Terminology Series   J

If you’re new to the Oil and Gas industry, it’s likely that you will come across many new and unfamiliar terms. To succeed within Oil and Gas, you’ll need to learn and understand these terms. To help you, we’ve collated a range of terminology that you may need in your new role.

This week, we’re focusing on the letter "J", and a handful of keywords associated with drilling and offshore platforms.

Jacket refers to the lower section of an offshore platform. Sometimes, this section can also be called the ‘legs’.

Jacking Frame is a hydraulically controlled support structure used to stabilize the injector head and pressure-control equipment on coiled tubing units. They are most commonly found on offshore units but can also be found on some special onshore units.

Jackup Rig refers to an offshore drilling system commonly used in water depths of 50-330ft. They are made up of a drilling rig, floating barge, and are fitted with long support legs that can be raised or lowered
independently of each other. If the ocean bottom is firm, an independent leg will be used whereas if the ocean bottom is soft, the rig will be mat supported.

Jamin Effect refers to an increase in flow resistance, commonly when one (or more) interfaces are present at one time in a channel.

Jar is a tool used in drilling or workover and is either hydraulic or mechanical. The tools purpose is to deliver a sharp upward or downward blow to the tools below it. An example of its use is to free a tool or bit that is
stuck. A jar accelerator, booster or intensifier can be used to speed up or increase the effect of the jar.

Jet refers to a high-velocity drilling fluid stream from a nozzle or bit. It’s used to drill a seismic shot hole.

Jet Hopper is a mud-flow device, (sometimes called a mud hopper) that is used to feed materials into a jet mixer which is a mechanical blender used to mix a dry material* with drilling mud. The jet hopper is powered by a centrifugal pump that allows the materials to flow at a high velocity.

*Dry materials are added to provide dispersion, rapid hydration and uniform mixing.

J factor (sometimes called the pseudo-geometrical factor) is a term used during the well-logging process. Well logging measures the depth and subsurface formation during drilling – the J factor is the response of a logging measurement as a function of distance from the tool.

Joint is a length of pipe, and usually refers to tubing, drillpipe or casing.

Joule-Thomson refers to the cooling of gas as it expands. This effect is sometimes called the ‘throttling effect’ and can be used to cool produced gas therefore removing natural gas liquids and hydrates.

Junk pusher refers to a downhole tool that prepares the casing for setting a packer. It works similarly to a casing scraper and ensures the wellbore is unobstructed before setting a packer or similar fullbore device. It is used with a gauge ring.

Junked and abandoned (J&A) is a term that refers to a well that has been abandoned due to a drilling problem.

J Slot is a type of mechanism commonly used to set and unset downhole tools*, like packers. It’s named this way because the slot is shaped like a J. The short side supports the protrusion weight and the long side is open to release the protrusion. A J Tool fits into the J Slot.

*Most conventional downhole tools operate upward, downward or they rotate.

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