For deeper and/or deviated sections, there is a greater risk of stopping casing before reaching the TD. Challenging wellbore obstructions such as tight spots, ledges, high doglegs, cutting "beds" or difficult dip zones are overcome through the ability to ream casing using a CRTi (or CRTe) and reaming shoe.
In some cases, level 1 casing reaming can save up to 50% or more in time.
in the drill assembly
In order to be able to ream the casing down, you must plan to use the proper reamer shoe. Fixed to the casing or lined string, it is designed to meet your application needs and minimize ECD and maximize Flow-By.
The reamer shoe has a cutting/reaming structure that resizes the hole. Dynamic directional flow orifices overcome casing difficulties and ensure effective wellbore cleaning.
Because they are easy to drill through and are part of the track, reamer tracks are mostly fitted with a high strength profiled alloy nose (“head”) that can be drilled with standard PDC or Rollercone bits. The exact nature of the well section determines which type of track shoe is most suitable, and likewise the choice of cutting structure depends on the type of obstacles likely to be encountered.
Some reamer shoes are also capable of cutting and drilling through formations (HD versions), so the operating parameters and aggressiveness of the reamer shoe should be properly planned and optimized.
centralizer
Depending on the well section and application, you need to plan the most suitable centralizer for your reaming operation.
Casing centralizers firmly secured around the joint will prevent the casing from contacting the wellbore wall and prevent differential pressure from seizing. Casing concentration is also one of the key factors in producing high quality cementing operations by preventing poor zone isolation.
The spacing term is related to casing centering and indicates how well the casing string is centered. When the casing is perfectly centered in the borehole, the spacing is 100%. 0% distance means your casing is touching the wellbore. The goal is always to provide a positive standoff with maximum torque and drag reduction and maximum flow.
on the surface
Without a doubt, the most important piece of equipment on the surface is the OWS CRTi/e tool, designed for casing, reaming or drilling on rigs equipped with top drives. It enables connection make-up, break-out, cycling and rotation and helps you get bushings to TD the first time, reducing non-productive time and associated costs.
Casing connection
Casing reaming needs to be considered during the planning stages of the project. Through torque and resistance analysis during the planning phase, well engineers must evaluate whether the casing connection will be able to withstand the combined mechanical stresses caused by down-casing reaming.
If heavy reaming is anticipated, a fatigue analysis of the connection must be performed using fatigue performance data from the casing supplier.
API casing connections are limited when casing reaming is required, and most applications may require a premium connection.
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