- Email: [email protected]
Wringing out the earth
Earth-Science Reviews 49 Ž2000. 279–284 www.elsevier.comrlocaterearscirev
Earth Reflections
Wringing out the earth A.J. van Loon ) Geocom, Benedendorpsweg 61, 6862 WC Oosterbeek, Netherlands Received 2 January 2000; accepted 2 January 2000
Abstract The increase in global energy consumption urges the exploitation of known energy resources in the most efficient way. The oil and gas industry seems well capable, but politics may hamper optimum recovery, even though politicians advocate that the laws and regulations laid upon the industry are meant to promote a sustainable society and to diminish environmental pollution. Lack of geological insight sometimes plays a role, which implies that an attitude of effectively wringing out the Earth is not sufficient: more attention for earth-scientific education may turn out to be even more important. This does not affect, however, the need for ever more effective technologies for wringing out the Earth. q 2000 Elsevier Science B.V. All rights reserved. Keywords: energy policy; mineral exploitation; natural gas; oil
1. Introduction Economic prosperity has, as far as known from historical sources, always been based on the availability of sufficient energy. In ‘classical’ times, like in the Egypt of the pharaos, the most important source of energy was manpower, just like it is still nowadays in many developing countries. The structural use of animals was a next development, but a main step forward was the taming of natural forces. Hydropower and wind energy have been used for a long time on a small scale, but it lasted until the 17th century before one of these sources, i.e., wind energy, became used at what might be called an industrial scale. The knowhow gained in the Netherlands )
Tel.: q31-26-339-0908; fax: q31-26-339-0783. E-mail address: [email protected] ŽA.J. van Loon..
and the common application of wind mills Žfor numerous purposes, including the reclamation of polders. and sailing ships Žfor ‘plundering’ colonies and for trade with other countries. then formed the basis for the Dutch ‘golden age’, during which time many more people than ever before lived in prosperity. This prosperity is still reflected in the beautiful houses along the canals in Amsterdam and several other cities, in the mansions that merchants built outside the larger cities, and — last but not least — in the pieces of art of the time Žfor instance, the paintings by Rembrandt van Rijn, Frans Hals and Jan Steen, to mention only a few.. Energy has been recognised as a most valuable and indispensable asset ever since, and both individuals and authorities worldwide have promoted the development of energy sources. Wood, peat, browncoal and coal were the first types of fossil fuels to be
0012-8252r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. PII: S 0 0 1 2 - 8 2 5 2 Ž 0 0 . 0 0 0 0 6 - 4
280
A.J. Õan Loon r Earth-Science ReÕiews 49 (2000) 279–284
exploited on a large scale, and it soon turned out that overexploitation Žby lack of alternatives. could raise huge problems. Western Europe became largely deforested during the Middle Ages because of the need for fuel; a similar problem is faced nowadays in several developing countries, particularly in the border zones along deserts. In England, the use of coal became forbidden in several cities because of the unbearable smog that resulted from the large-scale use of coal; the problem was solved only in the middle of the 20th century, when not only alternative energy sources became available, but also technologies to purify the exhaust gases of factories, power plants, etc. It is only slightly more than a century ago that oil — and even later natural gas — became alternatives for coal, and good alternatives, indeed. Not only because they cause less environmental problems Žwhich was not a topic at all one century ago., but because it can be transported much more efficiently and because it allows applications previously only dreamt of. The first oil derrick, owned by E.L. Drake Ž1819–1880., was constructed in the 1860s in Titusville, PA. It would later be recognised as the first of its kind of a technological device that would change the world. Now it is hardly possible to imagine a world without oil and gas. And where ‘wild cats’ may have proven to be profitable in the past, the hunt for oil and gas now needs sophisticated technologies to be successfully enough to meet the economical and environmental demands. It is highly alarming in this respect that, where new finds of oil and gas previously compensated for the exploited amounts, 1998 was the first year for decades during which more oil was used than discovered. This unfortunate — though expected — development emphasises once more the need to use the available natural sources as efficiently as possible, and to explore the Earth for more resources in the most effective way. This message is understood nowadays by all major companies involved in prospecting, exploiting and refining natural sources, and fossil fuels in particular. A result is that wringing out the Earth is common business now ŽGoode, 1999., even though it is generally acknowledged that this cannot go on forever, considering the limited sources ŽMeadows, 1972., especially in the context of a rapidly growing population that claims
increasing Žaverage. amounts of energy per capita Žcf. Abelson, 1999..
2. The hunt for energy in a changing world The hunt for oil and gas becomes increasingly difficult. As in the case of other natural resources, the best accessible occurrences were found Žand exploited. first, and the largest oil and gas fields found during the intensive exploration activities were also developed first. A consequence is that few exceptionally large fields Žlike those in the Gulf of Mexico, or like the Slochteren gasfield in The Netherlands. will become available in the future. Another consequence is that the investments per recoverable barrel of oil or cubic metre of gas strongly increased in the past decade. The low probability of discovering new huge fields is an additional reason to wring out all existing fields as much as possible. This is not only a task of the companies involved, but also of the national authorities involved. Their power, by means of regulations, tax facilities, etc., is great enough to prevent fields being given up when the potentially recoverable oil of gas has not yet been extracted entirely. Governments of oil-producing countries might favour wringing out the fields in their territory by financial encouragement of the companies involved. It is also possible for national authorities to develop policies that spare the giant occurrences for future use Žor for use during periods when demand will be higher than supply from other sides.. An example is the ‘small-fields’ policy in The Netherlands, which was developed after the oil crises of the 1970s ŽGasunie, 1998.. It is meant to prolong the lifetime of the huge Slochteren gasfield, which has a remaining expected reserve estimated at 1212 = 10 9 m3 wEZ ŽDutch Ministry of Economic Affairs., 1999x. This field Žalso known as the Groningen field. was discovered in 1959 and has been exploited since the beginning of the 1960s ŽDronkert and Dijkhuis, 1999.. It is used nowadays primarily as some kind of reservoir for cold days, when the production from other gasfields can, for technical reasons, not cope with the demand. Production at a sufficient level is helped by the installation of compressors ŽNAM, 1998.. A consequence of the ‘small-fields policy’ is,
A.J. Õan Loon r Earth-Science ReÕiews 49 (2000) 279–284
obviously, the necessity of investing more money to wring out the small fields both onshore and offshore. Practice shows, however, that the policies followed by authorities are not always mutually and internally consistent, and that they may even be counter-productive. This will be illustrated by another example from The Netherlands Žwhere relatively few parties are involved.. Authorities can, however, also stimulate developments that are profitable for all parties involved, as will be shown with developments taking place along the Gulf Coast Žwhere many parties are involved..
3. Inconsistent and counter-productive policy: the ‘ Wadden Sea debate’ Whereas the ‘small-fields policy’ in The Netherlands seems effective, a consistent policy is lacking at other points. This is reflected by the current ‘Wadden Sea debate’. The NAM company had been granted, already some decades ago, an ‘eternal’ right to explore for oil and gas in the Wadden Sea ŽFig. 1., the tidal-flat area north of The Netherlands Žand continuing off the coast of Germany and Denmark.. Since the Wadden Sea is an important natural reserve, environmentalists opposed the concession, which led several years ago — after discussions between NAM and the Dutch government — to a moratorium, during
Fig. 1. Characteristic part of the Dutch Wadden Sea Žnear the island of Texel. at ebb tide, showing a tidal channel between sandy shoals.
281
which period NAM would not start any new drilling activities in the area. After the period of the moratorium had recently been ended, government took, under the pressure of environmentalist groups, new steps to make NAM refrain from oil and gas exploitation in the Wadden Sea. For the purpose, the government considers to break up one-sidedly the concession. This development, which is backed by a great majority of the political parties, was defended with the argument that new research had to be carried out first. If such research would prove beyond any reasonable doubt that the NAM activities would impose 0% of risk on the environment, permission for drilling activities might be given; if some doubt would remain, no permission will be granted. It is obvious that such a governmental policy was not based on scientifically sound considerations: a 0% risk does not exist. 3.1. Lack of knowledge Even more alarming was that the governmental decision was taken apparently on the basis of lack of knowledge. NAM had developed plans for deviated drilling from the mainland, with the purpose of reducing risk for the tidal-flat environment to a minimum. The principle of deviated drilling was, however, not understood by the Prime Minister, Kok, as he proved during a television interview. He tried to show why such a boring could easily affect the environment: the borehole started on the mainlaind would, according to him, go down vertically, bend off to a horizontal position Ža technique that exists, indeed, but for other purposes: Cooney and Fisher, 1995., just underneath the surface of the Wadden Sea, until the location above the gasfield was reached, and then bend off again vertically towards the gas. The horizontal borehole just underneath the surface of the vulnerable natural reserve thus was ‘shown’ to represent a great risk. Also alarming is the fairly general belief in The Netherlands that subsidence of the sedimentary surface due to extraction of gas from underneath the Wadden Sea must be disastrous. Calculations predict a maximum subsidence in the central part of 28 cm during the next decades. This would, according to
282
A.J. Õan Loon r Earth-Science ReÕiews 49 (2000) 279–284
environmentalists, almost all political parties, and the Minister of Environment, Pronk, terminate the Wadden Sea, because the shoals Žin between channels. that are submerged during flood and that fall dry during ebb tide, would become continuously submerged. It is apparently not understood that the Wadden Sea is a dynamic environment, where the sedimentation rate will probably keep pace with subsidence; if not, the shoals will not disappear, but the channels will widen at the cost of the shoals until sufficient material will have been supplied to compensate for the subsidence. A continuous supply of sand and mud is guaranteed by the longshore currents. It is interesting in this framework that no authority seems to realise that the Wadden Sea is a consequence of the fast sea-level rise after the last glaciation, and that it is doomed to disappear now that the rise has become almost nil: erosion at the seaward side of the Wadden islands and aggradation of the islands at the tidal-flat side, in combination with the seaward growth of the salt marshes on the mainland, will result in the natural disappearance of the tidal-flat area, probably within a thousand years or so. Subsidence of the area by gas exploitation just might slow down this process a bit. 3.2. Inconsistency leading to counter-productiÕity One cannot deduce otherwise than that the policy of the Dutch goverment with respect to the Wadden Sea is unscientific and probably counter-productive as far as the environment is concerned. But it is certainly counter-productive with respect to the ‘small-fields’ policy: the development of the gas fields underneath the Wadden Sea would be a most welcome opportunity to save gas from the Slochteren field. The present decision must therefore be understood by the industry as a signal that the Dutch government does no longer adhere strictly to her own policy but rather follows an ad-hoc policy that seems largely based on electoral considerations. A consequence could well be that NAM Žand other companies. will become less interested in wringing out existing fields, as the cost of the last ‘drops’ are high.
4. A more integrated approach: the Gulf coast activities The Gulf of Mexico is one of the most productive areas in the world ŽLore, 1993; Abernathy, 1996; Simmons, 1996.. It is therefore not surprising that over a dozen of geological societies, sections of societies, etc. have joined in the Gulf Coast Association of Geological Societies ŽGCAGS., which organises a convention annually. The September 15–17, 1999 meeting in Lafayette ŽLA. was the 49th, with two parallel sessions, workshops, poster sessions and an exhibition. The transactions ŽTerrell and Czerniakowski, 1999. provide a valuable tool for analysing how the numerous activities are integrated, how they interact, and what their results are. Such an overview increases the insight into how the Gulf of Mexico and adjoining land ŽZimmerman, 1999. are being wrung out. Many contributions dealt with the computer-aided interpretation of seismic or other geophysical data Že.g., Young, 1999. and with modelling Že.g., Chhibber, 1999.. It is amazing how modelling and other techniques have developed in only a short time Žsee, for instance, Ungerer et al., 1984., with huge consequences: the percentage of oil Žand, to a lesser degree, gas. that can be recovered from a field has increased significantly, thus contributing largely to an increase of the reserves, even in cases when no additional hydrocarbons are discovered in a field. Effective prospecting and field monitoring ŽWeiHe et al., 1996. is not enough, however. Efficient exploration is the final objective, while minimizing the risks and the environmental impact Že.g., Johnston, 1999., optimizing the production by a better insight in the parameters relevant for oil migration Že.g., Prince, 1999., assessing the problems concerned with the possible temporary storage of oil ŽLooff and Looff, 1999., and even analyzing the opportunities and risks associated with the presence of large occurrences of gas hydrates in the Gulf’s bottom ŽSassen et al., 1999; see also Briaud and Chaouch, 1997.. A point of specific interest is the handling of old platforms. Over 3900 platforms have been installed offshore since 1947 ŽFig. 2.; 1700 rigs have been removed since 1973. The oil community remembers well the problems raised when Shell wanted to sink
A.J. Õan Loon r Earth-Science ReÕiews 49 (2000) 279–284
Fig. 2. One of the numerous platforms in the Gulf of Mexico, off the coast of Louisiana.
the Brent Spar platform that had served in the North Sea. The Brent Spar problem, which was a result of incorrect data presented by Greenpeace, caused not only a tremendous waste of money, but also led to a sub-optimum solution. In Louisiana, the authorities have opted for a different approach: they started the Louisiana Artificial Reef Program in 1973. In the meantime, 25 reef sites have been created Žat a water depth of at least 30 m, in a zone 22–115 km off the coast., utilizing jackets and decks of 75 obsolete platforms. This program has turned out to be highly successful in forming healthy reefs, reducing the cost for the companies involved, and attracting fish for commercial fishery ŽKasprzak, 1999.. It thus turns out that an active, positive approach by the authorities can be profitable from both an economic and an environmental point of view. This type of profitable cooperation facilitates a policy by the oil companies to wring out the fields: the relatively high costs for the last drops are compensated for by relatively low costs for getting rid of obsolete platforms.
5. Required: consistency based on information The successes of the oil and gas industry in keeping up, for a long time, a rough balance between exploration and detection of new reserves Žincluding the possible additional production by application of
283
new techniques. seems to have made some authorities confident that the predicted depletion of hydrocarbons will not come before alternative energy sources will have been developed. Possibly, the relatively short-term interest of politicians plays a role. It cannot be denied, however, that the increasing global consumption will raise problems in the foreseeable future, probably long before sustainable energy sources will be able to take over the role of hydrocarbons. This information is not new, but earth scientists apparently have not been sufficiently successful in transferring the message to the public. Nor is it generally accepted that a future lack of fuel may destroy our society. It is therefore of utmost importance to convince society that only a combination of all possible types of measures can safeguard the future energy supply. Industry should inform governments about new technical developments, and governments should encourage investments by the oilrgas industry by keeping their promises. In addition, governments should encourage worldwide small-field policies, but they should also encourage the industry to extract as much oil or gas from a field as possible. They might achieve this by, for instance, accepting lower revenues with an increasing percentage of extraction. In the meantime, industry can help postpone an energy crisis by further wringing out the Earth.
References Abelson, Ph.A., 1999. Avoiding an oil crunch. Science 286, 47. Abernathy, C.K., 1996. Exploring the Gulf of Mexico — for a second time. Sea Technology 37 Ž8., 10–15. Briaud, J.L., Chaouch, A., 1997. Hydrate melting in soil around hot conductor. Journal of Geotechnical and Geoenvironmental Engineering 123, 645–653. Chhibber, R., 1999. Accurate reservoir volumes using 3-D geological modeling — seismic attributes and a workflow approach. In: Terrell, W.C., Czerniakowski, L. ŽEds.., Transactions of the 49th Annual Convention of the Gulf Coast Association of Geological Societies, GCAGS. p. 11. Cooney, M., Fisher, K., 1995. Horizontal drilling makes re-entry attractive in US Gulf. Offshore 55, 30–32. Dronkert, H., Dijkhuis, E. ŽEds.., 1999. Abstract Book of the Conference ‘Groningen — catalyst for the North West European oil and gas industry’ ŽGroningen, 31 May–1 June.. 91 pp.
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EZ ŽDutch Ministry of Economic Affairs., 1999. Olie en gas in Nederland — opsporing en winning 1998. wOil and gas in the Netherlands — exploration and production 1998x EZ, ’sGravenhage, 104 pp. Gasunie, 1998. Holland and its natural gas. Gasunie, Groningen, 36 pp. Goode, P., 1999. Getting the most from the reservoir. In: Dronkert, H., Dijkhuis, E. ŽEds.., Abstract Book of the Conference ‘Groningen — catalyst for the North West European oil and gas industry’. p. 26. Johnston, J.E. III, 1999. Geologic review: reducing oil and gas environmental impacts. In: Terrell, W.C., Czerniakowski, L. ŽEds.., Transactions of the 49th Annual Convention of the Gulf Coast Association of Geological Societies, GCAGS. p. 3. Kasprzak, R.A., 1999. Use of oil and gas platforms as habitat in Louisiana’s Artificial Reef Program. In: Terrell, W.C., Czerniakowski, L. ŽEds.., Transactions of the 49th Annual Convention of the Gulf Coast Association of Geological Societies, GCAGS. pp. 292–298. Looff, K.M., Looff, K.M., 1999. Possible geologic influence on salt falls associated with the storage caverns at Bryan Mound, Brazoria County, TX. In: Terrell, W.C., Czerniakowski, L. ŽEds.., Transactions of the 49th Annual Convention of the Gulf Coast Association of Geological Societies, GCAGS. pp. 322–331. Lore, G.L., 1993. Conventional gas resources of the Gulf of Mexico outer continental shelf — past experience, current activities, future potential. US Geological Survey Professional Paper 1570, pp. 157–170. Meadows, D.L., 1972. The Limits to Growth — A Report for the Club of Rome Project on the Predicament of Mankind. Universe Books, New York. NAM ŽNederlandse Aardolie Maatschappij., 1998. Keeping Up the Pressure. NAM, Hoogezand, 28 pp.
Prince, Chr.M., 1999. Textural and diagenetic controls on sandstone permeability. In: Transactions of the 49th Annual Convention of the Gulf Coast Association of Geological Societies, GCAGS. pp. 42–53. Sassen, R., Sweet, S.T., Milkov, A.V., DeFreitas, D.A., Salata, G.G., McDade, E.C., 1999. Geology and geochemistry of gas hydrates, central Gulf of Mexico continental slope. In: Terrell, W.C., Czerniakowski, L. ŽEds.., Transactions of the 49th Annual Convention of the Gulf Coast Association of Geological Societies, GCAGS. pp. 462–468. Simmons, M.R., 1996. Gulf of Mexico — ‘silicon valley’ to offshore oil and gas industry. Sea Technology 37 Ž8., 27–32. Terrell, W.C., Czerniakowski, L., 1999. Transactions of the 49th Annual Convention of the Gulf Coast Association of Geological Societies, GCAGS. 540 pp. Ungerer, P., Bessis, F., Chenet, P.Y., Durand, B., Nogaret, E., Chiarelli, A., Oudin, J.L., Perrin, J.F., 1984. Geological and geochemical models in oil exploration: principles and practical examples. American Association of Petroleum Geologists. Memoir 35, 53–77. Wei-He, A., Liquing-Xu, R.N., Boulanger, A., Meadow, B., Neal, R., 1996. 4D seismic monitoring grows as production tool. Oil and Gas Journal 94, 41–46. Young, R.A., 1999. A technology to extract lithology, porosity and hydrocarbon content from conventional seismic data. In: Terrell, W.C., Czerniakowski, L. ŽEds.., Transactions of the 49th Annual Convention of the Gulf Coast Association of Geological Societies, GCAGS. pp. 62–73. Zimmerman, R.K., 1999. Potential oil generating capacity of the North Louisiana hydrocarbon system. In: Terrell, W.C., Czerniakowski, L. ŽEds.., Transactions of the 49th Annual Convention of the Gulf Coast Association of Geological Societies, GCAGS. pp. 532–540.
Earth Reflections
Wringing out the earth A.J. van Loon ) Geocom, Benedendorpsweg 61, 6862 WC Oosterbeek, Netherlands Received 2 January 2000; accepted 2 January 2000
Abstract The increase in global energy consumption urges the exploitation of known energy resources in the most efficient way. The oil and gas industry seems well capable, but politics may hamper optimum recovery, even though politicians advocate that the laws and regulations laid upon the industry are meant to promote a sustainable society and to diminish environmental pollution. Lack of geological insight sometimes plays a role, which implies that an attitude of effectively wringing out the Earth is not sufficient: more attention for earth-scientific education may turn out to be even more important. This does not affect, however, the need for ever more effective technologies for wringing out the Earth. q 2000 Elsevier Science B.V. All rights reserved. Keywords: energy policy; mineral exploitation; natural gas; oil
1. Introduction Economic prosperity has, as far as known from historical sources, always been based on the availability of sufficient energy. In ‘classical’ times, like in the Egypt of the pharaos, the most important source of energy was manpower, just like it is still nowadays in many developing countries. The structural use of animals was a next development, but a main step forward was the taming of natural forces. Hydropower and wind energy have been used for a long time on a small scale, but it lasted until the 17th century before one of these sources, i.e., wind energy, became used at what might be called an industrial scale. The knowhow gained in the Netherlands )
Tel.: q31-26-339-0908; fax: q31-26-339-0783. E-mail address: [email protected] ŽA.J. van Loon..
and the common application of wind mills Žfor numerous purposes, including the reclamation of polders. and sailing ships Žfor ‘plundering’ colonies and for trade with other countries. then formed the basis for the Dutch ‘golden age’, during which time many more people than ever before lived in prosperity. This prosperity is still reflected in the beautiful houses along the canals in Amsterdam and several other cities, in the mansions that merchants built outside the larger cities, and — last but not least — in the pieces of art of the time Žfor instance, the paintings by Rembrandt van Rijn, Frans Hals and Jan Steen, to mention only a few.. Energy has been recognised as a most valuable and indispensable asset ever since, and both individuals and authorities worldwide have promoted the development of energy sources. Wood, peat, browncoal and coal were the first types of fossil fuels to be
0012-8252r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. PII: S 0 0 1 2 - 8 2 5 2 Ž 0 0 . 0 0 0 0 6 - 4
280
A.J. Õan Loon r Earth-Science ReÕiews 49 (2000) 279–284
exploited on a large scale, and it soon turned out that overexploitation Žby lack of alternatives. could raise huge problems. Western Europe became largely deforested during the Middle Ages because of the need for fuel; a similar problem is faced nowadays in several developing countries, particularly in the border zones along deserts. In England, the use of coal became forbidden in several cities because of the unbearable smog that resulted from the large-scale use of coal; the problem was solved only in the middle of the 20th century, when not only alternative energy sources became available, but also technologies to purify the exhaust gases of factories, power plants, etc. It is only slightly more than a century ago that oil — and even later natural gas — became alternatives for coal, and good alternatives, indeed. Not only because they cause less environmental problems Žwhich was not a topic at all one century ago., but because it can be transported much more efficiently and because it allows applications previously only dreamt of. The first oil derrick, owned by E.L. Drake Ž1819–1880., was constructed in the 1860s in Titusville, PA. It would later be recognised as the first of its kind of a technological device that would change the world. Now it is hardly possible to imagine a world without oil and gas. And where ‘wild cats’ may have proven to be profitable in the past, the hunt for oil and gas now needs sophisticated technologies to be successfully enough to meet the economical and environmental demands. It is highly alarming in this respect that, where new finds of oil and gas previously compensated for the exploited amounts, 1998 was the first year for decades during which more oil was used than discovered. This unfortunate — though expected — development emphasises once more the need to use the available natural sources as efficiently as possible, and to explore the Earth for more resources in the most effective way. This message is understood nowadays by all major companies involved in prospecting, exploiting and refining natural sources, and fossil fuels in particular. A result is that wringing out the Earth is common business now ŽGoode, 1999., even though it is generally acknowledged that this cannot go on forever, considering the limited sources ŽMeadows, 1972., especially in the context of a rapidly growing population that claims
increasing Žaverage. amounts of energy per capita Žcf. Abelson, 1999..
2. The hunt for energy in a changing world The hunt for oil and gas becomes increasingly difficult. As in the case of other natural resources, the best accessible occurrences were found Žand exploited. first, and the largest oil and gas fields found during the intensive exploration activities were also developed first. A consequence is that few exceptionally large fields Žlike those in the Gulf of Mexico, or like the Slochteren gasfield in The Netherlands. will become available in the future. Another consequence is that the investments per recoverable barrel of oil or cubic metre of gas strongly increased in the past decade. The low probability of discovering new huge fields is an additional reason to wring out all existing fields as much as possible. This is not only a task of the companies involved, but also of the national authorities involved. Their power, by means of regulations, tax facilities, etc., is great enough to prevent fields being given up when the potentially recoverable oil of gas has not yet been extracted entirely. Governments of oil-producing countries might favour wringing out the fields in their territory by financial encouragement of the companies involved. It is also possible for national authorities to develop policies that spare the giant occurrences for future use Žor for use during periods when demand will be higher than supply from other sides.. An example is the ‘small-fields’ policy in The Netherlands, which was developed after the oil crises of the 1970s ŽGasunie, 1998.. It is meant to prolong the lifetime of the huge Slochteren gasfield, which has a remaining expected reserve estimated at 1212 = 10 9 m3 wEZ ŽDutch Ministry of Economic Affairs., 1999x. This field Žalso known as the Groningen field. was discovered in 1959 and has been exploited since the beginning of the 1960s ŽDronkert and Dijkhuis, 1999.. It is used nowadays primarily as some kind of reservoir for cold days, when the production from other gasfields can, for technical reasons, not cope with the demand. Production at a sufficient level is helped by the installation of compressors ŽNAM, 1998.. A consequence of the ‘small-fields policy’ is,
A.J. Õan Loon r Earth-Science ReÕiews 49 (2000) 279–284
obviously, the necessity of investing more money to wring out the small fields both onshore and offshore. Practice shows, however, that the policies followed by authorities are not always mutually and internally consistent, and that they may even be counter-productive. This will be illustrated by another example from The Netherlands Žwhere relatively few parties are involved.. Authorities can, however, also stimulate developments that are profitable for all parties involved, as will be shown with developments taking place along the Gulf Coast Žwhere many parties are involved..
3. Inconsistent and counter-productive policy: the ‘ Wadden Sea debate’ Whereas the ‘small-fields policy’ in The Netherlands seems effective, a consistent policy is lacking at other points. This is reflected by the current ‘Wadden Sea debate’. The NAM company had been granted, already some decades ago, an ‘eternal’ right to explore for oil and gas in the Wadden Sea ŽFig. 1., the tidal-flat area north of The Netherlands Žand continuing off the coast of Germany and Denmark.. Since the Wadden Sea is an important natural reserve, environmentalists opposed the concession, which led several years ago — after discussions between NAM and the Dutch government — to a moratorium, during
Fig. 1. Characteristic part of the Dutch Wadden Sea Žnear the island of Texel. at ebb tide, showing a tidal channel between sandy shoals.
281
which period NAM would not start any new drilling activities in the area. After the period of the moratorium had recently been ended, government took, under the pressure of environmentalist groups, new steps to make NAM refrain from oil and gas exploitation in the Wadden Sea. For the purpose, the government considers to break up one-sidedly the concession. This development, which is backed by a great majority of the political parties, was defended with the argument that new research had to be carried out first. If such research would prove beyond any reasonable doubt that the NAM activities would impose 0% of risk on the environment, permission for drilling activities might be given; if some doubt would remain, no permission will be granted. It is obvious that such a governmental policy was not based on scientifically sound considerations: a 0% risk does not exist. 3.1. Lack of knowledge Even more alarming was that the governmental decision was taken apparently on the basis of lack of knowledge. NAM had developed plans for deviated drilling from the mainland, with the purpose of reducing risk for the tidal-flat environment to a minimum. The principle of deviated drilling was, however, not understood by the Prime Minister, Kok, as he proved during a television interview. He tried to show why such a boring could easily affect the environment: the borehole started on the mainlaind would, according to him, go down vertically, bend off to a horizontal position Ža technique that exists, indeed, but for other purposes: Cooney and Fisher, 1995., just underneath the surface of the Wadden Sea, until the location above the gasfield was reached, and then bend off again vertically towards the gas. The horizontal borehole just underneath the surface of the vulnerable natural reserve thus was ‘shown’ to represent a great risk. Also alarming is the fairly general belief in The Netherlands that subsidence of the sedimentary surface due to extraction of gas from underneath the Wadden Sea must be disastrous. Calculations predict a maximum subsidence in the central part of 28 cm during the next decades. This would, according to
282
A.J. Õan Loon r Earth-Science ReÕiews 49 (2000) 279–284
environmentalists, almost all political parties, and the Minister of Environment, Pronk, terminate the Wadden Sea, because the shoals Žin between channels. that are submerged during flood and that fall dry during ebb tide, would become continuously submerged. It is apparently not understood that the Wadden Sea is a dynamic environment, where the sedimentation rate will probably keep pace with subsidence; if not, the shoals will not disappear, but the channels will widen at the cost of the shoals until sufficient material will have been supplied to compensate for the subsidence. A continuous supply of sand and mud is guaranteed by the longshore currents. It is interesting in this framework that no authority seems to realise that the Wadden Sea is a consequence of the fast sea-level rise after the last glaciation, and that it is doomed to disappear now that the rise has become almost nil: erosion at the seaward side of the Wadden islands and aggradation of the islands at the tidal-flat side, in combination with the seaward growth of the salt marshes on the mainland, will result in the natural disappearance of the tidal-flat area, probably within a thousand years or so. Subsidence of the area by gas exploitation just might slow down this process a bit. 3.2. Inconsistency leading to counter-productiÕity One cannot deduce otherwise than that the policy of the Dutch goverment with respect to the Wadden Sea is unscientific and probably counter-productive as far as the environment is concerned. But it is certainly counter-productive with respect to the ‘small-fields’ policy: the development of the gas fields underneath the Wadden Sea would be a most welcome opportunity to save gas from the Slochteren field. The present decision must therefore be understood by the industry as a signal that the Dutch government does no longer adhere strictly to her own policy but rather follows an ad-hoc policy that seems largely based on electoral considerations. A consequence could well be that NAM Žand other companies. will become less interested in wringing out existing fields, as the cost of the last ‘drops’ are high.
4. A more integrated approach: the Gulf coast activities The Gulf of Mexico is one of the most productive areas in the world ŽLore, 1993; Abernathy, 1996; Simmons, 1996.. It is therefore not surprising that over a dozen of geological societies, sections of societies, etc. have joined in the Gulf Coast Association of Geological Societies ŽGCAGS., which organises a convention annually. The September 15–17, 1999 meeting in Lafayette ŽLA. was the 49th, with two parallel sessions, workshops, poster sessions and an exhibition. The transactions ŽTerrell and Czerniakowski, 1999. provide a valuable tool for analysing how the numerous activities are integrated, how they interact, and what their results are. Such an overview increases the insight into how the Gulf of Mexico and adjoining land ŽZimmerman, 1999. are being wrung out. Many contributions dealt with the computer-aided interpretation of seismic or other geophysical data Že.g., Young, 1999. and with modelling Že.g., Chhibber, 1999.. It is amazing how modelling and other techniques have developed in only a short time Žsee, for instance, Ungerer et al., 1984., with huge consequences: the percentage of oil Žand, to a lesser degree, gas. that can be recovered from a field has increased significantly, thus contributing largely to an increase of the reserves, even in cases when no additional hydrocarbons are discovered in a field. Effective prospecting and field monitoring ŽWeiHe et al., 1996. is not enough, however. Efficient exploration is the final objective, while minimizing the risks and the environmental impact Že.g., Johnston, 1999., optimizing the production by a better insight in the parameters relevant for oil migration Že.g., Prince, 1999., assessing the problems concerned with the possible temporary storage of oil ŽLooff and Looff, 1999., and even analyzing the opportunities and risks associated with the presence of large occurrences of gas hydrates in the Gulf’s bottom ŽSassen et al., 1999; see also Briaud and Chaouch, 1997.. A point of specific interest is the handling of old platforms. Over 3900 platforms have been installed offshore since 1947 ŽFig. 2.; 1700 rigs have been removed since 1973. The oil community remembers well the problems raised when Shell wanted to sink
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Fig. 2. One of the numerous platforms in the Gulf of Mexico, off the coast of Louisiana.
the Brent Spar platform that had served in the North Sea. The Brent Spar problem, which was a result of incorrect data presented by Greenpeace, caused not only a tremendous waste of money, but also led to a sub-optimum solution. In Louisiana, the authorities have opted for a different approach: they started the Louisiana Artificial Reef Program in 1973. In the meantime, 25 reef sites have been created Žat a water depth of at least 30 m, in a zone 22–115 km off the coast., utilizing jackets and decks of 75 obsolete platforms. This program has turned out to be highly successful in forming healthy reefs, reducing the cost for the companies involved, and attracting fish for commercial fishery ŽKasprzak, 1999.. It thus turns out that an active, positive approach by the authorities can be profitable from both an economic and an environmental point of view. This type of profitable cooperation facilitates a policy by the oil companies to wring out the fields: the relatively high costs for the last drops are compensated for by relatively low costs for getting rid of obsolete platforms.
5. Required: consistency based on information The successes of the oil and gas industry in keeping up, for a long time, a rough balance between exploration and detection of new reserves Žincluding the possible additional production by application of
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new techniques. seems to have made some authorities confident that the predicted depletion of hydrocarbons will not come before alternative energy sources will have been developed. Possibly, the relatively short-term interest of politicians plays a role. It cannot be denied, however, that the increasing global consumption will raise problems in the foreseeable future, probably long before sustainable energy sources will be able to take over the role of hydrocarbons. This information is not new, but earth scientists apparently have not been sufficiently successful in transferring the message to the public. Nor is it generally accepted that a future lack of fuel may destroy our society. It is therefore of utmost importance to convince society that only a combination of all possible types of measures can safeguard the future energy supply. Industry should inform governments about new technical developments, and governments should encourage investments by the oilrgas industry by keeping their promises. In addition, governments should encourage worldwide small-field policies, but they should also encourage the industry to extract as much oil or gas from a field as possible. They might achieve this by, for instance, accepting lower revenues with an increasing percentage of extraction. In the meantime, industry can help postpone an energy crisis by further wringing out the Earth.
References Abelson, Ph.A., 1999. Avoiding an oil crunch. Science 286, 47. Abernathy, C.K., 1996. Exploring the Gulf of Mexico — for a second time. Sea Technology 37 Ž8., 10–15. Briaud, J.L., Chaouch, A., 1997. Hydrate melting in soil around hot conductor. Journal of Geotechnical and Geoenvironmental Engineering 123, 645–653. Chhibber, R., 1999. Accurate reservoir volumes using 3-D geological modeling — seismic attributes and a workflow approach. In: Terrell, W.C., Czerniakowski, L. ŽEds.., Transactions of the 49th Annual Convention of the Gulf Coast Association of Geological Societies, GCAGS. p. 11. Cooney, M., Fisher, K., 1995. Horizontal drilling makes re-entry attractive in US Gulf. Offshore 55, 30–32. Dronkert, H., Dijkhuis, E. ŽEds.., 1999. Abstract Book of the Conference ‘Groningen — catalyst for the North West European oil and gas industry’ ŽGroningen, 31 May–1 June.. 91 pp.
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