Dictionary of Polymer Terminology

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Casing And Tubing


Casing and Tubing are an important part of oil well construction. Oil well is subjected to high pressure and temperature and has to be cased at every stage with the casing material in order to provide maximum strength and make the oil well proper functioning. Tubing is the conduit through which oil and gas are brought from the producing formations to the field surface facilities for processing.


Casing is a steel pipe used in the drilling to prevent the wall of the hole from caving in to allow drilling to next hole section safely to protect the potable water from contamination (land operations, to prevent movement of formation fluids from one to another, to allow the reservoir sands to be cased safely such that oil or gas can be produced to surface through completion tubing safely. The casing is run and cemented. Casings comes in various sizing, but the most common are 30’’, 20’’, 18.5’’, 16’’, 13.3/8’’, 9.5/8’’, 7’’, 5.1/2’’, 4.1/2’’, etc.

Tubing is used as a completion string in a well to be a conduit for the flow of oil and gas from the reservoir to the surface. Tubing comes in different sizes, grades and thread connections to suit the requirements of the completion design.