In addition to providing stabilization and keeping the perimeters of the well from caving in on themselves, casing protects the good stream from outside contaminants, furthermore as any H2O reservoirs from the oil or gas that’s being created.
Casing a well involves running steel quieten the within of a recently trained well. The little area between the casing and therefore, the untreated sides of the well is stuffed with cement to for good set the casing in situ. This is usually done by casing pipes manufacturers.
Once a well has been trained, if it’s to become a production well, the well should undergo completion. Whereas drilling well cuts through the rock formations and permits drilling engineers to achieve the reservoir below, the raw sides of the well cannot support themselves.
Almost like the bones of your spine protect the funiculus, the casing is a conduit that’s set within the trained well to safeguard and support the good stream.
The casing is a giant diameter pipe that is assembled and inserted into a recently trained section of a borehole. Almost like the bones of a spine protective the funiculus, the casing is about within the trained borehole to safeguard and support the good stream.
The lower portion (and generally the entirety) is usually command in situ with cement. Deeper strings sometimes aren’t cemented all the thanks to the surface, that the weight of the pipe should be partly supported by a casing hanger in the wellhead.
Know about the complete Casing Process –
Casing a well
The casing is fictitious in sections, or joints, that area unit sometimes concerning forty feet long and screwed along to make longer lengths of the casing, referred to as casing strings. Every end of the casing joint has male threads that area unit protected by cap referred to as a thread preserver till the casings area unit was able to be articulated.
Then, a collar or coupling, composed of a brief cylindrical steel pipe that’s slightly larger in diameter than the joints and additionally has feminine threads, is employed to attach the two male joint ends. A thread compound is employed on the two ends to make sure of a good seal.
A rounded section of pipe with the associate open hole on the tip, a guide shoe is connected to the primary casing string to guide the casing crew in running the casing into the well. In addition, the surface of the casing has spring-like centralizers attached to them to assist position in casing string within the centre of the well.
After running casing and before the cementing the well, a used drill bit is inserted into the well via a drill string, and drilling fluid is then circulated for a precise quantity of your time to get rid of any remaining cuttings from the well. Additionally, the wall scratchers area unit sent into the well to get rid of any filter cake that will have shaped the perimeters of the well.
A cement suspension is then wired into the well and allowed to harden to for good fix the casing in situ. Once the cement has hardened, all-time low of the well is trained out, and therefore the completion method continues.
Casing Programs
Sometimes the well is trained little by little referred to as a casing program. Here, a well is trained to a precise depth, cased and cemented, then the well is trained to a deeper extent, cased and cemented once more, and so on. Every time the well is cased, a smaller diameter casing is employed.
Casing Alternatives
In a trial to avoid wasting cash, generally, a liner string is run into the well rather than a casing string, whereas a liner string is exceptionally almost like casing string in this. It’s created of separate joints of the conduit; the liner string isn’t run the entire length of the well. A liner string is decorated within the well by a liner hanger, then cemented into place.
Conclusion
The casing is run into the well and officially landed when the burden of the casing string is transferred to the casing hangers, that area unit placed at the highest of the well, and use slips or threads to suspend the casing within the well.
- Prevents contamination of freshwater well zones.
- Prevents unstable higher formations from caving in and projected the drill string or forming vast caverns.
- It provides a robust higher foundation to permit the use of high-density drilling fluid to continue drilling deeper.
- Isolates varied zones, which can have different pressures or fluids within the trained formations from each other.
- Seals off high zones from the surface, minimizing the potential for a blowout
- It provides a swish internal bore for putting in production instrumentation.
Optimum style of the casing program decreases the reasonable construction prices, enhances the potency of operations, and additionally diminishes the environmental impacts. Casing organized on a rack at a rig in preparation for installation.
A slightly different metal string, called production conduit, is usually used while not cement within the ultimate casing string of a well to contain production fluids associated convey them to the surface from an underground reservoir.