University of Texas at Austin

GCCC Listens in High Resolution for CO2 Stored off Japan’s Coast

October 5, 2017
GCCC Japan survey

After 4 days of mobilization, the 52-meter long Kaiko-maru #7 vessel was used for the survey.

In late August, the Gulf Coast Carbon Center’s Tip Meckel led a crew of 20 on a 6-day data-collection cruise off Japan’s north island of Hokkaido. Meckel’s team arrived in Japan with unique acoustic instrumentation for mapping the geology below the seafloor in three dimensions with ultra-high resolution. 

The key to the equipment is a set of four 25-m-long streamers containing eight-channel acoustic sensors that are towed behind a research vessel. When an acoustic signal from a compressed air source is deployed, changes in the speed of the sound returning to the dense array of sensors are converted to a very fine scale three-dimensional model of the geology beneath the seafloor.

The survey was conducted offshore from the industrial port of Tomakomai, the site of an extensive CO2 capture, transport, and injection-demonstration project. At the time of the survey, approximately 65,000 tons of CO2 had been injected into a geologic formation 1,100 m below the seafloor. The ultimate goal of the project is to store 100,000 tons of CO2 per year. 

The surveys conducted in August were the first to attempt high-resolution subsurface imaging at an active offshore CO2 demonstration project. Obtaining such information reduces the risk of leakage and could provide an estimate of the volume of CO2 stored in the reservoir. Meckel notes that the technology is suitable for deployment at other offshore sequestration sites, including sites located in the Gulf of Mexico. A second survey has already been funded to further test imaging and time-lapse capabilities. 
This work was supported by the DOE–NETL carbon sequestration research program. The Tomakomai demonstration project is operated by the Japanese Ministry of Economy, Trade, and Industry and an industrial consortium, JCCS Co., Ltd.
 

GCCC Japan survey

A compressed air acoustic source is deployed at the Tomakomai CO2 storage demonstration project in Hokkaido, Japan.

towing configuration

View of rear of the research vessel showing how for four 25-meter, 8-channel streamers and compressed air source were towed. The distant shoreline below the left crane is the industrial site where CO2 is produced and injected.