Assessing the Long-Term Risks in Subsurface Carbon Storage Projects: Tordis Field (Water Injection Project, Example 4 of 8) #13

In the Tordis Field (Norwegian sector, North Sea) oily water was injected for disposal into a shallow aquifer thought to be the Utsira Sands, a well-known, good-quality reservoir. However, a miscorrelation incorrectly identified the intended storage reservoir. It was not the Utsira, which was later determined to be absent due to a pinch-out.

Instead, the water was injected into a sand lens within the overlying Nordland Group (denoted by a star at the Tordis well location in the Figure below). Because this lens had a limited volume, reservoir pressure increased rapidly during injection and the seal was breached resulting in fluid escape and the leakage of oily water upward to the seafloor.

This leakage created a crater 30-40 meters across and 7 meters deep on the seabed. In the wake of this, because the Utsira Sands are the CO2 storage reservoir at the Sleipner carbon storage project, environmental organizations began questioning the security of storing CO2 in the Utsira Sands.

Not only does this case study illustrate how we can misinterpret the target injection reservoir and its potential impacts, but it also demonstrates how the failure of one project can implicate others.