I walk by the “Electric Drilling Technologies” company. When I look up its website, I discover that it serves the oil and gas industry by providing utility electric power to drilling sites. Apparently, electricity is only one of many ways to power a drilling rig. The oil and gas industry is 35% of the state economy of Texas and 5% of the state economy of Oklahoma. So, growing up in Oklahoma and living in Texas, I have been around people associated with the oil & gas business. For 30 years I lived 10 miles from Kilgore, Texas, where the East Texas oil field — the largest in the contiguous United States — was discovered in 1930. My niece and her husband both work for oil companies in Oklahoma City. I have been worried about their livelihoods since the pandemic started, and people are driving and flying less. However, according to the American Petroleum Institute, America’s oil and natural gas industry supports 10.3 million jobs in the United States and nearly 8% of the nation’s gross domestic product. So, I don’t think it’s going away anytime soon. Although I have known people in the oil business, I have never seen a drilling rig up close. Let’s find out more about them.
According to Wikipedia, a drilling rig is an integrated system that drills wells — such as oil or water wells — in Earth's subsurface. Drilling rigs can be massive structures housing equipment used to drill water wells, oil wells or natural gas extraction wells, or they can be small enough to be moved manually by one person and such are called augers. Drilling rigs can sample subsurface mineral deposits, test rock, soil and groundwater physical properties, and also can be used to install subsurface fabrications such as underground utilities, instrumentation, tunnels or wells. Drilling rigs can be mobile equipment mounted on trucks, tracks or trailers, or more permanent land or marine-based structures such as oil platforms, commonly called “offshore oil rigs” even if they don't contain a drilling rig. The term "rig" therefore generally refers to the complex equipment that is used to penetrate the surface of the Earth's crust.
Small to medium-sized drilling rigs are mobile, such as those used in mineral exploration drilling, blast-hole, water wells and environmental investigations. Larger rigs are capable of drilling through thousands of meters of the Earth's crust, using large "mud pumps" to circulate drilling mud or slurry through the drill bit and up the casing annulus, for cooling and removing the "cuttings" while a well is drilled. Hoists in the rig can lift hundreds of tons of pipe. Other equipment can force acid or sand into reservoirs to facilitate extraction of the oil or natural gas; and in remote locations there can be permanent living accommodations and catering for crews which may be more than a hundred. Marine rigs may operate thousands of miles distant from the supply base with infrequent crew rotation or cycle.
History
Until internal combustion engines were developed in the late 19th century, the main method for drilling rock was muscle power of man or animal. The technique of oil drilling through percussion or rotary drilling has its origins dating back to the ancient Chinese Han Dynasty in 100 BC, where percussion drilling was used to extract natural gas in the Sichuan province. Early oil and gas drilling methods were seemingly primitive, as it required several technical skills. The skills involved the availability of heavy iron bits and long bamboo poles, the manufacturing of long and sturdy cables woven from bamboo fiber and levers. Heavy iron bits were attached to long bamboo cables suspended from bamboo derricks and then were repeatedly raised and dropped into a manually dug hole by having two to six men jumping on a lever. Han Dynasty oil wells made by percussion drilling was effective, but only reached 10 meters deep and 100 meters by the 10th century. By the 16th century, the Chinese were exploring and drilling oil wells more than 2,000 feet deep. A modernized variant of the ancient Chinese drilling technique was used by American businessman Edwin Drake to drill Pennsylvania's first oil well in 1859 using small steam engines to power the drilling process rather than by human muscle.
In the 1970s, outside of the oil and gas industry, roller bits using mud circulation were replaced by the first pneumatic reciprocating piston reverse circulation or RC drills, and became essentially obsolete for most shallow drilling. They are now only used in certain situations where rocks preclude other methods. RC drilling proved much faster and more efficient, and continues to improve with better metallurgy, deriving harder, more durable bits and compressors delivering higher air pressures at higher volumes, enabling deeper and faster penetration. Diamond drilling has remained essentially unchanged since its inception.
Petroleum drilling industry
Oil and natural gas drilling rigs are used not only to identify geologic reservoirs, but also to create holes that allow the extraction of oil or natural gas from those reservoirs. Primarily in onshore oil and gas fields, once a well has been drilled, the drilling rig will be moved off of the well and a service rig — a smaller rig — that is purpose-built for completions will be moved on to the well to get the well on line. This frees up the drilling rig to drill another hole and streamlines the operation as well as allowing for specialization of certain services, i.e. completions vs. drilling.
Mining drilling industry
Mining drilling rigs are used for two main purposes — exploration drilling which aims to identify the location and quality of a mineral and production drilling which is used in the production-cycle for mining. Drilling rigs used for rock blasting for surface mines vary in size, depending on the size of the hole desired, and is typically classified into smaller pre-split and larger production holes. Underground mining or hard rock uses a variety of drill rigs dependent on the desired purpose, such as production, bolting, cabling and tunneling.
Mobile drilling rigs
In early oil exploration, drilling rigs were semipermanent in nature, and the derricks were often built onsite and left in place after the completion of the well. In more recent times, drilling rigs are expensive custom-built machines that can be moved from well to well. Some light-duty drilling rigs are like a mobile crane and are more usually used to drill water wells. Larger land rigs must be broken apart into sections and loaded to move to a new place, a process which can often take weeks.
Small mobile drilling rigs are also used to drill or bore piles. Rigs can range from 100 short tons continuous flight auger or CFA rigs to small, air-powered rigs used to drill holes in quarries, etc. These rigs use the same technology and equipment as the oil drilling rigs, just on a smaller scale.
Drilling rig classification by power used
Mechanical
The rig uses torque converters, clutches and transmissions powered by its own engines, often diesel.
Electric
The major items of machinery are driven by electric motors, usually with power generated onsite using internal combustion engines.
Hydraulic
The rig primarily uses hydraulic power.
Pneumatic
The rig is primarily powered by pressurized air.
Steam
The rig uses steam-powered engines and pumps — obsolete after middle of 20th century.
Rig equipment
Petroleum onshore drilling rigs typically include at least some of the following items:
1. Mud tank – often called mud pits, provides a reserve store of drilling fluid until it is required down the wellbore.
2. Shale shakers – separates drill cuttings from the drilling fluid before it is pumped back down the borehole.
3. Suction line (mud pump).
4. Mud pump – reciprocal type of pump used to circulate drilling fluid through the system.
5. Motor or power source.
6. Hose.
7. Drawworks – mechanical section that contains the spool, whose main function is to reel in/out the drill line to raise/lower the traveling block.
8. Standpipe – a solid metal pipe attached to the side of a drilling rig’s derrick that is a part of its drilling mud system.
9. Kelly hose – a flexible, steel reinforced, high pressure hose that connects the standpipe to the kelly — or more specifically to the goose-neck on the swivel above the kelly — and allows free vertical movement of the kelly while facilitating the flow of drilling fluid through the system and down the drill string. The kelly hose has an inside diameter of 3-5 inches.
10. Gooseneck.
11. Traveling block – the freely moving section of a block and tackle that contains a set of pulleys or sheaves through which the drill line or wire rope is threaded or reeved and is opposite and under the crown block, the stationary section.
12. Drill line – a multi-thread, twisted wire rope that is threaded or reeved through in typically 6 to 12 parts between the traveling block and crown block to facilitate the lowering and lifting of the drill string into and out of the wellbore.
13. Crown block – stationary section of a block and tackle that contains a set of pulleys or sheaves through which the drill line is threaded or reeved and is opposite and above the traveling block.
14. Derrick – a lifting device composed at minimum of one guyed mast, as in a gin pole, which may be articulated over a load by adjusting its guys.
15. Racking board, sometimes referred to as the monkey board.
16. Stand (of drill pipe) – joints of hollow tubing used to connect the surface equipment to the bottom hole assembly or BHA and acts as a conduit for the drilling fluid. In the diagram, these are "stands" of drill pipe which are two or three joints of drill pipe connected together and "stood" in the derrick vertically, usually to save time while tripping pipe.
17. Setback (floor).
18. Swivel — a mechanical device that hangs directly under the traveling block and directly above the kelly drive, that provides the ability for the kelly — and subsequently the drill string — to rotate while allowing the traveling block to remain in a stationary rotational position, yet allow vertical movement up and down the derrick, while simultaneously allowing the introduction of drilling fluid into the drill string. On newer rigs this may be replaced by a top drive.
19. Kelly drive – device that employs a section of pipe with a polygonal (three-, four-, six-, or eight-sided) or splined outer surface, which passes through the matching polygonal or splined kelly (mating) bushing and rotary table.
20. Rotary table – rotates the drill string along with the attached tools and bit.
21. Drill floor – area where the drill string begins its trip into the earth.
22. Bell nipple – a section of large diameter pipe fitted to the top of the blowout preventers that the flow line attaches to via a side outlet, to allow the drilling fluid to flow back over the shale shakers to the mud tanks.
23. Blowout preventer or BOP annular type – often referred to as the "Hydril," which is one manufacturer.
24. Blowout preventer or BOP pipe ram & blind ram.
25. Drill string – a column or string of drill pipe that transmits drilling fluid via the mud pumps and torque — via the kelly drive or top drive — to the drill bit.
26. Drill bit – a tool designed to produce a generally cylindrical hole or wellbore in the Earth’s crust by the rotary drilling method.
27. Casing head – a simple metal flange welded or screwed onto the top of the conductor pipe — also known as drive-pipe — or the casing and forms part of the wellhead system for the well – or wellhead – component at the surface of an oil or gas well that provides the structural and pressure-containing interface for the drilling and production equipment.
28. Flow line – a large diameter pipe (typically a section of casing) that is connected to the bell nipple (under the drill floor) and extends to the possum belly (on the mud tanks) and acts as a return line, (for the drilling fluid as it comes out of the hole), to the mud.
Well done!