Houston, Texas-based Enterprise Products Partners and Canadian Enbridge Inc. have completed the construction of a 512-mile section of the Seaway Pipeline system, running from Cushing, Oklahoma, to the Jones Creek terminal near Freeport, Texas.

However, oil will not flow through the newly built loop until testing and commissioning work have been completed as well, the two companies said in a joint statement. Additional procedures are expected to wrap up in the third quarter of 2014, when the pipeline will officially go online. Once the loop is running at full capacity it will carry about 850,000 barrels of oil per day, which is more than double the current capacity of the Seaway System. Experts believe that the launch of the new pipeline will significantly relieve the glut of oil in Cushing.

In addition to the pipeline, the Seaway System includes a terminal facility and a distribution network based in Texas City, which delivers crude to the Houston area and serves local refineries. The pipeline is owned by Seaway Crude Pipeline Company LLC — a 50/50 joint venture formed by Enbridge and Enterprise Products Partners.

Meanwhile, Enterprise Products Partners said that its 100-mile pipeline from Enbridge's storage tanks in Houston to Beaumont and Port Arthur would also be completed later this month. This pipeline is also expected to go through commissioning work in the third quarter, Enterprise said.