Got a pipe problem? Challenges faced when centralising a pipe

Across all pipeline construction and installation, pipe centralisation is crucial to overall pipe function, integrity and lifespan. As different materials are used for pipe casings, it is important that the right centraliser or spacer is chosen for your project.HDX 125 in RCP

Civil and pipelines

Pipeline surface cradle stanchions or piles constructed from square or C section beams need to be grouted in place to stabilise and prevent corrosion. However, because of the irregular profiles and square beams, it is often difficult to find a spacer that can be applied.

The unique flexibility of the collars on the kwik-ZIP spacer system however, can provide the answer to most of these specification
problems. They are greatly flexible and able to be applied to a large range of irregular profiles.

Soil stabilisation and foundation

Providing protection of the tendon, bolt or nail in the post tensioning, soil stabilisation and foundation drilling industries is a major factor considered by project managers. Rock Bolts, Anchors, Soil Nails, Double Corrosion Protection Sheathing (DCP), Piles and Micro Piles can each be affected by corrosion.

Maintaining even grout cover when centralising a pipe can also be a challenge, and if not executed correctly, can cause timely disruptions to the project. The inert properties of kwik-ZIP products, being made from high grade thermoplastic, help to protect the tendon, bolt or nail from corrosion, and also aid in maintaining even grout cover during construction.

Increases in pipe diameter

When centralising a pipe, increases in pipe diameter would commonly require different types of spacers to be brought to the construction site. This is not only bothersome, but can also be costly or slow down project works.

As with otherWhen using kwik-ZIP spacer and centraliser products, more spacer segments can simply be added to accommodate increases in pipe diameter. This removes the need to carry different spacer models for different diameters.

Oil and gas

Fiberglass and GRP well casings are now commonly used within the oil and gas sectors, often within coal seam gas (CSG) wells. Composite casings can vary greatly in diameter, therefore it is often difficult to find a centraliser that can adapt to different specifications.  

As the casings are not as strong as standard steel casings, metallic centralisers pose risk to the fibreglass or GRP surface. If metallic centralisers were attached to a fibreglass casing, any movement of the two components could cause damage to the casing. Metallic spiralisers and conventional steel API 10D Bow spring centralisers for oil and gas wells that require stop collars are also problematic, as the bolts that fix along the stop collar to the casing can crack the fibreglass or GRP.

kwik-ZIP products overcome these hurdles, and are routinely used for well completions on CSG well casing. Each product is totally adjustable in diameter, and will not damage composite casing materials as steel centralisers can.

Another oil and gas application in which kwik-ZIP products are often used is in waterflood or produced water injection wells. These wells are used to dispose of saline water produced from oil and gas wells and to help maintain pressure in the reservoir. In most cases the fluid being re-injected is highly corrosive and thus it is essential that inert centralisers are considered.

Water well and environmental

kwik-ZIP centralisers are also used on both casing and gravel packed screens. It is not possible to correctly grout a casing and maintain protection without the use of correctly designed inert centralisers. Keeping the pipe from touching the borehole wall during grouting is crucial, and to do this, spacers must be inserted at appropriate intervals.

The same applies for on all gravel packed screens, as inert centralisers are required before gravel pack is installed.  

The casing annulus in all water wells and monitor wells should be cement grouted from the top of the production zone back to surface. The grout seal protects the casing from corrosion, and both the well itself and aquifers through which it is drilled, from surface and sub-surface sources of contamination.

Correct cement grouting has also been shown to dramatically reduce vertical leakage via the annulus to the production zone of heavy metals. Studies have indicated that a correctly grouted casing can reduce recorded heavy metal levels in the water produced from a well. kwik-ZIP Centralizers are ideal for this application for both domestic household wells and deep large diameter commercial wells.