Low Risk High Return Solutions

Used alone or in combined with a SANCCUS chemical package our Pipeline Gel and Gel Pig technology gives the operator a very powerful tool in their flow assurance arsenal.

Gel technology is very versatile and can be applied anytime during the lifetime of a field from helping to remove hydrotest fluids when commissioning to the bulk removal of hydrocarbons and solids prior to maintenance or when preparing a pipeline for responsible decommissioning.
Pipeline Gels are viscous shear thinning liquids, some with self-healing properties, used in pipelines to clean, lubricate, to remove debris and solids or for spool protection. Pipeline Gels can be deployed though very small ports and will fill into larger pipelines and so overcome most access restrictions.

Gel Pigs are elastic and flexible cylindrical solid objects, primarily used when mechanical pigs cannot be deployed due to issues such as restricted pipeline access or egress. Gel Pigs are capable of extruding through bore restrictions and chokes down to half their diameter but will break up when the choke is more severe than this so the risk of gel pigs sticking in pipelines is negligible.
The cleaning of high risk or unpiggable pipelines is at the heart of why SANCCUS liquid pipeline gels and solid gel pigs are such an incredibly useful tools for any operator to have in their armoury.

During their lifetimes most assets will have to undergo a great deal of maintenance and modification and these modifications can often result in situations where there is multi diameter pipework or pigging facilities have been removed rendering many pipelines unpiggable.

Accumulation of debris or wax can also make the risk of conventional pigging so great that it cannot be undertaken without prior remedial treatments. Also, it is common to clean a pipeline from subsea to topside using a vessel and a long narrow downline so clearly this is unpiggable.
The accumulation of debris in pipelines is a common problem but a difficult one to manage safely and effectively. Typically, we think of debris as sand produced into the pipeline or deposited during construction, but it can also be mechanically recovered scale, corrosion and even welding goods.

To effectively remove any debris requires the use of mechanical scraper pigs but the risk of the pig sticking by building up debris in front of it can be severe depending on the balance between the pipeline diameter and the quantity of debris.

Another factor which complicates debris removal is that it is very difficult to accurately estimate the actual amount of debris in the pipeline and how it is distributed. All this creates risk and uncertainly.

In crude oil lines the situation is worsened by the fact that the debris that the client wants to remove can be oily, sticky and compacted so it is advised to try to clean and loosen the debris as part of any removal project.
Degassing is a very common operation usually performed during a change of service, maintenance and inspection or decommissioning.

Wherever possible this is done with mechanical pigs but there are many unpiggable pipelines which require this service. Often, pure Monoethylene Glycol is used but this is far from ideal as it does not form a strong barrier to the gas and relies very much on rapid, reliable pumping and even then, will use a large volume of MEG.
The ultimate aim for any client is to clean their pipelines as thoroughly and efficiently as possible. The contents of a pipeline can vary greatly so cleaning can involve a number of processes including;
  1. Dewaxing
  2. Deoiling
  3. Removal of Debris
  4. Removal of Black Powder
  5. Removal of toxic materials such as NORM scale or elemental Mercury
Effective dewatering is a critical part of any commissioning operation after hydrotesting has been completed and is often done during the lifetime of pre-existing pipework. Typically, this is achieved with conventional mechanical pigs either set up in temporary subsea launchers or performed from a platform or FPSO. In such cases the pigs used require full PLR facilities so the pig must be recovered, and this can add significant cost to an operations.

Further to this, the bore of the pipeline can vary along its length if it is an older pipeline which makes the line unpiggable by conventional means.
Deoiling is a very common operation and is typically performed during change of service, maintenance and inspection or decommissioning. In all cases the level of cleanliness is critical to prevent contamination of the aquatic environment.

A commonly required level of cleanliness is 30ppm Oil in Water. This is a necessarily strict target and can be difficult, time consuming and expensive to obtain, especially when operating from a vessel with very high daily rental costs.

To make matters more difficult, especially during decommissioning when the pipeline may have undergone many changes during its lifetime, the pipeline may have different diameters along its length making it unpiggable. In addition, access to the pipelines may only be possible through a narrow downline from a vessel.
During pipeline construction or maintenance, it is common to install new or replacement pipeline spools which are connected subsea. These spools are typically prefilled with glycol and brought out on vessel then are lower to the seabed by crane where the end caps are removed, and the spools connected. As soon as the caps are removed this allows seawater to flood into the spool which is a clear corrosion risk as well as ejecting the glycol contents to the sea which is a poor environmental practice.
The accumulation of wax and debris is a main cause of the blockage in pipelines.

Because the actual severity of the wax or debris accumulation cannot be known with absolute certainly a common issue with progressive pigging is that even the first foam pig can get stuck. This often results in a recovery pig being sent in to retrieve this stuck pig but then the recovery pig also gets stuck doubling the problem. Additionally subsequent pigs can get stuck because they remove too much wax which builds up in front of the pig causing it to stick further down the pipeline.
When pigging a very long pipeline or a pipeline which has scale or corrosion issues that can increase wear on discs there is always an elevated risk that the pig will get stuck in the pipeline due to disc abrasion and loss of differential pressure due to bypass.
RESCUE Stuck Mechanical Pig Recovery
An all-too-common occurrence in the pigging industry is when a mechanical pig gets stuck in a pipeline. This can be due to a build of wax or debris in front of the pig, though disc wear on long pipelines or they can get stuck at tight bends.

Sometimes it can be back flowed but often a rescue pig is sent in to recover this stuck pig only to end up getting stuck itself. The resultant cost of mechanical intervention can be eye wateringly expensive.

By selecting SANCCUS gel pig or pipeline gel technology as the first option the client massively reduces the risk of a rescue effort.
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