Vilyui and Priverkhoyansk Composite Tectono-Sedimentary Elements, northeastern East Siberia

A vast region of northeastern Siberia west of the Verkhoyansk Range includes two large sedimentary basins: the Vilyui Basin and the Priverkhoyansk Basin. Combined, these basins constitute the Lena–Vilyui petroleum province, which contains the largest gas reserves in northeastern Asia. Both basins have a long and complex geological history that resulted in the accumulation of a more than 14 km-thick succession of Upper Proterozoic, Paleozoic, Mesozoic and Cenozoic sedimentary rocks. According to the volume's terminology, this sedimentary body was subdivided into two composite tectono-sedimentary elements (CTSEs), the Vilyui (VI) CTSE and the Priverkhoyansk (PV) CTSE, which closely correspond to the basins of the same name. The CTSEs consist of 10 distinct tectono-sedimentary elements (TSEs), each representing a distinct tectonic setting. This region has been studied very irregularly. In total, more than 400 deep wells have been drilled, mostly within the VI CTSE and only a few tens of wells have been drilled in the PV CTSE. Eleven gas and gas condensate accumulations have been discovered in the VI CTSE. The PV CTSE remains poorly explored, with only two commercial discoveries made as of the present day.