Gas storage: safety and modernisation

To guarantee continuity of service, the inspection of equipment is a priority. It applies in particular to equipment covered by the pressure equipment regulations:

• pressurised containers (vessels, columns, separators);

• pipework at storage centres;

• associated equipment (pressure release valves, storage tanks, valves and fittings etc.).
  

We apply a maintenance plan, built around a Computerised Maintenance and Management System (CMMS). Actions cover six areas:

• troubleshooting;

• repairs;

• adjustment;

• overhaul;

• inspection;

• verification of equipment.

We also undertake preventive maintenance, to check that equipment is operating correctly, in accordance with the maintenance plan: one verification every 6, 12, 18 months etc.

Lastly, corrective maintenance is undertaken if a malfunction is identified. Actions are then defined by our Maintenance department, once a work request has been approved by the Operations department.

Surface operations – maintenance, work – that we undertake on the gas storage sites are in accordance with organisation and supervision that are prepared in advance. Scheduled works at Lussagnet and Izaute represent considerable investment. They have three main objectives for installations: to develop, modernise, and improve reliability.

Those operations are supervised by sections within the Storage Operations department. They are specialised in the coordination of on-site operations, Health Safety and Environmental (HSE) aspects, supervision and monitoring of the work.

The WELL54 project at Lussagnet is the result of a campaign of improvements to the underground storage platform equipment. The work will secure the reliability of installations and storage injection and draw-off capacities.

In 2019, we finalised the drilling of two new additional injection and production wells – LUG-79 and LUG-80 – on the site. Their completion follows the construction of two wells in 2018. The drilling of a new inspection well is already under way.

In addition, as part of our maintenance and safety campaign, a change has been made to the production section of four of the wells at Lussagnet. Our aim is to maintain their conformity with the industry standard over time.

Our storage installations are monitored remotely and permanently (24 hours a day) from a control room. This is the place where all information about the storage facilities and pipes in the distribution grid is centralised. It is in permanent contact with the grid distribution office based in Pau.

Distributors manage the flows of gas. They have information available about valve positions, pressures, compressor status (run/stop), warnings etc. They can view all operating parameters in real time.

The harmonised approach of our Geoscience and Drilling & Wells departments mean we can optimise the operation of storage sites and ensure the integrity of the reservoir is monitored.

The Geoscience department determines which injection and draw-off profiles are implemented, according to technical, administrative and contractual constraints. It also monitors research programmes (geophysics, geology, modelling and monitoring). They are essential to our understanding and management of the reservoirs, as well as the development of storage capacity. In addition, it ensures that our activities do not have any impact on other users of the aquifer in which the gas is stored.

The Drilling & Wells department is in charge of monitoring and tracking work on operating wells. It undertakes the construction of new wells, which allow it to monitor the groundwater or improve storage operations.