The U.S. Department of Energy (DOE) methane-hydrate program is making a giant leap forward in 2015 with a new field test. Field tests are critical to understanding the characteristics of in-situ hydrates and their potential to produce methane. However, field experiments are expensive and complicated, requiring a drillship and the participation of many scientists and engineers from multiple organizations. One does not need a calculator to tally the number of offshore and arctic production experiments.
One question might be why we should care about methane hydrates. There are three major reasons why we should. First, the world will continue to depend on fossil fuels well past 2040—as far ahead as most reliable projections—and natural gas is the cleanest option. Second, some countries that do not have sufficient indigenous energy have potentially large methane hydrate resources—Japan, Korea and India for example. Finally, methane hydrates occur in low concentrations over vast areas of the seafloor and shallow subsea sediments around the world, including the Arctic. If these areas get warmer, the hydrates may dissociate releasing methane.
We may not need the natural gas today, but remember that in the early 1990s research into shale gas was considered a waste of time and money. It was this research that helped industry develop the technology that has made the U.S. a global energy power.
In the past 15 years global methane-hydrate research has moved from predicting general locations where deposits might occur to using sophisticated geophysical techniques to pinpoint potentially commercial subsurface deposits.
The small numbers of field tests are the product of dozens of laboratory and geophysical studies and field measurements by scientists in many countries. These studies clarified the geologic conditions necessary for highly concentrated hydrate deposits and developed the remote sensing technologies needed to locate concentrated deposits. In addition, scientists have clarified the role of methane hydrates in the global carbon cycle.
The next U.S. field test is planned by the University of Texas at Austin, in partnership with The Ohio State University, Columbia University-Lamont-Doherty Earth Observatory, the Consortium for Ocean Leadership and the U.S. Geological Survey. Their four-year effort plans to characterize prospective drilling locations in the Gulf of Mexico, then collect pressure cores and well logs and conduct short-duration pressure drawdown tests in 2018.
The last Gulf of Mexico coring and pressure drawdown testing expeditions were in 2005 and 2009.
Japan, India and South Korea are also characterizing offshore hydrate deposits in anticipation of future production testing.
- The Japanese government completed a successful flow test, producing methane from marine hydrates in the Pacific Ocean offshore southeastern Japan in 2012-13. This followed a 2004 coring and well logging expedition. In addition, in 2014 Japan measured and sampled methane hydrates in the Sea of Japan.
- In 2006 a multi-national team led by the Indian Directorate General of Hydrocarbons collected cores and well logs at 21 sites offshore India.
- South Korea conducted offshore expeditions in 2007 and 2010 to characterize and quantify their resource, and plans to conduct a production test in 2015.
The production potential of methane hydrates has also been tested in the Arctic.
- In 2007-08 a multi-national team led by Canada and Japan completed experiments on the thermal and depressurization production of methane from hydrates at a location in the Mackenzie delta, Northwest Territories, Canada. These experiments were preceded by a 1998 stratigraphic test well and a 2002 thermal heating experiment.
- In 2007 a DOE-BP project successfully drilled, cored and tested a well in the Prudhoe Bay field to help define how hydrate deposits respond to depressurization.
- In 2011-12 the DOE partnered with ConocoPhillips and the Japan Oil, Gas and Metals National Corporation to inject carbon dioxide (CO2) into a Prudhoe Bay well to determine the efficiency of simultaneous methane production and CO2 storage in the hydrate reservoir.
About the photo: IODC is an international program of which the US is one of 26 member countries. IODC has two large drill ships: Japan operates the Chikyu in the above picture and the US (National Science Foundation) operates the Joides Resolution. The Chikyu is a new ship (launched 2002) and the Joides (launched in 1978) was refitted in 2009. Both have been used by for methane hydrate expeditions.