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Success rates of petroleum and geothermal wells and their impact on the European geothermal industry

Sass, I. and Weinert, S. and Bär, K. (2017):
Success rates of petroleum and geothermal wells and their impact on the European geothermal industry.
In: Swiss Bulletin für angewandte Geologie, pp. 57-65, 21, (2), DOI: 10.5169/seals-658197, [Online-Edition: http://doi.org/10.5169/seals-658197],
[Article]

Abstract

Geothermal energy, as a renewable resource is already used since more than 2000 years. Hence the rapidly increasing experience with this energy resource, new deep geothermal applications are still under debate in politics and public, especially in European countries. Investments are often missing or investors retract their financial support due to the unsecure political situation. Despite all debates, the quantity of geothermal applications is steadily increasing in e. g. Germany over the last three decades. Taking only German deep geothermal applications into account, a total of 31 systems were running, 34 more were still in the planning phase and a total of 34 were canceled due to various reasons. Of the canceled ones, the majority was shut down for missing investments, uneconomic operation or political reasons. Engineering issues and low discharge only summed up to approx. 21 % of the canceled operations, which leads to the assumption, that neither drilling nor geological exploration and planning is a main failure reason for such projects. Furthermore in this study shows, that the success rate of geothermal drillings is remarkably high and also exceeds success rates published by the petroleum industry. Also, success rate is not bound to the geology of the explored reservoir, nor to the drilling depth needed for exploitation and indeed was improved significantly over the past decades. In fact, most internationally available data for suecess rates are derived from high enthalpy systems, in which geothermal resources are explored more efficiently than for low enthalpy systems e.g. in European countries. By a single deep but slim exploration well prior to any production wells, reservoirs can be investigated and their potential evaluated. Such cheap exploration wells can significantly reduce the project risk due to better understanding of the reservoir and therefore shift main investments to a project phase of significantly lower risk.

Item Type: Article
Erschienen: 2017
Creators: Sass, I. and Weinert, S. and Bär, K.
Title: Success rates of petroleum and geothermal wells and their impact on the European geothermal industry
Language: English
Abstract:

Geothermal energy, as a renewable resource is already used since more than 2000 years. Hence the rapidly increasing experience with this energy resource, new deep geothermal applications are still under debate in politics and public, especially in European countries. Investments are often missing or investors retract their financial support due to the unsecure political situation. Despite all debates, the quantity of geothermal applications is steadily increasing in e. g. Germany over the last three decades. Taking only German deep geothermal applications into account, a total of 31 systems were running, 34 more were still in the planning phase and a total of 34 were canceled due to various reasons. Of the canceled ones, the majority was shut down for missing investments, uneconomic operation or political reasons. Engineering issues and low discharge only summed up to approx. 21 % of the canceled operations, which leads to the assumption, that neither drilling nor geological exploration and planning is a main failure reason for such projects. Furthermore in this study shows, that the success rate of geothermal drillings is remarkably high and also exceeds success rates published by the petroleum industry. Also, success rate is not bound to the geology of the explored reservoir, nor to the drilling depth needed for exploitation and indeed was improved significantly over the past decades. In fact, most internationally available data for suecess rates are derived from high enthalpy systems, in which geothermal resources are explored more efficiently than for low enthalpy systems e.g. in European countries. By a single deep but slim exploration well prior to any production wells, reservoirs can be investigated and their potential evaluated. Such cheap exploration wells can significantly reduce the project risk due to better understanding of the reservoir and therefore shift main investments to a project phase of significantly lower risk.

Journal or Publication Title: Swiss Bulletin für angewandte Geologie
Volume: 21
Number: 2
Divisions: 11 Department of Materials and Earth Sciences > Earth Science > Geothermal Science and Technology
11 Department of Materials and Earth Sciences > Earth Science
11 Department of Materials and Earth Sciences
Date Deposited: 13 Nov 2017 07:40
DOI: 10.5169/seals-658197
Official URL: http://doi.org/10.5169/seals-658197
Alternative Abstract:
Alternative abstract Language
Geothermische Energie, als erneuerbare Energie, wird von der Menschheit bereits seit mehr als 2000 Jahren genutzt. Trotz der schnell wachsenden Erfahrung im Umgang mit dieser Ressource sind tiefengeothermische Anwendungen noch immer unter Diskussion, sowohl auf politischer, als auch gesellschaftlicher Ebene. Dieser Widerstand ist besonders in Europa stark ausgebildet. Investitionen in geothermische Projekte sind selten und oft werden aufgrund der politischen Lage Finanzierungen zurückgezogen. Trotz aller Schwierigkeiten steigt in den letzten 30 Jahren die tiefengeothermisehe Nutzung in Deutschland stetig. Allein in Deutschland sind insgesamt 31 tiefengeothermische Projekte in Betrieb, 34 weitere sind in Planung. Stand 2015 wurden jedoch auch insgesamt 34 Projekte aufgrund verschiedenster Gründe gestoppt. Die Mehrzahl dieser Projekte wurde wegen mangelnder Investitionen, einem unwirtschaftlichen Betrieb oder politischen Beweggründen abgebrochen. Ingenieurtechnische Probleme, sowie geringe Schüttungsraten wurden nur bei ca. 21% der Projekte als Abbruchskriterium genannt. Aufgrund dieser geringen Zahl lässt sich die Annahme treffen, dass weder die geologische Exploration noch die ingenieurtechnische Planung Hauptgründe für Misserfolg sind. Weiterhin zeigt diese Studie, dass die Fündigkeitsquote geothermischer Bohrungen relativ hoch ist und zum Teil die publizierten Fündigkeitsquoten der Erdöl und -gasindustrie übersteigt. Es wird gezeigt, dass das Fündigkeitsrisiko nicht an geologische Gegebenheiten oder der maximalen Endteufe geothermischer Bohrungen gebunden ist und sich über die letzten Jahrzehnte deutlich verbessert hat. Allerdings stammen die meisten der verfügbaren Daten aus Hochenthalpiesystemen, in denen ein der Erdölindustrie ähnelndes Explorationskonzept angewendet wird und die Erschließung neuer geothermischer Reservoire im Vergleich zu europäisehen Niedrigenthalpiesystemen vergleichsweise einfach ist. In Hochenthalpiesystemen wird die Exploration meist durch eine, oder einige wenige günstige Explorationsbohrungen durchgeführt. Erst bei Fündigkeit dieser Explorationsbohrungen werden die teureren, großkalibrigen Produktionsbohrungen abgeteuft, wodurch das Hauptinvestitionsvolumen in eine Projektphase geringen Risikos verschoben wird.UNSPECIFIED
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