Tesoro Logistics LP will restart its High Plains crude oil pipeline in North Dakota that has been shut down since Sept. 29 when a rupture and leak were discovered, the San Antonio pipeline master limited partnership announced.
The announcement came a day after the US Pipeline and Hazardous Materials Safety Administered issued a safety order requiring TLLP’s Tesoro High Plains Pipeline Co. (THPP) to take corrective measures after 20,000 bbl of crude leaked from a small hole in the line into a field north of Tioga, ND.
TLLP reported that PHMSA has accepted a detailed restart plan the company submitted under the safety order. The agency and carrier also have completed a preliminary analysis of the failed segment, which was removed and sent to an independent laboratory for further study, the pipeline operator said.
The US Department of Transportation agency issued the order Oct. 31. PHMSA ordered THPP to perform frequent aerial and ground inspections and install additional leak detection equipment. It said the company also must update maps of the entire system and evaluate the 700-mile long pipeline to identify further preventative measures to protect important water bodies.
THPP also will be required to conduct mechanical and metallurgical testing and analysis of the failed pipe, and evaluate previous inspection results, according to PHMSA. The failed pipe segment has been removed and sent to a lab for analysis, it said. New pipe has been installed and tested, and pressure and flow detection systems have been installed, PHMSA said.
“While final results are pending, the preliminary report indicates that the likely cause of the small diameter hole in the pipeline was from electrical discharge,” TLLP said Nov. 1. “The source of the electrical current remains under investigation. According to the initial lab report, there were no signs of corrosion or other defects at the failure location.”
Specific steps
It said to ensure integrity before restarting the line, THPP performed a hydrotest of the replaced segment, and executed a tightness test holding pressure on the 35-mile section of the line from Tioga to Black Slough to verify the system was sound.
Investigations also were conducted at six different locations along the pipeline to address findings from the Sept. 10-11 smart pig inspection of the 35-mile section from Tioga to Black Slough, and found no areas of concern, TLLP indicated.
It said THHP also installed additional integrity monitoring equipment and online analysis along the entire 35-mile section designed to detect indications of a potential leak.
“As of Oct. 31, more than 4,500 of the estimated 20,000 bbl released have been recovered from the site,” TLLP said. “There have been no injuries or known impacts to water or wildlife as a result of this incident. Remediation is under way. Since becoming aware of the spill, TLLP has worked closely with the landowner; PHMSA; the North Dakota Department of Health; and public safety and regulatory authorities.”
North Dakota’s Department of Health, meanwhile, reported that is developing a web page that will publish information about crude oil and product, agricultural, and commercial spills which are reported. Incident reports, which state law requires, are public documents already and would be easily accessible on the department’s website, it said on Oct. 25.
Contact Nick Snow at [email protected].
