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Innovative materials and designs for long-life high-temperature geothermal wells

Periodic Reporting for period 1 - GeoWell (Innovative materials and designs for long-life high-temperature geothermal wells)

Berichtszeitraum: 2016-02-01 bis 2017-07-31

The GeoWell project will address important bottlenecks in geothermal development like high investment and maintenance costs by developing innovative materials and designs that are superior to the state of the art concepts. This will significantly enhance the current technology position of constructing and operating a geothermal well.

The project aims to develop reliable, economical and environmentally friendly technologies for design, completion and monitoring of high-temperature geothermal wells with the intent to expedite the development of geothermal exploitation globally. GeoWell will address all relevant steps in the geothermal well completion process to enhance the lifetime of high-temperature geothermal wells. These include cement and sealing technologies, material selection and coupling of casings. Methods of temperature and strain measurements in wells, using fibre optic technologies to monitor well integrity, will be developed as well as methods for risk assessment with respect to the design and operation of high-temperature geothermal wells.

To assure an outstanding quality of the approach and the final results of the project, the research is focused on both traditional production wells and deeper wells where the pressure is as high as 150 bar and temperatures exceed 400°C. The developed technologies will be tested under in-situ conditions in laboratories, and also in existing geothermal environment, moving the TRL (Technology Readiness Level) from 3-4 to 4-5.

The strength of the GeoWell consortium lies in the long and broad experience of the partners and the specific competence that each of them has within their field of expertise. The partners have access to world-class research facilities for validation of innovative technologies by testing in laboratories and existing geothermal environment. This will ensure a successful project implementation.
Generally, we can say that the progress has been good and according to the schedule. Out of a total number of 30 deliverables planned in the project, 12 have already been submitted and approved by the EU. These include reports on high-temperature composite casings, candidate materials for geothermal wells and design of a flexible coupling of casings as well as well integrity and risk assessment methods. Among other ongoing work we can mention activities for improving cement used in high-temperature geothermal wells, testing of a prototype design of flexible couplings and well monitoring with distributed fibre optic sensing technologies.
The main results expected from the GeoWell project are summarised below.

1. Improved cements and cementing methods for high-temperature geothermal wells with reduced curing time and better durability.
2. Development of lightweight composite casings for high-temperature geothermal wells.
3. Development of a ductile intermediate layer to allow for axial expansion and contraction of the casing while protecting the cement in geothermal wells.
4. Flexible couplings to reduce stresses and failures in high-temperature geothermal casings.
5. Testing and selection of casing and wellhead equipment metallic materials for improved endurance against aggressive geothermal environment.
6. Testing and selection of corrosion resistant candidate materials for cladding on commonly used casing materials and evaluate the possibilities of using this method for high-temperature geothermal wells.
7. Innovative method for analysing the structural integrity of geothermal wells, based on distributed fibre optic sensing technology. The parameters measured within the annulus of the well will be temperature, strain and noise.
8. Tools for analysis of geothermal well integrity risk and reliability. Risks related to the materials and tools developed in WP3 and WP4 will be assessed.

GeoWell will contribute to the expected impacts in different ways:

Technology performance: GeoWell identifies and addresses main areas for improving the technical performance of geothermal wells and will enable technical solutions to efficiently utilize high-enthalpy geothermal reservoirs. The targeted technology development and innovation is focused on certain highly important elements of the geothermal well technology, such as casing, cementing and fibre optic sensing.

Economic benefits: As GeoWell proposes a total well concept with design, drilling and construction targeted to make the whole process more secure and reliable, this will shorten the installation time and reduce the overall cost of productive wells. A successful development of cements with dedicated curing kinetics as proposed will allow much faster cementing of the casings. In this way the installation time and accompanying costs can be reduced significantly.

Environment: GeoWell’s material development and innovative solutions will help to improve the integrity and safety of high-enthalpy geothermal wells, also in the long-term. GeoWell innovations will reduce the environmental risk and footprint of drilling and producing from a geothermal well. Closing the identified research gaps by both innovative material solutions and an integrated risk management procedure for the entire life-cycle of geothermal well will lead to:

• Better zonal isolation, less risk of leakage and better environmental protection of adjacent formations and overlying aquifers
• Less well maintenance work and thus minimizing greenhouse gas emissions of geothermal energy production generated by workover operations
• A decrease in rig time by using composite casings (installed rig-less) which will result in a lower energy consumption, less surface activities and lower emissions
• Optimized assessment and evaluation of risk related to geothermal wellbore operations
• Extended life-cycle of high enthalpy geothermal wells by more durable materials

Replicability: The applicability of the expected development within GeoWell is not limited to a few countries and not to only “very high” temperature. The new technology is relevant for deep geothermal wells at a wide temperature range and at many places in Europe.

Socio-economics: Utilization of geothermal energy does not depend on climate conditions as wind or solar energy may do. As a result, base load can be provided. GeoWell contributes significantly to the reliability of the operation by reduction of down time and reducing risk of workovers for high enthalpy wells, improving further the reliability and stability of energy delivery.

Market transformation: GeoWell aims at d