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Casing that is cemented in place aids the drilling process in several ways: [2] Prevents contamination of fresh water well zones. Prevents unstable upper formations from caving in and sticking the drill string or forming large caverns. Provides a strong upper foundation to allow use of high-density drilling fluid to continue drilling deeper.
Bell nipple: An enlarged pipe at the top of a casing string that serves as a funnel to guide drilling tools into the top of the well. Big bear: A big bear is a hitch (see hitch) that lasts a minimum of 50 straight days. Black Leg : Joints of pipe racked back in the derrick. Blowout: A sudden, uncontrolled release of underground pressure from ...
An underreamer is a device used to enlarge the borehole below an existing casing or restriction, during a well drilling operation. It can be positioned either above the drill bit or above a pilot assembly run inside the existing borehole. Numerous designs exist, in sizes varying from a couple of inches to above 40".
Preserving well integrity is a vital task for the operators. This includes ensuring that the annuli remain intact. One major threat to annulus integrity is overpressure within the annulus, which could lead to burst or collapse of a casing or damage to the formation below. This will happen first at the shoe of the annulus because the pressure ...
Provide a means of casing suspension (Casing is the permanently installed pipe used to line the well hole for pressure containment and collapse prevention during the drilling phase). Provides a means of tubing suspension (Tubing is removable pipe installed in the well through which well fluids pass).
In general, well completions may not incorporate a packer when the annular space is used as a production conduit. A production packer is designed to grip and seal against the casing ID. Gripping is accomplished with metal wedges called "slips." These components have sharpened, carburized teeth that dig into the metal of the casing. Sealing is ...
In a completed well, there may be many annuli. The 'A' annulus is the void between the production tubing and the smallest casing string. The 'A' annulus can serve a number of crucial tasks, including gas lift and well kills. A normal well will also have a 'B' and frequently a 'C' annulus, between the different casing strings.
Sometimes, the process of running in and cementing the casing is also included. After a well has been drilled, should the drilling fluids be removed, the well would eventually close in upon itself. Casing ensures that this will not happen while also protecting the wellstream from outside incumbents, like water or sand. [1] Perforated shoe