What is a casing in drilling?

Casing is a series of steel pipes that are run into a drilled oil well to stabilize the well, keep contaminants and water out of the oil stream, and prevent oil from leaching into the groundwater. Casing is installed in layers, in sections of decreasing diameter that are joined together to form casing strings.

What is the purpose of casing?

The casing forms a major structural component of the wellbore and serves several important functions: preventing the formation wall from caving into the wellbore. isolating the different formations to prevent the flow or crossflow of formation fluid.

What is the purpose of casing pipe?

The casing pipe is used to support the oil and gas well walls to ensure the normal operation of the entire well after the drilling process is completed. Each well is based on different depths of drilling and geology, using several layers of casing. After the casing is down, the cement is to be cemented.

How a borehole is cased?

Also known as setting pipe, casing a Borehole involves running the PVC pipes down the inside of a recently drilled Borehole. The small space between the casing and the untreated sides of the Borehole is filled with Gravel Pack to permanently set the casing in place.

What are the two basic types of casing?

There are six basic types of casing strings:

• Conductor Casing.
• Surface Casing.
• Intermediate Casing.
• Production Casing.
• Liner.
• Liner tieback casing.

What is the difference between casing and a liner?

Casing is very necessary for smooth drilling operations in deep and ERD wells so that hole collapsing may be got rid of. Liner is a string of casing which does not extend to the surface but is hung from inside the previous casing string and is cemented in place.

How well casing is installed?

Hanging above the drill floor, casing tongs screw each casing joint to the casing string. Sometimes the well is drilled in stages called a casing program. Here, a well is drilled to a certain depth, cased and cemented, and then the well is drilled to a deeper depth, cased and cemented again, and so on.

How long is a borehole casing?

Supplied in lengths of 0.75, 1.0, 1.5 and 3.0 m. Other lengths available up to 6m to order. On request, larger diameters can be supplied with a coarser 2 t.p.i. thread form to facilitate rapid coupling and uncoupling.

What is casing and its types?

There are five different types of casing pipe: Conductor Casing, Surface Casing, Intermediate Casing, liner String, Production Casing. In general, casing provides structure and strength to the walls of the well hole so that it doesn’t collapse on itself.

What is a surface casing?

A large-diameter, relatively low-pressure pipe string set in shallow yet competent formations to protect fresh-water aquifers onshore.