This project and the resulting report present sedimentological, geochemical, and petrophysical data from the Triassic Haisborough Group, derived from a single, continuously cored reference well, SM14, in North Yorkshire. SM14 is located relatively far from the basin margin making it ideal for comparison with the offshore stratigraphy. The data set generated by this study is unparalleled in scope due to the comprehensive observational and analytical programme undertaken, making it an essential resource for validating seal integrity and providing regulatory assurance.

The analytical data sets are underpinned by a detailed sedimentary log, accompanied by a facies analysis of the entire 285 m thickness of the Haisborough Group in SM14. Sixteen lithofacies were identified and grouped into ten lithofacies associations, enabling the establishment of a revised lithostratigraphy for the Haisborough Group. Subaqueous depositional settings range from shallow marine shelf environments, through restricted lagoons, sabkhas, and salterns to playa lakes. These settings are evident in the lower, transgressive part of the succession and reappear with renewed transgression in the uppermost part of the Haisborough Group. The remainder of the succession was deposited on a pedogenic clayplain or claypan and in the transition to playa environments. Supporting petrographic analysis coincidentally identifies 16 microfacies. The sedimentary log and lithostratigraphy are provided alongside industry-standard wireline logs for SM14, enabling basin-wide correlation.

Integrated compositional data were obtained through XRF, QXRD, and SEM-EDS analyses. Densely spaced handheld XRF measurements revealed transgressive–regressive halite cycles within the Röt Halite Member, which are thought to correlate at the basin scale. Ground-truthing for the XRF results was provided by QXRD analysis, which identified common cements and phyllosilicate components. Oxide percentages derived from SEM-EDS analysis offer an additional independent measure of component abundance.

A suite of 50 samples, representing most lithofacies, was subjected to helium porosity, air permeability, and MICP analyses. These data enable the confining capacity, in terms of CO₂ column height, to be calculated. Additionally, results from a variety of rock strength tests are provided in Excel format. These include:

Axial and Diametral Point Load (49 samples), Unconfined Uniaxial Compressive Strength (26 samples), Young’s Modulus (12 samples), Poisson’s Ratio (12 samples), Slake Durability (8 samples), Cerchar Abrasivity (7 samples), Brazilian Tensile Strength (6 samples), Triaxial Strength (13 samples), Rock Shear Box (6 samples).

Delivery of data

The data are provided in a fully illustrated physical and electronic report (197 pages). An accompanying Appendix (428 pages) provides a catalogue of sample images including whole core, petrographic and SEM-EDS images.

Completed: December 2024

Report details: Composition and sealing capacity of the Haisborough Group in the SM14 borehole, North Yorkshire, UK: a reference well for the Southern North Sea

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