The Condorcet heat delivery project aims delivering geothermal heat from an oilfield to a high school located in Arcachon, France. This area of France is located in a large sedimentary basin, hence the presence of numerous oilfields, whose production started in the 60’s. Today most of them are exploited by VERMILION. These so- called “mature” oilfield produce large volumes of water today, up to 95% of the total fluid produced. One of the objectives of the MEET project was to valorise this hot brine prior to reinjection in the oil field. The concept is called geothermal coproduction, because both oil and geothermal energy are exploited from the same wells.
In the first phase of the MEET project, a match-making mapping study compared the geothermal power available at all VERMILION sites with the heating needs of existing third-party buildings and facilities nearly. The Condorcet high-school, named after a famous philosopher from the 18th century, appeared as a good fit because its is located 300 m from on of VERMILION oil field, called Les Pins.
The high-school owner, region Nouvelle-Aquitaine, saw the opportunity to replace the gas boiler with a cheaper and cleaner energy source. A feasibility study was undertaken to quantify the long-term thermal resource and design the surface equipments needed to transfer the heat from the petroleum site to the heat user. A key question addressed by the geoscience team is the thermal impact in the petroleum reservoir 3 km deep, caused by the cooling of the injection brine in the heat exchanger. Geological and thermal models concluded that despite a slight cooling effect in the reservoir, a temperature of 60°C is expected to remain available in the next 20 years on the hot side of the heat exchanger (Figure 1).
Figure 1. Thermal model of the petroleum reservoir during injection phase (map view)
The next phase of detailed surface design aimed at maximising system robustness in an economic way . The heat exchanger is a 400 kW plate and shell exchanger (Figure 2). This compact technologies is easy to fit in our petroleum process, and can hold our high process pressure conditions. The piping network between the petroleum site and the end-user is made of a reinforced and pre-isolated 4’’ polyethylene (Figure 3).
Figure 2. Plate and shell heat exchanger
Figure 3. Polyethylene pre-isolated pipe
Field work started in march 2021 with the trenching operations to lay the pipe from the petroleum site to the high-school (Figures 4, 5 and 6).
Figure 4. Pipe laid at high school
Figure 5. Pipe laid in Forest
Figure 6. Exit of buried piping at petroleum site
Then the heat exchanger got connected to the injection line on the one side, and to the piping network on the other side (Figure 7). Pressure and temperature gauges will allow continuous monitoring of the performance of the system.
Figure 7. Heat exchanger connected to hot side and cold side
On the end-user side, work continues in the boiler room to disconnect the gas heater and connect the heat network to the heating system of the building (Figure 8 and 9).
Figure 8. End-user pipe to be connected in boiler room
Figure 9. Piping entry to boiler room
The project is going to be commissioned in November.
By switching from gas to geothermal energy, this project will deliver 800 MWh of heat and cover more than 90% of energy needs of the high-school. It will also save 200 T/year of CO2 emissions.
It will demonstrate than geothermal energy is a safe, affordable and local energy that is worth developing.