From Berkeley Lab: “Depleted Gas Reservoirs Can Double as Geologic Carbon Storage Sites”

Berkeley Lab

Berkeley Lab scientists help verify science behind geologic carbon sequestration

Dan Krotz
JANUARY 05, 2012

“A demonstration project on the southeastern tip of Australia has helped to verify that depleted natural gas reservoirs can be repurposed for geologic carbon sequestration, which is a climate change mitigation strategy that involves pumping CO2 deep underground for permanent storage.

The project, which includes scientists from Lawrence Berkeley National Laboratory (Berkeley Lab), also demonstrated that depleted gas fields have enough CO2 storage capacity to make a significant contribution to reducing global emissions.

Aerial view of the Otway Project in Australia (Image: CO2CRC).

During an 18-month span beginning in April 2008, an international team of researchers injected 65,000 tonnes of CO2-rich gas two kilometers underground into a depleted gas field in western Victoria, Australia. That’s about 130 tonnes of CO2 per day, or the amount emitted by a small, 10-megawatt power plant. It’s also the daily CO2 emissions required to supply 6000 average U.S. homes with electricity.

Geological cross-section of the Otway Project. CO2-rich gas is extracted from the Buttress well (on the left), injected into the depleted gas field using CRC-1, and the Naylor-1 well houses the monitoring equipment installed by Berkeley Lab scientists. Faults are black lines.

‘There was no discernible leakage. The CO2 stayed within the reservoir and behaved as expected,’ says Barry Freifeld, a mechanical engineer in Berkeley Lab’s Earth Sciences Division who helped set up and interpret the site’s well-based monitoring equipment.”

See the full article here. There is a whole lot more in this article than I could possibly include.

A US Department of Energy National Laboratory Operated by the University of California

From Livermore Labs: “Hydrocarbons in the deep earth”

Anne M Stark
04/14/2011

“A new computational study published in the Proceedings of the National Academy of Sciences reveals how hydrocarbons may be formed from methane in deep Earth at extreme pressures and temperatures.

The thermodynamic and kinetic properties of hydrocarbons at high pressures and temperatures are important for understanding carbon reservoirs and fluxes in Earth.

The work provides a basis for understanding experiments that demonstrated polymerization of methane to form high hydrocarbons and earlier methane forming reactions under pressure.

Hydrocarbons (molecules composed of the elements hydrogen and carbon) are the main building block of crude oil and natural gas. Hydrocarbons contribute to the global carbon cycle (one of the most important cycles of the Earth that allows for carbon to be recycled and reused throughout the biosphere and all of its organisms).

The team includes colleagues at UC Davis, Lawrence Livermore National Laboratory and Shell Projects & Technology. One of the researchers, UC Davis Professor Giulia Galli, is the co-chair of the Deep Carbon Observatory’s Physics and Chemistry of Deep Carbon Directorate and former LLNL researcher.

Geologists and geochemists believe that nearly all (more than 99 percent) of the hydrocarbons in commercially produced crude oil and natural gas are formed by the decomposition of the remains of living organisms, which were buried under layers of sediments in the Earth’s crust, a region approximately 5-10 miles below the Earth’s surface.

But hydrocarbons of purely chemical deep crustal or mantle origin (abiogenic) could occur in some geologic settings, such as rifts or subduction zones said Galli, a senior author on the study.

‘ Our simulation study shows that methane molecules fuse to form larger hydrocarbon molecules when exposed to the very high temperatures and pressures of the Earth’s upper mantle,’ Galli said. ‘ We don’t say that higher hydrocarbons actually occur under the realistic dirty Earth mantle conditions, but we say that the pressures and temperatures alone are right for it to happen.’ ”

A snapshot taken from a first-principles molecular dynamics simulation of liquid methane in contact with a hydrogen-terminated diamond surface at high temperature and pressure. The spontaneous formation of longer hydrocarbons are readily found during the simulations.

See the full article here.