Features of the structure, sedimentary complexes and hydrocarbon systems of the Leno-Vilyui oil and gas basin

The Leno-Vilyui basin, consisting of the Vilyui syneclise and the Pre-Verkhoyansk deflection, is made of a thick (more than 10 km) sedimentary rock that has formed over a very long geological history (at least 1 billion years). Almost all of the fields identified here are confined to two gross structures, and gas is predominant in the composition of hydrocarbon reservoirs. Studies show that the main hydrocarbon system (Permian-Cretaceous) in most areas is formed by Permian gas source formations, deposited in continental environments with predominance of type III kerogen. Systems with a significant proportion of liquid hydrocarbons may be associated with areas of predominantly marine sedimentation (Pre-Verkhoyansk deflection) or more ancient (Lower Paleozoic) sediments. In all cases, natural reservoirs are distinguished by a complex structure due to sharp facial variability and intensive secondary transformations.