European geothermal drilling experience: problem areas and case studies

Conference · Thu Jan 01 00:00:00 EST 1981

OSTI ID:7369369

Baron, G ^[1]; Ungemach, P

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1. Commission of the European Communities, Paris, France

Geothermal drilling has long been restricted in Western Europe to the sole dry steam field of Larderello in Italy. In the last few years, a wider experience is building up as a consequence of intensified exploration and development programs carried out for evaluation and production of both low- and high-enthalpy geothermal resources. A sample of some 40 boreholes indicates the following problem areas. Due to similar settings - hot water system flowing in sedimentary units at temperatures and depths ranging from 40/sup 0/ to 140/sup 0/C (104/sup 0/ to 284/sup 0/F) and from 1000 to 3500 metres (3281 to 11,484 feet), respectively - the technology here is strongly dependent on oil and gas drilling practice. Still, specific problems remain in the areas of multiple-reservoir reconnaissance and well completion at production and reinjection levels, particularly in poorly consolidated fluvio-deltaic sequences leading to sand control and swelling clay problems. Expertise needs to be developed to minimize costs, secure high production capacities, long lifetimes, and minimum maintenance compatible with the economics and the lack of suitable workover facilities. Exploratory drilling is currently combining wildcatting and deeper investigations of known fields. Lost circulation, drill string corrosion, tubulars, mud, cementing, and deviation control are the most frequently encountered difficulties while drilling in hostile water-dominated environments. Formation temperatures in excess of 300/sup 0/C (572/sup 0/F) are often the rule, and recent drilling conducted in volcanic areas have hit fluids approaching supercritical state. Whenever these problems do not remain under control, they result in rig standby and extra costs which severely penalize an industry which needs sharp improvements to be fully reliable and cost effective.

• OSTI ID: 7369369
• Report Number(s): SAND-81-0036C; CONF-810105-
• Resource Relation: Conference: International geothermal drilling and completions technology conference, Albuquerque, NM, USA, 21 Jan 1981; Related Information: In: Proceedings of the international conference on geothermal drilling and completion technology, by
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
EUROPE
GEOTHERMAL EXPLORATION
GEOTHERMAL WELLS
DRILLING
CLAYS
DRILLING EQUIPMENT
EXPLORATORY WELLS
GEOTHERMAL FLUIDS
GEOTHERMAL GRADIENTS
GEOTHERMAL RESOURCES
SAND
SEDIMENTARY ROCKS
WELL COMPLETION
WELL LOGGING
EQUIPMENT
EXPLORATION
FLUIDS
MINERALS
RESOURCES
ROCKS
TEMPERATURE GRADIENTS
WELLS
Geothermal Legacy
150303* - Geothermal Exploration & Exploration Technology- Exploratory Drilling & Well Logging