testing.
Desilt
To remove the ultra fine and larger particles from the drilling fluid.
Desilter
A centrifugal device capable of removing a very high proportion of the ultra fine and larger particles from a drilling fluid.
Destination Price Amount
The weighted-average sales price received at a delivery point.
Desuperheater
A device for the removal of superheat from steam by the injection of water.
Detector Group
SEE: Receiver Group.
Detector Orientation
SEE: Receiver Orientation.
Detector Shoe
A scanning shoe carrying one or more transducers. Is used to protect transducers from mechanical damage from the pipe surface, etc.
Detector Spacing
SEE: Receiver Spacing.
Detergent
A substance that has cleansing action due to a combination of properties including lowering of surface tension, wetting action, emulsifying and dispersing action, and foam formation in some cases.
Developed Gross Areal Extent
The sum of all developed tract gross acres or hectares on a lease. Contains the total number of acres or hectares covered by the legal description of the entity in which it is included.
Developed Net Areal Extent
The sum of all developed tract net acres or hectares on a lease. Contains the total number of net acres or hectares covered by the legal description of the entity in which it is included.
Developing Field
An oil or gas property whose reserve life is undetermined.
Development Activity Type
Those activities which take place following discovery of hydrocarbons, CO2, or minerals in paying quantities, including geophysical activity, drilling, platform construction, and operation of all support facilities, and which are for the purpose of ultimately producing the minerals, hydrocarbons, or CO2 discovered.
Development Well
Well drilled to a pay zone in an area already proven productive.
Deviated Hole
SEE: Deviation.
Deviated Well
A well having a wellbore path that deviates from the vertical.
Deviation
(1) Departure of the axis of a wellbore path from vertical.
Deviation Angle
The angle from vertical derived from the directional sensor during the surveying at the point the measurement was taken.
Deviation Bit
A drill bit specifically designed to reduce the tendency to drill a crooked wellbore.
Deviation Control Technique
(1) Fulcrum Technique: Utilizes a bending moment principle to create a force on the drill bit to counteract reaction forces which are tending to push the drill bit in a given direction. (2) Mechanical Technique: Utilizes bottomhole equipment which is not normally a part of the conventional drill string to aid deviation control. This equipment acts to force the drill bit to turn axis of the borehole in inclination. (3) Packed hole Technique: Utilizes the borehole wall to minimize bending of the bottom
Deviation Depth
The measured depth from the surface datum reference to the point of departure of the axis of the wellbore or drainhole path from vertical.
Deviation Survey Measured Depth
The measured depth of the directional sensor at the point the measurement was taken during the deviation survey.
Deviation Survey True Vertical Depth
True vertical depth (TVD) of the directional sensor at the point the measurement was taken during the deviation survey.
Deviation Survey Type
A well activity performed to determine wellbore path deviation. There are two basic deviation survey or drift survey instruments. One measures the angle of deviation only and the other measures both the angle and direction of deviation.
Deviation Tool
Drilling tool or equipment used to change the inclination and direction of the borehole axis.
Deviation Type
(1) Abnormal Deviation: Usually associated with highly faulted rocks having fracture planes on either side of a fault. (2) Abrupt Deviation: Usually associated with interbedded, anisotropic, or laminar rocks. (3) Drift Deviation: Usually associated with a gradual change of borehole axis. (4) Induced Deviation: Engineered, intentional or unintentional. (5) Rotational Deviation: Usually results from the drill bit moving in a slow spiral due to drill stem rotation.
Dew Point
Temperature and pressure at which a liquid begins to condense out of a gas.
Dew Point Pressure
SEE: Saturation Pressure.
Dew Point Tester
An instrument for visually determining the temperature at which a liquid condenses from a gas.
Dextral Fault
SEE: Right Lateral Strike Slip Fault.
Diagenesis
Post-depositional alteration of a rock or its constituent minerals.
Diastem
A relatively short interruption of deposition, involving a brief period of time, with little or no erosion before depostion is resumed.
Diatomaceous Earth
An infusorial earth composed of siliceous skeletons of diatoms and being very porous. (1) Sometimes used for combatting lost circulation and as an additive to cement.(2) Additive to special drilling fluids for a particular purpose.(3) Used for filtration and polishing.
Diatomaceous Earth Filtration
A process in which a filter cake or precoat of diatomaceous earth is used as a filter medium.
Diesel Electric Rig
A rotary drilling rig using self generated electric power.
Diesel Oil Plug
SEE: Gunk Plug.
Differential
(1) A difference in quantity or degree between two measurements or units (as the pressure differential across a choke; i.e., the pressure on one side of the choke compared with the pressure on the other side.
Differential Angle Deck
A screen deck in which successive screening surfaces of the same deck are at different angles.
Differential Liberation Value
A pressure-volume-temperature (PVT) test performed on oils in which evolved gas is withdrawn from the fluid as the system pressure is reduced.
Differential Pen
Marking device on an orifice meter recording the difference between upstream pressure and downstream pressure across an orifice plate. Usually calibrated in inches of water difference.
Differential Pressure Measurement
(1) The difference between hydrostatic borehole pressure and reservoir pressure.(2) The difference in pressure between two points in a fluid system. It may represent the drop in pressure of the fluid in passing from the tubing to the flow line,(3) In the case of an orifice meter, the difference of the pressure on the upstream and the downstream sides of the orifice.
Differential Pressure Sticking
Sticking which occurs because part of the drillstring (usually the drill collars) becomes embedded in the filter cake resulting in a nonuniform distribution of pressure around the circumference of the pipe. The conditions essential for sticking require a permeable formation and a pressure differential across a nearly impermeable filter cake and drillstring.
Differential Sp Log
A curve recorded as a result of simultaneous spontaneous potential (SP) measurements from two electrodes located downhole, each serving as a reference potential for the other.
Differential Sticking
The action of a differential pressure holding the drillstem against the wall of the borehole.
Differential Vaporization Gas Gravity
Gravity of the gas phase at the given temperature and pressure.
Differential Vaporization Gas Oil Ratio
Cumulative standard volume of gas evolved per unit volume of oil at saturation pressure.
Differential Vaporization Relative Volume
Volume of the liquid hydrocarbon phase at the given temperature and pressure relative to saturation pressure.
Differential Vaporization Z Factor
Compressibility factor for the gas phase at the given temperature and pressure.
Differential Wiring
Electrically connected in opposed series such that the output of one coil effectively opposes the other coil. In search coils, the differential wiring results in equal and opposite voltages being developed when the magnetic field changes equally in each coil. Thus, no net voltage output is produced.
Diffraction
The deflection of a wave front when passing the edges of an obstacle.
Diffuse Indication
With magnetic particles, this is an indicationis that is not clearly defined as; e.g., indication of subsurface defects.
Diffuse Reflection
Scattered incoherent reflections caused by rough surfaces or associate interface reflections of waves from irregularities of the same order of magnitude or greater than the wave length.
Diffusion
The spreading, scattering, or mixing of a material; e.g., gas; liquid; solid.
Dilatant Fluid
A dilatant or inverted plastic fluid is usually made up of a high concentration of well dispersed solids which exhibits a nonlinear consistency curve passing through the origin. The apparent viscosity increases instantaneously with increasing rate of shear. The yield point, as determined by conventional calculations from the direct indicating viscometer readings, is negative; however, the true yield point is zero.
Diluent
Liquid added to dilute or thin a solution.
Dilution
Increasing the liquid content of a slurry, by addition of water, oil or other fluid constituting the liquid phase.
Dilution Ratio
Ratio of volume of dilution liquid to the volume of raw mud in the feed to a liquid-solid separator.
Dilution Water
Water used for dilution of raw mud.
Ding
A flattened area or indentation on a chamfer or thread crest caused by mechanical impact.
Dip Angle
The maximum angle that a surface ( e.g., a bedding or fault surface), makes with the horizontal, measured perpendicular to the line of strike direction of the structure and is measured in the vertical plane.
Dip Azimuth
The azimuth of maximum dip or slope of a surface, such as a bedding or fault surface. Dip direction is perpendicular to the line of strike direction, and is oriented in the down dip direction.
Dip Log
SEE: Dipmeter Log.
Dip Slip Fault
A fault in which the movement of the fault blocks is parallel to the dip of the fault.
Dip Tube
Tubing inserted in the orifice fitting of meter tubes upstream and downstream of the orifice plate.
Dipmeter Log
A well log from which dip magnitude and azimuth of bedding of rocks surrounding the borehole can be determined. Also referred to as: Dip Log.
Dipmeter Tool
A downhole tool used to make a dipmeter log or dip log.
Direct Charge
Those costs permitted under Direct Charges in the COPAS Materials Classification Manual.
Direct Cost
SEE: Direct Charge.
Direct Current
Refers to an electric current flowing continually in one direction only through a conductor.
Direct Fired Vessel
A vessel in which the temperature of fluids is increased by the addition of heat supplied by a flame. The flame is applied direct to the fluid container.
Direct Ignition Source
A point of sufficient temperature and heat capacity to ignite a combustible mixture.
Direct Indicating Viscometer
Commonly called a V-G meter. The instrument is a rotational type device powered by means of an electric motor or handcrank, and is used to determine the apparent viscosity, plastic viscosity, yield point, and gel strengths of fluids.
Direct Sale
Contract sale of natural gas by producer to end user or local distibution company, usually for a term of a year or longer. The pipeline company transports the gas for a fee.
Direction
In the description of the a wellbore path, refers to the azimuth. The direction of vertical projection of the wellbore path onto a horizontal plane.
Direction Control
SEE: Directional Drilling.
Directional Drilling
Intentional drilling of an off-vertical wellbore path at a closely-controlled, predetermined angle and direction through use of special equipment and surveys.
Directional Drilling Contractor
A service company that can supply the special deflecting tools, bottomhole assemblies, survey instruments, and a technical representative to perform the directional drilling aspects of an operation.
Directional Drilling Data Sheet
Data sheet on which a detailed description of the bottomhole assembly and operating parameters are indicated as a function of depth.
Directional Hole
SEE: Directional Well; Directional Drilling; Directional Sidetrack.
Directional Permeability
An oriented permeability measurement.
Directional Redrill
SEE: Directional Sidetrack.
Directional Service Company
SEE: Directional Drilling Contractor.
Directional Sidetrack
A drilling activity in which an additional wellbore segment, called a sidetrack, is drilled from an existing wellbore between the wellbore origin and wellbore bottomhole. A whipstock is set in the existing wellbore as the starting point. This new wellbore segement is directionally drilled to a new target.
Directional Surveillance
SEE: Directional Drilling.
Directional Survey
An engineering survey that measures the deviation of a wellbore path from vertical and the direction of departure. Measurements are made of drift, azimuth and inclination of a borehole axis with the vertical. A directional survey is often made as part of a dipmeter survey or sometimes as a continuous log with a photoclinometer. Sometimes measurements are made at discrete depths with a photoclinometer.
Directional Survey Dogleg Severity
The rate of change of deviation angle and/or direction evaluated between the current survey point and the next shallowest survey point.
Directional Survey Drift Angle
The deviation at the depth of measurement.
Directional Survey East West Offset
The distance, at the depth of measurement, that the axis of the wellbore path lies east or west of the axis of the wellbore path at its wellbore origin. A positive number denotes east, a negative number west.
Directional Survey Flag
An indicator of whether a directional survey was performed.
Directional Survey Gravity Tool Face
The gravity tool face measured by the directional sensor.
Directional Survey Inclination
The inclination from the vertical, at the depth of measurement, of the axis of the wellbore path as measured by the directional sensor in the wellbore.
Directional Survey Instrument Type
The type of instrument used for a directional survey, e.g., measurement while drilling, magnetic single shot, magnetic multi-shot, gyro rate integrating.
Directional Survey Interval
An interval of a wellbore path that has been surveyed in a manner that is consistent with the surveying criteria specified for a directional surveying activity.
Directional Survey Interval Base Depth
The measured depth to the bottom of the directionally surveyed interval.
Directional Survey Interval Top Depth
The measured depth to the top of the directionally surveyed interval.
Directional Survey Magnetic Tool Face
The magnetic tool face measured by the directional sensor.
Directional Survey Method Code
The method of measurement that was used for the directional survey taken; e.g., acid bottle; continous dipmeter; gyroscope; multishot.
Directional Survey North South Offset
The distance, at the depth of measurement, that the axis of the wellbore pathl lies north or south of the axis of the wellbore path at its wellbore origin. A positive number denotes north, a negative number south.
Directional Survey Source
The vendor which supplies directional survey information.
Directional Survey Tool
An instrument for measuring angular or positional data within a wellbore.
Directional Survey Tvd
The true vertical depth (TVD) at the depth of measurement for the directional survey.
Directional Survey Walk
A measurement of the tendency of the drillstem to be displaced to either side of the intended wellbore path.
Directional Turbodrill
A turbodrill which can follow the borehole curvature developed with a bent sub, usually shorter in length than a straight hole turbodrill.
Directional Well
A well having a wellbore path purposely deviated from the vertical using controlled angles to reach an objective that is not directly beneath the wellbore origin of the wellbore path.
Dirty Sand
Sand that is poorly sorted, having a wide range of particle sizes including some shale particles.
Discharge Lip
SEE: Discharge Spout.
Discharge Spout
Extension at the discharge end of the screen deck. It may be vibrating or stationary.
Discontinuity
A detectable interruption in the material which may or may not have undesirable connotations; e.g., any interruption in the normal physical structure or configuration of a pipe such as cracks, laps, seams, pits and laminations. A discontinuity may or may not affect the usefulness of a pipe or critical flaw size. Also referred to as: A flaw or imperfection.
Discounted Return On Investment
The ratio of the (1) present worth of the ultimate value of the reserves attributable to a well less the drilling investment, taxes, operating costs, and other needed investment anticipated during the life of the well, to (2) the present worth of the drilling and other investments anticipated during the life of the well.
Discounted Roi
SEE: Discounted Return on Investment.T
Discovery Date
SEE: Field Discovery Date.
Discovery Gas Reserves
Field gas reserves reported for the discovery well.
Discovery Well
A wellbore that encounters a new and previously untapped petroleum reservoir and is believed to be capable of producing in paying quantities.
Discovery Well Name
The name used by the operator to label the discovery well.
Discovery Well Pool Flag
An indicator of whether the data reported is for a discovery well or pool.
Dispersant
Agent, compatible with the solvent, which holds very finely divided matter in a scattered or broken up state.
Dispersed Oil Recovery Unit
A vessel which removes minute amounts of oil from water via coalescing (droplet growth). The vessel would normally include a large holding pond, a media filter, gas flotation, etc.
Dispersed Phase
The scattered phase (solid, liquid, or gas) of a dispersion. The particles are finely divided and completely surrounded by the continuous phase.
Dispersion Of Aggregates
Subdivision of aggregates. Dispersion increases the specific surface of the particle; hence results in an increase in viscosity and gel strength.
Dispersoid
A colloid or finely divided substance.
Displaceable Gas Saturation
The difference in the gas saturation at the start of the secondary and enhanced recovery project and that which existed behind the flood front.
Displacement Efficiency
The relative effectiveness with which a saturating fluid is displaced by another fluid with which it is in contact.
Displacement Fluid Type
The type of fluid; e.g., water, oil, mud, in the wellbore when a sand control well activity is in progress or the type fluid used to displace resin into the rocks surrounding the borehole.
Displacement Fluid Volume Required
The volume of fluid used to displace the treatment fluid into the formation.
Displacement Measurement
In the drilling of a well, the lateral distance from the surface location to the primary target.
Displacement Saturation
The saturation of the displacing fluid at the displacement shock front.
Displacement Velocity
The velocity of the shock or displacement front.
Disposal
The placement or discarding of unwanted material.
Disposal Pit Count
The number (count) of disposal pits on a facility. These disposal pits are used to dispose of water by evaporation and must be approved prior to use.
Disposal Well
A well used for permanent disposal of fluids wastes, such as salt water.
Disputed 8g Acreage
The acreage contained in areas within the 8(g) zone which are under the jurisdiction of the United States government but which is claimed as state waters by a coastal state. The dispute is evidenced by a lawsuit.
Disputed Federal Acreage
The acreage contained in areas seaward of the 8(g) zone which are under the jurisdiction of the United States government but which are claimed as state waters by a coastal state. The dispute is evidenced by a lawsuit.
Dissociation
The splitting up of a compound or element into two or more simple molecules, atoms, or ions. Applied usually to the effect of the action of heat or solvents upon dissolved substances. The reaction is reversible and not as permanent as decomposition; i.e., when the solvent is removed, the ions recombine.
Dissolved Gas
SEE: Solution Gas.
Dissolved Gas Drive
A natural reservoir drive mechanism where an oil reservoir derives its energy for production from the dissolved gas in solution with the crude oil.
Dissolved Load
That part of the total stream load that is carried in solution.
Dissolved Oxygen
The oxygen dissolved in water or sewage. Adequately dissolved oxygen is necessary for the life of fish and other aquatic organisms and for the prevention of offensive odors. Low dissolved oxygen concentrations generally are due to discharge of excessive organic solids having high BOD, the result of inadequate waste treatment.
Dissolved Solids Concentration Measurement
The concentration of dissolved material, organic and inorganic, contained in water or wastes. Excessive dissolved solids make water unpalatable for drinking and unsuitable for industrial use.
Distillate
(1)The condensed overhead product of a fractionator. (2) Liquid hydrocarbons, usually of high API gravity (above 60 degrees API), recovered from wet gas by a separator that condenses the liquid out of the gas stream. (Distillate is an old term for the liquid; today it is called condensate or natural gasoline.)
Distillate Recovery Percentage
The percentage of distalliate recovered at or over the boiling point.
Distillation
Process of first vaporizing a liquid and then condensing the vapor into a liquid (the distillate), leaving behind nonvolatile substances, the total solids of a drilling fluid. The distillate is the water and/or oil content of a fluid.
Distillation End Point Temperature
The highest temperature observed on the distillation thermometer before the mercury starts to fall consistently, after the bottom of the distillation flask has become dry.
Distortion Energy Theory
Failure theory defined where the applied stresses are positive for tension and negative for compression.
Distributee Code
An indicator of the fund for distribution purposes.
Distribution Tax Flag
An indicator of whether or not the company is or is not required to remit production taxes on gas produced and sold.
Distribution Tax Reimbursement Flag
An indicator of whether or not a gas purchase contract requires the company to reimburse the seller for any portion of production tax increases.
District Expense
An accumulation of overhead costs incurred at the property operation level, and of such a nature as to benefit proportionately all wells, leases, and facilities in a specified territory or district.
Divergence
Spreading of ultrasonic waves after leaving search unit, a function of diameter and frequency.
Diverter
(1) A device attached to the wellhead or marine riser to close the vertical access and direct any flow into a line away from the rig. Diverters differ from blowout preventers in that flow is not stopped but rather the flow path is redirected away from the rig.(2) A device used to direct tools at a branch connection.
Diverting Tool Measured Depth
The measured depth of the cement diverting (DV) tool at the time of the cement job.
Divestment Package
A package of information regarding a group of lease parcels and/or assets which are offered for sale to prospective purchasers.
Divided Agreement
A type of operating agreement that provides for sharing of costs and benefits based on participating areas that may change.
Divided Deck
A deck having a screening surface longitudinally divided by partition(s).
Division Order
A written statement which, among other things, describes a certain property and stipulates the basis for distribution of the proceeds resulting from the sale of production from the property.
Document
A writing conveying information, either electronic or hard copy.
Document Due Date
The date a document is required.
Document Line Number
The line number of each individual transaction in an invoice.
Document Lines Billed Count
The total number of lines being billed from an original document.
Document Supplement Code
An indicator of whether the report is complete or is supplemented with additional transactions.
Doe
SEE: Department of Energy.
Doe Eia Field Code
The code assigned by the Department of Energy/ Energy Information Administration (EIA) as an industry standard.
Doe Eia Field Name
The assigned Department of Energy/ Energy Information Administration (EIA) name that relates to the DOE/EIA field code.
Doe State Field Number
Field number assigned by Department of Energy.
Dog Leg
SEE: Dogleg.
Doghouse
A small house used for keeping lease records, changing clothes, or any other use around a lease.
Dogleg
A term applied to a sharp change of direction in the borehole axis or ditch. Applied also to the permanent bending of wire rope or pipe.
Dogleg Angle
SEE: Dogleg Severity.
Dogleg Control Program
Drilling program designed specifically to decrease the severity of or eliminate doglegs in a wellbore.
Dogleg Severity
A measure of the amount of change in the inclination and/or direction of a borehole axis, usually expressed in angular units per length of wellbore path.
Dogleg Type
(1) Abrupt Dogleg: A dogleg caused by a sudden change in inclination and/or direction of the borehole axis over a short distance.(2) Decreasing Dogleg: A dogleg in the borehole axis with the change in inclination returning the borehole axis toward vertical.(3) Excessive Dogleg (Severe Dogleg): Doglegs larger than Permissible Doglegs.(4) Increasing Dogleg: A dogleg in the borehole axis with the change in inclination increasing the angle away from vertical.(5) Long Dogleg: A dogleg with a gradu
Dollie
A low frame with wheel or rollers designed to support heavy loads to be moved, as casing dollie to support the end of casing as it is taken into the derrick from the walkway.
Dolomite
A type of sedimentary rock similar to limestone but rich in magnesium carbonate.
Domain
The set of values which an independent variable may take.
Dome
(1) An uplift or anticlinal structure in which the rocks dip gently away in all directions.(2) The volume chamber inside the bellows of a gas lift valve.
Dominant
Strongest. For filters, this is generally the modal frequency, or the frequency in the spectrum passing most of a signal's amplitude.
Dominion Canada Township Range Section Survey System A Rectilinear System Used To Locate A Block Of Land In Canada.
Dope
(1) A viscous material used on casing or tubing as a lubricant, and to prevent corrosion.(2) A tar for pipelines to prevent corrosion.
Dor Unit
SEE: Dispersed Oil Recovery Unit.
Dose Rate
The amount of ionizing radiation energy absorbed per unit of mass and time of irradiated material.
Dosimeter
A device that measures radiation dose, such as film badge or ionization chamber.
Dot
SEE: Department of Transportation.
Double
A section of drill pipe, casing or tubing consisting of two joints screwed together.
Double Crystal Method
The method of ultrasonic testing, using two transducers with one acting as the transmitter and one as the receiver.
Double Doglegging
SEE: S-Type Borehole.
Double Flute
Two flutes advancing simultaneously at the same angle and 180 degrees apart.
Double Lead
SEE: Double Flute.
Double Seam Pipe
Pipe having two longitudinal seams formed by the submerged arc welding process or the gas metal arc welding process or the combination welding process.
Double Section
SEE: Repeated Section.
Double Wall Drill Pipe
A two tube concentric drill pipe assembled with the inner pipe in compression and the outer pipe in tension. Used to replace drill collars in directional wellbores.
Doughnut
A ring of wedges or a threaded, tapered ring that supports a string of pipe.
Downcomer
A tube that conducts liquids downward in a vessel; e.g., an absorber; stripper; heater-treater.
Downhole
(1) A term to describe tools, equipment, and instruments used within the wellbore e.g., downhole motor and downhole pump.(2) Conditions or techniques applying to the wellbore.
Downhole Commingling
The combining of hydrocarbons produced from multiple reservoirs within the wellbore.
Downhole Commingling Approval Flag
Indicates whether downhole commingling has been approved.
Downhole Motor
A power source located just above the bit to rotate the bit. Usually refers to the turbodrill or the Dyna Drill.
Downhole Motor Rpm Average
The average rotary speed (revolutions per minute - RPM) of a downhole motor as measured by a measurement while drilling (MWD) tool over the interval.
Downstream
A term used in describing operations after those at a point of reference.
Downstream Pipeline
The pipeline receiving natural gas at a pipeline inter-connect point.
Downthrown Side
The side of a fault that has slipped down relative to the other side.
Downthrown Side Of Fault Formation Name
The formation penetrated by the wellbore on the downthrown side and adjacent to the fault.
Downtime
The period of time a well is shut down for workover, maintenance, or other reasons.
Dp
SEE: Drill Pipe.
Drag
The extra force needed to move the drillstem resulting from the drillstem being in contact with the wall of the borehole.
Dragline
A machine used to drag material along the ground or any other surface.
Drain Deck
SEE: Beach.
Drain Holes
Several high-angle wellbore segements drilled laterally from a single wellbore into the reservoir.
Drainage Area
(1) Petroleum: That area from which one well can produce the hydrocarbons contained in the reservoir rock.(2) Streams: The horizontal projection ofthe area whose surface directs water toward a stream above a specified pointon that stream.(3) Also know as: Drainage Basin.
Drainhole Direction
The direction or bearing of the drainhole bottom or terminus from the surface location.
Drainhole Number
The number of the drainhole in the wellbore of a horizontal well for which data is being submitted.
Drainhole Turn Radius Value
The extrapolated radius of the turn of a horizontal drainhole. The turn is the averaged or extrapolated deviation arc between the beginning point of deviation and the point where the drainhole reaches its final angle from vertical.
Draw Off
Draining one fluid from a measurement vessel to determine relative volumes of heavy vs. light fluid.
Drawdown
(1) The difference in shut in and flowing bottomhole pressures, at a constant rate of fluid production. (2) The difference between levels in a water well when the pump is not working (static level) and when it is working (pumping level).
Drawdown Pressure
SEE: Drawdown.
Drawworks
The hoisting mechanism on a drilling rig. It is essentially a large winch which spools off or takes in the drilling line and thus raises or lowers the drillstring and bit.
Dress
To sharpen or repair items of equipment in order to make them ready for reuse; e.g., drill bits; tools; sucker rod pumps.
Dresser Sleeve
A slip type collar that is used to join plain end pipe.
Drift
(1) The horizontal component of the distance from the surface reference position to a point within the wellbore.(2) A gauge used to check minimum inside diameter flowlines, nipples, etc.
Drift Angle
(1) The angle between the axis of the borehole and the gravity vertical (Inclination).(2) More or less constant angle at which the axis of the borehole is carried after sufficient angle has been obtained in the buildup.
Drift Flag
SEE: Inclinometer.
Drift Mandrel
A precision dimensioned cylinder sized to pass through each diameter and weight of pipe. It is passed through the pipe ID to locate obstructions and/or to assure compliance with appropriate specifications.
Drift Survey
SEE: Deviation Survey.
Drill
An implement with cutting edges used to bore holes.
Drill Bit
A cutting or pulverizing tool attached to the drill pipe for drilling.
Drill Bit Activity
Describes the operating conditions while using the bit during a drilling activity.
Drill Bit Bearing Grading
The grade value assigned to a bit following its use to indicate its bearing condition.
Drill Bit Center Jet Diameter
The diameter of the center jet (nozzle).
Drill Bit Company Name
The name of the company that manufactured the drill bit.
Drill Bit Depth
The measured depth of a drill bit at a specific point in time.
Drill Bit Diameter
The outside diameter of the bit.
Drill Bit Distance
The total distance drilled by the bit during a particular run.
Drill Bit Dulling Characteristic
The dulling characteristic of the cutting structure of the drill bit, such as broken cone, broken teeth/cutters, balled up.
Drill Bit Elapsed Time
The number of hours the bit was in the wellbore.
Drill Bit Geometry
Refers to the geometric construction of a bit; e.g., 3 cone; 4 cone; 2 cone; flat face; configuration of the teeth.
Drill Bit Hydraulic Horsepower
The hydraulic horsepower generated by the flow of fluid through the bit nozzles.
Drill Bit Hydraulic Horsepower Area
The total hydraulic horsepower divided by the cross sectional area of the bit.
Drill Bit Iadc Type
The identifying code assigned by the International Association of Drilling Contractors (IADC) for the bit type.
Drill Bit Jet
The nozzle in a drill bit used to force drilling fluids into the borehole.
Drill Bit Jet Diameter
The diameter of the drill bit jet or drill bit nozzle.
Drill Bit Jet Impact Force
The force exerted on the wellbore bottomhole by the flow of drilling fluid through the drill bit.
Drill Bit Jet Velocity
The velocity of the drilling fluid as it exits the bit nozzles.
Drill Bit Mechanical Horsepower
The horse power required to rotate the bit only, not including that required to rotate the drill string contacting the walls.
Drill Bit Name
The manufacturer's name for the bit.
Drill Bit Number
Number assigned to a drill bit as it is used sequentially in the drilling of the well.
Drill Bit Overswing
Term denoted to excessive walk of the bit. Walk of the bit greater than expected.
Drill Bit Penetration Rate
The average distance drilled per unit of time during the bit run.
Drill Bit Pilot
A drill bit with a smaller diameter than the ultimate borehole. Used on deflecting tools; e.g., the whipstock and knuckle joint. Also used with borehole openers which follow and enlarge the original borehole.
Drill Bit Plan
Identification of drill bits required to drill the wellbore.
Drill Bit Port
A fluid flow port in a bit.
Drill Bit Pulled Depth
The measured depth at which the bit was removed from drilling service. The leading character, d, is used to indicate that the bit is still drilling.
Drill Bit Pulling Reason
The reason for pulling a drill bit from the wellbore; e.g., change bottomhole assembly, condition mud, downhole motor failure.
Drill Bit Ream Time
The elapsed time spent reaming during this bit run.
Drill Bit Rotation Speed
The average speed of rotation of the drill bit, normally reported in revolutions per minute.
Drill Bit Run Date
The initial date that the bit was being used during drilling operations.
Drill Bit Serial Number
The manufacturer's serial number of the bit.
Drill Bit Stabilization
Refers to stabilization of the downhole assembly near the bit. A stabilized bit is forced to rotate around its own axis.
Drill Bit Torque
Measured downhole (bit) torque, averaged over the interval.
Drill Bit Total Flow Area
The total flow area for fluid calculated for any bit.
Drill Bit Type
SEE: Drill Bit IADC Type.
Drill Collar
Heavy, thick walled tube, usually steel, employed between the drill pipe and the bit in the drill string to provide weight on the bit in order to improve its performance.
Drill Collar Inside Diameter
The inside diameter of drill collars used in the bottomhole assembly.
Drill Collar Length
The total length of drill collars used in the bottomhole assembly.
Drill Collar Outside Diameter
The outside diameter of drill collars used in the bottomhole assembly.
Drill Collar Top Depth When Pipe Stuck
The measured depth to the top of the drill collar when the pipe became stuck.
Drill Collar Type
Round, square or triangular drillstem elements utilized to provide a load on the bit while drilling.
Drill Core Valve
Valve in the top of the gas lift valve used in charging the bellows with nitrogen.
Drill Pipe
Tubular goods used in drilling a well with rotary tools.
Drill Pipe Inside Diameter
The inside diameter of the drill pipe.
Drill Pipe Outside Diameter
The outside diameter of the drill pipe.
Drill Pipe Safety Valve
An essentially full opening valve located on the rig floor with threads to match the drill pipe in use. This valve is used to close off the drill pipe to prevent flow.
Drill Pipe Stand Joints
The number of tool joints per stand of drill pipe.
Drill Pipe Stand Length
The average length of a stand of drill pipe.
Drill Pipe Upset
The thicker wall part of a tubular that is usually located at the ends.
Drilled By Cable Tools Interval
The distance drilled using cable tools.
Drilled By Rotary Tools Interval
The interval drilled using rotary tools.
Drilled Interval
A planned or actual wellbore segment which has a single nominal diameter.
Drilled Measured Depth
The maximum measured depth the driller is able to penetrate down the borehole prior to any given logging run.
Drilled True Vertical Depth
The depth to the base of the borehole currently drilled measured from a surface lreference point straight down to the base of the borehole.
Driller
An individual directly in charge of a drilling rig and crew. Operation of the drilling and hoisting equipment constitute his main duties.
Driller's Report
A record kept on the rig for each tour to show the footage drilled, drilling fluid tests, bit record, and all important occurrences during that tour.
Driller's Total Depth
The total depth of the well as reported by the drilling contractor.
Drilling
The using of a rig and crew for the drilling, suspension, completion, production testing, capping, plugging and abandoning, deepening, plugging back, sidetracking, redrilling or reconditioning of a well (except routine cleanout and pump or rod pulling operations) or the converting of a well to a source, injection, observation, or producing well, and including stratigraphic tests. Also includes any related environmental studies. Associated costs include completion costs but do not include equipping costs.
Drilling Clause Type
Used to describe the type of action required on the expiration date to maintain a lease beyond its normal expiration date. Examples are: Completion (production) prior to expiration date; Start drilling operations prior to expiration date; No drilling clause in lease; Start operations for drilling prior to expiration date; Not applicable.
Drilling Collision
SEE: Intersection.
Drilling Contract Type
Identifies rig contract as: daywork ($/hour); footage ($/foot); or turnkey ($/well).
Drilling Contractor Name
The name of the company that owns and operates the drilling rig and does the actual drilling. Can be the operating company.
Drilling Design
A specification of how wells can be drilled in a given geological environment. It will include details of the development strategy and specify the type of resources required to meet the design criteria.
Drilling Direction Code
An indicator of the diviation of the path of the wellbore; e.g., horizontal, straight, directional, etc.
Drilling Fluid
A fluid circulated through the borehole during drilling and workover operations to remove rock cuttings made by the drill. Drilling fluid also helps to cool the bit, prevent the sides of the borehole from caving, and control flow of rock fluids into the borehole.
Drilling Fluid Additive
The additive to the drilling fluid.
Drilling Fluid Analysis
Examination and testing of the drilling fluid to determine its physical and chemical properties and condition.
Drilling Fluid Annular Velocity
The calculated velocity of the drilling fluid in the annulus.
Drilling Fluid Balance
A beam type balance used in determining drilling fluid density. It consists primarily of a base, graduated beam with constant volume cup, lid, rider, knife edge, and counterweight.
Drilling Fluid Cake
The sheath of drilling fluid solids which coats the wall of the borehole when the drilling fluid filtrate is forced into the rocks surrounding the borehole.
Drilling Fluid Cake Resistivity
A surface measurement of the drilling fluid cake resistivity at a reported temperature.
Drilling Fluid Cake Temperature
Temperature at which the resistivity was measured for the drilling fluid cake.
Drilling Fluid Cake Thickness
The measure of the wall thickness of the drilling fluid upon removal of the fluid content.
Drilling Fluid Conditioning Equipment
Equipment used to condition the drilling fluid.
Drilling Fluid Cycle Time
The time of a cycle, or down the wellbore and back, is the time required for the pump to move the drilling fluid in the wellbore along this path.
Drilling Fluid Density
The density of the drilling fluid at the surface.
Drilling Fluid Filtrate
The liquid component of the drilling fluid with the solids removed or filtered out.
Drilling Fluid Filtrate Resistivity
A surface measurement of the filtrate resistivity at a reported temperature.
Drilling Fluid Filtrate Temperature
Temperature at which the resistivity was measured for the drilling fluid filtrate.
Drilling Fluid Function
The most important function of drilling fluids in rotary drilling is to bring cuttings from the wellbore bottomhole to the surface. Other important functions are: control subsurface pressures, cool and lubricate the drill bit and drill string, deposition of impermeable well cake, etc.
Drilling Fluid Inhibitor
A drilling fluid having an aqueous phase with a chemical composition that tends to retard and even prevent (inhibit) appreciable hydration (swelling) or dispersion of formation clays and shales through chemical and/or physical means.
Drilling Fluid Logging
The recording of information derived from examination and analysis of return drilling fluid and associated drill bit cuttings. A portion of the drilling fluid is diverted through a gas detecting device and examined further under ultraviolet light for the purpose of detecting the presence of oil or gas.
Drilling Fluid Loss
The measurement at the surface of the fluid loss for a standard period of time and pressure differential. This serves as an indicator of the rate of drilling fluid filtrate invasion into permeable rocks penetrated while drilling.
Drilling Fluid Measured Bottom Depth
The measured depth to the bottom of the interval in which a specified drilling fluid is used.
Drilling Fluid Measured Top Depth
The measured depth to the top of the interval in which a specified drilling fluid is used.
Drilling Fluid Ph
The alkalinity/acidity (pH) of the drilling fluid measured at the surface.
Drilling Fluid Plan
Identification of drilling fluids required to drill the wellbore.
Drilling Fluid Pump
A large reciprocating pump used to circulate drilling fluid in order to maintain the flow of drilling fluid through the wellbore to the settling pit.
Drilling Fluid Resistivity
A surface measurement of the resisitivity of the drilling fluid at a reported temperature.
Drilling Fluid Resistivity Temperature
The temperature at which the resistivity of the drilling fluid was measured.
Drilling Fluid Salinity
The salinity of the drilling fluid present during the logging run.
Drilling Fluid Screen
SEE: Shale Shaker.
Drilling Fluid Tank Volume
The total volume of drilling fluid, indicated by sensors, in all the compartments of the tank. The reading is averaged over a time interval.
Drilling Fluid Temperature
The temperature of the drilling fluid at the surface.
Drilling Fluid Type Code
An indicator of the type of drilling fluid present in the drilling media; e.g., chemical gel mud; crude oil; caustic (high pH); gypsum mud; native mud; air; salt water.
Drilling Fluid Viscosity
The viscosity of the drilling fluid measured at the surface.
Drilling Fluid Weight
The density of the drilling fluid.
Drilling Fluid Weight Recorder
An instrument in the drilling fluid system which continuously measures drilling fluid density.
Drilling Fluid Yield Point
An additional thixotropic measurement yield point which is the resistance to internal fluid flow measured as stress.
Drilling Hydraulics
The employment of the science of the effects of fluid velocities and pressures and forces involved.
Drilling In
The process of drilling into or through the oil or gas pay zone for well completion.
Drilling Jar
A jointed section in a string of tools made with slack between the joints.
Drilling Line
The wireline used in the rig's main hoisting system.
Drilling Log
A log of drilling parameters; e.g., penetration rate; rotary speed; weight on the bit; pump pressure; pump strokes.
Drilling Mud
SEE: Drilling Fluid.
Drilling Operations Suspended Date
The date drilling operations were suspended for a well.
Drilling Out
The drilling out of the residual cement which normally remains in the lower section of casing and the borehole after the casing has been cemented.
Drilling Overhead Percentage
The operating agreement may provide that the operator will charge the joint interest account using a percentage of the cost of drilling the well rather than the normal per well overhead charge.
Drilling Overhead Rate
The monthly rate of overhead that can be charged on a drilling or recompletion/workover well. This is usually defined in an attachment to the operating agreement.
Drilling Permit
The authorization obtained from a regulatory agency to drill a well or extend the wellbore of an existing well.
Drilling Permit Approval Date
The date the application for the drilling permit was approved and work can begin to construct the drill site and start drilling. Commonly referred to as Application for Pemit to Drill (APD).
Drilling Permit Extension Approval Date
The date the extension to a drilling permit is approved.
Drilling Permit Number
The number assigned to the permit, granting authority to drill, plug back, or deepen.
Drilling Permit Number Assigned Date
The date the drilling permitnumber was assigned to the permit granting authority to drill, plugback, or deepen a well.
Drilling Permit Received Date
The date an application for a drilling permit or a notice for staking (NOS) is received.
Drilling Plan
Plan of the materials, directional drilling, projections, and schedules to drill a particular wellbore.
Drilling Problem Type
The type of drilling problem that occurred; e.g., blow out; fishing; storm; abnormal pressure.
Drilling Report
Describes the drilling rig activities.
Drilling Rig
Equipment and machinery assembled primarily for the purpose of drilling.
Drilling Rig Rotary
Includes prime movers, hoisting, rotating, circulating, and auxiliary equipment necessary for drilling.
Drilling Rig Rotating System
SEE: Rig Rotary System.
Drilling Schedule
Projection of daily costs and depths for drilling the wellbore.
Drilling Show Basis
The basis used in determining drilling shows; e.g., bailer; mud log; samples.
Drilling Slot
Opening in a drilling platform or drilling vessel through which drilling operations are conducted.
Drilling Slots Available
The number of drilling slots that are available on the offshore drilling platform.
Drilling Spool
A connection component with ends either flanged or hubbed. It must have an internal diameter at least equal to the bore of the blowout preventer and can have smaller side outlets for connecting auxiliary lines.
Drilling Through Valve
A valve with an oversize bore. These valves must pass a drift test.
Drilling Unit
The smallest area permitted by state authorities in which a well may be completed. Determined in accordance with a well spacing plan for the field.
Drillship
A large seagoing vessel which incorporates a derrick amidships and all the associated drilling equipment.
Drillstem
The entire drilling assembly from the swivel to the bit consiting of the kelly, drill string, subs, drill collars, and other downhole tools; e.g., stabilizers; reamers. This assembly is used to rotate the bit, carry the drilling fluid to the bit and conduct downhole activities, such as drillstem tests.
Drillstem Buckling
(1) To bend the drillstem.(2) To have the drillstem become distorted due to effects of forces on the drillstem while in the wellbore.
Drillstem Test
A test through the drillstem taken by means of special testing equipment attached to the drillstem to determine if oil or gas in commercial quantities have been encountered in the wellbore. Because the drillstem test is a temporary well completion, it is not necessary to set casing or to remove drilling fluid from the wellbore to conduct the test.
Drillstem Test Bottomhole Pressure Measurement
The bottomhole pressure recorded during a drillstem test.
Drillstem Test Bottomhole Temperature
The bottomhole temperature recorded during a drillstem test.
Drillstem Test Cumulative Gas Production
The total gas production during a drillstem test up to the time the record is generated.
Drillstem Test Cumulative Liquid Production
The total liquid production during a drillstem test up to the time the record is generated.
Drillstem Test Cumulative Total Production
The total production of all products up to the time the record is generated.
Drillstem Test Damage Ratio
The percentage of the estimated damage done to the formation from drillstem test (DST) pressure build up.
Drillstem Test Date
The date that a drillstem test was taken.
Drillstem Test Elapsed Time
The time elapsed since the tool began running for a drillstem test (DST).
Drillstem Test Gas Rate
The measured gas flow rate during a drillstem test (DST).
Drillstem Test Liquid Rate
The measured liquid flow rate during a drillstem test (DST).
Drillstem Test Perforation Distance
The distance obtained by totaling the individual perforated intervals of each of the zones tested while conducting a drillstem test (DST).
Drillstem Test Type
Indicates what type of drillstem test (DST) was performed and whether the DST was taken through perforations and with a treatment, or if wireline test was used; e.g., bailer test; casing packer with treatment; straddle packer.
Drillstem Test Well Status
The well status value at the time of the drillstem test operation.
Drillstring
SEE: Drillstem.
Drillstring Behavior
A term describing the mechanics and action of the drillstring/ drillstem.
Drillstring Fatigue
The cumulative effect of the stresses imposed on the drillstring due to cyclic stressing during drilling operations.
Drillstring Float
A check valve in the drillstring that will allow fluid to be pumped into the wellbore but will prevent flow from the wellbore through the drill pipe.
Drillstring Section
A unique element or contiguous group of unique elements belonging to the drillstring.
Drip
A vessel attached to a gas well or gas line to capture and accumulate any liquid that might find its way into the gas lines. Drips are installed in low places in the line and must be blown out or emptied periodically.
Drive
All the immediate elements used to provide motive power to the mud processing equipment; e.g., V-belts; sheaves; motor; motor base.
Drive Head
A circular steel coupling like tool, used to protect a coupling from drive clamp damage.
Drive Mechanism
SEE: Reservoir Energy; Reservoir Drive Mechanism.
Drive Pipe
A relatively short string of large diameter pipe driven or forced into the ground to function as conductor pipe.
Droop Error
The error introduced by the hanging downward of the protruding instrument extending through and ahead of the trigger bit.
Drop Angle
The average rate of angular decrease at which a deviated wellbore path departs from the hold angle in an s-type well.
Drop Off
That portion of the wellbore path in which the inclination is reduced.
Drop Off Angle
Rate of change (degrees/100 ft) of the inclination angle in the section of the wellbore path that is decreasing toward vertical.
Drop Off Interval
The wellbore path interval where the inclination angle is purposely decreased and returned toward the vertical while drilling.
Drop Off Measured Depth
Measured depth to the wellbore point the hold angle begins to decrease in an s-type wellbore.
Drop Off Rate
The rate of change of the inclination in the part of the wellbore path where the inclination angle is purposely returned toward the vertical while drilling.
Drop Time
The amount of time needed for a go devil type instrument to fall from the surface through the drilling fluid within the drillstem to the desired position.
Drop Type Survey
A directional or inclination survey taken with an instrument that is free released to fall within the drillstem to the desired position within the wellbore.
Drum
The small scrubbers, separators, and coalescers are referred to as drums in a gas processing plant; i.e., reflux drum, surge drum, etc.
Drum Rope
A rotating cylinder with side flanges on which wire rope used in machine operation is wrapped.
Drunken Thread
Distortions in the spiral path of a thread around the pin. Sometimes applied to wavy threads or threads with crests that undulate around the periphery of the threads.
Dry And Abandoned
SEE: Plugged and Abandoned.
Dry Bottom
A dry condition at the underflow of a hydrocyclone.
Dry Btu
Heating value contained in a cubic foot of natural gas measured and calculated free of moisture content. Contractually, dry may be defined as less than or equal to seven pounds of water per one million cubic feet of gas.
Dry Gas
Gas which does not contain significant liquifiable hydrocarbons.
Dry Hole
An unsuccessful well. A well drilled to a certain depth without finding commercial quantities of oil or gas.
Dry Hole Money Contribution
Money given to an operator in payment for drilling a well on property in which the contributor has no direct interest, but payable only in the event the well is a dry hole.
Dry Inspection Method
A magnetic particle inspection method in which the particles employed are in dry powder form.
Dry Plug
The plugging of the underflow opening of a dry bottom hydrocyclone.
Dryer ( Air/gas)
Equipment used to remove water/condensation from air/gas lines.
Dst
SEE: Drillstem Test.
Dual Completion
SEE: Multiple Well Completion.
Dual Search Unit
A probe or search unit containing two elements, one a transmitter, the other a receiver.
Dual Transducer
An ultrasonic probe containing two piezoelectric crystals, one for transmitting and one for receiving.
Due The Owner After Tax Amount
Net amount, after tax deduction, due to the owner based on the owner's interest in the lease, calculated against the total lease production.
Due The Owner Before Tax Amount
Net amount, before tax deduction, due to the owner based on the owner's interest in the lease, calculated against the total lease production.
Dummy
A blank tool installed in a side pocket gas lift mandrel landing nipple and/or sliding sleeve.
Dump Bailer
A cylindrical container with a valve that is used to release small batches of cement, water, or mud downhole in a remedial cementing operating or for other special purposes.
Dump Valve
A valve used to reduce liquid level in a vessel or line, usually an automatic drain valve.
Duns Number + 4
An extension of the DUN & BRADSTREET (DUNS) unique corporate identifier code commonly used as an electronic mailing address for Electronic Commerce (EC) documents. The "+4" refers to a 4-digit suffix that is defined and maintained separate of the DUNS number by the referenced entity. The suffix typically is used to more uniquely identify sub-entities such as subsidiaries, locations, and/or cost centers. The two primary uses for this code within American National Standards Institute (ANSI) X12 documents a
Duster
SEE: Dry Hole.
Dutchman
(1) A piece of pipe that has been twisted off inside a female connection.(2) A short section of material; i.e., belting or pipe, used to lengthen existing equipment.
Dv Tool
A tool used to divert cement, when pumping, to control the placement of cement slurry.
Dynamic Loading
Loads introduced into a structure or the machine or its components due to accelerating or decelerating forces.
Dynamic Positioning System
A mechanism by which floating rigs may maintain their position above a wellbore. Normally done by thrusters on the hull(s) of a rig being controlled by a computerized positioning system.
Dynamic Range
The ratio of maximum to minimum reflective areas that can be distinguished on the cathode ray tube at a constant gain setting.
Dynamic Stress
Varying or fluctuating stress occurring in a structural member as a result of dynamic loading.
Dynamometer
As applied to sucker rod load measurements, an instrument which measures the polished rod loads in relation to the position of the rod within the pumping cycle.
Dynamotor
A special form of motor generator combining the motor and generator in a single machine.
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