دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: the pipe that connects thesubsea BOP (q.v.) stack with the floating drilling rig. The riser allow mud to be circulated back to surface,and provides guidance for tools being lowered into the wellbore.

an easily identified formation that is used to identify the start of a rock sequence. In the wellbore, a marker is a material placed in the circulating fluid that can be easily seen when the fluid returns to surface – helps identify the swept volume of th

n: 1. a large valve located on the Christmas tree and used to control the flow of oil and gas from a well. Also called master gate. 2. the blind or blank rams of a blowout preventer (obsolete).

n: A valve located on the Christmas tree that controls all flow from the wellbore. A correctly functioning master valve is so important that two master valves are fitted to most Christmas trees. The upper master valve is used on a routine basis, with the low

the main shut-in valve on the well.

n: an acidizing treatment using low or no pressure to improve the permeability of a formation with fracturing it. See wellbore soak. Compare fracture acidizing.

acidizing a rock below the fracturing pressure, either to reduce the formation damage or to improve the initial permeability.

n: (MD) the total length of the wellbore, measured in feet along its actual course through the earth. Measured depth can differ from true vertical depth, especially in directionally drilled wellbores. Compare true vertical depth.

n: the distance measured along the path of the wellbore (i.e. the length of the drill string).

depth measurement of a wellbore as measured along the drill pipe without respect for vertical penetration.

n: (MWD) 1. directional and other surveying during routine drilling operations to determine the angle and direction by which the wellbore deviates from the vertical. 2. any system of measuring downhole conditions during routine drilling operations.

n: a mothod of measuring parameters downhole and sending the results to surface without interrupting routine drilling operations.a special tool containing sensors,power supply and transmitter is installed as part of BHA (q.v.).the information is transmitted

downhole logging while drilling. “Logging While Drilling” is one form of measurement while drilling" - to differentiate it from mud logging, wireline logging, etc. See Logging While Drilling.

n: a drilling rig in which the source of power is one or more internalcombustion engines and in which the power is distributed to rig components through mechanical devices (such as chains, sprockets, clutches, and shafts). Also called a power rig. Compare electric rig. mechanical sticking n: a condition in which solid material such as sloughing shale, sand, or shale driven uphole by a blowout, or junk in the hole causes the drill stem to become stuck against the wall of the wellbore.

n: The limiting or prevention of motion of the drillstring by anything other than differential pressure sticking. Mechanical sticking can be caused by junk in the hole, wellbore geometry anomalies, cement, keyseats or a buildup of cuttings in the annulus.

a special resistivity tool that measures the resistivity of the mud cake on one curve and the resistivity of the fluids in the formation, but near the wellbore, on a different curve. Separation between the curves is an indication of permeability since mud

n: a proprietary name for a logging tool that measures resistivity of the flushed zone of the formation adjacent to the wellbore.