This book is a companion to "Natural Gas Hydrate in Oceanic and Permafrost Environments" (Max, 2000, 2003), which is the first book on gas hydrate in this series. Although other gases can naturally form clathrate hydrates (referred to after as 'hydrate'), we are concerned here only with hydrocarbon gases that form hydrates. The most important of these natural gases is methane. Whereas the first book is a general introduction to the subject of natural gas hydrate, this book focuses on the geology and geochemical controls of gas hydrate development and on gas extraction from naturally occurring hydrocarbon hydrates. This is the first broad treatment of gas hydrate as a natural resource within an economic geological framework. This book is written mainly to stand alone for brevity and to minimize duplication. Information in Max (2000; 2003) should also be consulted for completeness. Hydrate is a type of clathrate (Sloan, 1998) that is formed from a cage structure of water molecules in which gas molecules occupying void sites within the cages stabilize the structure through van der Waals or hydrogen bonding.
This is the first book that attempts to broadly integrate the most recent knowledge in the fields of hydrate nucleation and growth in permafrost regions and marine sediments. Gas hydrate reactant supply, growth models, and implications for pore fill by natural gas hydrate are discussed for both seawater precursors in marine sediments and for permafrost hydrate. These models for forming hydrate concentrations that will constitute targets for exploration are discussed, along with exploration methods. Thermodynamic models for the controlled conversion of hydrate to natural gas, which can be recovered using conventional industry practices, suggest that a number of different types of hydrate occurrence are likely to be practical sources of hydrate natural gas. Current progress in the various aspects of commercial development of hydrate gas deposits are discussed, along with the principal extractive issues that have yet to be resolved.
The book will be of interest to petroleum geologists, earth scientists (marine geology and geophysics), government departments and institutions concerned with energy resources.