Our core database can be searched by well name, core type, geological age, lithology and depositional environment. We try and keep it as up to date as possible, but it is best to contact us about a section of interest.
All our core has been cleared for donation by the North Sea Transition Authotity (NSTA). North Sea Core CIC also collaborates with the British Geological Survey (BGS) to ensure any missing or key core material is collected by them, rather than redistributed by us.
Please be aware due to the size of our database, it is best viewed on a computer or tablet.
You can view the well locations from where of all our core material originated using the map below. Please be aware due to the size of our database, it is best viewed on a computer or tablet.
We want to make geoscience accessible and available to everyone through core material. Take a look at the map to find out where our core has gone!
Its important to understand not only about core material, but also where it comes from and how it is collected. The following information gives more details about how wells are drilled and core is taken in an effort to gain knowledge about the rocks beneath the surface.
Core is usually collected meters to kilometers below the earth's surface and provides undisturbed rock samples. This differs from normal well operations, where drilling is destructive and crushes the rock into small bits called "cuttings".
Typically core is only collected from stratigraphic zones of interest, which in the North Sea have been reservoir sections where hydrocarbons are thought to be present, although this isn't always the case. By understanding the sedimentology, stratigraphy and architecture of the rocks, geologists can interpret how they formed and make predications where similar rocks may be.
Depending on the rock being drilled, not all core is recovered to surface. If it is very weak or unconsolidated, it can break up and cause missing sections. Therefore other data is taken, such as wireline logs which help us know where we are in the borehole and can provide additional information on stratigraphy.
While most core is cut to understand specific zones of interest, it can be used to prove a well has reached geological basement (hard crystalline rock) in a "Total Depth Core", such as in the West of Shetland. More rarely, coring can be used instead of drilling when extremely hard rock exists that would otherwise cause the drill bit to wear down too quickly.
All information and images have been supplied by Andy Moffat and North Sea Core CIC, and are licensed under a CC-BY-4.0 License. Please credit Andy Moffat and North Sea Core CIC for any material used.
When a well has been drilled to the correct depth to collect core, the drill bit is swapped for a core bit. This often costs significant time and money as to attach the core bit, all of the drilling equipment (drill string) is taken out of the borehole, and is the reason core is very expensive and usually only cut at stratigraphy of interest.
Core bits are similar to drill bits, with the exception that they have a hollow centre which allow for rock to be cut in a cylinder and pushed through up the equpiment. There are different types of core bits depending on the type of rock being cored.
HALF CUT CORE
Core material is cut down the length of the core barrel and can either be a half, a third or a quarter of the original core diameter. Core is available in lengths of 3 ft/1 m or by the 10 ft/3 m box, but can be shorter if sections have been removed for analysis.
BISCUIT CUT CORE
Thin sections (2-3 cm thick) or "slabs" of core in lengths of 3 ft/1 m. They are produced by cutting down the length and through the middle of the core barrel. They are typically preserved in resin, although the type and quality of resin will vary depending on the age of the sample.