Float Collar, Casing Centralizer & Other Cement Floating Equipment

 

Float Collar, Casing Centralizer & Other Cement Floating Equipment 

Float collar and float shoe are important floating equipment in petroleum and natural gas fields. They are used to guide the casing to set in the hole and ensure the quality of cementing. They are widely used in the lower section of the well to help decrease strain on the derrick while directing packaging past edges and bog zones in the opening.

A casing centralizer is also one of the most important cement tools used in the field. Let’s have a glimpse of these tools and understand their applications:

Float Shoe

The float shoe contains a backpressure valve that prevents fluids from entering the casing while the pipe is lowered into the hole and prevents cement from flowing back into the casing after placement while enabling circulation down through the casing. The float collar includes a back pressure valve and serves basically the same function as the float shoe.

Float Collar

The float collar is run in a casing assembly, usually several joints above the float shoe. It provides a seat for the cement plugs to help top plugs shuts off the fluid flow and prevents over-displacement of the cement. The space between the float shoe and float collar provides a containment area to entrap the likely-contaminated fluids from the wiping action of the cementing plug, securing the contaminated fluid away from the shoe where a strong cement bond is of primary importance.

Casing Centralizer

A casing centralizer is a steel apparatus that is secured around the casing at different locations in the borehole to prevent it from contacting the wall. The casing centralizer is fitted with bowsprings and a hinged collar to keep the casing centralized in the borehole. There are two classes of a casing centralizer, namely, bow-spring design and rigid blade design.

It helps efficient cement placement between the casing and the bore wall preventing uneven and imperfect seals that can cause drilling fluid to be pushed up the borehole, contaminating aquifers and upper-level strata.

The bow-spring design casing centralizer is slightly larger than the wellbore, and it provides complete centralization even if the well has deviated. But in some cases, it may not be able to support the casing weight. A rigid blade design needs the wellbore to be in good condition, or it may cause trouble downhole.

Float Collar & Casing Centralizer | How Are They Used?

 

Float Collar & Casing Centralizer | How Are They Used?

 

 

 

A casing centralizer is a mechanical device secured around the casing at various locations to keep the casing from contacting the wellbore walls. As a result of casing centralization, a continuous annular clearance around the casing allows cement to completely seal the casing to the borehole wall.

Definition of the Casing Centralizer

Casing centralization is one of the key elements to ensure the quality of a cementing job by preventing mud channeling and poor zonal isolation. Centralizers can also assist in the running of the casing and the prevention of differential sticking.

Applications

Centralizer’s usage is extensive! It is estimated that 10 million centralizers are manufactured and used every year globally. Centralizer manufacturers likely want to increase the demand for centralizers. However, operators, on the other hand, may wonder: “Should we use that many?”

WhileCasing Centralizer is used extensively, wellbore problems continue to arise due to poor cementing jobs. Centralizer properties and placements directly or indirectly affect the quality of the cementing job.

The challenge that both operators and service companies face is to choose the right type of centralizers and place the right amount at the optimum positions on the casing to achieve a good standoff profile.

What does Float Collar Mean? An Overview

A float collar is a special short coupling device that has threads installed generally after one, two, or three joints of casing from the float shoe. The float collar has a check valve, which allows the circulation of flow of fluid in only one direction. It only allows fluids to flow downward through the casing but not upward through the casing.

Float Collar Applications

Couplingdevices like the float collar are usually installed at the bottom of the casing string on which the cement plugs are joined during cementing operations. The primary role of a float collar is to prevent mud from entering into the casing while running in the hole, thereby making the casing float on the hydrocarbons at the bottom of the casing string. This reduces the weight and also prevents any backflow of cement during cementing operations. This is the place where the cementing bottom and top plugs land.

Types of float collars:

• Flapper valve type

• Spring-loaded ball valve type

These two are some of the crucial components required for cementing, and you may observe their extensive use in the relevant industry.