The 22-inch line was immediately shut and initial estimates of the release volume indicated about 30 barrels, the spokesperson told Reuters via email.

The Zydeco pipeline system alleviates transportation bottlenecks of crude arriving in Houston from the Eagle Ford, Permian and Bakken regions, according to Shell Midstream Partners' website. The system connects several crude oil pipelines in Houston and Port Neches, and spans over 350 miles (563.27 km), with a mainline capacity of 375,000 barrels per day.

(Reporting by Arundhati Sarkar and Kavya Guduru in Bengaluru; Editing by Christopher Cushing and Uttaresh Venkateshwaran)