Well completion is the process of creating a drilled well ready for production. One of the stages in well completion is casing and this article will focus on this. oil field competitions services include well completion. Keep reading to know how casing is done:
Pressure Builds
In terms of downhole operations, it is essential to have an understanding of the complexity of the calculations to ensure the proper balance between the drilling mud weight and the shifting downhole environment. An increase in depth means an increase in pressure and temperature. It is important to understand that geological formations have different pore pressure and it is possible for faulting to shift the formations being worked through.
Joint Casing
The casing can be surface, intermediate or production casing. Surface casing runs from the surface down to the deepest known aquifer. It is designed to protect the hole from contaminates and protect surface water from erosion and well contamination. Meanwhile, an intermediate casing may be run at different intervals to balance the impacts of pore pressure against fracture pressure over the open column of mud weights. Production casing is designed to protect the production zone and isolates the producing intervals.
Nesting
Nesting is one of the ideas about how drilling and casing are set up. The hole and casing near the surface are big. While the hole progresses downward the hole’s size steps down periodically allowing the next part of the well to be drilled by a bit that fits within the previous portion.
Once the desired length of the new nested portion is reached, this section must be cased before moving on. There are different ways to flow the cement in such as running continuous steel piping, pumping cement in the piping, putting a wiper plug into the piping, letting the cement set up, and sending the next stage drill bit through the piping.
Casing Materials and Operations
As the casing operation is segmented in nature, it often takes place in sequence with the drilling operation and thus, largely performed with the drilling rig in place. The piping is often steel. Fixed pieces of pipe joined together are used for the vertical surface and intermediate sections. Rolls of coiled tubing may be used when the situation downhole becomes more directional. The coiled tubing is designed to make the necessary directional changes. As the cement slurry is mixed, it is mixed with additives to adjust the density and cure time and weight according to the environmental conditions of downhole.
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