| Abstract: | Basic regularities of secondary processes in reservoir rocks of the Yarakta Horizon are described with rocks in the Yarakta
field as example. To achieve the formulated goal, we elucidated rock types in the studied section, its structure and distribution
of reservoir rocks, as well as types of secondary alterations and their influence on filtration-capacity properties. The studies
revealed that reservoir rocks of the Yarakta Horizon were formed on an alluvial-deltaic plain on the southeastern slope of
the Nepa-Botuoba anteclise. The pore space of reservoir rocks is determined by conditions of their formation and peculiarities
of secondary alterations. Maximal filtration-capacity values are characteristic of gritstones, as well as coarse-grained and
inequigranular sandstones developed in the lower and middle parts of the Yarakta Horizon. The intergranular space of reservoir
rocks in the lower part of the reservoir is substantially “healed” by secondary processes (regeneration, dolomitization, sulfatization,
and salinization), probably, due to the gravitational seepage of stratal fluids, mineralization of which increased with time. |
