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Casing Diameters of a Borehole Casing Diagram premium gas tight connections on a casing string. Casing is a large diameter pipe that is assembled and inserted into a recently drilled section of a borehole. Similar to the bones of a spine protecting the spinal cord, casing is set inside the drilled borehole to protect and support the wellstream.
Casing head (#27) is a large metal flange welded or screwed onto the top of the conductor pipe (also known as drive-pipe) or the casing and is used to bolt the surface equipment such as the blowout preventers (for well drilling) or the Christmas tree (oil well) (for well production).
Borehole digging for a borewell or tube well Borewell digging A woman in Uganda collects water from a borehole and attached hand pump A drilled well in Ghana; the borehole is not visible. A borehole is a narrow shaft bored in the ground, either vertically or horizontally.
Digging a borewell in Kerala, India The tube well casing houses the inlet, cylinder, piston valves and rising main of a "down-the-hole" type hand pump. Casing to support the external surfaces of the borehole against collapse may be needed, either temporarily or permanently, and is often made of PVC pipe , which has the advantages of being both ...
With these zones safely isolated and the formation protected by the casing, the well can be drilled deeper (into potentially higher-pressure or more-unstable formations) with a smaller bit, and then cased with a smaller size pipe. Modern wells generally have two to as many as five sets of subsequently smaller hole sizes, each cemented with casing.
The casing is constructed by welding, either chemically or thermally, segments of casing together. If the casing is installed during the drilling, most drills will drive the casing into the ground as the bore hole advances, while some newer machines will actually allow for the casing to be rotated and drilled into the formation in a similar ...
Steel casing pipe is often specified as ASTM A-252 which is a structural grade material that does not require hydrostatic testing and the inspection requirements are not stringent and it usually costs less than other grades such as A-53, [2] A-139 or API 5L. Used natural gas line pipe is also used as casing on many projects because it is often ...
Production casing is the final casing string set in a well and usually reaches from the surface to Target Depth (TD). The type of casing used depends upon the different conditions in the well. Commonly, production casing sizes range from 4 + 1 ⁄ 2 in (110 mm) to as large as 9 + 5 ⁄ 8 in (240 mm). It is the last string cemented in a well ...