Haven't the Russians been using the regeneration model for decades with great success?
Yes.
"Finally, a word of caution on the essential fragility of a study on the very long-term future for the world's energy supply which accepts without question the validity of the original 18th century hypothesis that all oil and gas resources have been generated from biological matter in the chemical and thermodynamic environments of the earth's crust. There is an alternative theory - already 50 years old - which suggests an inorganic origin for additional oil and gas. This alternative view is widely accepted in the countries of the former Soviet Union where, it is claimed, "large volumes of hydrocarbons are being produced from the pre-Cambrian crystalline basement". Recent applications of the inorganic theory have, however, also led to claims for the possibility of the Middle East fields being able to produce oil "forever" and to the concept of repleting oil and gas fields in the gulf of Mexico. More generally, it is argued, "all giant fields are most logically explained by inorganic theory because simple calculations of potential hydrocarbon contents in sediments shows that organic materials are too few to supply the volumes of petroleum involved.""
I do know of situations where horizontal drilling in anisotropic reservoirs has found additional untapped production here in the US, but that is just tapping a stratigraphically isolated reservoir pool.
If, however, the Russians are drilling heavily faulted or fractured areas or along deep crustal lineament trends, (which logically would be the ideal for the model), those areas also are ideal for migration of petroleum from 'conventionally' sourced reservoirs to strata under production.
SOme of the exploration in the Williston Basin in the US which was not along the Nesson Anticline occurred at the intersection of major crustal lineaments.
The fracturing associated with such zones has additional beneficial effects on the reservoir (Carbonates: Limestone and Dolomite):
1 it provides a pathway for fluids high in magnesium to migrate, improving existing carbonate petrofabrics by dolomitization, resulting in higher porosity and permeability, and
2: it provides primary pathways for vertical and lateral oil migration and permeability enhancement within the reservoir along fracture ('joint') sets. Many fields exist at the intersection of the lineament trends, though I know of none of these which are 'regenerating'.
Any enhanced or additional production is the result of refinements in production and drilling technology, or the discovery of previously 'missed' oil in old fields.
That does not prove regeneration, only that there is more oil at depth, which likely comes from biogenic sources as well.
Without familliarity with the Geology of the Russian fields, I cannot completely discount that there might appear to be production from basement (crystalline igneous or metamorphic rock), nor can I address that appearance--or possible more conventional causes thereof.