A method of prospecting for methane has been devised. The impetus for this method lies in the abundance of CH4 and the growing shortages of other fuels. The method is intended especially to enable identification of subpermafrost locations where significant amounts of methane are trapped in the form of methane gas hydrate (CH4·6H2O). It has been estimated by the U.S. Geological Survey that the total CH4 resource in CH4·6H2O exceeds the energy content of all other fossil fuels (oil, coal, and natural gas from non-hydrate sources). Also, CH4·6H2O is among the cleanest-burning fuels, and CH4 is the most efficient fuel because the carbon in CH4 is in its most reduced state. The method involves looking for a proxy for methane gas hydrate, by means of the combination of a thermal-analysis submethod and a field submethod that does not involve drilling. The absence of drilling makes this method easier and less expensive, in comparison with prior methods of prospecting for oil and natural gas.
The proposed method would include thermoprospecting in combination with one more of the other non-drilling measurement techniques, which could include magneto-telluric sounding and/or a subsurface-electrical-resistivity technique. The method would exploit the fact that the electrical conductivity in the underlying thawed region is greater than that in the overlying permafrost.
This work was done by N. Duxbury of Caltech and V. Romanovsky of the University of Alaska at Fairbanks for NASA’s Jet Propulsion Laboratory.
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Methane Clathrate Hydrate Prospecting
(reference NPO-30257) is currently available for download from the TSP library.
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Overview
The document presents a novel method for prospecting methane hydrate deposits, specifically focusing on methane clathrate hydrate (CH₄·6H₂O), developed by researchers at NASA's Jet Propulsion Laboratory. This method is particularly relevant in the context of the global energy crisis, as methane hydrates are estimated to contain more energy than all other fossil fuels combined, making them a significant potential energy resource.
The proposed technique emphasizes a non-drilling approach to identify subpermafrost locations where methane is trapped. This is achieved through a combination of thermoprospecting and geophysical measurement methods, such as magneto-telluric sounding and subsurface electrical resistivity techniques. The method exploits the differences in electrical conductivity between the thawed region beneath the permafrost and the overlying permafrost itself, which has lower conductivity.
Key to the method is the observation of the 0°C isotherm, which serves as the boundary between permafrost and thawed zones. The curvature of this isotherm can indicate the presence of underlying methane hydrate deposits. During the formation of methane hydrates, latent heat is released, increasing heat flow to the permafrost above, which results in a characteristic cap-shaped curvature of the isotherm. Conversely, during dissociation, latent heat is absorbed, leading to a bowl-shaped curvature. This bending of the isotherm can be detected using electromagnetic sounding methods, allowing for the identification of methane hydrate deposits without the need for drilling.
The document also highlights the advantages of this method, including reduced costs associated with prospecting, as it narrows down search areas and minimizes unnecessary drilling. Additionally, it notes that gas deposits are often found beneath gas hydrate deposits, and the presence of coal is frequently associated with these hydrates in permafrost regions.
In conclusion, the document outlines a promising and innovative approach to methane hydrate prospecting that could significantly enhance our ability to locate and utilize this abundant energy resource, contributing to future energy solutions while addressing environmental concerns associated with fossil fuel use.
