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ABANDONED WELL - A well no longer in use; a dry hole that, in most states, must be properly plugged.

ACIDIZING A WELL- A technique for increasing the flow of oil from a well. Hydrochloric acid is pumped into the well under high pressure to reopen and enlarge the pores in the oil-bearing limestone formations.

ACID TREATMENT - A refining process in which unfinished petroleum products such as gasoline, kerosene, diesel fuels, and lubricating stocks are treated with sulfuric acid to improve color, odor, and other properties.

ACOUSTIC LOG - A generic term for a well log that displays any of several measurements of acoustic waves in rocks exposed in a borehole, e.g., compressional-wave transmit time over an interval (sonic log) or relative amplitude (cement bond log).

ADJUSTABLE CHOKE - A choke in which the position of a conical needle, sleeve, or plate may be changed with respect their seat to vary the rate of flow; may be manual or automatic.

ADT - Actual Drilling Time

AFE - Authorization for Expenditure

AMERICAN PETROLEUM INSTITUTE (API) – The American Petroleum Institute is the primary trade association representing the oil and natural gas industry in the United States. Founded in 1920, API is the leading standard-setting organization for all types of oilfield equipment. It maintains departments of production, transportation, refining and marketing in Washington D.C. It offers publications regarding standards, recommended practices, and bulletins.

AMINE - Organic base used in refining operations to absorb acidic gases (H2S, COS, CO2) occurring in process streams. Two common amines are monoethanolamine (MEA) and diethanolamine (DEA).

AMINE UNIT - A natural gas treatment unit for removing contaminants (H2S, COS, CO2) by the use of amines. Amine units are often skid-mounted so they can be moved to the site of new gas production. Gas containing H2S and other impurities must be cleaned up before it is acceptable to gas transmission pipelines.

ANGLE OF DEFLECTION - In directional drilling, this is the angle at which a well diverts from vertical; usually expressed in degrees, with vertical being 0 degrees.

ANTICLINE - Rock layers folded in the shape of an arch. Anticlines sometimes trap oil and gas.

APPRAISAL DRILLING - Wells drilled in the vicinity of a discovery or wildcat well in order to evaluate the physical extent and the importance of the find.

ARO - At Rate Of

AREA OF INTEREST (AOI) - The area immediately surrounding a successful well in which the investors (in the good well) have an implied right to participate in any future wells drilled by the same operator.

ARTIFICIAL LIFT - Pumping an oil well with a rod, tubing, or bottom-hole centrifugal pump may be termed artificially lifting crude oil to the surface or doing so by mechanical means.

ASSIGNMENT - In oil and gas usage, assignment is a transfer of a property or an interest in an oil or gas property; most commonly, the transfer of an oil or gas lease. The assignor does the transferring and the assignee receives the interest of property.

ASSOCIATED GAS - Gas that occurs with oil, either as free gas or in solution. Gas occurring alone in a reservoir is unassociated gas.

ATTIC OIL - An unscientific, but descriptive term for the oil above the borehole in horizontal wells; oil in the top few feet of a productive interval which will gravitate or be pressured into the horizontal drain hole.

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BACK-IN-PROVISION - A term used to describe a provision in a farmout agreement whereby the person granting the farmout (the farmor) has the option to exchange a retained override for a share of the working interest.

BARREL (BBL) - A unit of volume measurement used for petroleum consisting of forty two-(42) gallons.

BARREL OF OIL EQUIVALENT – Generally, this is a term used when cubic feet of natural gas, either flow rates or reserves, are converted into the equivalent of one barrel of crude oil. This term is used frequently when exploration and production companies are reporting the amount of combined reserves they may have without breaking it down into barrels of crude oil and cubic feet of natural gas.

BARRELS PER DAY (BPD) - In the United States, a measure of the rate of flow of a well; the total amount of oil and fluids produced or processed per day.

BATTERY - Two or more tanks connected together to receive oil production on a lease; tank battery.

BB - Bridged Back

BBL - Barrels of Oil

BCF - Billion Cubic Feet

BCFPD - Billion Cubic Feet Per Day

BED - A specific layer of earth or rock that presents a contrast to other layers of different material lying above, below, or adjacent to it.

BEDROCK - Solid rock just beneath the soil.

BCF -  Billion cubic feet

BEHIND THE PIPE - Refers to oil and gas reservoirs penetrated or passed through by wells, but never tapped or produced. Behind the pipe usually refers to tight formations of low permeability that, although recognized, were passed through because they were uneconomical to produce at the time. Today, however, with the growing scarcity of oil and high prices, many of these passed-through formations are getting a second look by producers.

BF - Barrels of Fluid

BFPD - Barrels of Fluid Per Day

BFPH - Barrels of Fluid Per Hour

BFW - Barrels of Formation or Fresh Water

BH - Bottom Hole

BHA - Bottom Hole Assembly

BHFP - Bottom Hole Flowing Pressure

BHL - Bottom Hole Location

BHP - Bottom Hole Pressure

B.H.T. - Bottom-hole temperature. In deep wells, 15,000 feet and deeper, bottom-hole temperatures are above the boiling point of water, ranging up to 400 degrees Fahrenheit. At these depths and temperatures, water-base drilling muds can not be used, only oil-based.

BIOGENESIS - Formed by the presence or the actions of living organisms, for example, coral reefs and atolls. Biogenesis is also the theory that all life is derived from previously living organisms.

BIT, ROTARY - The cutting or boring element used in drilling oil and gas wells; the tool attached to the lower end of the drillpipe; a heavy steel head equipped with various types of cutting or grinding teeth. Some are fixed; some turn on bearings. A hole in the bottom of the drill permits the flow of drilling mud being pumped down through the drillpipe to wash the cuttings to the surface and also cool and lubricate the bit.

BIT RECORD - A report that lists each bit used during a drilling operation, giving the type, the footage it drilled, the formation it penetrated, its condition, and so on.

BIT, SPUDDING - A bit used to start the borehole; a bit that is some variation of the fishtail or drag bit, one used in soft, unconsolidated, near-surface material.

BL - Barrels Load

BLO - Barrels Load Oil

BLOW-DOWN  - Condensate and gas is produced simultaneously from the outset of production.

BLOWING A WELL - Opening a well to let it blow for a short period to free the well tubing or casing of accumulations of water, sand, or other deposits.

BLOWOUT - Out-of-control gas and/or oil pressure erupting from a well being drilled; a dangerous, uncontrolled eruption of gas and oil from a well; a wild well. A blowout, or gusher, can occur when formation pressure exceeds the pressure applied to it by the column of drilling fluid.

BLOWOUT PREVENTER (BOP) - A stack or an assembly of heavy-duty valves attached to the top of the casing to control well pressure; a “Christmas tree”.

BO - Blew Out

BOE - Barrels of Oil Equipment

BONUS - Usually, the bonus is the money paid by the lessee for the execution of an oil and gas lease by the landowner. Another form is called an oil or royalty bonus. This may be in the form of an overriding royalty reserved to the landowner in addition to the usual one-eighth royalty.

BOPD - Barrels of Oil per Day

BOPE - Blowout Preventer Equipment

BOTTOMHOLE - The lowest or deepest part of a well pertaining to the bottom of the wellbore.

BOTTOMHOLE ASSEMBLY - The portion of the drilling assembly below the drill pipe. It can be very simple-composed of only the bit and drill collars-or it can be very complex and make up of several drilling tools.

BOTTOMHOLE PRESSURE - The pressure at the bottom of a borehole caused by the hydrostatic pressure of the wellbore fluid and, sometimes, by any back-pressure held at the surface, as when the well is shut in with blowout preventers.

BOP - Blowout Preventer

BOREHOLE - The hole in the earth made by the drill; the uncased drill hole from the surface to the bottom of the well.

BP - Bridge Plug

BPD - Barrels Per Day

BPH - Barrels Per Hour

BPM - Barrels per minute. The pumping rate of small rotary pumps.

BRIDGE PLUG - An expandable plug used in a well’s casing to isolate producing zones or to plug back to produce from a shallower formation; also to isolate a section of the borehole to be filled with cement when a well is plugged.

BTU - British Thermal Unit

BUTANE - A hydrocarbon fraction; at ordinary atmospheric conditions, butane is a gas but it is easily liquefied; one of the most useful L.P.-gases; widely used household fuel.

BWL - Barrels Water Load

BWPD - Barrels of Water per Day

BWPH - Barrels of Water Per Hour

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C.O.P. - Completed on Pump

C/H - Cased Hole

CARRIED WORKING INTEREST - A fractional interest in an oil and gas property conveyed or assigned to another party by the operator or owner of the working interest. In its simplest form, a carried working interest is exempt from all costs of development and operation of the property. However, the carried interest may specify “to casing point”, “to setting of tanks”, or “through well completion”. If the arrangement specifies through well completion, then the carried interest may assume the equivalent fractional interest of operating costs upon completion of the well. There are many different types of carried interests, the details varying considerably from arrangement to arrangement. One authority has observed, “The numerous forms this interest is given from time to time make it apparent the term ‘carried interest’ does not define any specific form of agreement but serves only as a guide in preparing and interpreting instruments”.  

CASED HOLE - A wellbore in which casing has been run.

CASING – Steel pipe cemented in an oil or gas well to seal off formation fluids or keep the hole from caving in.  

CASING STRING - The steel tubing that lines a well after it has been drilled. It is formed from sections of steel tube screwed together.

CASING POINT - A term that designates a time when a decision must be made whether casing is to be run and set or the well abandoned and plugged. In a joint operating agreement, casing point refers to the time when a well has been drilled to objective depth, tests made, and the operator notifies the drilling parties of his recommendation with respect to setting casing and a production string and completing the well. On a marginal well, the decision to set pipe is often difficult. To case a well often costs as much as the drilling. On a very good well there is no hesitation; the operators are glad to run casing and complete the well.

CATCH SAMPLES - To obtain cuttings for geological information as the bit penetrates formations.

CCL - Casing Collar Locator

CEMENT CASING - To fill the annulus between the casing and the wall of the hole with cement to support the casing and to prevent fluid migration between permeable zones.

CFG - Cubic Feet of Gas

CFGPH - Cubic Feet of Gas Per Hour

CFGPD - Cubic Feet of Gas Per Day

CH - Casing Head, Closed Hole

CHOKE - A device with an orifice installed in a line to restrict the flow of fluids.

CHP - Casing Head Pressure

CHRISTMAS TREE - An assembly of valves mounted on the casinghead through which a well is produced. The Christmas tree also contains valves for testing the well and for shutting it in if necessary.

CIP - Closed In Pressure

CIRCULATE - To pass from one point throughout a system and back to the starting point. For example, drilling fluid is circulated out of the suction pot, down the drill pipe and drill collars, out the bit, up the annulus, and back to the pits while drilling proceeds.

CMT(d)(g)(r) - Cement (ed) (ing) (er)

CNTN - Containment

CO - Crude Oil

COF - Calculated Open Flow (potential)

COILED TUBING - A continuous string of flexible steel tubing, often hundreds or thousands of feet long, that is wound onto a reel, often dozens of feet in diameter. The reel is an integral part of the coiled tubing unit, which consists of several devices that ensure the tubing can be safely and efficiently inserted into the well from the surface. Because tubing can be lowered into a well without having to make u joints of tubing, running coiled tubing into the well is faster and less expensive than running conventional tubing. Rapid advances in the use of coiled tubing make it a popular way in which to run tubing into and out of a well.

COLL - Collect (ed) (ing) (er)

COME OUT OF THE HOLE - To pull the drill steam out of the wellbore to change the bit, to change from a core barrel to the bit, to run logs, to prepare for a drill stem test, to run casing and so on. Also called trip out.

COMMERCIAL QUANTITY - An amount of oil and gas production large enough to enable the operator to realize a profit, however small.

COMPLETION - To finish a well so that it is ready to produce oil or gas. After reaching total depth (T.D.), casing is run and cemented; casing is perforated opposite the producing zone, tubing is run, and control and flow valves are installed at the wellhead. Well completions vary according to the kind of well, depth, and the formation from which the well is to produce.

COMPLETION FUNDS - Completion funds are formed to invest in well completions, to finance the completing and equipping of a potentially productive well. After a well is drilled into a productive formation, there remain the costs of setting pipe, (casing the well); perforating, testing, acidizing, or fracturing the formation; and running production tubing and installing pumping equipment, separators, stock tanks, etc. The operator who drills the well may not have the financial resources to complete the well, so he may sell part or all of his interests to a completion fund. Completion funds are not as risky an investment as drilling funds, but are less certain than income funds and royalty funds.

COMP - Complete (ed) (tion)

COMPR - Compressor

CONDENSATE - Hydrocarbons which are in the gaseous state under reservoir conditions and which become liquid when temperature or pressure is reduced.

COP - Crude Oil Purchasing

CP - Casing Pressure

CPF - Casing Pressure Shut-in

CORE - A cylindrical sample taken from a formation for a geological analysis. To obtain a solid, cylindrical formation sample for analysis.

CORE SAMPLE - A solid column of rock, usually from 2 - 4 inches in diameter, taken from the bottom of a well bore as a sample of an underground formation. Cores are also taken in geological studies of an area to determine the oil and gas prospects

CORING - Taking rock samples from a well by means of a special tool -- a "core barrel".

CRUDE OIL - Oil as it comes from the well; unrefined petroleum.

CSA - Casing Set At

CSG - Casing

CTHF - Center of Tubing Flange

CTS - Cement to Surface

CU - Clean Up

CUBIC FOOT - A standard unit used to measure quantity of gas (at atmospheric pressure); 1 cubic foot = 0.0283 cubic meters.

CUTTINGS - Rock chips cut from the formation by the drill bit, and brought to the surface with the mud. Used by geologists to obtain formation data.

CV - Control Valve

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D&A - Dry & Abandoned

D&C - Drill and Complete

DAILY DRILLING REPORT - A record made each day of the operations on a working drilling rig and, traditionally, phoned or radioed in to the office of the drilling company every morning. Also called morning report.

DC - Drill Collar

DEP - Depletion

DEPOSIT - An accumulation of oil or gas capable of being produced commercially.

DEEPEN -  To increase the distance of a well below a specified reference datum.

DERRICK - A wooden or steel structure built over a wellsite to provide support for drilling equipment and a tall mast for raising and lowering drillpipe and casing; a drilling rig.

DEVELOPMENT PHASE - The phase in which a proven oil or gas field is brought into production by drilling production (development) wells.

DEVELOPMENT WELLS - Wells drilled in an area already proved to be productive.

DF - Drill Floor

DHC - Dry Hole Cost

DISCOVERY WELL - An exploratory well that encounters a new and previously untapped petroleum deposit; a successful wildcat well. A discovery well may also open a new horizon in an established field.

DL - Density Log

DOC - Drilled Out Cement

DOD - Drilled Out Depth

DOWNHOLE - A term to describe tools, equipment, and instruments used in the well bore; also conditions or techniques applying to the well bore.

DP - Drill Plug

DPT - Depth

DRILL - To bore a hole.  

DRILLING - The using of a rig and crew for the drilling, suspension, completion, production testing, capping, plugging and abandoning, deepening, plugging back, sidetracking, re-drilling or reconditioning of a well.  

DRILLING PERMIT - In states that regulate well spacing, a drilling permit is the authorization to drill at a specified location; a well permit.

DRILLPIPE - The drillpipe connects the rig surface equipment with the bottomhole assembly and the bit, both to pump drilling fluid to the bit and to be able to raise, lower and rotate the bottomhole assembly and bit.

DRILLSTRING - The combination of the drillpipe, the bottomhole assembly and any other tools used to make the drill bit turn at the bottom of the wellbore.

DRL - Drill

DRY GAS - A natural gas from the well free of liquid hydrocarbons; gas that has been treated to remove all liquids; pipeline gas.

DRY HOLE - A well which has proved to be non-productive.

DSI - Drilling Suspended Indefinitely

DTD - Driller’s Total Depth

DWC - Drilling Well Completion

DWD - Dirty Water Disposal

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E&P - Abbreviation for exploration and production.    

EFFECTIVE POROSITY - The percent of the total volume of rock that consists of connecting pores or interstices. The part of a rock that is capable of holding a fluid (oil, water, or gas) is the effective porosity.

ELECTRIC LOG - An electrical survey made on uncased holes. A special tool is lowered into the hole which ejects an electrical current into the rock and records its resistance to the current. The data from the survey is used by the geologist to determine the nature of the rock and its contents.

EXPLORATION - A general term referring to all efforts made in the search for new deposits of oil and gas.

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FARO - Flowing at the Rate Of

FBHP - Flowing Bottom Hole Pressure

FBHPF - Flowing Bottom Hole Pressure Flowing

FBHPSI - Flowing Bottom Hole Pressure Shut-in

FCP - Flowing Casing Pressure

FCV - Flow Control Valve

FDL - Formation Density Log

FE/L - From East Line

FF - Full of Fluid

FFP - Final Flowing Pressure

FI - Flow Indicator

FIELD - A geographical area under which an oil or gas reservoir lies.

FIELD POTENTIAL - The producing capacity of a field during a 24-hour period.

FIH - Fluid in Hole

FIN DRLG - Finished Drilling

FISH - Fishing

FL - Flush

FLARE - (1) To burn unwanted gas through a pipe or stack (Under conservation laws, the flaring of natural gas is illegal.) (2) The flame from a flare; the pipe or the stack itself.

FLOWING WELL - A well capable of producing oil or gas by its own energy without the aid of a mechanical pump. Normally a pump is put on the well after the pressure reduction inhibits the rate of production.

FLU - Fluid

FLWG PR - Flowing Pressure

FORMATION PRESSURE - The pressure at the bottom of a well when it is shut in at the wellhead.

FNEL - From Northeast Line

FNL - From North Line

FNWL - From Northwest Line

FOSSIL ENERGY - Energy derived from crude oil, natural gas, or coal.

FRACKING - The process of pumping fluids into a productive formation at high rates and pressures to hydraulically break down the rock. The objective is to increase production rates from a reservoir.  

FORMATION WATER - The salt water underlying the gas and oil in a formation.

FP - Flowing Pressure, Final Pressure

FPH - Feet Per Hour

FPS - Feet Per Second

FR - Flow Rate

FW - Formation Water

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G - Gas

G & O - Gas and Oil

GAL - Gallon (s)

GAL SOL - Gallons of Solution

GAL/MCF - Gallons Per Thousand Cubic Feet

GAL/MIN - Gallons Per Minute

GAS - “Any fluid, combustible or noncombustible, which is produced in a natural state from the earth and which maintains a gaseous or rarified state at ordinary temperature and pressure conditions”. Code of Federal Regulations, Title 30, Mineral Resources, Chap. II, Geological Survey, 221.2

GAS CAP - The portion of an oil-producing reservoir occupied by free gas; in a free state above an oil zone.

GAS FIELD - A field containing natural gas but no oil.  

GAS INJECTION - The process whereby separated associated gas is pumped back into a reservoir for conservation purposes or to maintain the reservoir pressure.    

GAS/OIL RATIO - The volume of gas at atmospheric pressure produced per unit of oil produced.  

GAS WELL - A well that produces natural gas which is not associated with crude oil. GEOLOGY - The science of the history of the Earth and its life as recorded in rocks.

GIH - Go in Hole

GL - Gas Lift

GLO - Gas Lift Oil

GLR - Gas Liquid Ratio

GO - Gallons Oil

GPC - Gas Purchase Contract

GPD - Gallons Per Day

GPM - Gallons Per Minute

GPS - Gallons Per Second

GRT - Grand (of land)

GSW - Gallons Salt Water

GTS - Gas to Surface (time)

GW - Gallons Water

GWPH - Gallons of Water Per Hour

GWSI - Gas Well Shut In

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HFO - Hole Full of Oil

HFSW - Hole Full of Salt Water

HFW - Hole Full of Water

HP - Hydraulic Pump

HPG - High Pressure Gas

HVL - High Volume Lift

HYDROCARBONS - Organic chemical compounds of hydrogen and carbon atoms. There are a vast number of these compounds, and they form the basis of all petroleum products. They may exist as gases, liquids, or solids. An example of each is methane, hexane, and asphalt.

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I/O - Input/Output

IBHP - Initial Bottom-Hole Pressure

IBHPF - Initial Bottom-Hole Pressure, Flowing

IBHPSI - Initial Bottom-Hole Pressure, Shut in

IDC - (Intangible Drilling Costs) All cost incurred in drilling a well other than equipment or leasehold. These expenses are 100% tax deductible even if the well is productive.

IFL - Initial Fluid Level

IFP - Initial Flowing Pressure

INJECTION WELL - A well used for pumping water or gas into the reservoir.

IP - (Initial Production) Production from a well is generally broken down into three categories: a. Flush or Initial b. Settled c. Stripper. It is important to realize that a well cannot maintain the flow rates it made during the first stages of its life.

IPE - Install (ing) Pumping Equipment

IPF - Initial Production Flowed (ing)

IPG - Initial Production Gas Lift

IPS - Initial Production Swabbing

ISIP - Initial Shut in Pressure

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JIB - Joint Interest Billing

JV - Joint Venture

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KICK - A well is said to "kick" if the formation pressure exceeds the pressure exerted by the mud column.  

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L.P. - Line Pipe

LC - Lower Casing

LIGHT ENDS - The more volatile products of petroleum refining, e.g., butane, propane, and gasoline.

LIQUEFIED NATURAL GAS (LNG) - Oilfield or naturally occurring gas, chiefly methane, liquefied for transportation.  

LO - Load Oil

LP - Line Pressure

LW - Load Water

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MBOE - Million Barrels Oil Equivalent.  

MCF - Thousand Cubic Feet

MCFGPD - Thousand Cubic Feet of Gas per Day

MECHANICAL INTEGRITY TEST (MIT) - The act of setting a packer or retrievable bridge plug above the perforations in a wellbore and applying pressure to the annulus in order to ensure soundness of the casing.

MFP - Maximum Flowing Pressure

MI - Moving In (Equipment)

MICR - Moving In Completion Rig

MIE - Moving In Equipment

MIR - Moving In Rig

MISR - Moving In Service Rig

MMCFD - Millions of cubic feet per day (of gas).

MUD - A mixture of base substance and additives used to lubricate the drill bit and to counteract the natural pressure of the formation.

MWD - Marine Wholesale Distributors

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NATURAL GAS - Gas, occurring naturally, and often found in association with crude petroleum.  

NG - Natural Gas

NGTS - No Gas to Surface

NON-COMMERCIAL - A well that is not capable of producing enough oil to pay for the drilling.

NRI - (Net Revenue Interest) That percent of the production revenue allocated to the working interest after first deducting proceeds allocated to royalty and overriding interest.

NTD - New Total Depth

NYD - Not Yet Drilled

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O & GL - Oil and Gas Lease

OC - Open Choke

OFFSET WELL - (1) A well drilled on the next location to the original well. The distance form the first well to the offset well depends upon spacing regulations and whether the original well produces oil or gas. (2) A well drilled on one tract of land to prevent the drainage of oil or gas to an adjoining tract where a well is being drilled or is already producing.

OFP - Open Flow Potential

OIL - A liquid hydrocarbon. (see "Crude Oil")

OIL BEHIND THE PIPE - Refers to oil and gas sands or formations knowingly passed through, never produced. Such formations usually were of low permeability (tight formations) that, say 20 years ago, were uneconomical to produce when oil was around $5 or less a barrel. Other times formations would be purposely ignored because the operator was going deeper for bigger game, so the less-spectacular, plain-Jane sands were cased off. When the price of crude oil reached $30 per barrel, the bypassed formations looked pretty good and were opened up and produced.

OIL-CUT MUD - Drilling mud with which crude oil has been unintentionally mixed. This may occur when drilling into or through an oil-bearing formation whose pressure is sufficient to overcome the pressure or weight of the column of mud in the hole. Oil also may become mixed with the drilling mud when a drillstem test is taken.

OIL FIELD - A geographic area under which an oil reservoir lies.  

OIL GRAVITY - The most widely used indicator of a crude oil's worth to the producer is its API gravity. Normally, the price which a producer receives for his oil depends on its gravity, the less dense oils (higher API gravity) being the most valuable. This price schedule is based on the premise that the lighter oil contains higher percentages of the more valuable products such as gasoline. API Gravity (degrees) = (141.5/ - 131.5.

OIL IN PLACE - An estimated measure of the total amount of crude oil contained in a field or reservoir, and, as such, a higher figure than the estimated recoverable reserves of oil.  

OIL & GAS LEASES - A contract between an oil operator and a landowner which gives the operator the right to drill for oil and gas on his property for a consideration. It is simply a "ticket to hunt".

ON THE PUMP - An expression that means a well is incapable of flowing and that the oil is being pumped to the surface by a "pumping unit".

OPEN HOLE - An uncased well bore; the section of the well bore below the casing; a well in which there is no protective string of pipe.

OPEN-HOLE LOGGING - Logging operations in an uncased well bore. The well is logged below the relatively shallow surface pipe.

OPERATING EXPENSE - The expenses incurred through the operation of producing properties.

OPERATOR - The company that has legal authority to drill wells and undertake the production of hydrocarbons that are found. The Operator is often part of a consortium and acts on behalf of this consortium.

ORGANIZATION OF PETROLEUM EXPORTING COUNTRIES (OPEC) - Oil producing and exporting countries in the Middle East, Africa, and South America that have organized for the purpose of negotiating with oil companies on matters of oil production, prices, and future concession rights. OPEC was created in 1960.

OSI - Oil Well Shut In

OTD - Original Total Depth

OWF - Oil Well Flowing

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P & A - Plug and Abandoned

PACKER - An expanding plug used in a well to seal off certain secti0ons of the tubing or casing when cementing and acidizing or when a production formation is to be isolated. Packers are run on the tubing or the casing and when in position can be expanded mechanically or hydraulically against the pipe wall or the wall of the well bore.

PARAFFIN - A white, odorless, tasteless, chemically inert, waxy substance derived from distilling petroleum; a crystalline, flammable substance composed of saturated hydrocarbons.

PAYOUT - When the costs of drilling, producing and operating have been recouped from the sale of products on a well.

PAYZONE - Rock in which oil and gas are found in exploitable quantities.

PBTD - Plugged Back Total Depth

PCV - Pressure Control Valve

PD - Proposed Depth

PERF - Perforate (ed) (ing) (or)

PERF CSG - Perforated Casing

PERFORATING GUN - A special tool used downhole for shooting holes in the well’s casing opposite the producing formation. The gun, a steel tube of various lengths, has steel projectiles placed at intervals over its outer circumference, perpendicular to the gun’s long axis. When lowered into the well’s casing on a wireline opposite the formation to be produced, the gun is fired electrically, shooting numerous holes in the casing that permit the oil or gas to flow into the casing.

PERMEABILITY - The property of a formation which quantifies the flow of a fluid through the pore spaces and into the wellbore. Rocks may have holes or void spaces in them (porosity), but if these holes do not connect, the permeability can be drastically reduced.

PETROLEUM - A generic name for hydrocarbons, including crude oil, natural gas liquids, natural gas and their products.  

PG - Plug

PGW - Producing Gas Well

PINCHOUT - The disappearance or “wedging out” of a porous, permeable formation between two layers of impervious rock. The gradual, vertical “thinning” of a formation, over a horizontal or near-horizontal distance, until it disappears.

PIPELINE GAS - Gas under sufficient pressure to enter the high-pressure gas lines of a purchaser; gas sufficiently dry so that liquid hydrocarbons - natural gasoline, butane, and other gas liquids usually present in natural gas - will not condense or drop out in the transmission lines.

PJ - Pumpjack

PL - Pipeline

PLGD - Plugged

PLUG - To fill a well’s borehole with cement or other impervious material to prevent the flow of water, gas or oil from one strata to another when a well is abandoned; to screw a metal plug into a pipeline to shut off drainage or to divert the stream of oil to a connecting line to stop the flow of oil or gas.

PLUGGING A WELL - To fill up the borehole of an abandoned well with mud and cement to prevent the flow of water or oil from one strata to another or to the surface. In the industry’s early years, wells were often improperly plugged or left open. Modern practice requires that an abandoned well be properly and securely plugged.

POOH - Pulled Out of Hole

POROSITY - A measure of the relative volume of void space in rock to the total rock volume. These spaces or pores are where oil and gas accumulate; therefore, a formation containing a high percentage of porosity can contain more hydrocarbons.

POSSIBLE RESERVES - Those reserves which at present cannot be regarded as ‘probable’ but are estimated to have a significant but less than 50% chance of being technically and economically producible.

PPG - Pounds Per Gallon

PRIMARY RECOVERY - Recovery of oil or gas from a reservoir purely by using the natural pressure in the reservoir to force the oil or gas out.    

PROBABLE RESERVES - Those reserves which are not yet proven but which are estimated to have a better than 50% chance of being technically and economically producible.  

PROVEN FIELD - An oil and/or gas field whose physical extent and estimated reserves have been determined.

PROVEN RESERVES - Oil and gas which has not been produced but has been located and have better than a 90% chance of being recoverable.

PSI - Pounds per Square Inch

PUMP, CASING - A sucker-rod pump designed to pump oil up through the casing instead of the more common method of pumping through tubing. A casing pump is run into the well on the sucker rods; a packer on the top or bottom of the pump barrel provides packoff or seal between the pump and the wall of the casing at any desired depth. Oil is discharged from the pump into the casing and out the wellhead.

PUMP, ROD - A class of downhole pumps in which the barrel, plunger, and standing valve are assembled and lowered into the well through the tubing. When lowered to its pumping position, the pump is locked to the tubing to permit relative motion between plunger and barrel. The locking device is a holddown and consists either of cups or a mechanical, metal-to-metal seal.

PUMPING UNIT - A pump connected to a source of power; an oil-well pumping jack; a pipeline pump and engine.

PUMPER - An employee of an operator who is responsible for gauging the oil and gas sold off the leases he has been assigned and who is also responsible for maintaining and reporting the daily production.

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No definitions.

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R & T - Rods and Tubing

RC - Running Casing

RECOMPLETE - An operation involving any of the following: (1) Deepening from one zone to another zone; (2) Completing well in an additional zone; (3) Plugging back from one zone to another zone; (4) Sidetracking to purposely change the location of the bottom of the well, but not including sidetracking for the sole purpose of bypassing obstructions in the borehole; (5) Conversion of a service well to an oil or gas well in a different zone; (6) Conversion of an oil or gas well to a service well in a different zone.  

RECOVERABLE RESERVES - That proportion of the oil and/gas in a reservoir that can be removed using currently available techniques.  

RECOVERY FACTOR - That proportion of the oil and/gas in a reservoir that can be removed using currently available techniques.  

REENTER - To enter a previously abandoned well.

REEF RESERVOIR - A type of reservoir trap composed of rocks, usually limestone, made up of the skeletal remains of marine animals. Reef reservoirs are often characterized by high initial production that falls off rapidly, requiring pressure maintenance techniques to sustain production.

REL - Running Electric Log

RESERVOIR - A porous, permeable sedimentary rock formation containing accumulated quantities of oil and/or gas enclosed or surrounded by layers of less-permeable or impervious rock that prevents its escape; a structural trap; a stratigraphic trap.    

RFR - Ready for Rig

REWORK OPERATIONS - Any major operation performed on a well after its completion in an attempt to restore or improve its ability to produce.

RIH - Run in Hole

ROUGHNECK - Drill crewmembers that work on the derrick floor, screwing together the sections of drillpipe when running or pulling a drillstring.  

ROUSTABOUT - Drill crewmembers who handle the loading and unloading of equipment and assist in general operations around the rig.

ROTARY TONGS - The massive, counter-weighted tongs used on the drill floor to screw joints of drillpipe, tubing or casing; the generic term for the heavy wrenches used by the rough necks on the rig floor.

ROYALTY, LANDOWNER’S - A share of gross production of oil and gas, free of all costs of production. Occasionally, the term is used to describe an interest in production created by the landowner outside the lease and distinguished from the conventional lessor’s royalty. In this case the landowner’s royalty, outside of the lease, may have any specified duration. In general usage, landowner’s and lessor’s royalty are synonymous.

ROYALTY PAYMENT - The cash or kind paid to the owner of mineral rights.

RR - Rig Release

RR & T - Ran (running) Rods and Tubing

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S & F - Swab and Flow

SALT WATER DISPOSAL WELL - Many wells produce salt water while producing oil. The disposal of this water is a problem to an operator because of pollution. The best solution to the problem is to pump the waste back into a formation that is deep enough not to pollute shallow water sands. Many stripper wells which are no longer commercial are converted for this purpose.

SATURATION - (1) The extent to which the pore space in a formation contains hydrocarbons or connate water. (2) The extent to which gas is dissolved in the liquid hydrocarbons in a formation.

SCF - Standard Cubic Feet

SCFD - Standard Cubic Feet Per Day

SCFH - Standard Cubic Feet Per Hour

SCFM - Standard Cubic Feet Per Minute

SCOUT TICKETS - A written report of wells drilling in the area. The reports contain all pertinent information - all that can be found out by the enterprising oil scout; operator, location, lease, drilling contractor, depth of well, formations encountered, results of drillstem tests, logs, etc. On tight holes the scout is reduced to surreptitious means to get information. Talks to water hauler, to well-service people who may be talkative or landowner’s brother-in-law. The bird-dogging scout estimates the drillpipe set-backs for approximate depth; he notes the acid trucks or the shooting (perforating) crew; and through his binoculars, he judges the expressions on the operator’s face: happy or disgruntled.

SD & SH - Sand and Shale

Sd SG - Sand Showing Gas

Sd SO - Sand Showing Oil

SDFN - Shut Down for Night

SDP - Set Drill Pipe

SDPA - Shut Down to Plug and Abandon

SDPL - Shut Down For Pipeline

SDW - Shut Down for Weather

SDWTRFRACT - Sand-water Fracked

SECONDARY RECOVERY - A broad term encompassing any method of extracting oil from a reservoir after a well or field has exhausted its primary production.

SEDIMENTARY ROCKS - Rock is generally classified in one of three categories: a. Sedimentary; b. Igneous; c. Metamorphic.

SEPARATOR GAS - Natural gas separated out of the oil by a separator at the well.

SET CASING - To cement casing in the hole. The cement is pumped downhole to the bottom of the well and is forced up a certain distance into the annular space between casing and the rock wall of the drill hole. It is then allowed to harden, thus sealing off upper formations that may contain water. The small amount of cement in the casing is drilled out in preparation for perforating to permit the oil to enter the casing. The decision to set casing (or pipe) is an indication that the operator believes he has a commercial well.

SETTLED PRODUCTION - The second phase of production in the producing life of a well. (see IP).

SHALE - A very fine-grained sedimentary rock formed by the consolidation and compression of clay, silt, or mud. It has a finely laminated or layered structure. Shale breaks easily into thin parallel layers; a thinly laminated siltstone, mudstone, or claystone. Shale is soft, but sufficiently hard packed (indurated), so as not to disintegrate upon becoming wet. However, some shales absorb water and swell considerable, causing problems in well drilling. Most shales are compacted, and consequently, do not contain commercial quantities of oil and gas.

SHOT HOLE - A small-diameter hole, usually drilled with a portable, truck-mounted drill, for “planting” explosive charges in seismic operations.

SHUT IN - To close the valves at the wellhead so that the well stops flowing or producing; also describes a well on which the valves have been closed.

SHUT IN WELL - A well that is capable of producing but is not presently producing. Reasons for a well being shut in may be lack of equipment, market or other.  

SHUTDOWN - A production hiatus during which the platform ceases to produce while essential maintenance work is undertaken.    

SIBHP - Shut in Bottom-hole Pressure

SICP - Shut in Casing Pressure

SIDETRACK - A wellbore segment extending from a wellbore intersection along a wellbore path to a different wellbore bottomhole from any previously existing wellbore bottomholes.  

SIDETRACKING - The well activity of drilling a new wellbore segment from a wellbore intersection to a new wellbore bottomhole or target.    

SIGW - Shut in Gas Well

SIOW - Shut in Oil Well

SIWOP - Shut in, Waiting on Potential

SO - Show of Oil

SO & G - Show of Oil and Gas

SOH - Shot Open Hole

SOUR GAS - Natural gas containing chemical impurities, a notable hydrogen sulfide (H2S) or other sulfur compounds that make it extremely harmful to breathe even small amounts; a gas with disagreeable odor resembling that of rotten eggs.

SP - Surface Pressure

SPF - Shot Per Foot

SPUD-IN - The operation of drilling the first part of a new well.

SQUEEZING A WELL - A technique to seal off with cement a section of the well bore where a leak or incursion of water or gas occurs; forcing to the bottom of the casing and up the annular space between the casing and the wall of the borehole to seal off a formation or plug a leak in the casing; a squeeze job.

ST&C - Short Threads & Coupling

STRATIGRAPHIC TEST - A test well drilled to obtain information on the thickness, lithology, porosity, and permeability of the rock layers drilled through or to locate a key bed. Such wells are often drilled to evaluate a potentially productive pay zone.

STRIPPER WELL - The final state in the life of a producing well.

STRUCTURAL TRAP - A fold or break (or both) in the earth's crust which creates an impervious trap for oil and gas. Oil will migrate underground through rock until it is "trapped".

SUCKER ROD - Steel rods that are screwed together to form a “string” that connects the pump inside a well’s tubing downhole to the pumping jack on the surface; pumping rods.

SURFACE LOCATION - The location of a well or facility/measurement point.

SURFACE PIPE - Pipe which is set with cement through the shallow water sands to avoid polluting the water and keep the sand from caving in while drilling a well.

SW - Saltwater

SWAB - A tool which is lowered down the pipe on a wire line. The "swab" is then pulled out of the hole. As it travels up the pipe, rubber elements expand so that the fluid in the pipe is trapped above the swab and pushed to the surface. This operation is necessary when the formation pressure is not high enough to blow the fluids in the pipe to the surface.

SWBD - Swabbed, Swabbing

SWC - Sidewall Cores

SWDS - Saltwater Disposal System

SWDW - Saltwater Disposal Well

SWEET CRUDE - Crude oil containing very little sulfur and having a good odor.

SWEET GAS - Natural gas free of significant amounts of hydrogen sulfide (H2S) when produced.

SWI - Saltwater Injection

SWION - Shut Well In Overnight

SWS - Sidewall Samples

SWTS - Saltwater to Surface

SWU - Swabbing Unit

SX - Sacks

3-D SEISMIC PROGRAM - Seismic surveys shot from surfaces to map underground stratigraphy; to profile the underlying strata in search of up-dips, down dips, faults, and other promising anomalies.

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T & B - Top and Bottom

T & BC - Top and Bottom Chokes

T & R - Tubing and Rods

T/Pay - Top of Pay

T/SD - Top of Sand

TANK BATTERY - A group of tanks at a well site used to store oil prior to sale to a pipeline company.

TB - Tank Battery

TCF - Trillion Cubic Feet (of gas).  

TD - Total Depth

TEMPORARILY ABANDONED - 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.

TESTING - When each new well is competed, a series of tests are run on the well. The various tests are used to estimate the daily deliverability, payout, and reserves.

THF - Tubinghead Flang

THFP - Top Hole Flow Pressure

TIGHT HOLE - A drilling well about which all information - depth, formations encountered, drilling rate, logs - is kept secret by the operator.

TOC - Top of Cement

TOCP - Top of Cement Plug

TOOLPUSHER - Second-in-command of a drilling crew under the drilling superintendent. Responsible for the day-to-day running of the rig and for ensuring that all the necessary equipment is available.

TOTAL DEPTH (T.D.) - The depth of a well when drilling is completed. Total depth of a well is the vertical distance from the rig floor to the bottom of the hole. A 10,000-foot well may take 11,300 feet of casing to complete the well because the well bore has drifted several degrees from vertical, adding 1,300 feet to the depth of the hole, not the depth of the well.

TPSI - Tubing Pressure Shut in

TRAP - A type of geological structure that retards the free migration of oil and concentrates the oil in a limited space. A mass of porous, permeable rock that is sealed on top and down both flanks by nonporous, impermeable rock, thus forming a trap.

TSI - Temporarily Shut in

TUBING - Small diameter pipe which is installed in the casing. Oil is produced through tubing because it increases the viscosity of fluid and a well's flow capabilities.

TURNKEY CONTRACT - A contract in which an operator or drilling contractor agrees to furnish all labor and materials necessary to drill a well to a certain depth or stage of completion for a specified sum of money. The operator or contractor assumes all of the responsibility and risks involved in completing the operation.

TVD - Total Vertical Depth

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U/L - Upper and Lower

UC - Upper Casing

UNASSOCIATED GAS - Natural gas occurring alone, not in solution or as free gas with oil or condensate.

UT - Upper Tubing

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VISCOSITY - The resistance of fluid to flow. A high viscosity fluid will not flow as easily as a low viscosity fluid (Mud will not move as easily as water).

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WATER CONNING - The encroachment of water in a well bore in a water-drive reservoir owing to an excessive rate of production. The water below the oil moves upward to the well bore through channels, fissures, and permeable streaks, leaving the oil sidetracked and bypassed.

WATER FLOODING - A secondary recovery method for the production of oil from a formation. Oil will float on water. When water is injected into some formations, the oil will float or be washed to the surface, thereby, increasing the amount of production from a well or field. Some formations will not react to this type of stimulation.

WD - Water Disposal Well

WELLBORE - The borehole itself, including the open hole or uncased portion of the well. Wellbore may also refer to the inside diameter of the borehole wall, the rock face that bounds the drilled hole.

WELL COMPLETION - The work of preparing a newly drilled well for production. This is a costly procedure and includes setting and cementing the casing, perforating the casing, running production tubing, hanging the control valves (nippling up the production tree, i.e., Christmas tree), connecting the flow lines, and erecting the flow tanks or lease tanks.

WELL LOGGING - Gathering and recording information about the surface formation, the nature and extent of the various downhole rock layers. Also included are records kept by the driller, the record of cuttings, core analysis drillstem tests, and electric, acoustic, and radioactivity logs. Any pertinent information about a well, written and saved, is a log - from sailing ship days.

WELL LOG - A record of geological formation penetrated during drilling, including technical details of the operation.        

WHIPSTOCK - A tool used at the bottom of the borehole to change the direction of the drilling bit. The whipstock is, essentially, a wedge that crowds the bit to the side of the hole, causing it to drill at an angle to the vertical.

WHITE OIL - A colloquial term for condensate, gas condensate, casinghead gasoline; liquid hydrocarbons produced with natural gas.

WI - Water Injection

WI - Working Interest

WIH - Water in Hole

WILDCAT - A well that is drained one or more miles from a proven well.

WIW - Water Injection Well

WLM - Wire Line Measurement

WOC - Waiting on Cement

WOCR - Waiting on Completion Rig

WOCT - Waiting on Tools or Completion Tools

WODP - Waiting on Drillpipe

WOG - Water Oil or Gas

WOP - Waiting on Permit

WOP - Waiting on Pipe

WOPE - Waiting on Production Equipment