projects currently supported by the Program, including their achievements and the remaining knowledge gaps.
The “goal” in methane hydrate research and development is the identification and quantification of technically and economically recoverable natural gas from methane hydrate occurrences. Because of the paucity of reliable field data, past research focused on the basic documentation of the existence and regional locations of global methane hydrate occurrences. More recently, a number of new quantitative estimates of in-place methane hydrate volumes have been undertaken using petroleum systems concepts developed for conventional oil and natural gas exploration. When combined with field investigations to establish the physical properties of methane hydrate deposits in different geologic settings, a basis has also been established for considering production methods and recoverability.
Over the past 30 years a number of researchers have compiled global inventories of the total potential volumes of natural gas occurring as methane hydrate (Kvenvolden, 1988, 1993; Milkov, 2004). These estimates have garnered much interest and served to stimulate consideration of methane hydrate as a possible global energy resource. However, the utility and application of these estimates are limited because they range over several orders of magnitude and the knowledge and data upon which the predictions have been made remain largely speculative and with correspondingly large uncertainties. For example, early methane hydrate resource determinations in the 1980s and 1990s relied mainly on indirect evidence such as bottom-simulating reflectors (BSRs) identified in marine seismic surveys, or on estimates of the portion of the methane hydrate stability field that might reasonably contain methane hydrate from microbial and thermogenic sources. In the past 15 years a number of dedicated methane hydrate drilling campaigns have been undertaken around the world (see