Problems with Operational Pigging In Low Flow Oil Pipelines

Abstract

Pigging of pipelines within the oil industry has been around for well over 100 years and has been used as the preferred (if not the only) internal method for cleaning, maintaining operational efficiency, data gathering and inspection for integrity management purposes. The benefits in carrying out routine “operational” pigging cannot be underestimated and operational pigging to remove water, wax, scale and other debris which is formed during routine operations whilst transporting crude oil and gas is paramount in maintaining the integrity of any crude oil and gas pipeline system. The build up of such debris is common whether the pipeline is offshore between production platforms, from a production platform to onshore or a totally land based pipeline. Similar problems are encountered to varying degrees dependent on pipeline size, location and type of the crude product being transported. Pipelines are normally designed for a specific maximum flowrate, this maximum rate is generally maintained on a “plateau” for several years of a field’s life, during which routine pigging operation presents little or no real problem to the pipeline operator. The cleaning pigs which are used are generally designed for the “maximum” of “potential flowrate” which the pipeline is due to see during it’s plateau phase of operation. This assumption, that these pigs will be suitable for the life of field operations, is common place with pipeline operators and as such there is a significant increase in the risk that pigs will become “stalled” on a regular basis or potentially “stuck” causing significant disruption to operation, production and in the worst case scenario a very costly subsea intervention. As can be seen from Industry Analysts¹ there will be a decline in overall oil production not just from the UK Sector but from the North Sea Basin and Europe as a whole. Therefore the need to understand pigging operations in “low flow” modes of operation cannot be stressed highly enough.

Original document

The different versions of the original document can be found in:

• http://pdfs.semanticscholar.org/b9ca/f4f0d5c599da506927a914a5b4ecc063ff39.pdf

• http://www.onepetro.org/google/Papers/SPE/eLibrary_Papers/spe/2011/11OE/SPE-143748-MS/SPE-143748-MS-P.pdf?id=SPE-143748-MS&soc=SPE,

http://dx.doi.org/10.2118/143748-ms

• https://www.onepetro.org/conference-paper/SPE-143748-MS,

https://academic.microsoft.com/#/detail/2039688160