J

J J J: Productivity index. Jack: An oil well pumping unit that operates with an up-and-down, or seesawing, motion; also called a pumping jack. Jack (Beam Lift): Usually a pump jack, operating the rods in a lift and fall motion. Jacket: The steel lattice structure that supports an offshore platform. Jacket Platform: (1) An offshore platform constructed entirely of steel. Such platforms generally are held in position by long steel piles driven deep into the seabed. (2) The steel support structure from the sea ¤oor to the top sides. Jack Knife Rig: A rig with a folding mast that can be lowered and raised relatively quickly. Jack-Up Drilling Rig: A mobile drilling unit that can elevate itself well above the sea surface on three or more legs to become a stable seabed-supported drilling platform. Drilling jack-ups can operate in water depths up to 150 m. On most jack-up drilling rigs, the drill tower is placed on cantilever beams such that wells supported by an adjacent platform can be drilled in workover mode by skidding the cantilever over that xed platform. Jack-Up Rig: (1) A type of mobile offshore platform with retractable legs that stand on the seabed to help support the drilling platform. (2) An offshore rig with retractable steel legs that can be placed on the ocean ¤oor and raise the rig above the water line. Jar: A device run on slickline, coiled tubing, tubing, or drill pipe that will sharply increase the impact force of the conveyance when trying to retrieve a stuck tool or equipment. Jar Accelerator: A hydraulic tool used in combination with a jar to increase the impact of the jar on the sh. Jerk Line (Drilling Rig): A cable from the tongs through a pulley in the mast and to the cat head. Jet Basket: A device with nozzles and a basket or catch basin to catch smaller pieces of junk stirred up by circulation. Jet Charge: A shaped charge used in perforating. Jet Cone Mixer: A mixer that introduces additives to a moving ¤uid stream through the use of the low pressure formed with ¤uid passage through a nozzle. An “on-the-¤y” mixing device. Jet Cutter: A radial-shaped charge (explosive) cutter for pipe. Jet Fuel: (1) High-quality, kerosene-like fuel. (2) Kerosene-type fuels or blends of gasoline, distillate, and residual oils that are used as fuels for gas

turbine-powered aircraft. (3) A kerosene-based fuel that is used as a fuel for turbine engines in airplanes. Jet Mixer: A type of mixer for cement that uses air pressure to propel the dry cement into the ¤owing water. Jet Nozzle: A nozzle through which ¤uid is pumped to produce an impact force. Used in jetting tools and bits. This nozzle often has a designed shape to maximize impact. Jet Perforating: Shaped charge perforating. Jet Pump: An articial lift device that uses the ¤ow of a power ¤uid through a nozzle to create a low-pressure area that draws well ¤uids into the chamber and assists in lift the ¤uids to the surface. Jetting: Injecting ¤uid at high pressure against a target, often with ¤uid focused through a nozzle tool. JIB: See Joint interest billing. J-Lay Tower: A pipe-lay method used in deep water to allow the pipe to leave the pipe-lay unit at a vertical departure angle. The tower supports the up-ended pipes. JOA: See Joint operating agreement. Joint (Connection): Tubular connection. Joint (Geologic): A large, generally planar fracture through a rock across which there has been no movement. Joint Interest Billing: Process of distributing the costs related to well completions and operations among working interest partners. Joint Operating Agreement: (1) Contract between cotenants or separate owners of oil and gas properties being jointly operated. It denes the agreement with respect to initial drilling, further development, operations, and accounting. (2) A written agreement that sets the terms under which a property will be developed by the working interest owners. Joint (Pipe Length): A section of tubular. Joint Venture: (1) A project in which two or more parties are involved. Funding may be in direct money or work-in-kind. (2) An investment undertaken by a consortium of companies, usually with one member acting as operator. Joule-Thomson Effect: (1) The change in temperature of a ¤uid that occurs when the ¤uid is allowed to expand in such a way that no external work is done and no heat transfer takes place. The case of most interest is cooling of a compressed gas upon J-T expansion. Note that the J-T effect is not limited to gases; also J-T expansion can, in some cases, produce an increase in temperature, rather than a decrease, although this is not frequently encountered. (2) Thermodynamic effect in a ¤uid whereby the reduction in its temperature is caused by pressure reduction without energy exchange with the environment. (3) When a real (not ideal) gas expands, the temperature of the gas drops. During passage of a gas through a choke, the internal energy is transferred to kinetic energy with a corresponding reduction in temperature as

velocity increases. The effect for natural gas is approximately 7°F for every 100 psi pressure reduction. Joule-Thomson Valve: Device that, taking advantage of the Joule-Thomson effect, enables the cooling of a ¤uid through throttling or reduction of its pressure. Journal Bearing: A bearing on a rotating shaft. J Pro–le: A prole design (less common than F, S, and X). The F allows circulation with the annulus. Used in place of a sliding sleeve but does present a restriction. JRA: Job risk assessment. JRC™: Jet Research Center. JSA: Job safety analysis. J-Slot: A pin and groove assembly that keeps a tool in the unset position while running and then can be worked or “Jayed” to operate the tool. Common in retrievable packers and liner hangers. J-T: Joule-Thomson. Jug: Geophone. Junction Box: A box, usually metal, that encloses cable connections for their protection. Junction (Multilateral): The intersection of the lateral and the mother bore when two or more laterals are drilled in a multilateral well or when a single kick-off lateral is drilled from a vertical well. The junction may be unsealed or sealed and may or may not hold pressure. Junk: Debris in the well. Junk Basket: See Jet basket. Junk Mill: A rough, sturdy mill for grinding up odd-shaped materials in the well. Junk Retriever: Junk basket (jet basket). Jurassic: A geologic time period 140 to 200 million years ago.