Geothermal Resources: An Energy Alternative

224 Pages·1980·9.704 MB·1-227\224

by  Harsh K. Gupta (Eds.)

Further titles in this series
1. I.L. ELLIOTT and W.K. FLETCHER (Editors)
GEOCHEMICAL EXPLORATION 1974
2. P.M.D. BRADSHAW (Editor)
CONCEPTUAL MODELS IN EXPLORATION GEOCHEMISTRY
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3. GJ.S. GOVETTandM.H. GOVETT (Editors)
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6. R.A. RICH, H.D. HOLLAND and U. PETERSEN
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PRODUCTION
8. M. KUZVARTandM. BOHMER
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9. C.R.M. BUTT and I.G.P. WILDING (Editors)
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Developments in Economic Geology 12
geothermal
resources:
an energy
alternative
by
Harsh K. Gupta
Assistant Director
National Geophysical Research Institute, Hyderabad, India
and
Adjunct Professor, Institute for Geosciences,
University of Texas at Dallas, Texas, U.S.A.
ELSEVIER SCIENTIFIC PUBLISHING COMPANY
Amsterdam - Oxford - New York 1980
ELSEVIER SCIENTIFIC PUBLISHING COMPANY
335 Jan van Galenstraat
P.O. Box 211, 1000 AE Amsterdam, The Netherlands
Distributors for the United States and Canada:
ELSEVIER/NORTH-HOLLAND INC.
52, Vanderbilt Avenue
New York, N.Y. 10017
Library of Congress Cataloging in Publication Data
Gupta, Harsh K 19^2-
Geothermal resources.
(Developments in economic geology ; 12)
Bibliography: p.
Includes index.
1. Geothermal engineering. 2. Geothermal
resources. I. Title. II. Series.
TJ280.7.G86 621.hk 80-1^659
ISBN 0-hkk-klQ65-2
ISBN 0-444-41865-2 (Vol. 12)
ISBN 0-444-41250-6 (Series)
© Elsevier Scientific Publishing Company, 1980.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or
transmitted in any form or by any means, electronic, mechanical, photocopying, recording or oth­
erwise, without the prior written permisson of the publisher, Elsevier Scientific Publishing Company,
P.O. Box 330, 1000 AH Amsterdam, The Netherlands.
Printed in The Netherlands
To My Parents
Smt. Sushila Devi and
Shri Vishnu Kumar
FOREWORD
The monograph Geothermal Resources: An Energy Alternative by Harsh
K. Gupta presents for the first time a readable, coherent account of all facets
of geothermal energy development. The development of alternative, renew­
able energy resources during the past decade has been spurred by a crunch in
the supplies of traditional hydrocarbon energy resources, which have
previously been inexpensive and readily available. The result has been a hur­
ried pace of research and development to bring alternative energy resources
on line. Geothermal energy promises to play a role in supplying electric
power, industrial process heating, and heat for buildings.
The book introduces the underlying concepts that are necessary for under­
standing the factors controlling the occurrence and characteristics of geo­
thermal systems. Earth's structure and the distribution of radiogenic sources
are integrated with the plate tectonic picture of the earth. The locations of
volcanic activity both present and recent geologic past are presented in this
plate tectonic context. The mechanisms of heat transfer are dominant factors
in understanding the potential pitfalls in the interpretation of heat flow sur­
veys and problems in producing geothermal energy.
Geothermal energy development draws together scientists from diverse
traditional disciplines, such as geologists, mechanical engineers, geophysicists,
and investors. While they may easily keep abreast of the developments in
their specialty, they must be able to converse with those from different
backgrounds. The account of these various fields is complete. The traditional
surveys such as the seismic reflection technique are used less frequently in
geothermal work than in hydrocarbon exploration, whereas seismic refrac­
tion or magnetotelluric are used considerably more. The technology related
to drilling and reservoir modelling at high temperatures in hostile environ­
ments raises problems that are unique to the geothermal industry. The treat­
ment and choice of material from each discipline reflects this emphasis.
After treating each of these disciplines in detail a unified case study is
presented of the Cerro Prieto geothermal field in Mexico. From the explora­
tion architecture used to establish a model of the geothermal system, Dr.
Gupta leads us through the problems of drilling and producing this resource.
The up to date accounts of geothermal resource models; geological, geo-
chemical, and geophysical exploration techniques; and drilling and produc­
tion technology appear in diverse technical journals and proceedings of
symposia. Dr. Gupta has extracted the important concepts and current tech­
nical developments from these sources and meshed them into a single volume
for these individuals whether graduate students or scientists, engineers, or
investors seeking a current account of this new technological field.
May, 1980 RONALD W. WARD
Director, Center for Energy Studies
University of Texas at Dallas
PREFACE
Although hot springs have been used for centuries for balneological pur­
poses, the use of earth's heat as a source of energy began early in this century
when electricity was generated for the first time from geothermal steam at
Larderello, Italy, in 1904. The spread of technology to other parts of the
world had been rather slow during the first half of this century. As a conse­
quence of the continuously increasing demand for energy and the rapid
depletion of other easily available sources of energy, geothermal resource
development has received a tremendous impetus during the last two decades.
The United Nations has contributed significantly to this development by
periodically organizing conferences. These include the conference on New
Sources of Energy held in Rome in 1961, the U.N. Symposium on the Devel­
opment and Utilization of Geothermal Resources at Pisa, Italy in 1970, and
the Second U.N. Symposium on the Development and Use of Geothermal
Resources held at San Francisco, California, in 1975. The growth during the
last decade can be visualized from the fact that during 1971, the total world­
wide production of electricity from geothermal resources was estimated to
be 700 MW, while today The Geysers installation in California, U.S.A., alone
produces 750 MW of electric power. Most of the recent developments have
been reported in research papers published in research journals and pro­
ceedings of various symposia. In the absence of a modern text covering these
developments, it is difficult for one to learn about the assessment, explora­
tion and exploitation of geothermal resources. The present text will fill this
gap.
This book summarizes the present-day knowledge on geothermal resources,
their exploration and exploitation. The first chapter draws attention to the
ever-growing world-wide consumption of energy and comments briefly upon
new methods of power generation. Special attention is given to the existing
and possible future potential of geothermal energy including an assessment
of geothermal resources in the United States. The second chapter deals with
the earth's structure, temperature and heat flow within the earth, and plate
tectonics hypothesis. In the third chapter the basic concepts of heat transfer
are discussed and quantitative relations for the heat flow from some geomet­
rically simple bodies are given. The fourth chapter explains the classification
of different kinds of geothermal systems. In the fifth chapter different
exploration techniques, viz. geological and hydrological, geochemical, geo­
physical and airborne, as practiced in geothermal exploration, are presented.
The sixth chapter deals with the assessment and exploitation of the geo­
thermal resources. The topics addressed in this chapter include drilling tech­
nology, reservoir physics and engineering, and production technology. The
Cerro Prieto geothermal field, Mexico, is one of the very successful geo-
X
thermal projects generating electrical power for which relatively complete
information is available. It is discussed in detail in the seventh chapter.
Chapter 8 presents the world-wide status of the geothermal resource utiliza­
tion as it exists at the time of the writing of this book. It is likely that some
geographical locations are not adequately covered due to lack of information.
In the last, the ninth, chapter, other important topics are addressed, such as
the artificial simulation of geothermal systems, the first geopressured geo­
thermal well, environmental factors and waste disposal, reinjection of geo­
thermal fluids, and the legal and the institutional aspects of geothermal devel­
opment. The coherent presentation of these topics in a single volume shall
serve as a text for graduate students as well as an introductory reference to
the field for explorationists and investors. An abundant bibliography, given
at the end, shall be helpful to readers in referencing more detailed documen­
tation when so desired.
Numerous researchers, research organizations, and companies involved in
geothermal resource development have been directly or indirectly helpful in
preparing the text presented here. They are too many to list. Discussions and
encouragement given by Professor Jim Combs during his tenure as Director
of the Center for Energy Studies, University of Texas at Dallas, have been
extremely useful. Much of the material was collected during extensive visits
to geothermal fields and installations in the U.S.A., Japan, Italy and Mexico.
Help and hospitality of concerned individuals and organizations is acknowl­
edged. Interaction with Professor J. Singh and Dr. R.N. Singh was useful.
Professors Ron Ward and Carlos Aiken offered some useful suggestions
during the final stages of production of this book. Assistance of Karen
Bellecci, Mike Hill, D.D. Singh, K. Suryaprakasam, Navin Chandra, K. Ramana
Rao, Chandra Pal, and Del Hunt in the preparation of the material for the
production of the book is gratefully acknowledged.
In the end, I would like to thank my wife Manju and my daughters Nidhi
and Benu for their continuing support of my activities throughout the years.
Dallas HARSH K. GUPTA
May, 1980
Chapter 1
THE ENERGY OUTLOOK
INTRODUCTION
With the increase in world population, industrialization and improvement
in the standard of living, there has been a continuously increasing consump­
tion of energy. In the absence of substantial historical data to estimate world
population prior to the seventeenth century, circumstantial evidence is often
used. It is generally believed that prior to 8000 B.C., agriculture was not
known and our ancestors at that time made their living by hunting and
gathering. Speculating on the basis of the population densities of the hunting
and gathering tribes of today, and that only one third of the world's total
land area could successfully be used for such living, the world's population
of 8000 B.C. is estimated to have been 5 million people. An examination of
archaeological remains and recent census figures for agricultural societies sug­
gest a world population of about 250 million people at the time of Christ,
which doubled to a population of about 500 million by A.D. 1650.
As a consequence of cultural, agricultural, industrial and medical revolutions,
time for the population to double has reduced from about 1500 years
(approximated for the period 800 B.C. to A.D. 1650) to 45 years during the
period 1930—1975. Table 1-1 shows the alarmingly decreasing trend in the
doubling time.
With the current rate of population growth, the United Nations forecasts
that the fifth billion would be added in about a decade and the world popula­
tion would exceed 6 billion much before the turn of this century.
TABLE 1-1
World population and the doubling time (United Nations, Statistical Office, Demographic
Year Book)
Year Estimated world Approximate time
population for population to
(in millions) double (in years)
8000 B.C. 5 1500
A.D. 1650 500 200
A.D. 1850 1000 (1 billion) 80
A.D. 1930 2000 (2 billions) 45
A.D. 1975 4000 (4 billions) 35
2
In the early times, say 400,000 years ago in the "early man" era, the
energy consumption of an individual was limited to what he ate (approxi­
mately 2000 calories) and this energy was obtained from the sun through
vegetable and animal life. Gradually he tamed animals and used them to bear
his burden of labor. Invention of the wheel improved the efficiency in the
use of energy. Then man learned to harness the energy of wind and water,
which became two prime movers. At about the time of the beginning of the
Christian era, water and wind mills were invented and were put to a variety
of uses. In the seventeenth century, coal began to be used for heating and
the mining industry developed in Europe. The invention and improvement of
the steam engine in the eighteenth century made power available on the spot
and ushered in the industrial revolution. By the turn of the 19th century, all
coal mines in England were equipped with steam engines to haul coal and
men, and to pump the water. Use of these steam engines for motive power
on mine railroads in 1828 was so successful that railroads spread all over the
world in the next 4 to 5 decades.
Michael Faraday's discovery of electromagnetic induction in 1831 laid the
foundation of the immense electrical industry of today. The invention of
electric light by Edison, although it has a more profound effect on living,
does not constitute a major factor in energy consumption. Then came the
invention of the internal combustion engine which has proved itself to be
extremely robust and reliable, and with it there has been an ever-increasing
demand for oil and discoveries of oil fields.
In recent years, the increase in energy consumption has been at least as
dramatic as the population explosion. Table 1-2 shows an estimate of the
world's energy consumption and production for the years 1951,1961,1966,
1971 and 1973. These statistics have been obtained by the United Nations
(World Energy Supplies Series) from the data available for approximately 185
countries with a combined population of 3802 million people in 1973. The
global trend of a continuously increasing demand for energy is evident from
this table. From 1961 to 1971, in a decade, world energy consumption in­
creased by more than 80%. There are two factors contributing to this increase:
(1) an approximately more than 20% increase in the world population, and
(2) a world-wide improvement in the standard of living, pushing the per
capita energy consumption up by almost 40%. Fig. 1-1 shows the past and
projected future growth of the world population, based on the United
Nations' "constant fertility projection" (with a 'medium estimate', expecting
a decreasing fertility, the world population is estimated to be 6.5 billion in­
stead of 7.4 billion by the year 2000) and of total and per capita energy
consumption. Obviously, a very sincere effort needs to be made to cut down
on population increase, limit our energy consumption and to find new
sources of energy to maintain present standards of living in the developed
countries and improve those of the developing countries.
It is interesting to note how closely per capita income and per capita
energy consumption are related. The United States of America, the most
3
TABLE 1-2
World energy consumption and production (United Nations, Statistical Office, World
Energy Supplies Series)
Year Total production Total consumption Consumption per
(106 metric tons (106 metric tons capita (kilograms
of coal equivalent) of coal equivalent) of coal equivalent)
1951 2822 2710 1075
1961 4418 4329 1387
1966 5621 5506 1653
1971 7260 7096 1931
1973 8485 7885 2074
D POPULATION, IN BILLIONS (left scale)
• ENERGY CONSUMPTION, IN
BILLION METRIC TONS OF
COAL EQUIVALENT (left scale)
A PER CAPITA CONSUMPTION,
METRIC TONS OF COAL
EQUIVALENT (right scale) /
I960 2000
Fig. 1-1. Past and projected future growth of world population and energy consumption.
The future growth of population is based on the United Nations' constant fertility pro­
jection.
affluent country in the world today, with 6% of the world's total population,
consumes energy amounting to about one third of the world's total energy
consumption. Fig. 1-2 shows the wide diversity in energy consumption and
per capita incomes that exists today in different parts of the world. This
figure also helps in visualizing the ever-growing energy demands of the future
that would result from the improving standard of living in developing coun-