How is oil well casing made?
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. Each time the well is cased, a smaller diameter casing is used.
Which is the type of casing?
There are five different types of casing pipe: Conductor Casing, Surface Casing, Intermediate Casing, liner String, Production Casing.
What is casing in oil production?
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. Well casing should withstand hydraulic fracturing pressure, production pressures, and corrosive conditions.
What is the purpose of production casing?
Production casing is used to isolate production zones and contain formation pressures in the event of a tubing leak. This casing can either be run through the production zone or is set above the production zone.
Why is casing important in drilling?
The purpose of surface casing is to isolate freshwater zones so that they are not contaminated during drilling and completion.Casing placement is selected so that the hydrostatic pressure of the drilling fluid remains at a pressure level that is between formation pore pressures and fracture pressures.
How is casing setting depth determined?
Two main factors determine the depth of the casing shoe, namely, the fracture pressure and the pore pressure. A third factor is the lithology, because it is desirable to place the casing shoe in a competent shale section. Methods to predict fracture gradients for deeper wells already exist.
How does a well casing work?
Casing is the tubular structure that is placed in the drilled well to maintain the well opening. Along with grout, the casing keeps possibly contaminated surficial water from reaching the aquifer zone underground and prevents contaminants from mixing with the water.
