State proposes ROW change for CIGGS
Change will allow Hilcorp to use one CIGGS line for shipping oil under Cook Inlet to eliminate need for the Drift River terminal
The Alaska State Pipeline Coordinator’s Section is proposing to approve a change to the right-of-way agreements for two Cook Inlet gas pipelines, to allow the lines to carry oil rather than gas. The right-of-way changes are required as part of Hilcorp Alaska’s Cross Inlet Extension Project, a project to enable the shipment of oil by pipeline west to east under Cook Inlet. The project will eliminate the need for the Drift River oil terminal on the west side of the inlet. Currently, crude oil is shipped by tanker from Drift River to Nikiski on the Kenai Peninsula. There are safety concerns associated with the terminal because of the terminal’s proximity to Redoubt Volcano.
CIGGS linesThe two gas lines being switched to oil transportation consist of one of the twin Cook Inlet Gas Gathering System, or CIGGS, lines that run under the inlet, and the CIGGS LP line that used to deliver natural gas produced from the Middle Ground Shoal field to the currently mothballed Nikiski fertilizer plant. Hilcorp is also constructing some relatively short sections of new oil line to connect up the converted gas lines and to connect the lines to the oil infrastructure.
To compensate for the loss of gas carrying capacity across the inlet through CIGGS, Hilcorp is laying a new subsea gas line between the Tyonek offshore gas production platform and Ladd Landing on the west side of the inlet. An existing gas line connects the Tyonek platform with the gas transmission infrastructure near Nikiski - Hilcorp is replacing an onshore section of that line.
The CIGGS line is entirely located in state land, while the CIGGS LP line is located in a mixture of state and privately owned land. Conversion is anticipated in late summer, with the startup of oil transportation through the line planned for the fall, DNR’s right of way approval document says.
Commissioned in 1972The CIGGS pipeline system was originally commissioned in 1972. The twin pipelines are each 10 inches in diameter and 21.9 miles in length. Both pipelines have been operational since commissioning, with no known leaks, the approval document says. The CIGGS LP line is also 10 inches in diameter and is 3.77 miles in length. It was also constructed in 1972 and has no record of any leaks.
The state’s approval document says that repeated inspections of the CIGGS pipelines have revealed some wear but have found that the condition of the lines is well within acceptable operating standards. Regular inspections and maintenance of the system will continue, the document says. In addition, Harvest Alaska, the Hilcorp subsidiary that operates the company’s Alaska pipelines, will limit pressure in the converted CIGGS line to a maximum of 600 pounds per square inch, the document says.
Prior to a final decision on the right-of-way approval, the state requires public comments by Sept. 5.