J Slot (J-Slot)
A type of mechanism commonly used in the setting and unsetting of downhole tools and equipment such as packers. Most conventional downhole tools operate by upward or downward movement, rotation, or a combination of both. The J-slot profile creates the track for an actuating cam or pin that combines rotation and up or down movement to provide a simple yet reliable means of tool activation.
A support structure used to stabilize the injector head and pressure-control equipment on some offshore, or special onshore, coiled tubing units. The jacking frame is hydraulically controlled to enable the injector head to be located at a safe and secure working height. Additional features, such as the ability to skid the injector head to the side for access to the wellbore are included in some of the more complex designs of jacking frame.
A self-contained combination drilling rig and floating barge, fitted with long support legs that can be raised or lowered independently of each other. The jackup, as it is known informally, is towed onto location with its legs up and the barge section floating on the water. Upon arrival at the drilling location, the legs are jacked down onto the seafloor, preloaded to securely drive them into the seabottom, and then all three legs are jacked further down. Since the legs have been preloaded and will not penetrate the seafloor further, this jacking down of the legs has the effect of raising the jacking mechanism, which is attached to the barge and drilling package. In this manner, the entire barge and drilling structure are slowly raised above the water to a predetermined height above the water, so that wave, tidal and current loading acts only on the relatively small legs and not the bulky barge and drilling package.
A mud-flow device, also called a mud hopper, through which materials are put into the circulating mud system. The mud hopper is powered by a centrifugal pump that flows the mud at high velocity through a venturi nozzle (jet) below the conical-shaped hopper. Dry materials are added through the mud hopper to provide dispersion, rapid hydration and uniform mixing. Liquids are sometimes fed into the mud by a hose placed in the hopper.