This paper discusses the benefits of inline pipeline isolation as an alternative to line stopping. Real world examples are discussed where double block inline isolation tools have facilitated pipeline modification, resulting in reduced project costs and production downtime, while minimising the discharge of emissions.
Operators can often encounter difficulties in isolating sections of their pipeline to facilitate essential safe repair or maintenance activities if appropriate valves are absent from the line. Inline isolation pigs provide fully proven and monitored dual seal barriers that ensure the safe breaking of containment on pressurized systems in compliance with the highest industry standards.
Unlike traditional Line Stopping activities, piggable isolation tools require no welding or cutting into live lines, leaving no residual fittings or hardware on the pipeline. This eliminates project costs associated with fittings, welding and inspection and reduces the risk of leak paths from buried pipeline flanges post operations.
Line stopping often requires pipeline excavation and site establishment including lifting and rigging operations which is usually eliminated by deploying inline isolation pigs. Tracking, operation and communication with in-line isolation pigs can be achieved remotely through ground and pipe wall preventing the need for costly site establishment and reducing the risk of digging and lifting operations around the pipe.
In-line isolation tools significantly reduces, and in some cases eliminates, the requirement to vent or flare harmful emissions into the atmosphere during maintenance activities. One of the most significant environmental advantages is the substantial reduction in greenhouse gas emissions verses venting the pipeline. In the case of long, large diameter gas pipelines, this can prevent the potential discharge of thousands of tons of methane into the atmosphere.
Following the completion of the maintenance activities, a reinstatement leak-test of the replaced valve or pipework can be performed while the isolation is still in place. And provides an alternative to golden welds.
Real world examples will be discussed where double block inline isolation tools have facilitated pipeline modification, resulting in reduced project costs and production downtime, while minimising the discharge of emissions.
The utilization of in-line isolation tools not only enhances the efficiency and safety of pipeline repair and maintenance but also aligns with increasing demand to reduce emissions and create a more sustainable energy infrastructure for the future.
Challenges for this technology will also be discussed, including long distance deployments in gas pipelines where the tools must be stopped midline with suitable accuracy. Also, a high degree of confidence of pipeline condition (bore, wall thickness) is required before inline isolation tool pigging as the hard OD of the tools is close to the ID of the pipe and good information is sometimes difficult to obtain.
Author: Wes Gardner