دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a roller cone bit that is specially designed for air or gas drilling. It is very similar to a regular bit, but features screens over the bearings to protect them from clogging with cuttings and thicker hardfacing on the shirttail to protect them from abrasive, high-velocity air or gas drilling fluid.

n: Installed in the bearing race of cone. There are a ball bearing and two roller bearing in every cone, both absorbing radial load.

n: the cutting or boring element used in drilling oil and gas wells. The bit consists of a cutting element and a circulating element. The cutting element is steel teeth, tungsten carbide buttons, industrial diamonds, or polycrystalline diamonds (PDCs). The circulating element permits the passage of drilling fluid and utilises the hydraulic force of the fluid stream to improve drilling rates. In rotary drilling, several drill collars are joined to the bottom end of the drill pipe column, and the bit is attached to the end of the drill collars.

a drill bit, commonly either a roller cone, button bit, PDC, diamond or drag bit, used with a rotary string or a mud motor to drill through rock.

n: on a roller cone bit, a coneshaped steel device from which the manufacturer either mills or forges steel teeth, or into which the manufacturer inserts tungsten carbide buttons. Most roller cone bits have three cones, which roll, or rotate, on bearings as the bit rotates. As the cones roll over the formation, the cutters on the cone scrape or gouge the formation to remove the rock.

n: a drilling bit with tungsten carbide inserts on the cones that resemble plugs or buttons. See roller cone bit.

nn: The cone bit which is installed with obtuse tungsten carbide insert.

n: a tool composed of a mandrel on which are mounted several heavy-duty rollers with eccentric roll surfaces. It is used to restore buckled, collapsed, or dented casing in a well to normal diameter and roundness. Made up on tubing or drill pipe and run into the well to the depth of the deformed casing, the tool is rotated slowly, allowing the rollers to contact all sides of the casing and restore it to roughly its original condition.

n: The tool for repairing and maintaining casing. Consisted by arbor and a set of bias gyro wheel.

a downhole tool, commonly run on pipe to try to reform the casing after a partial collapse.

n: a mechanical drive using a driving chain and chain gears to transmit power. Power transmissions use a roller chain, in which each link is made of side bars, transverse pins, and rollers on the pins. A double roller chain is made of two connected rows of links, a triple roller chain of three, and so forth. chain guard n: in a chain-and-sprocket drive, a case that protects workers from the moving drive. It also protects die drive from dirt and is part of the cooling and lubrication systems. Some enclose only one drive and some enclose several drives. May be made of sheet metal or plate metal. Heavier guards also support the shafts on bearings. Both types have access panels for inspection and maintenance.

n: The compounding transmiting and variable speed driving rig whose power package uses multi-line roller chain.

n: in roller chain, the width of the rollers, which is the distance between the inside faces of the roller link plates.

n: a conical-shaped metal device into which cutting teeth are formed or mounted on a roller cone bit. See roller cone bit.

n: See bit cone.