WP3 - Special Instruments and Tools
STIFTELSEN SINTEF, EGP
The tool will consist of a high temperature electronics platform embedded in a heat shield (Dewar flask) that isolates the electronics from the ambient pressure and temperature. The high temperature electronics will be based on the silicon-oninsulator
(SOI) technology platform NextGen and an existing oil and gas tool for noise recording developed by SINTEF ICT. The pressure and temperature measurements are fundamental for characterization of geothermal wells. The tool design will attempt to incorporate flexibility with respect to future additions of measurements. A study describing the field trial experiences including the opportunities for further development will be performed.
The main objectives are:
- To develop a tool for logging temperature and pressure that allows for a minimum of 8 hours of operation at maximum 450°C.
- To validate the tool through laboratory testing and in situ testing.
- To establish knowledge on how to build on the demonstrated technology and expand the portfolio of logging tools to include other geophysical measurements, and for verification of well integrity, at temperatures above 400 °C. SINTEF ICT will own the novel logging tool after the project. The tool will be used for further R&D on logging tools for high temperatures. In addition it will be made available for research on wells where high temperatures may be encountered. The tool will be advertised through the SINTEF website.
Task 3.1 Tool design (SINTEF ICT)
Overall tool simulation/specification with respect to heat generation and power requirements. Requirement specification (environment, size, functionality, interfaces) for the delivered Dewar. System specification including heat sink, electronics and sensors. After the requirements phase the detailed design will be performed.
The detailed design includes:
- Research and selection of Dewar seals and characterization of the Dewar heat conductance.
- Research and selection of an appropriate pressure port. The use of a capillary tube to transmit the ambient pressure to the sensor will be verified by simulations and possibly small scale experiments. If a capillary tube severely limits the performance of the tool, a wireless pressure sensor capable of operation in ambient temperature or an external measurement bridge will be considered.
- Optimize electronics power consumption, heat sink capacity and characterization of the tool using thermal simulations in a finite element simulator (e.g. COMSOL Multiphysics).
- Research and select appropriate temperature sensors interface. A wireless temperature sensor based on infrared sensing or the use of a wired measurement bridge will be investigated.
- Modify the NextGen platform (electronics and firmware) to satisfy the requirements. The modifications include prototyping of a packaged components circuit board including the characterization of performance and power consumption. Design of a final pilot circuit board with bare dies, ceramic board and optimized geometry.
- Evaluate options for die attach and perform relevant environmental tests such as vibration and temperature cycling tests.
- Design of high temperature DC/DC converter for minimum heat generation. The design will be based on an existing high temperature converter design.
- Powering scheme with selection of battery combination.
- Perform risk assessment and incorporate risk reducing measures in the tool design.
- Specify test requirements.
Task 3.2 Manufacturing (SINTEF ICT)
- Electronic components will be purchased and assembled by SINTEF ICT and selected PCB and hybrid assembly partners. The Dewar will be purchased according to specification from a subcontractor. The demanding requirements for the Dewar require room for additional testing and possible re-machining and re-welding during manufacturing. The Dewar and electronics will be assembled by SINTEF ICT with assistance from the subcontractor. A suitable software program for plotting the data retrieved from the tool will be made.
Task 3.3 Laboratory testing (SINTEF ICT)
- Component and system testing will be performed in SINTEF laboratories. Comprehensive lab facilities to characterize and test industrial systems, intended for use in harsh environments, are available. A large (350cm long and Ø30cm) pressure vessel rated for 120 MPa and 200°C is available for testing and characterization of the complete tool operation in water. For sensor characterization, small silicone oil pressure vessels can be used up to 50 MPa and 200°C.
Environmental testing facilities for electronics such as vibration, temperature cycling and bond characterization labs are also available, enabling characterization of sensor behaviour and of failure mechanisms.
The procured Dewar will be tested as part of the manufacturing process. The Dewar will be leak tested by the manufacturer at 450°C at 1 atm and at room temperature with 50 MPa. The critical parts such as seals will be individually qualified for operation at 450°C and at least 25 MPa. This will ensure that the complete tool can be operated at super critical conditions.
Risk assessment of test will be performed according to SINTEF procedures.
Task 3.4 In situ testing (EGP, SINTEF ICT)
- The tool will be lowered into the supercritical well using a slickline service. This service will be purchased from a subcontractor (EGPs responsibility).
SINTEF and/or EGP HSE procedures are available and will be used for the field trials and safe handling of the tool. SINTEF ICT will ensure transportation of the tool to Larderello and provide personnel at the well location to assist in using the tool.
Data collected from the tool will be made available to the consortium in a suitable format such as a CSV file. This data will be used particularly in Task 4.5 and Task 5.2.
The novel high temperature tool will receive power from lithium cells designed for operation at high temperatures. If the cells are run outside of specification they may experience thermal runoff which may cause harm to personnel. Risk reducing measures will be incorporated in the design of the tool, the laboratory testing procedures and in the operational handling procedures. Only trained and qualified personnel will be allowed to handle the tool.