A casing pipe or casing string is a series of long sections of connected pipe–about 40 feet long–that are lowered into the wellbore of an oil well in order to prevent the collapse of the borehole as it is being drilled. The casing pipe also prevents formation fluids from entering the borehole uncontrolled and prevents the fluids that are collected from contaminating other formations such as fresh water aquifers.
These pipes are suspended, connected and cemented into place so that they can reach greater depths within the ground. Many oil wells are drilled in sections—the well is drilled to a specific depth, the casing is inserted and cemented in place, and then the operator continues drilling deeper and repeats the process, over and over until the well is as deep as it needs to be.
Types of Casing Pipe
Conductor Pipe – These are the widest casings–up to 42” offshore and 20” onshore. This is the first pipe or string set below the wellhead. These pipes are designed to prevent the well from caving in and keeping the drilling fluid at the bottom of the well circulating.
Surface Pipes – These comprise the main length of the casing pipe that can dig up to several thousand feet. Their main function is to protect fresh water zones from being contaminated by the drilling process, but also is used to anchor blow out preventors and support the deeper casing pipes.
Intermediate Pipes – Intermediate pipes serve as transitions between areas of different pressure. Some sections of the well may have low pressure zones, zones where circulation is lost or might be unstable. The intermediate pipes also help seal off the high-pressure areas from the low-pressure areas. Basically, anywhere there might be a problem, an intermediate pipe is probably going to be installed to resolve it.
Production Pipe – The production pipe (or production casing) is the smallest pipe in the well and goes the deepest into it. The production pipe is the conduit to pull the oil or gas from the deposit up to the surface.
Forged Components is One of the World’s Leading Wellhead Component Suppliers
Whether you are looking for custom pressure vessel connections, pipe flanges, or wellhead casings and components, Forged Components can help. Call us at (281) 441-4088 or contact us online for more information.