Magnetostratigraphic data and assisted well correlation: Some thoughts and first results, Triassic North Sea.

@inproceedings{CAUMON_RM2021,
 abstract = { Finding relative or absolute time lines between stratigraphic sections is a challenging problem, for which only one deterministic solution is generally provided by expert interpretation. However, time line uncertainty can have a strong impact on subsurface compartmentalization, reservoir behavior and source-to-sink models. This paper's aim is to assist the automation and the uncertainty assessment in chronostratigraphic well correlation with a specific focus on magnetostratigraphic data. Indeed, most clastic sediments record the Earth magnetic field at the time of their deposition (detrital remanent magnetization), so remanent magnetism direction measurements in stratigraphic sections provide essential constraints for the interpretation of isochron surfaces. \\We first review the dynamic programming method CuPy2 (Lallier et al, 2013), which computes a probability distribution of the age range of sediments by matching a magnetostratigraphic series to the reference Global Polarity Time Scale (GPTS). However, this dating technique is prone to uncertainty, which partly stem from possible variations in the sediment preservation rate, the presence of gaps at multiple scales, and the limited length of the input section. Therefore, we also consider the use of magnetostratigraphic data in a relative sense to constrain multi-well correlation in the WeCo code (Antoine et al, 2018). For this, the associated well samples are forced to have the same magnetic polarity, and we also propose some specific strategies for dealing with the presence of stratigraphic hiati. Finally, we propose to build a composite magnetostratigraphic section from a given multi-well correlation result to propose a possible absolute dating with CupPy2. \\We show some first example of the approach on subsurface Triassic sections of the Central North Sea, using the GPTS proposed by Maron et al (2019). Although some aspects still call for further research, these preliminary results show that magnetostratigraphic data can be used in a principled way to inform absolute and relative chronostratigraphic correlation. },
 author = { Caumon, Guillaume AND Antoine, Christophe AND Baville, Paul AND Hoth, Silvan AND Charreau, Julien },
 booktitle = { 2021 RING Meeting },
 publisher = { ASGA },
 title = { Magnetostratigraphic data and assisted well correlation: Some thoughts and first results, Triassic North Sea. },
 year = { 2021 }
}