Radioactive tracers OK’d at Prudhoe plant

The Alaska Oil and Gas Conservation Commission recently approved a request from BP to inject low-level radioactive tracers into a plant that processes crude oil in the Prudhoe Bay field.

The company said it planned to use the tracers in a capacity study at Gathering Center 2, in Prudhoe’s western operating area. The plant separates oil, gas and water.

The study will look at the efficiency of various vessels in GC2 and guide “appropriate upgrades to the facility for increased separation capacity,” BP said in a May 14 letter to the commission.

Radioactive tracers are chemical compounds with widespread application in industry, medicine and research.

The tracers can be detected or measured easily by their emissions, and can show the movement of liquids within piping and vessels.

BP told the commission the half-lives of the tracers it planned to use in the GC2 study would be less than two days.

‘Exceedingly small’ volume

BP said it considered using alternatives to radioactive tracers, but decided against them.

“A non-radioactive tracer would require frequent sampling, and there is a possibility the tracer would pass through the system between samples, yielding no data,” BP said. “The ability to characterize vessel inefficiencies would be compromised with a non-radioactive tracer.”

To allow the use of radioactive tracers, the commission on June 20 amended area injection orders for Prudhoe and related oil pools including Aurora, Borealis, Polaris and Orion.

“After passing through the production facility the radioactive tracers would be entrained in the produced water injection system and injected in enhanced oil recovery and disposal wells,” the order for the Prudhoe oil pool said.

The order added: “The volume of radioactive tracer material will be exceedingly small in proportion to the millions of gallons of produced water that GC2 handles on a daily basis.”

—Wesley Loy