THE FUTURE OF ENERGY GASES

PREFACE The ever-present concern of meeting U.S. energy needs led the Geological Survey in 1992 to initiate a series of publications that addresses the potential for an expanding role of energy gases to help sustain our domestic energy needs. This series is drawn from the Survey's own wealth of research as well as from academic, business, other government facilities, and private sources. We use the term "energy gases" to distinguish those natural gases, primarily methane, that have utility for energy purposes from the many other forms of natural gas. Recent discussions among economists, environmentalists, lobbyists, and scientific research groups within the energy industry have focused on the contributions of energy gases to the world's energy requirement. These discussions center around questions of gas supplies, assessing economic risk, future prices, and uncertainties of deliverability. What is often missing from these discussions, however, is a firm understanding of the fundamentals of energy gases: What are they? How do they form? Where are they found? How can they be exploited and at what costs? What are the environmental consequences associated with an expanded role of energy gases? Energy gases, particularly methane, are commonly associated with oil, and, indeed, huge supplies of methane have been found while exploring for oil. But only a small share of all methane is associated with oil and, importantly, methane forms in some settings totally independent of oil. Methane is found in association with coal; it is a byproduct of metabolic processes in microorganisms; it originates from great depths in the Earth's crust (it may even occur in the mantle); it occurs in the molecular lattice of ice in the Arctic and offshore areas below the sea floor; and it is often dissolved in water in large aquifers. Thus exploration efforts for gas are in many ways fundamentally different from exploration strategies for oil. Additionally, a variety of these settings contain truly enormous amounts of gas, but it is either dispersed throughout low-permeability horizons or concentrated in an ice lattice (hydrates); therefore, exploitation of these resources involves unique engineering problems rather than exploration uncertainties. T o start the process of addressing these energy-gas issues, we organized a workshop in October of 1992 to which a spectrum of researchers was invited from government, universities, and the gas industry. Approximately 75 specialists participated in discussions ranging from the origin of energy gases to how methane may provide a bridge to a hydrogen-based energy system in the future. This volume reflects the themes discussed at the workshop; it makes no attempt to offer new resource assessments because a variety of such studies already exists. Rather, its goal is to provide the fundamental information about energy gases, describe the attributes that make gas a beneficial fuel, provide ideas on how gas could be more fully integrated into an energy strategy, and explore the problems that may lie ahead if society shifts toward heavier use of energy gases. Woven throughout the volume are indications that a great deal is still unknown; these unknown factors may provide the focus for future research. Besides this volume, two additional companion products have been produced as follow-up products to the workshop. One is a 30-minute video entitled The Future of Energy Gases that is directed to nontechnical audiences and provides a general introduction to energy gases. The second is a pamphlet, also entitled The Future of Energy Gases (U.S. Geological Survey Circular 11 15), which provides a nontechnical summary of energy-gas issues with numerous illustrations. Together, the three products constitute a package offering a look at the topic of energy gases ranging from very general to highly technical. We would appreciate comments from readers, both in terms of the effectiveness of each piece as well as any suggestions for future products and research directions

District Chief U.S. Geological Survey

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