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Key seating occurs when the drill string becomes off-centered in the wellbore, and the pipe collars become caught on a deviation in the wellbore. If the rig is able to move the drill string freely downhole, but every time the drill string is pulled upward it becomes stuck at the same point, then it is likely that the pipe is caught in a key seat.
Rotary assemblies [2] are commonly used where formations are predictable and the rig economics are an issue. In such an assembly the weight of the drill collars gives the BHA the tendency to sag or flex to the low side of the hole, collar stiffness length and stabiliser diameter and placement are engineered as a means of controlling the flex of the BHA.
Drill pipe makes up the majority of the drill string back up to the surface. Each drill pipe comprises a long tubular section with a specified outside diameter (e.g. 3 1/2 inch, 4 inch, 5 inch, 5 1/2 inch, 5 7/8 inch, 6 5/8 inch). At each end of the drill pipe, tubular larger-diameter portions called the tool joints are located.
The drill string consists of both drill pipe and the bottom hole assembly (BHA), which is the tubular portion closest to the bit. The BHA will be made of thicker walled heavy weight drill pipe (HWDP) and drill collars, which have a larger outside diameter and provide weight to the drill bit and stiffness to the drilling assembly.
A list, usually tabular and often on the drawing (if not accompanying the drawing on a separate sheet), listing the parts needed in an assembly, including subparts, standard parts, and hardware. There is no consistently enforced distinction between an L/M, a BoM, or a P/L. PLM: product lifecycle management; plant lifecycle management: See also ...
To latch around a piece of pipework a set of elevators need a precise internal diameter, with an appropriately profiled shoulder to accommodate the lower profile of a tool joint. The latch mechanism has to prevent opening under radial loads of up to hundreds of tons. For some purposes (casing elevators, and loading pipe into and out of the ...
Working in El Dorado, Arkansas, in the 1920s, E.C. Johnston and his brother M.O. Johnston developed the first drill stem tester and ran the first commercial drill stem test in 1926. In April 1929, the Johnston Formation Testing Corporation was granted a patent (U.S. Patent 1,709,940) and they subsequently refined the testing system in the early ...
MWD tools may be semi-permanently mounted in a drill collar (only removable at servicing facilities), or they may be self-contained and wireline retrievable. [citation needed] Retrievable tools, sometimes known as Slim Tools, can be retrieved and replaced using wireline through the drill string. This generally allows the tool to be replaced ...