Current Status of Oil Recovery from Bazhenov Formation: Efficiency Analysis of Existing Technologies and New Approach

Bazhenov formation in West Siberia is featured by vast hydrocarbon reserves, however, its development is difficult due to the geological structure and properties of the deposit. The principal part of organic substances is contained in the impermeable rock matrix in the form of solid kerogen. The fundamental problem which must be solved for recovery of hydrocarbon reserves is to convert kerogen into fluids, and create a connected fracture system allowing flow of synthetic oil towards permeable reservoirs available. Existing technologies of enhanced oil recovery (including hydraulic fracturing and thermal gas treatment) are reviewed, and their applicability to Bazhenov formation conditions is discussed. It is shown that none of the technologies is capable of solving the problem of hydrocarbon recovery from the rock matrix where most of the kerogen reserves is concentrated. A new approach is proposed consisting in the combination of hydraulic fracturing and thermal methods, together with proper arrangement of hydrocarbon flow path in the induced crack system. Necessity for comprehensive mathematical modeling on the basis of coupled geomechanical, chemical, and filtration models is highlighted.