Complex analysis of the structure of the Lower Jurassic J1-I bed within the Khapchagai megaswell of the Vilyuy syneclise

The object of research is the Lower Jurassic terrigenous deposits that compose the productive J1-I formation of the Gettang-Plinsbach age. In the studied area, these deposits are characterized by shallow occurrence depths and are promising for hydrocarbon exploration. Based on the sedimentological analysis of the new well core, it was determined that the J1-I formation deposits were formed in the proximal part of the delta front and in sublittoral environments. The surface of the unconformity was identified on the basis of sedimentological, lithological and ichnofacies analysis of core material and it was traced across the entire study area using the sequence stratigraphic method to correlate geological and geophysical information from wells. Based on the results of sedimentological analysis, using logging data and seismic CDPM 3D, a lithofacies model of the J1-I formation was constructed, which reflects the distribution of sedimentary material in the study area.