دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: diving in which a diver uses a normal atmospheric mixture of oxygen and nitrogen as a breathing medium. It is limited to depths less than 190 feet (58 metres) because of the dangers of nitrogen narcosis;however, dives with bottom times of 30 minutes or less may be conducted to a maximum of 220 feet (67 metres).

n: (ADS) a oneperson atmospheric suit rated to depths of 2,300 feet (701 metres). Advantages include allowing the operator to work in a safe environment for debris salvage or recovery operations.

bacteria generated natural gas, found at shallow depths and in many water wells. Usually contains C14 isotope. See also thermogenic gas as a gas that has a biological origin but has been modified from the original organic state by time at temperature and

n: a mobile submersible drilling structure constructed of several steel cylinders or bottles. When the bottles are flooded, the rig submerges and rests on bottom;when water is removed from the bottles, the rig floats. The latest designs of this type of rig drill in water depths up to 100 feet (30.5 metres). See submersible drilling rig.

n: an electric heater screwed onto lengths of tubing and lowered into the well. It raises the bottomhole temperature of the well to prevent solidification of paraffin in subsurface equipment.

n: 1. a failure of equipment.2. in a fracture treatment or a squeeze job, the failure of formation rock to withstand pressure, allowing it to rupture. adj: pertaining to the amount of pressure needed at the wellhead to rupture the formation in a fracture treatment or a squeeze job (as in formation breakdown pressure).

fracture.

n: a pipe or vessels ability to withstand rupture from internal pressure.

n: See internal pressure strength.

n: a sucker rod pumping unit. not commonly used. that employs cable wound around a spool. one end going into the hole. the other with a suspended counterweight. This type of unit can achieve 40- to SO-foot ( 12- to 24- metre) stroke lengths. reducing dynamic loads, rod reversals. gas locking. and power usage and can be applied to deep pump applications

n: a drilling platform that rests on a steel or concrete caisson. Used mainly in the Arctic, caissontype drilling platforms are mobile offshore drilling units built to withstand the ravages of moving ice in Arctic waters.

n: a means of cementing casing in a well so that the casing may, if necessary, be retrieved with minimum difficulty. A special mud, usually an oil mud, is placed in the well ahead of the cement after the casing has been set. Nonsolidifying mud is used so that it does not bind or stick to the casing in the hole in die area above the cement Since the mud does not gel for a long time, the casing can be cut above the cemented section and retrieved. Casing packs are used in wells of doubtful or limited production to permit reuse of valuable lengths of casing.

n: The cementing method that flow in some non-petrified special fluid at first before cementing. The casing above cement can be retrieved since this kind of drill fluid is non-condensing.