The Nederlandse Aardolie Maatschappij (Dutch Petroleum Company), the NAM, engages in the exploration and production of oil and gas from onshore and offshore fields in the Netherlands. It offers natural gas, petroleum, and other products, and engages in the storage of gas. The company was founded in 1947 and operates as a joint venture of Royal Dutch Shell and ExxonMobil Corporation.

In 1959 a gas field was discovered in the northern part of the Netherlands and is with 2,800 billion m³ one of the world’s largest gas fields. The NAM has been producing this natural gas since 1963, and a significant volume of gas is still present in the field today. The field supplies gas to 98 percent of the population of the Netherlands and natural gas accounts for 45% of all the energy that is used in the Netherlands.

Norg gas storage is one of NAM’s underground gas storages. It exists since 1997 and uses a former gas field as storage. During the summer natural gas is injected into the empty gas field and during the winter this supply is being used when gas is needed. Due to its utilization, the pressure in this gas field was slowly decreasing. To keep up with the demand and to improve access to the reservoir and to deliver gas faster in the winter, the capacity of the gas storage facility needed to be increased.

Clafis was retained by the NAM to oversee this expansion and was in this role responsible for the project drawings and corresponding documentation of the underground gas storage. Other responsibilities included overseeing well drilling activities, electro-technical and instrumentation activities, construction of a new compressor, as well as project safety.

Additionally, measuring equipment has been placed in the area above the underground gas storage at Norg. To minimalize disruption to adjacent residents, a special drilling tower producing less noise and less light was used. Geophones and accelerometers were installed to collect information to provide more accurate measurements regarding the incoming and outgoing gas. This system also provides, together with the information from three building sensors that were installed elsewhere, valuable information regarding earthquakes possibly related to the gas storage.