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Editor 's Note: High-velocity pipelines often require significant cutbacks in production to achieve safe operating parameters for routine pig runs or ILI programs. P2D/Inline introduces their latest development in intelligent speed control, designed to maintain acceptable pigging speeds for routine pigging and intelligent cleaning for flow assurance management with minimal impact on production.
This article discusses development of the dynamic speed control system, initial field trials, operational success and its application for maintenance pigging, intelligent cleaning, debris mapping, and black powder removal as part of an operator's pipeline integrity management strategy.
Pipeline cleaning and dewatering is most effective when a cleaning pig is traveling at no more than 1 1 mph (5 m/s). Above this speed the pig's cleaning performance is adversely affected, meaning the pipeline will no longer be cleaned effectively. There are also pig receipt issues when running pigs at high velocities. In most cases pig speed is not an issue as product flow velocity does not exceed the optimum pig speed and a standard cleaning pig such as a BD6 steel mandrel pigs.
However, there are an increasing number of gas pipelines which have "ultra-high velocity flow" in which the product can be flowing at speeds of up to 24 mph ( 1 1 ms-1 ). These pipelines tend to be large-diameter (36-42-inch) trunk pipelines covering large distances. The usual procedure for pigging these high-speed pipelines is to reduce pressure and flow to suitable levels to allow the cleaning pig to run close to the magic 1 1 mph (5 m/s) value. From an operator's perspective this is a costly exercise as flow often has to be reduced for several days. This needs extensive planning and leads to lost revenue from reduced gas flow.
Speed control pigs have been used for some time to provide inline inspection (ILI) companies with a stable platform to tow inspection tools. However, there has been very little use of speed control for cleaning pipelines. So a speed control pig (SCP) that is suitable for cleaning of these high-velocity pipelines was the way to go. This tool has now been run in several pipelines with great success.
By using a cleaning pig capable of speed control it is possible to very effectively and safely clean a high-velocity...