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| Is the point in time when the drilling of the hole begins. |
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| The first commercial oil well |
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| was drilled in the United States in 1857 near Titusville, Pennsylvania by Edwin L. Drake. |
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Drilling has been accomplished by two primary methods:
Before World War II |
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| cable tool drilling was the primary method. |
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Drilling has been accomplished by two primary methods:
After World War II, |
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| the advent of the tri-cone bit, rotary drilling became much more popular and is the predominant method used today. |
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| are typically leased by oil and gas companies (the operator) from drilling companies and are subject to terms specified in a drilling contract. |
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| There are four primary types of drilling contracts: |
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Footage,
Daywork,
Turnkey and
Combination. |
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| The operator agrees to pay the drilling company based on a dollars per foot price. This type of contract favors the operator. The drilling contactor makes money only when the hole gets deeper, any downtime is “on’ the drilling contractor. |
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| is probably most commonly used today, the drilling contractor is paid so many dollars per day for each day the rig is on location, regardless of whether it’s drilling or not. This contract tends to favor the drilling contractor. |
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| This contract requires the operator to pay the drilling contractor a pre-determined amount when the well is finished. If a drilling contractor can execute a trouble-free operation, a meaningful profit is obtainable. If the drilling contractor encounters a bunch of trouble in drilling the hole, they may actually lose money on the operation. |
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| This contract combines terms from two or more of the above contract types. For example a combination contract may provide for a turnkey rate to a certain depth, and a daywork rate thereafter. |
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| The Rotary Drilling System |
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| A typical land drilling rotary drilling system is a collection of equipment that is designed to be moved easily from location to location. The modern rotary drilling rig can be subdivided into four main systems: hoisting, rotating, circulating, and power. |
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Definition
| Primary purpose is to hoist drill pipe and bit in and out of the hole and to pull up on the drilling pipe while drilling to keep the drill string in tension. |
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| Hoisting System – The primary components |
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Definition
| include the drawworks, drilling line, crown block, traveling block and mast or derrick. The traveling block is equipped with a drilling hook to pick up necessary equipment. |
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| A large spool where the drilling line is wrapped. It can move in either direction, either releasing line which lowers the traveling block, or retrieving line, which raises the traveling block. |
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| A woven wire rope, typically ranges in diameter between 7/8” to 2”. It’s wound around the drawworks and is threaded through the traveling block and crown block, and then is fastened to the base of the rig. It’s used to raise or lower the traveling block. |
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| The portion of the drilling line between the drawworks and the crown block is called the ________ because it moves faster than any other part of the drilling line. |
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| The portion of the drilling line between the crown block and the point where it is fastened to the rig is called the ________ because it doesn’t move. |
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| A derrick is a more or less permanent structure, its legs sit on the rig floor and it must be dissembled to move. A mast is designed to either fold or telescope, which makes it much more portable. Most land rigs use masts, and most offshore rigs use derricks. |
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| A set of fixed pulleys located at the top (crown) of the mast or derrick. |
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| A set of pulleys that move up and down inside the mast or derrick. It is equipped with a hook (drilling hook) which is used to pick up equipment (like the kelly or top drive) and to pick up drill pipe to add to the drill string. |
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Definition
| Primary components include the swivel, kelly, rotary table, drill pipe, drill collars, and bit. |
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| This device hangs from the drilling hook on the traveling blocks and allows everything below it to rotate. |
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| It is a piece of pipe typically 40-60 feet long attached below the swivel. It is either a square or hexagonal shaped piece of pipe, typically 40-60 feet long. It fits inside _______ bushing, which in turn fits into part of the rotary table called the master bushing. When the rotary table turns, the master bushing and the ______ bushing also turn, and causes it to rotate. The shape of it insures that it does not “slip” inside the _____ bushing. |
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Definition
| are fit around the drill string and sit in the master bushing to hold the pipe while additional joints are added or removed. |
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Definition
| With its master bushing and kelly bushing, this device supplies the necessary torque to turn the drill string. |
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| The alternative way to rotate drill pipe, this drive is suspended below the traveling blocks, and is equipped with a motor to turn the drill string. Its able to deliver more torque to the drill string than the rotary table, and are preferred when drilling long horizontal holes. On a ______ rig, there is no kelly, kelly bushing or master bushing. The rotary table’s only purpose is to hold the slips. |
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| consists of drill pipe and drill collars. The primary difference is drill collars are much thicker walled pipe, and are placed just above the bit to place weight on the bit. Drilling fluid is circulated down the interior of the drilling string to the bit, and is circulated out of the hole in the annular space (space between the outside of the drill string and the diameter of the hole). |
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| When drilling first commences, |
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Definition
| the drill collars and drill pipe are picked up and connected one piece (joint) at a time. |
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| When a drilling bit wears out, |
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Definition
| the string must be removed (tripped) from the hole to replace the bit. |
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| During the tripping process, |
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Definition
| the drilling string is stored in the mast or derrick. |
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| Since masts and derricks are different heights, |
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Definition
| the drill string may be stored in single joints, double joints or triple joints. |
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Definition
| Each length of pipe that is stored in the mast or derrick is called _________, and will be 30’, 60’, or 90’ in length depending if you’re pulling singles, doubles or triples. |
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Definition
| Rigs capable pulling 3 joints of drill pipe at time are referred to as |
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| is drilled adjacent to the drilling hole and holds the next joint of drill pipe to be added to the string. |
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| A second and larger hole is drilled to hold the kelly when it’s not in use. |
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Definition
| The predominant bit is the tri-cone, which consists of three cones that rotate as the bit is turned. |
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| The most common type of bit now in use is the polycrystalline diamond compact (PDC) cutters |
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| -Primary purpose is to circulate fluids down hole to keep the drill bit cool and remove cuttings from the hole. |
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| Circulating System-The main components |
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| include the mud pit or tank, shale shaker, desander, desilter, degasser, mud pumps, and various hoses and pipes to connect the equipment together. |
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Definition
| primary purpose is to generate power for the rig. Modern rigs use diesel engines to drive electrical generators, which in turn, power motors on the rig to run the mud pumps, rotary table (or top drive), and drawworks. |
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| The primary drilling fluid |
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Definition
| is drilling mud, a mixture of finely ground bentonite clay and water. |
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| If a higher mud density is required, |
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| the mixture is “weighted up” with the addition of barite. |
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| If the rock strata are free of water, |
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| it is possible to use air for a drilling fluid rather than mud. This requires the addition of an air compressor to the equipment on location. |
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| cannot be used to drill through high pressure zones, because there is no liquid in the hole to keep down a kick. |
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Definition
| is an uncontrolled flow of fluids from the formation into the wellbore. |
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| can lead to a blowout, which is the uncontrolled release of formation fluids at the surface. If ignited, a blowout can easily burn down a rig. |
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| Drilling mud serves three primary purposes: |
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Definition
| keep the bit cooled, remove cuttings from the hole, and maintain a hydrostatic pressure greater than formation pressure to prevent kicks. |
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| Drilling with air meets only two purposes: |
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Definition
| keep the bit cooled and remove cuttings from the hole. |
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| The onshore drilling rig is supervised by |
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| includes a driller, derrickhand, and two or three “rough necks or floormen”. When the rig is not tripping pipe, the derrickhand is responsible for monitoring the condition of the mud. |
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| roustabouts are also employed to load and unload equipment and supplies. |
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| In inland waters and near-shore locations of shallow water depth, drilling rigs are often located on a barge. When the barge is towed to location, the hull is flooded and the barge sinks to the bottom. This drilling is limited to shallow water, typically not more than 15 feet deep. |
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| is a large barge equipped with legs which can be raised for towing, and then lowered when the rig reaches the location. The legs rest of the sea floor, the barge is “jacked up” so that the barge is above the ocean surface enough to avoid wave action. These can be used in water depths up to 400 feet. |
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| are platforms that can be moved from place to place. The lower portion of the platform consists of columns and pontoons which can be flooded to add stability to the platform while drilling. When the drilling is completed, the flooded tanks are emptied, and the platform can be towed to other locations. Modern semi-submersibles are held over the drilling hole by dynamic positioning, which utilizes multiple thrusters in combination with global positioning (GPS). Semis are typically utilized in water depths between 200 and 10,000 feet. |
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| is a purpose-build ocean ship that is equipped with a drilling rig, and most often is used for exploration drilling where one or two wells are required to evaluate and assess the size of an offshore reservoir. Modern drill ships also use dynamic positioning to keep the drilling rig positioned above the hole. Drill ships have been used in water depths up to 12,000 feet. |
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