Krafla geothermal field © BRGM - François Girault

About GeoWell

Framework

In 2008, European countries agreed the ambitious target to increase use of renewable energies to 20% of the European energy consumption by 2020, one of the instruments for EC was defined through the Horizon 2020 program. To help achieving this goal the GeoWell project was established and will contribute to the 2020 goal through new and improved well technology.

New concepts for high-temperature geothermal well technologies are strongly needed to accelerate the development of geothermal resources for power generation in Europe and worldwide in a cost effective and environmentally friendly way. The Geowell project will address major bottlenecks identified for geothermal wells, like high investment and maintenance costs by testing, proposing and developing innovative materials and designs that are expected to be superior to the state of the art concepts.

Overall concept

The overall concept of GeoWell is to enhance well design and completion techniques. It includes all relevant steps in the geothermal well completion process to enhance the lifetime of high-temperature geothermal wells through strongly improved well design, casing connectors, cement and materials used and monitoring. A particular focus will be on improvements for wells that have to sustain high temperature fluctuations and are thus particularly prone to casing failure and degradation. Environmental aspects during well testing will be analysed and improvements suggested; and finally a novel monitoring concept for the entire development from safe installation to well-integrity and the lifetime performance of the well is proposed.

 

Necessary Improvement

GeoWell contribution

Develop cement with reduced supplementary water pressure in cement sheet

Two approaches will be evaluated to reduce the generated pressure and enhance casing protection: (1) Introduce additives that are able to absorb water; (2) Use different ways to reduce the amount of water in the formulations.

Ductile intermediate layer

A ductile intermediate layer will be used with ductility in axial direction and high strength in radial direction. Approaches assessed include thin layer of low-friction layer and composite coating.

Testing and predicting behaviour of hardened cement and cement/casing interfaces

P/T-effects in the near-well area will be modelled by Finite Element Models (FEM). Casing and cement testing will be performed by heating small scale samples in autoclaves to required temperature and pressure.

High-Temperature Composite Casings / HTCC

Material research for HTCC in deep geothermal environments and selection of suited materials based on their chemical and mechanical properties. Develop connection technology. Prepare and execute (qualification-like) HTCC test program.

Flexible coupling

Design flexible coupling and verify the design by building a prototype. Test flexible coupling in laboratory and perform strain measurements.

Material performance

Material testing and investigations, first in laboratory, were expected downhole conditions are simulated in autoclaves, and later in situ testing were real geothermal environment will be applied in testing.

Cladded materials

Cladded candidate materials selection, coupon design, testing and analysing. Testing in situ of cladded material.

EDAS Development

Develop breadboard interrogator demonstrator for field measurements on strain and temperature.

Casing and cement integrity evaluation

Measure strain and temperature during the cement job of a geothermal well. Measure strain, temperature and noise during flow/injection testing.

Mapping the status and availability of qualitative and quantitative risk assessment methods for geothermal wells

Conduct a literature review on risk assessment and perform survey/questionnaire for the geothermal industry

Evaluate which methods that can be transferred from the oil & gas domain to the geothermal well domain.

Conduct a literature review and perform a survey for the oil & gas industry and develop criteria for transferability.

Development risk assessment methods for phenomena that are not currently covered for geothermal wells, particularly at elevated temperatures up to 450°C.

Develop framework for a quantitative approach to risk assessment for geothermal wells. Deliver probabilistic risk assessment methods for selected phenomena.

Develop a European protocol for risk assessment in geothermal drilling in compliance with European and domestic regulations

Check requirements and structure for European protocols and establish a “recipe-based” approach to risk management and assessment for industrial application.

Reliability analysis of new developed materials and technology

Place the materials developed in WP3 and WP4 in a barrier element setting. Use a probabilistic approach to evaluate failure probability and consequences.

Dernière mise à jour le 02.06.2016