Utah Admin. Code R614-2-2 - Drilling Industry - Definition of Terms

A. General Terms.

1. "Act" means the Utah Occupational Safety and Health Act of 1973.

2. "Administration" means the Division of Occupational Safety and Health of the Labor Commission, also known as UOSH (Utah Occupational Safety and Health).

3. "Administrator" means the director of the Division of Utah Occupational Safety and Health.

4. "Commission" means the Labor Commission.

5. "Employee" includes any person suffered or permitted to work by an employer.

6. "Employer" means:

a. The state;

b. Each county, city, town, and school district in the state; and

c. Every person, firm, and private corporation, including public utilities, having one or more workers or operatives regularly employed in the same business, or in or about the same establishment, under any contract of hire.

B. Industry Terms.

1. "Accumulator" - On a drilling rig, the nitrogen and hydraulic oil for closing the blowout preventer in an emergency is kept in an accumulator.

2. "Acidizing" - The treatment of oil-bearing limestone or other formations by chemical reaction with acid in order to increase production. Hydrochloric or other type acid is injected into the formation under pressure, bringing about an enlargement of the pore spaces and passages through which the reservoir fluids flow. The acid is held under pressure for a period of time and then pumped out; the well is swabbed and put back into production. Chemical inhibitors are combined with the acid to prevent corrosion of the pipe.

3. "A-frame" - A form of derrick or crane used to handle heavy loads.

4. "Air Drilling" - Drilling using air or gas as the circulating medium.

5. "Anchor, Deadline" - Holding the deadline to the derrick or substructure.

6. "Annular Space" - The space surrounding pipe suspended in the wellbore. The outer wall of the annular space may be an open hole or it may be a string or larger pipe.

7. "Approved" - sanctioned, endorsed,accredited certified, or accepted by a duly constituted and recognized authority or agency.

8. "Authorized Person" - A person approved or assigned by the employer to a specific type of duty or duties or to be at a specific location or locations at the job-site.

9. "Back-up Line (Snub Line)" - A wire rope, one end of which is fastened to the end of a pipe tong handle and the other end secured to hold the tongs stationary while such tongs are in use.

10. "Back-up Post" - A post, column or stanchion secured to the derrick, derrick floor or derrick foundation, the purpose of which is to make secure the dead end of the back-up line.

11. "Back-up Tong" - The name applied to the drill pipe tong suspended in the derrick and used to hold a section of drill pipe while another section is unscrewed from it by use of another tong.

12. "Barricade" - An obstruction to deter the passage of persons or vehicles.

13. "Berm" - A pile or mound of material capable of restraining a vehicle.

14. "Bit" - The cutting element attached to the bottom of the drill stem. These are broken down into three general categories: roller bits, usually having three rolling cones with milled teeth or inserts; diamond bits using diamonds for cutting; and drag bits with fixed blades.

15. "Bleed" - To drain off liquid or gas, generally slowly, through a valve called a bleeder. To bleed down or bleed off, means a controlled release of the pressure of a well or of pressurized equipment.

16. "Block" - In mechanics, one or more pulleys or sheaves mounted to rotate on a common axis; any assembly of pulleys on a common frame work. The crown block is an assembly of sheaves mounted on beams at the top of the derrick. The drilling line, is reeved over the sheaves of the crown block alternately with the sheaves of the traveling block, which is hoisted and lowered in the derrick by means of the drilling line.

17. "Blowout" - A sudden, violent escape of gas and oil (and sometimes water) from a well.

18. "Blowout Preventer" - A device attached immediately above the casing to control pressures and prevent escape of fluids from the annular space between the drill pipe and casing or shut off the hole if no drill pipe is in the hole, should a kick or blowout occur.

19. "Board" -A platform installed in the derrick approximately 90 feet above the derrick floor. The derrickman works on this board while the pipe is being hoisted from or lowered into the wellbore.

20. "Boom" - a movable arm of wood or steel used on some types of cranes or derricks to support the hoisting lines that carry the load.

21. "Bowline" - A knot much used in lifting heavy equipment with the catline. Its advantage lies in the fact that it can be readily untied irrespective of the load that has been placed on it.

22. "Breaking down" - Usually means unscrewing the drill stem into single joints and placing them on the pipe rack. This operation takes place at the completion of the well when the drill pipe will no longer be used. It also takes place when changing from one size drill pipe to another during drilling operations. It is necessary to "break the pipe down" in order that it will be in lengths short enough to be handled and moved. Also called Laying Down.

23. "Breakout Line" - Either a wire rope or a manila or fiber rope used in conjunction with a pipe tong and a cathead which serves to impart a pulling power on the tong handle to start the unscrewing or breaking of a threaded pipe joint or tool joint when the pipe is in a vertical position in the well and projecting above the rotary table.

24. "Breakout" - Refers to the act of unscrewing one section of pipe from another section, especially in the case of drill pipe while it is being withdrawn from the wellbore. During this operation the Breakout Tongs are used to start the unscrewing operation.

25. "Casing" - Steel pipe placed in an oil or gas well as drilling progresses. The function of casing is to prevent the wall of the hole from caving during drilling and to provide a means of extracting the oil if the well is productive.

26. "Cat" - A crawler type tractor noted for its ability to move over difficult terrain. It is much used in clearing the location, earth-moving operations, and skidding rigs. The operator or driver is frequently referred to as a CAT DRIVER. This term is probably a shortening of the trade name Caterpillar, which is a brand of this type of equipment.

27. "Cathead" - Is a spool shaped steel mechanical device mounted on the end of a shaft of a drawworks, well pulling hoist or other machinery onto which a fiber rope such as a catline, breakout line, make-up line, spinning line, is wrapped to impart a pulling power to such rope or line.

28. "Cathead--automatic" - A steel mechanical device, generally in such shapes as a sheave, hoist, drum, pulley or wheel, and is mounted on the shafting of a drawworks, well pulling hoist or other machinery to which is attached a breakout line, make-up line, or a spinning line. The primary purpose of the automatic cathead is to impart a pulling power on the breakout line, make-up line, and/or spinning line. (See definitions for Breakout Line, Make-up Line and Spinning Line.)

29. "Catline" - a rope, usually a manila rope which is usually reeved over a single sheave in the mast or on a sheave suspended from the derrick gin pole. It serves a general utility purpose for making pulls, lifting or lowering objects up into or from the derrick, lifting and transferring materials about the derrick floor. One end of the line is attached to the object, other end is wrapped around the cathead to effect the source of power.

30. "Cellar" - Excavation under the derrick to provide space for items of equipment at the top of the wellbore. Also serves as a pit to collect drainage of water and other fluids under the floor for subsequent disposal by jetting.

31. "Cementing" - The operation by which cement slurry is forced down through the casing and out at the lower end in such a way that it fills the space between the casing and the sides of the wellbore to a predetermined height above the bottom of the well. This is for the purpose of securing the casing in place and excluding water and other fluids from the wellbore.

32. "Christmas Tree" - A term applied to the valves and fittings assembled at the top of a well to control the flow of the fluids.

33. "Circulating Fluid"--drilling Fluid, Mud - A fluid consisting of water, oil, or other liquid which may contain clay, weighting materials and/or chemicals which is circulated through the drill pipe and well bore during rotary drilling and workover operations.

34. "Closed-container" - A container so sealed by means of a lid or other device that neither liquid nor vapor will escape from it at ordinary temperatures.

35. "Collar" - Usually refers to a coupling device used to join two lengths of pipe.

36. "Combustion" - Any chemical process that invloves oxidation sufficient to produce light or heat.

37. "Combustible Liquids" - Any liquid having a flash point at or above 100 degrees F. (37.8 degrees C.)

38. "Competent Person" - One who is capable of identifying existing and predictable hazards in the surroundings of working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.

39. "Corrosion" - The complex chemical or electrochemical process by which metal is destroyed through reaction with its environment. The familiar coating of rust that appears on steel is a product of corrosion.

40. "Corrosive" - An agent which, in contact with animal tissue, by chemical reaction will cause more or less severe destruction and with which systematic effects are either of secondary nature or less pronounced than with poisons.

41. "Counter Weight" - A ladder climbing assist device.

42. "Crown Block" - Two or more metal beams of plates and other metal parts assembled into a framework within which are mounted one or more sheaves. The crown block is mounted on top of the derrick. The hoisting line is reeved on the crown block sheaves.

43. "Dead Line" - This refers to the end of the drilling line which is not reeled on the hoisting drum of the rotary rig. This end of the drilling line is usually anchored to the derrick substructure and does not move as the traveling block is hoisted, hence the term "dead line."

44. "Dead Man" - A buried anchor to which guy-wires are tied to steady the derrick, boiler stacks, etc.

45. "Density" - The weight of a substance per unit volume. For instance, the density of drilling mud may be described as "10.0 lbs. per gallon" or "74.9 lbs. per cubic foot."

46. "Derrick" - Any one of a large number of types of load-bearing structures. In drilling work, the standard derrick has four legs standing at the corners of the substructure and reaching to the crown blocks. The substructure is an assembly of heavy beams used to elevate the derrick above the ground and provide space to install blowout preventers, casing heads, etc. The standard derrick has largely been replaced by the mast for drilling. The mast is lowered and raised without disassembly. For land transport it may be divided into two or more sections to avoid excessive length on the highway.

47. "Derrick Foundation" - Is either concrete, wood, or other solid and substantial material placed on the ground upon which the derrick is built and/or supported, and includes all the substructure which supports the derrick legs and derrick floor.

48. "Derrick Gin Pole" - An assembly of two or more vertical or upright members supporting one or more cross members, erected on the top of a derrick above the opening in the top thereof. It serves as a support for a block and tackle, primarily for raising or lowering the crown block to or from the top of the derrick.

49. "Derrick Ladder" - A fixed ladder attached to a derrick as a means of access to the top and/or any inside platform on the derrick.

50. "Derrick Walk" (Cat Walk) - This is a walkway extending from the V Door Ramp beyond the outer end of the drill pipe and casing storage rack at a well, the purpose of which is to facilitate the handling of the pipe between the rack and the derrick.

51. "Derrickman" - The crew member whose work station is in the derrick while the drill stem is being hoisted from or being lowered into the hold. He attaches the elevators to the drill stem members as they are being lowered into hold and detaches the elevators and racks the drill stem in the finger board after it is unscrewed and set on the floor. Other responsibilities frequently include the conditioning of the drilling fluid and maintenance of the mud and slush pumps.

52. "Diesel Electric Power" - The power supplied to a drilling rig by diesel engines driving electric generators. This type of power is widely used on drilling barges and offshore platforms.

53. "Drawworks" - Includes an assembly of shafts, sprockets, chains, pulleys, belts, clutches, catheads, and/or other mechanical devices, suitably mounted and provided with controls, for hoisting, operating, and handling the equipment used for drilling a well or servicing a producing well. Drawworks may be either stationary or portable.

54. "Elevator" - A steel mechanical device used in connection with the hoisting equipment, suspended from the traveling block or traveling block hook, for holding in suspension pipe or sucker rods being lowered into or pulled from a well. There being so many types of elevators only the most common type is herein described as follows: one side of the elevator body is a gate or door which, when closed, forms a conjunction with the remaining part of the elevator body a circular opening that fits snugly around the pipe or rod just below the threaded joint, sleeve, or coupling thereof. The threaded joint, sleeve, or coupling being larger than the circular opening in the elevator body, the pipe or rods are held in suspension from the elevator.

55. "Fast Line" - The end of the drilling line which is affixed to the drum or reel. It is so called because it apparently travels with greater velocity than any other portion of the drilling line.

56. "Feed-off" - The act of unwinding a cable from a drum. Also a device on a drilling rig that keeps the weight on the bit constant, and lowers the drilling line automatically. Known as the "automatic driller."

57. "Finger Board" - A rack with fingers located in the derrick to contain the top of the stands of pipe while they are racked in the derrick.

58. "Finger Brace" - Any structural member either in direct or indirect contact with the finger to resist either horizontal, vertical, or diagonal movement of the finger.

59. "Fireman" - The member of the crew on a steam-powered rig who is responsible for the care and operation of the boilers. On a mechanical rig his counterpart is the motorman.

60. "Fish" - An object accidentally lost in the hole.

61. "Fishing" - Operations on the rig for the purpose of retrieving from the wellbore sections of pipe, casing or other items which may have become stuck or inadvertently dropped in the hole.

62. "Flammable" -Capable of being easily ignited,burning intensely, or having a rapid rate of flame spread.

63. "Flammable Liquid" - Any liquid having a flash point below 100 degrees F. and having a vapor pressure not exceeding 40 pounds per square inch (absolute) at 100 degrees F.

64. "Flare" - An open flame used to dispose of unwanted gas.

65. "Flash Point" (of the liquid) - The temperature at which it gives off vapor sufficient to form an ignitable mixture with the air near the surface of the liquid or within the vessel used as determined by appropriate test procedure and apparatus as specified below.

a. The flash point of liquids having a viscosity less than 45 Saybolt Universal Second(s) at 100 degrees F. (37.8) degrees C.) and a flash point below 175 degrees F. (79.4 degrees C.) shall be determined in accordance with the standard Method of test for Flash Point by the Tag Closed Tester, American Standard Testing Method ASTM D-56- 69.

b. The flash point of liquids having a viscosity of 45 Saybolt Universal Second(s) or more at 175 degrees C.) or higher shall be determined in accordance with the Standard Method of Test for Flash Point by the Pensky Martens Closed Tester,(ASTM) D-93-69.

66. "Floor Hole" - An opening measuring less than 12 inches but more than 1 inch in its least dimension in any floor, roof, or platform through which materials but not persons may fall, such as a belt hold, pipe opening, or slot opening.

67. "Floor Opening" - An opening measuring 12 inches or more in its least dimension in any floor, roof, or platform through which persons may fall.

68. "Floorman" - A member of the drilling crew whose work station is usually on the derrick floor.

69. "Fracturing"(Formation) -A method of stimulating production by increasing the permeability of the producing formation. Under extremely high hydraulic pressure, a fluid such as distillate, diesel fuel, crude oil, dilute hydrochloric acid, water, or kerosene is piped downward through production tubing or drill pipe and forced out below a packer between two packers. The pressure causes cracks to open in the formation, and the fluid penetrates the formation through the cracks. Sand grains, aluminum pellets, walnut shells, or similar materials are carried in suspension by the fluid into the cracks. These are called propping agents. When the pressure is released at the surface, the fracturing fluid returns to the well. The cracks partially close on the pellets, leaving channels for oil to flow around them to the well. Sometimes shortened to "Frac."

70. "Gas Cut Mud" - Mud with entrained formation gas which gives the mud a characteristic fluffy texture.

71. "Gas" or "Gases" - The vapor state of the hydrocarbons occurring in, or derived from, petroleum or natural gas.

72. "Gel" -A gelatinous substance formed by certain colloidal dispersions at rest. Gel Strength is a measure of the ability of a colloidal dispersion to form such a gel, and is based upon its resistance to shear. The gel strength of a drilling mud determines its ability to hold solids in suspension, and for this reason bentonite and other colloidal clays are added to drilling fluids. It is important that the gel formed by the mud, when drilling is not in progress, be thixotropic--that is, it should be readily converted to a fluid state by agitation and then gel again when at rest in order to prevent the cuttings from settling to the bottom of the hole.

73. "Geronimo Escape Line" - A wire line attached near the board which has a man-riding trolley to convey personnel to the ground by use of a friction control speed device.

74. "Handrail" - A bar or pipe supported on brackets from a wall or partition, as on a stairway or ramp, to furnish persons with a handhold in case of tripping.

75. "Hazardous Substance" - A substance which, by reason of being explosive, flammable, poisonous, corrosive, oxidizing, causing irritation, or otherwise harmful, is likely to cause death or injury.

76. "Kelly" - The heavy square or hexagonal steel pipe which goes through the rotary table and in conjunction with the drive bushing turns the drill string.

77. "Kelly Cock" - A valve installed between the swivel and the kelly. When a high pressure backflow begins, the operator can close this valve and keep the pressure off the swivel and rotary hose.

78. "Liquefied Petroleum Gases" - "LPG: and LP-Gas" mean and include any material which is composed predominantly of any of the following hydrocarbons or mixtures of them, such as propane, propylene, butane, (normal butane or iso-butane), and butylenes.

79. "Log" - A running account listing a series of events in chronological order. The driller's log is a tour-to-tour account of progress made in drilling. An electric well log is the record of geological formations which is made by a well logging device. This device operates on the principle of differential resistance of various formations to the transmission of electric current.

80. "Logging" - A generic term used when instruments are run in the hole for any of several purposes during drilling or completion operations.

81. "Lubricator" - An extension of casing or tubing above a valve on top of the casing or tubing head. Lubricators are supplied with a pack-off, or pressure sealing, device at the upper end to afford a seal on the wireline, or other connection, attached to tools run into a well.

82. "Making a Trip" - Consists of hoisting the drill pipe to the surface and returning it to the bottom of the wellbore. This is done for the purpose of changing bits, preparing to take a core, and for other reasons.

83. "Motorman" - The man on a mechanical rotary drilling rig responsible for the care and operation of the drilling engines.

84. "Mouse Hole" - A shallow cased hole close to the rotary table through the derrick floor in which a joint of drill string can be placed to facilitate connecting the joint to the kelly.

85. "Mud" - The liquid that is circulated through the wellbore during rotary drilling and workover operations. In addition to its function of bringing cutting to the surface, drilling mud also cools and lubricates the bit and drill string, protects against blowouts by containing subsurface pressures, and deposits a mud cake on the wall of the borehole to prevent loss of fluids to the formations. Although it originally was a suspension of earth solids, especially clays, in water, the mud used in modern drilling operations is a somewhat more complex three-phase mixture of liquids, reactive solids, and inert solids. The liquid phase may be fresh water, diesel oil, or crude oil, and may contain one or more conditioners.

86. "Mud Balance" - An instrument consisting of a cup and graduated arm with a sliding weight and resting on a fulcrum, used to measure weight of the mud.

87. "Mud Gun" - A pipe that shoots a jet of drilling mud under high pressure into the mud pit to mix the additives and stir the mud for other reasons.

88. "Mud Log" - To record information derived from examination and analysis of return circulation mud and drillbit cuttings.

89. "Mud off" - In drilling, to seal the hole off from the formation water or oil by using mud. Applies especially to the undesirable blocking off of the flow of oil from the formation into the wellbore. Special care is given to the treatment of drilling fluid to avoid this.

90. "Mud Pit" - The reservoir or tank through which the drilling mud is cycled to allow sand and fine sediments to settle out, where additives are mixed with mud,and where the fluid is temporarily stored before being pumped back into the well. Mud pits may be further classified as the shaker pit, settling pit, and suction pit, according to their main purpose.

91. "Mud (Slush) Pump" - A large single (triplex) or double (duplex) acting pump used to circulate mud down the drill pipe and up the annulus, under normal operations. It is a piston type pump whose pistons reciprocate in replaceable liners.

92. "Outside Derrick Platform" - A walkway extending across one or more outer sides of a derrick at an elevation of 10 feet or more above the derrick floor.

93. "Pipe Rack" - A series of parallel heavy wooden or steel bents, secured in place by bracing, on which pipe is stored. Flooring may be laid upon the bents.

94. "Platform" - A working space for persons, elevated above the surrounding floor or ground, such as a balcony or platform for the operation of machinery and equipment.

95. "Pressure Relief Device" - A device for relieving pressure, such as a direct spring-loaded safety valve, rupture disc, or piston shear pin valve.

96. "Prime Mover" - As applied to oil well drilling, this is the steam or diesel engine, electric motor, or other internal-combustion engine which is the source of power for the drilling rig.

97. "Qualified" - Means one who, by possession of a recognized degree, certificate, or professional standing, or who by knowledge, training and/or experience, has successfully demonstrated his ability to solve or resolve problems relating to the subject matter, the work, or the project.

98. "Ram" - On a blowout preventer, the closing and sealing component.

99. "Respiratory Equipment" - Is approved self-contained oxygen breathing apparatus, canister-type gas masks, air hose masks, and other approved equipment providing equivalent protection.

100. "Rig" - All mechanical equipment directly connected with the drilling of a well or for producing petroleum from a well.

101. "Rigging down" - The act of dismantling the drilling rig and auxiliary equipment following the completion of drilling operations. Also referred to as tearing down.

102. "Rigging up" - The act of assembling the drilling rig and auxiliary equipment prior to commencement of drilling operations.

103. "Rotary Drilling" - The drilling method by which a hole is drilled by a rotating bit to which a downward force (drill collars) is applied. The bit is fastened to and rotated by the drill stem, which also provides a passage for the circulating fluid.

104. "Rotary Hose" - The hose that conducts the circulating fluid from the standpipe to the swivel and kelly.

105. "Roustabout" - A laborer who assists the foreman in the general work about producing oil wells and around the property of the oil company. Also used on large offshore drilling rigs to help maintain the rig and load and unload material.

106. "Runway" - A passage for a person, elevated above the surrounding floor or ground level, such as a footwalk along shafting or a walkway between buildings.

107. "Safety Can" - Means an approved closed container, of not more than 5 gallons capacity, having a spring-closing lid and spout cover and so designed that it will safely relieve internal pressure when subjected to fire and exposure.

108. "Shale Shaker" - A vibrating screen that removes coarser cuttings from the circulating fluid before it flows into the return mud pit, disilters or desanders.

109. "Shall" - Means mandatory.

110. "Shutdown" - A term denoting that work has been temporarily stopped as on an oil well.

111. "Slurry" - Any mixture of solids and water or cement slurry which is pumped into the well to cement casing or plug back.

112. "Source of Ignition" - Any flame, arc, spark, or heat which is capable of igniting flammable liquids, sour gas, or oil, gases, or vapors.

113. "Spudding" - Refers to the act of hoisting the drill stem and permitting it to fall freely so that the drill bit strikes the bottom of the wellbore or bridge with considerable force. This is done to clean the bit of an accumulation of sticky shale which has slowed the rate of penetration and/or remove bridges or other obstructions. Careless execution of this operation can result in kinks in the drill string as well as damaged bit cones and bearings.

114. "Spudding in" - The very beginning of drilling operations of a well. The term has been handed down from cable tool operations in the early days of the oil industry.

115. "Stabbing Board" - A temporary platform in the derrick, 20 to 40 feet above the floor, on which a crewman works while casing is being run to guide a joint while it is being screwed into the joint in the rotary table.

116. "Stair Railing" - A vertical barrier erected along exposed sides of a stairway to prevent falls of persons.

117. "Stairs" or "Stairways" - A series of steps leading from one level or floor to another, or leading to platforms, pits, boiler rooms, crossovers, or around machinery, tanks, and other equipment that are used more or less continuously or routinely by employees or only occasionally by specific individuals. A series of steps and landings having three or more rises constitutes stairs or stairway.

118. "Standard Railing" - A vertical barrier erected along exposed edges of a floor opening, wall opening, ramp, platform, or runway to prevent falls of persons.

119. "Standpipe" - Part of the circulating system. A pipe extending, usually along a derrick leg, to a height suitable for attaching the rotary hose.

120. "Substructure" - The foundation on which, normally, the derrick and engines sit. Height varies depending upon the equipment required, such as the blowout preventers, for the particular operation.

121. "Swabbing" - Operation of a lifting device on a wireline to bring well fluids to the surface when the well does not flow naturally. This is a temporary operation to determine whether or not the well can be made to flow or require artificial lift or stimulation to bring oil to the surface.

122. "Thribble" - A stand of drill pipe made up of three joints, each about 30 feet in length.

123. "Toeboard" - A vertical barrier at floor level erected along exposed edges of a floor opening, wall opening, platform, runway, or ramp to prevent falls of materials.

124. "Toolpusher" - The rig owner's supervisor who is in charge of one or more rigs. Usually the drilling contractor's highest level of direct field supervision.

125. "Tour" - The word which designates the shift of a drilling crew or other oil field workers.

126. "Traveling Block" - Two or more steel plates and other metal parts assembled into a framework within which are mounted one or more sheaves on which the hoisting line is reeved in connection with the sheaves on the crown block.

127. "Traveling Block Hook" - A hook suspended from the traveling block to which the elevator links, swivel bail, or other equipment is attached.

128. "V-door Ramp" - A ramp on the side of the drilling rig where pipe is laid to be lifted to the derrick floor by the catline.

129. "V-door (Window)" - An opening in a side of a standard derrick at the floor level having the form of an inverted V. This opening is opposite the drawworks. It is used as an entry to bring in drill pipe and casing from the pipe rack.

130. "Vapor Proof" - A term used to describe a product which is not susceptible to the action of gases or other vapors.

131. "Viscosity" - A measure of liquid's resistance to flow. The viscosity of petroleum products or mud is usually expressed, and measured by the time it takes for a certain volume to flow through an orifice of specific size.

132. "Wall Opening" - An opening at least 30 inches wide, in any wall or partition, through which persons may fall, such as a yard-arm doorway or chute opening.

133. "Weight Indicator" - Instrument on a drilling or workover rig, which shows the weight suspended from hook.

134. "Weighting Material" - A material used to increase the density of drilling fluids or cement slurries.

135. "Wellbore" - The hole made by the drilling bit.

136. "Wildcat" - A well in unproved territory. With present day exploration methods and equipment about one wildcat of every 10 drilled proves to be commercially productive.

137. "Wildcatter" - One who drills wells in the hope of finding oil in territory not known to be an oil field.

138. "Wind Load Rating" - A specification of a derrick used to indicate the resistance of the derrick to the force of wind.

139. "Work-over" - To perform one or more of a variety of remedial operations on a producing oil well with the hope of restoring or increasing production. Examples of work-over operations are deepening, plugging back, pulling and resetting the line, squeeze cementing, shooting and acidizing.

140. "Well Servicing" or "Special Services" - Consists of, but not limited to the operations listed in the 1972 Standard Industrial Classifications Manual under "1382 Oil and Gas Field Services" and "1389 Oil and Gas Field Services, Not Elsewhere classified."

Notes

Utah Admin. Code R614-2-2