Drilling rigs are sophisticated machines – so sophisticated that some of them can even “walk.” Nevertheless, some components of these advanced devices that can access hydrocarbons thousands of feet below the earth’s surface are described in a decidedly “low-tech” fashion. Consider the abundance of “animal” terms below in this installment of “A Newcomer’s Guide to Oil and Gas.”
What Is a Doghouse?
In oil and gas parlance, the doghouse is not an enclosure where Spot, Fido or Rover takes a nap or where husbands spend the night when they screw up. Instead, it’s a small building located on a rig floor that serves as the driller’s “office” or a storehouse for small objects. It can also house the driller’s controls on a modern, semi-automated rig. This page on the U.S. Occupational Safety and Health Administration (OSHA) website features a small photo of a doghouse.
What Is a Catwalk?
In this context, a catwalk is not a raised platform on which fashion models parade the latest – and sometimes bizarre – styles from Paris, Milan and New York. Rather, it is a horizontal ramp at right angles to a drilling rig’s Vee-door (remember that term?) used as a staging area for tubulars or drilling tools to be raised to or lowered from the derrick floor with the cathead and catline. The cathead, part of the drawworks, resembles a capstan and a catline is a rope that wraps around the rotating cathead. OSHA’s website shows a photo of a catwalk.
What Is a Monkey Board?
A monkey board is an elevated platform on a drilling rig where a crew member called a derrickman works while running the drillstring – a string of drill pipe – into the borehole or pulling it out.
What Is a Muleshoe?
A muleshoe is an open-ended section of pipe run at the bottom of the drillstring or tubing used to circulate or cement the hole. It resembles a horseshoe or muleshoe when cut at an angle.
What Is a Pony Joint?
Also known as a pup joint, a pony joint is a short joint of drill pipe, drill collar, casing or tubing used to adjust the length of the drill string.
What Is a Rabbit?
A rabbit is a steel gauge made with a high degree of accuracy that is run through casing or tubing to confirm or check the minimum bore.
What Is a Fish?
Anything left in a wellbore. It does not matter whether the fish consists of junk metal, a hand tool, a length of drillpipe or drill collars, or an expensive MWD and directional drilling package. Once the component is lost, it is properly referred to as simply “the fish.” Typically, anything put into the hole is accurately measured and sketched, so that appropriate fishing tools can be selected if the item must be fished out of the hole.
What Is a Wildcat?
An exploration well. The significance of this type of well to the drilling crew and well planners is that by definition, little if anything about the subsurface geology is known with certainty, especially the pressure regime. This higher degree of uncertainty necessitates that the drilling crews be appropriately skilled, experienced and aware of what various well parameters are telling them about the formations they drill. The crews must operate top-quality equipment, especially the blowout preventers, since a kick could occur at virtually any time.
What Is a Spider?
A spider is a tool used primarily in the oil industry for gripping the drill string while assembling or reassembling parts of the string. The spider is normally operated hydraulically from a remote location. The spider consists of multiple gripper tools, sometimes constructed as wedge-shaped arms that holds the string by the downward force of the pipe. Teeth on the inside of the slips grip the pipe and the resulting compressive force inward on the drill pipe holds the pipe securely.
What Is a Rathole?
Rathole has two meanings for oilfield usage. Firstly, it means a storage place for the kelly, consisting of an opening in the rig floor fitted with a piece of casing with an internal diameter larger than the outside diameter of the kelly, but less than that of the upper kelly valve so that the kelly may be lowered into the rathole until the upper kelly valve rests on the top of the piece of casing.
Secondly, it means an extra hole drilled at the end of the well (beyond the last zone of interest) to ensure that the zone of interest can be fully evaluated. The logging tool string may be as much as 36.5 m in length, so the rathole allows tools at the top of the logging string to reach and measure the deepest zone of interest. In addition, there is usually a small amount of extra hole drilled to allow for junk, hole fill-in and other conditions that may reduce the effective depth of the well prior to running logging tools.
What Is a Nodding Donkey?
Deviating from drilling terminology and moving into production, a nodding donkey is a pump jack that raises and lowers the pump rods in a low-pressure oil well. Nodding donkeys are arguably the most familiar pieces of oilfield equipment in the eyes of people outside the oil and gas industry. The end of the pump jack beam on a nodding donkey is called the horsehead.
What Is a Pig?
A device with blades or brushes inserted in a pipeline for cleaning purposes. The pressure of the oil stream behind pushes the pig along the pipeline to clean out rust, wax, scale and debris. These devices are also called scrapers.