Pipe Bending Explanation

BY CRAIG BARNSHAW,MANAGING DIRECTOR, BARNSHAWS METAL BENDING, UKPipelines International — March 2012

Many pipe bending methods are available, with considerable overlaps in capacity. Deciding on a suitable option ultimately depends on quantity and the quality required. All the processes have been described below with a suggested range/suitability, etc. While some companies have quite successfully developed processes that exceed the ranges suggested below, having processes outside of these ranges is not common.

Pipeline Bending

Pipeline Global Buckling

Pipelines like other slender strcutures with compressive forces, can buckle globally if the axial compresssion goes beyond a certain level. Buried pipeline normally tend to buckle in upheaval direction (upheaval buckling) and exposed pipelines normally tend to buckle laterally (lateral buckling).

In most cases, evaluations relevant to the global buckling threat will already start taking place in e.g. feasibility studies carried out during the concept phase. With regard to global buckling, the system risk review and strategy development activity should be initiated by participating in such early studies.

Pipeline Buckling

Why Apply Thermal Insulation Coatings?

Assets such as offshore pipelines, risers, spools and subsea structures which transport liquid products may be required to maintain a minimum temperature while the product is being transported within the asset, particularly offshore. Some liquids such as oil and gas can leave wax or hydrate deposits if a minimum temperature is not maintained. These deposits can, over time, build up and block the asset/pipeline either reducing or completely stopping flow/production. External wet insulation can be designed and applied to ensure the reduction in product temperature is kept within a range so the risk of deposits during production is acceptable. Insulation can also reduce the frequency of pigging operations during the life of the asset.

During other operational events, such as pipeline shutdowns, the product is contained in a stationary state within the asset/pipeline while the process facility has other operations performed. Similarly, to avoid deposits during these shutdown periods external insulation can be designed and applied to ensure the reduction in product temperature is kept within a range so the risk of deposits during shutdowns is acceptable.

Vortex Induced Vibrations, a Swinging Problem

Pipelines at the bottom of the sea are susceptible to ocean currents. Even relatively calm currents can induce turbulences in the wake of the pipeline, which results in the pipeline to start 'dancing'. Pipe vibrations can trigger fatigue, with catastrophic fracture as a result. Consequently, when designing submarine pipelines, caution is being paid to avoid such vibrations. Our research engineers use powerful software to predict submarine pipeline stability.

“The engine of our Western economy is continually being driven by oil and gas”, says FilipVan den Abeele, Research Engineer at OCAS. “The steadily increased demand for fuel, however, obliges the oil companies to explore and produce new oil and gas fields at remote locations. Wells are currently being drilled sometimes more than two thousand metres deep."

Effective Corrosion Prevention Methods For Pipelines

Unprotected pipelines corrode, no matter where the pipeline is. If it’s buried underground, above ground or in water, it’s going to deteriorate. As 60% of our nation’s transmission lines approach their life expectancy of a half century, we’re hearing more and more about pipeline failures. This should not be a surprise. Without implementing safety measures and having a corrosion control program, corrosion makes transporting hazardous material unsafe.

Pipeline Corrosion

The origin of Intelligent Pigs

One of the most crucial aspects of pipeline operation is ensuring pipeline integrity. The intelligent pig has become an important tool for assessing the condition of a pipeline, and is set to become an even more integral part of pipeline maintenance as steps are made towards solving the ‘unpiggable’ pipeline puzzle. Pipelines International spoke with Doug Woodley to trace the origins of the intelligent pig and examine how it developed into the essential tool that it is today.

Early intelligent pig technology

Pipelines are normally pigged for one or more of the following reasons: cleaning, batching, displacement or inspection. Pigging has been around for a long time – some say the process dates back to Roman aqueducts – but the earliest ventures into retrieving information from a pig originated in 1959.

How Does Pipeline Pigging Work?

While buildup in a pipeline can cause transmittal slows or even plugging of the pipeline, cracks or flaws in the line can be disastrous. A form of flow assurance for oil and gas pipelines and flowlines, pipeline pigging ensures the line is running smoothly.

The maintenance tool, pipeline pigs are introduced into the line via a pig trap, which includes a launcher and receiver. Without interrupting flow, the pig is then forced through it by product flow, or it can be towed by another device or cable. Usually cylindrical or spherical, pigs sweep the line by scraping the sides of the pipeline and pushing debris ahead. As the travel along the pipeline, there are a number functions the pig can perform, from clearing the line to inspecting the interior.

Foam pig
Source: www.pollypig.com