A New Angle On Solving Unpiggable Pipeline Challenges

This is a story of how GE's SmartLaunch™ system made in-line inspection (ILI) possible in “unpiggable lines” beneath the streets of New York.

Theoretically, any pipeline can be modified to allow in-line inspection. Practically however, the costs of excavations and permanent installations have been, in most cases to date, exceedingly prohibitive. Even where traditional modifications are feasible from engineering and logistics perspectives, flow interruption may not be an option – either because they are critical supply lines or because the associated lost revenues could be nearly insurmountable.

Notwithstanding, prudent pipeline integrity managers know the safety and productivity issues that are at stake over the long term. They are also well aware of the accuracy and planning benefits that high-quality in-line inspection data offer over potentially supply-disrupting alternatives such as hydrostatic testing. Compounding all these pressures is the simple fact that many operators, particularly in the U.S., now face strict regulatory deadlines to assess the integrity of their yet-uninspected pipelines.

So, many pipeline operators and distribution companies are in dire need of ways to proceed with in-line inspections of their “unpiggable” lines. But how--and at what cost?

New York City Autumn 2007

National Grid is one such company seeking an answer. Not yet facing a regulatory deadline, but taking a proactive approach to integrity planning, the company contracted GE Oil & Gas – PII Pipeline Solutions to inspect its two-mile Backbone pipeline running under the busy streets of Brooklyn and under an East River tributary into Queens.

Natural gas flow could not be interrupted for extended periods of time and there were no existing launch or receive traps. Essentially, there were no easy ways into this pipeline. Launch-site excavation had to be conducted near a busy traffic intersection with a population of nearly five million people around. This environment was truly a High Consequence Area and exactly the kind of situation for which SmartLaunch was created.

SmartLaunch

GE's system, which has a patent pending, utilizes an industry-standard angle hot-tapping process that leaves behind a stopple-type fitting that can be plugged and unplugged to facilitate installation of portable launch and retrieval spools to enable the current in-line inspection project and simplify future re-inspection.

SmartLaunch chute configuration.

To provide a manageable access point in restrictive environments (as was the case in Brooklyn and Queens), SmartLaunch's chute housings are installed temporarily to 45° angle split-tee fittings at both the launch and receive sites. Each housing incorporates a retractable chute that is hydraulically inserted through the angled fitting to ensure clean, safe passage of the ILI tools into and out of the operating pipeline. The equipment is configured to enable the use of conventional launchers and receivers as well as standard kicker pipe work to initiate inspection.

Designed for the most challenging settings, the SmartLaunch configuration requires that some very tight radius bends be navigated – including a 1D bend that cannot be passed by traditional ILI tools.